From: Arnd Bergmann arnd@arndb.de
[ Upstream commit 26515699863d68058e290e18e83f444925920be5 ]
clang points out that the computation of LOWMEM_PAGES causes a signed integer overflow on 32-bit x86:
arch/x86/kernel/head32.c:83:20: error: signed shift result (0x100000000) requires 34 bits to represent, but 'int' only has 32 bits [-Werror,-Wshift-overflow] (PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT); ^~~~~~~~~~~~ arch/x86/include/asm/pgtable_32.h:109:27: note: expanded from macro 'LOWMEM_PAGES' #define LOWMEM_PAGES ((((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT)) ~^ ~~ arch/x86/include/asm/pgtable_32.h:98:34: note: expanded from macro 'PAGE_TABLE_SIZE' #define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
Use the _ULL() macro to make it a 64-bit constant.
Fixes: 1e620f9b23e5 ("x86/boot/32: Convert the 32-bit pgtable setup code from assembly to C") Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Link: https://lkml.kernel.org/r/20190710130522.1802800-1-arnd@arndb.de Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/include/asm/pgtable_32.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h index b3ec519e39827..71e1df8601765 100644 --- a/arch/x86/include/asm/pgtable_32.h +++ b/arch/x86/include/asm/pgtable_32.h @@ -106,6 +106,6 @@ do { \ * with only a host target support using a 32-bit type for internal * representation. */ -#define LOWMEM_PAGES ((((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT)) +#define LOWMEM_PAGES ((((_ULL(2)<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
#endif /* _ASM_X86_PGTABLE_32_H */