diff options
| author | Andrey Konovalov <andreyknvl@google.com> | 2018-12-28 00:29:57 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 12:11:43 -0800 |
| commit | b2f557eae9ed0ab2b612ce9ce7e3f06174a83e76 (patch) | |
| tree | d5496a218f24a1963635bd4b478ca17fdd8894f7 | |
| parent | 2bd926b439b4cb6b9ed240a9781cd01958b53d85 (diff) | |
kasan, arm64: adjust shadow size for tag-based mode
Tag-based KASAN uses 1 shadow byte for 16 bytes of kernel memory, so it
requires 1/16th of the kernel virtual address space for the shadow memory.
This commit sets KASAN_SHADOW_SCALE_SHIFT to 4 when the tag-based KASAN
mode is enabled.
Link: http://lkml.kernel.org/r/308b6bd49f756bb5e533be93c6f085ba99b30339.1544099024.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/arm64/Makefile | 11 | ||||
| -rw-r--r-- | arch/arm64/include/asm/memory.h | 8 |
2 files changed, 13 insertions, 6 deletions
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 398bdb81a900..b025304bde46 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -101,10 +101,19 @@ else TEXT_OFFSET := 0x00080000 endif +ifeq ($(CONFIG_KASAN_SW_TAGS), y) +KASAN_SHADOW_SCALE_SHIFT := 4 +else +KASAN_SHADOW_SCALE_SHIFT := 3 +endif + +KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) +KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) +KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT) + # KASAN_SHADOW_OFFSET = VA_START + (1 << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT)) # - (1 << (64 - KASAN_SHADOW_SCALE_SHIFT)) # in 32-bit arithmetic -KASAN_SHADOW_SCALE_SHIFT := 3 KASAN_SHADOW_OFFSET := $(shell printf "0x%08x00000000\n" $$(( \ (0xffffffff & (-1 << ($(CONFIG_ARM64_VA_BITS) - 32))) \ + (1 << ($(CONFIG_ARM64_VA_BITS) - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) \ diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 0385752bd079..7640feed268d 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -74,13 +74,11 @@ #endif /* - * KASAN requires 1/8th of the kernel virtual address space for the shadow - * region. KASAN can bloat the stack significantly, so double the (minimum) - * stack size when KASAN is in use, and then double it again if KASAN_EXTRA is - * on. + * Generic and tag-based KASAN require 1/8th and 1/16th of the kernel virtual + * address space for the shadow region respectively. They can bloat the stack + * significantly, so double the (minimum) stack size when they are in use. */ #ifdef CONFIG_KASAN -#define KASAN_SHADOW_SCALE_SHIFT 3 #define KASAN_SHADOW_SIZE (UL(1) << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT)) #ifdef CONFIG_KASAN_EXTRA #define KASAN_THREAD_SHIFT 2 |