sparc64: Fix constraints on swab helpers.

commit 5a2b59d3 upstream.

We are reading the memory location, so we have to have a memory
constraint in there purely for the sake of showing the data flow
to the compiler.
Reported-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

arch/sparc/include/uapi/asm/swab.h

@@ -9,9 +9,9 @@ static inline __u16 __arch_swab16p(const __u16 *addr)
 {
 	__u16 ret;
 
-	__asm__ __volatile__ ("lduha [%1] %2, %0"
+	__asm__ __volatile__ ("lduha [%2] %3, %0"
 			      : "=r" (ret)
-			      : "r" (addr), "i" (ASI_PL));
+			      : "m" (*addr), "r" (addr), "i" (ASI_PL));
 	return ret;
 }
 #define __arch_swab16p __arch_swab16p
@@ -20,9 +20,9 @@ static inline __u32 __arch_swab32p(const __u32 *addr)
 {
 	__u32 ret;
 
-	__asm__ __volatile__ ("lduwa [%1] %2, %0"
+	__asm__ __volatile__ ("lduwa [%2] %3, %0"
 			      : "=r" (ret)
-			      : "r" (addr), "i" (ASI_PL));
+			      : "m" (*addr), "r" (addr), "i" (ASI_PL));
 	return ret;
 }
 #define __arch_swab32p __arch_swab32p
@@ -31,9 +31,9 @@ static inline __u64 __arch_swab64p(const __u64 *addr)
 {
 	__u64 ret;
 
-	__asm__ __volatile__ ("ldxa [%1] %2, %0"
+	__asm__ __volatile__ ("ldxa [%2] %3, %0"
 			      : "=r" (ret)
-			      : "r" (addr), "i" (ASI_PL));
+			      : "m" (*addr), "r" (addr), "i" (ASI_PL));
 	return ret;
 }
 #define __arch_swab64p __arch_swab64p