[PATCH 2/2] arm64: Define PAGE_OFFSET using GENMASK_ULL
From: Matthias Kaehlcke
Date: Wed Aug 02 2017 - 18:52:54 EST
As is the definition causes an integer overflow, which is expected,
however clang raises the following 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))
~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
Use GENMASK_ULL() instead of shifting explicitly, the macro takes care
of avoiding the overflow.
Reported-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
arch/arm64/include/asm/memory.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 32f82723338a..732d4eed8edd 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -65,7 +65,7 @@
*/
#define VA_BITS (CONFIG_ARM64_VA_BITS)
#define VA_START (UL(0xffffffffffffffff) << VA_BITS)
-#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1))
+#define PAGE_OFFSET GENMASK_ULL(BITS_PER_LONG_LONG - 1, VA_BITS - 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