The patch titled
Subject: arm64: enable armv8.5-a asm-arch option
has been added to the -mm tree. Its filename is
arm64-enable-armv85-a-asm-arch-option.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/arm64-enable-armv85-a-asm-arch-option.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/arm64-enable-armv85-a-asm-arch-option.patch
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------------------------------------------------------
From: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Subject: arm64: enable armv8.5-a asm-arch option
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.
Link: https://lkml.kernel.org/r/e7f69b87c86266c3671ec137f56e7740890155d3.1605046192.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/Kconfig | 4 ++++
arch/arm64/Makefile | 5 +++++
2 files changed, 9 insertions(+)
--- a/arch/arm64/Kconfig~arm64-enable-armv85-a-asm-arch-option
+++ a/arch/arm64/Kconfig
@@ -1588,6 +1588,9 @@ 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
@@ -1662,6 +1665,7 @@ 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
--- a/arch/arm64/Makefile~arm64-enable-armv85-a-asm-arch-option
+++ a/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)"'
_
Patches currently in -mm which might be from vincenzo.frascino@xxxxxxx are
mm-vmalloc-fix-kasan-shadow-poisoning-size.patch
arm64-enable-armv85-a-asm-arch-option.patch
arm64-mte-add-in-kernel-mte-helpers.patch
arm64-mte-reset-the-page-tag-in-page-flags.patch
arm64-mte-add-in-kernel-tag-fault-handler.patch
arm64-kasan-allow-enabling-in-kernel-mte.patch
arm64-mte-convert-gcr_user-into-an-exclude-mask.patch
arm64-mte-switch-gcr_el1-in-kernel-entry-and-exit.patch
kasan-mm-untag-page-address-in-free_reserved_area.patch
kselftest-arm64-check-gcr_el1-after-context-switch.patch
