From: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Hardware tag-based KASAN relies on Memory Tagging Extension (MTE) which is an armv8.5-a architecture extension. Enable the correct asm option when the compiler supports it in order to allow the usage of ALTERNATIVE()s with MTE instructions. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx> --- Change-Id: I172e15e4c189f073e4c14a10276b276092e76536 --- arch/arm64/Kconfig | 4 ++++ arch/arm64/Makefile | 5 +++++ 2 files changed, 9 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 25ead11074bf..c84a0e6b4650 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1591,6 +1591,9 @@ endmenu menu "ARMv8.5 architectural features" +config AS_HAS_ARMV8_5 + def_bool $(cc-option,-Wa$(comma)-march=armv8.5-a) + config ARM64_BTI bool "Branch Target Identification support" default y @@ -1665,6 +1668,7 @@ config ARM64_MTE bool "Memory Tagging Extension support" default y depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI + depends on AS_HAS_ARMV8_5 select ARCH_USES_HIGH_VMA_FLAGS help Memory Tagging (part of the ARMv8.5 Extensions) provides diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 5789c2d18d43..50ad9cbccb51 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -100,6 +100,11 @@ ifeq ($(CONFIG_AS_HAS_ARMV8_4), y) asm-arch := armv8.4-a endif +ifeq ($(CONFIG_AS_HAS_ARMV8_5), y) +# make sure to pass the newest target architecture to -march. +asm-arch := armv8.5-a +endif + ifdef asm-arch KBUILD_CFLAGS += -Wa,-march=$(asm-arch) \ -DARM64_ASM_ARCH='"$(asm-arch)"' -- 2.29.2.222.g5d2a92d10f8-goog
