The bitmask used to define these values produces overflow, as seen by
this compiler warning:
arch/arm64/kernel/head.S:47:8: warning:
integer overflow in preprocessor expression
#elif (PAGE_OFFSET & 0x1fffff) != 0
^~~~~~~~~~~
arch/arm64/include/asm/memory.h:52:46: note:
expanded from macro 'PAGE_OFFSET'
#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS -
1))
~~~~~~~~~~~~~~~~~~ ^
It would be preferrable to use GENMASK_ULL() instead, but it's not set
up to be used from assembly (the UL() macro token pastes UL suffixes
when not included in assembly sources).
Suggested-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
Suggested-by: Yury Norov <yno...@caviumnetworks.com>
Suggested-by: Matthias Kaehlcke <m...@chromium.org>
Signed-off-by: Nick Desaulniers <ndesaulni...@google.com>
---
arch/arm64/include/asm/memory.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 32f82723338a..ef39dcb9ca6a 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -64,8 +64,10 @@
* TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area.
*/
#define VA_BITS (CONFIG_ARM64_VA_BITS)
-#define VA_START (UL(0xffffffffffffffff) << VA_BITS)
-#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1))
+#define VA_START (UL(0xffffffffffffffff) - \
+ (UL(1) << VA_BITS) + 1)
+#define PAGE_OFFSET (UL(0xffffffffffffffff) - \
+ (UL(1) << (VA_BITS - 1)) + 1)
#define KIMAGE_VADDR (MODULES_END)
#define MODULES_END (MODULES_VADDR + MODULES_VSIZE)
#define MODULES_VADDR (VA_START + KASAN_SHADOW_SIZE)
--
2.14.0.rc1.383.gd1ce394fe2-goog
