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authorNick Desaulniers <ndesaulniers@google.com>2017-08-03 11:03:58 -0700
committerWill Deacon <will.deacon@arm.com>2017-08-04 15:06:35 +0100
commit82cd588052815eb4146f9f7c5347ca5e32c56360 (patch)
tree074b02c750f56f8d41f0f48eba80c031c6adf8bd /arch
parent6d332747fa5f0a6843b56b5b129168ba909336d1 (diff)
arm64: avoid overflow in VA_START and PAGE_OFFSET
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.biesheuvel@linaro.org> Suggested-by: Yury Norov <ynorov@caviumnetworks.com> Suggested-by: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/memory.h6
1 files 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)