diff options
| author | Andrey Konovalov <andreyknvl@google.com> | 2018-02-06 15:36:44 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-06 18:32:43 -0800 |
| commit | 917538e212a2c080af95ccb4376c5387fac08176 (patch) | |
| tree | 2e496fb322552a03ab64c9d2e78facec7db3c0c9 /arch/arm64/include/asm/kasan.h | |
| parent | 5f21f3a8f4dcba77792d60bcc711131470a689bb (diff) | |
kasan: clean up KASAN_SHADOW_SCALE_SHIFT usage
Right now the fact that KASAN uses a single shadow byte for 8 bytes of
memory is scattered all over the code.
This change defines KASAN_SHADOW_SCALE_SHIFT early in asm include files
and makes use of this constant where necessary.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/34937ca3b90736eaad91b568edf5684091f662e3.1515775666.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arm64/include/asm/kasan.h')
| -rw-r--r-- | arch/arm64/include/asm/kasan.h | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/arch/arm64/include/asm/kasan.h b/arch/arm64/include/asm/kasan.h index e266f80e45b7..8758bb008436 100644 --- a/arch/arm64/include/asm/kasan.h +++ b/arch/arm64/include/asm/kasan.h @@ -12,7 +12,8 @@ /* * KASAN_SHADOW_START: beginning of the kernel virtual addresses. - * KASAN_SHADOW_END: KASAN_SHADOW_START + 1/8 of kernel virtual addresses. + * KASAN_SHADOW_END: KASAN_SHADOW_START + 1/N of kernel virtual addresses, + * where N = (1 << KASAN_SHADOW_SCALE_SHIFT). */ #define KASAN_SHADOW_START (VA_START) #define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE) @@ -20,14 +21,16 @@ /* * This value is used to map an address to the corresponding shadow * address by the following formula: - * shadow_addr = (address >> 3) + KASAN_SHADOW_OFFSET; + * shadow_addr = (address >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET * - * (1 << 61) shadow addresses - [KASAN_SHADOW_OFFSET,KASAN_SHADOW_END] - * cover all 64-bits of virtual addresses. So KASAN_SHADOW_OFFSET - * should satisfy the following equation: - * KASAN_SHADOW_OFFSET = KASAN_SHADOW_END - (1ULL << 61) + * (1 << (64 - KASAN_SHADOW_SCALE_SHIFT)) shadow addresses that lie in range + * [KASAN_SHADOW_OFFSET, KASAN_SHADOW_END) cover all 64-bits of virtual + * addresses. So KASAN_SHADOW_OFFSET should satisfy the following equation: + * KASAN_SHADOW_OFFSET = KASAN_SHADOW_END - + * (1ULL << (64 - KASAN_SHADOW_SCALE_SHIFT)) */ -#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << (64 - 3))) +#define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << \ + (64 - KASAN_SHADOW_SCALE_SHIFT))) void kasan_init(void); void kasan_copy_shadow(pgd_t *pgdir); |