[PATCH v7 7/7] ARM: Enable KASan for ARM

[Florian Fainelli]

From: Andrey Ryabinin <ryabinin@xxxxxxxxxxxxx>

This patch enables the kernel address sanitizer for ARM. XIP_KERNEL has
not been tested and is therefore not allowed.

Acked-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Abbott Liu <liuwenliang@xxxxxxxxxx>
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
 Documentation/dev-tools/kasan.rst     | 4 ++--
 arch/arm/Kconfig                      | 9 +++++++++
 arch/arm/boot/compressed/Makefile     | 1 +
 drivers/firmware/efi/libstub/Makefile | 3 ++-
 4 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index e4d66e7c50de..6acd949989c3 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -21,8 +21,8 @@ global variables yet.
 
 Tag-based KASAN is only supported in Clang and requires version 7.0.0 or later.
 
-Currently generic KASAN is supported for the x86_64, arm64, xtensa and s390
-architectures, and tag-based KASAN is supported only for arm64.
+Currently generic KASAN is supported for the x86_64, arm, arm64, xtensa and
+s390 architectures, and tag-based KASAN is supported only for arm64.
 
 Usage
 -----
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 96dab76da3b3..70a7eb50984e 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -65,6 +65,7 @@ config ARM
 	select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
 	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
 	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
+	select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
 	select HAVE_ARCH_SECCOMP_FILTER if AEABI && !OABI_COMPAT
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
@@ -212,6 +213,14 @@ config ARCH_MAY_HAVE_PC_FDC
 config ZONE_DMA
 	bool
 
+config KASAN_SHADOW_OFFSET
+	hex
+	depends on KASAN
+	default 0x1f000000 if PAGE_OFFSET=0x40000000
+	default 0x5f000000 if PAGE_OFFSET=0x80000000
+	default 0x9f000000 if PAGE_OFFSET=0xC0000000
+	default 0xffffffff
+
 config ARCH_SUPPORTS_UPROBES
 	def_bool y
 
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 83991a0447fa..efda24b00a44 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -25,6 +25,7 @@ endif
 
 GCOV_PROFILE		:= n
 KASAN_SANITIZE		:= n
+CFLAGS_KERNEL		+= -D__SANITIZE_ADDRESS__
 
 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
 KCOV_INSTRUMENT		:= n
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index c35f893897e1..c8b36824189b 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -20,7 +20,8 @@ cflags-$(CONFIG_ARM64)		:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
 				   -fpie $(DISABLE_STACKLEAK_PLUGIN)
 cflags-$(CONFIG_ARM)		:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
 				   -fno-builtin -fpic \
-				   $(call cc-option,-mno-single-pic-base)
+				   $(call cc-option,-mno-single-pic-base) \
+				   -D__SANITIZE_ADDRESS__
 
 cflags-$(CONFIG_EFI_ARMSTUB)	+= -I$(srctree)/scripts/dtc/libfdt
 
-- 
2.17.1