__do_div64 clobbers the input register r0 in little endian system.
According to the inline assembly document, if an input operand is
modified, it should be tied to a output operand. This patch can
prevent compilers from reusing r0 register after asm statements.
Signed-off-by: Antony Yu <swpe...@gmail.com>
---
arch/arm/include/asm/div64.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h
index 898e9c78a7e7..809efc51e90f 100644
--- a/arch/arm/include/asm/div64.h
+++ b/arch/arm/include/asm/div64.h
@@ -39,9 +39,10 @@ static inline uint32_t __div64_32(uint64_t *n, uint32_t base)
asm( __asmeq("%0", __xh)
__asmeq("%1", "r2")
__asmeq("%2", "r0")
- __asmeq("%3", "r4")
+ __asmeq("%3", "r0")
+ __asmeq("%4", "r4")
"bl __do_div64"
- : "=r" (__rem), "=r" (__res)
+ : "=r" (__rem), "=r" (__res), "=r" (__n)
: "r" (__n), "r" (__base)
: "ip", "lr", "cc");
*n = __res;
--
2.23.0
