4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 1b57ec8c75279b873639eb44a215479236f93481 ] As of commit 6460d3201471 ("arm64: io: Ensure calls to delay routines are ordered against prior readX()"), MMIO reads smaller than 64 bits fail to compile under clang because we end up mixing 32-bit and 64-bit register operands for the same data processing instruction: ./include/asm-generic/io.h:695:9: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths] return readb(addr); ^ ./arch/arm64/include/asm/io.h:147:58: note: expanded from macro 'readb' ^ ./include/asm-generic/io.h:695:9: note: use constraint modifier "w" ./arch/arm64/include/asm/io.h:147:50: note: expanded from macro 'readb' ^ ./arch/arm64/include/asm/io.h:118:24: note: expanded from macro '__iormb' asm volatile("eor %0, %1, %1\n" \ ^ Fix the build by casting the macro argument to 'unsigned long' when used as an input to the inline asm. Reported-by: Nick Desaulniers <nick.desaulniers@xxxxxxxxx> Reported-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/arm64/include/asm/io.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h index b2bc7dbc1fa6..49bb9a020a09 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -119,7 +119,8 @@ static inline u64 __raw_readq(const volatile void __iomem *addr) */ \ asm volatile("eor %0, %1, %1\n" \ "cbnz %0, ." \ - : "=r" (tmp) : "r" (v) : "memory"); \ + : "=r" (tmp) : "r" ((unsigned long)(v)) \ + : "memory"); \ }) #define __iowmb() wmb() -- 2.19.1