4.20-stable review patch. If anyone has any objections, please let me know.
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[ 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@gmail.com Reported-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 d42d00d8d5b6..ee723835c1f4 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -117,7 +117,8 @@ 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()