xtensa: clean up inline assembly in futex.h

Replace numeric inline assembly parameters with named parameters.
Drop unused parameters from the futex_atomic_cmpxchg_inatomic.
Use new temporary variable to hold target address in the fixup code in
futex_atomic_cmpxchg_inatomic. Conditionalize function bodies so that
only 'return -ENOSYS' is left in configurations without futex support.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/asm/futex.h

@@ -19,59 +19,58 @@
 #include <linux/uaccess.h>
 #include <linux/errno.h>
 
-#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
+#define __futex_atomic_op(insn, ret, old, uaddr, arg)	\
 	__asm__ __volatile(				\
-	"1:	l32i	%0, %2, 0\n"			\
+	"1:	l32i	%[oldval], %[addr], 0\n"	\
 		insn "\n"				\
-	"	wsr	%0, scompare1\n"		\
-	"2:	s32c1i	%1, %2, 0\n"			\
-	"	bne	%1, %0, 1b\n"			\
-	"	movi	%1, 0\n"			\
+	"	wsr	%[oldval], scompare1\n"		\
+	"2:	s32c1i	%[newval], %[addr], 0\n"	\
+	"	bne	%[newval], %[oldval], 1b\n"	\
+	"	movi	%[newval], 0\n"			\
 	"3:\n"						\
 	"	.section .fixup,\"ax\"\n"		\
 	"	.align 4\n"				\
 	"	.literal_position\n"			\
-	"5:	movi	%0, 3b\n"			\
-	"	movi	%1, %3\n"			\
-	"	jx	%0\n"				\
+	"5:	movi	%[oldval], 3b\n"		\
+	"	movi	%[newval], %[fault]\n"		\
+	"	jx	%[oldval]\n"			\
 	"	.previous\n"				\
 	"	.section __ex_table,\"a\"\n"		\
-	"	.long 1b,5b,2b,5b\n"			\
+	"	.long 1b, 5b, 2b, 5b\n"			\
 	"	.previous\n"				\
-	: "=&r" (oldval), "=&r" (ret)			\
-	: "r" (uaddr), "I" (-EFAULT), "r" (oparg)	\
+	: [oldval] "=&r" (old), [newval] "=&r" (ret)	\
+	: [addr] "r" (uaddr), [oparg] "r" (arg),	\
+	  [fault] "I" (-EFAULT)				\
 	: "memory")
 
 static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
 		u32 __user *uaddr)
 {
+#if XCHAL_HAVE_S32C1I
 	int oldval = 0, ret;
 
-#if !XCHAL_HAVE_S32C1I
-	return -ENOSYS;
-#endif
-
 	pagefault_disable();
 
 	switch (op) {
 	case FUTEX_OP_SET:
-		__futex_atomic_op("mov %1, %4", ret, oldval, uaddr, oparg);
+		__futex_atomic_op("mov %[newval], %[oparg]",
+				  ret, oldval, uaddr, oparg);
 		break;
 	case FUTEX_OP_ADD:
-		__futex_atomic_op("add %1, %0, %4", ret, oldval, uaddr,
-				oparg);
+		__futex_atomic_op("add %[newval], %[oldval], %[oparg]",
+				  ret, oldval, uaddr, oparg);
 		break;
 	case FUTEX_OP_OR:
-		__futex_atomic_op("or %1, %0, %4", ret, oldval, uaddr,
-				oparg);
+		__futex_atomic_op("or %[newval], %[oldval], %[oparg]",
+				  ret, oldval, uaddr, oparg);
 		break;
 	case FUTEX_OP_ANDN:
-		__futex_atomic_op("and %1, %0, %4", ret, oldval, uaddr,
-				~oparg);
+		__futex_atomic_op("and %[newval], %[oldval], %[oparg]",
+				  ret, oldval, uaddr, ~oparg);
 		break;
 	case FUTEX_OP_XOR:
-		__futex_atomic_op("xor %1, %0, %4", ret, oldval, uaddr,
-				oparg);
+		__futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
+				  ret, oldval, uaddr, oparg);
 		break;
 	default:
 		ret = -ENOSYS;
@@ -83,42 +82,47 @@ static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
 		*oval = oldval;
 
 	return ret;
+#else
+	return -ENOSYS;
+#endif
 }
 
 static inline int
 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 			      u32 oldval, u32 newval)
 {
+#if XCHAL_HAVE_S32C1I
+	unsigned long tmp;
 	int ret = 0;
 
 	if (!access_ok(uaddr, sizeof(u32)))
 		return -EFAULT;
 
-#if !XCHAL_HAVE_S32C1I
-	return -ENOSYS;
-#endif
-
 	__asm__ __volatile__ (
 	"	# futex_atomic_cmpxchg_inatomic\n"
-	"	wsr	%5, scompare1\n"
-	"1:	s32c1i	%1, %4, 0\n"
-	"	s32i	%1, %6, 0\n"
+	"	wsr	%[oldval], scompare1\n"
+	"1:	s32c1i	%[newval], %[addr], 0\n"
+	"	s32i	%[newval], %[uval], 0\n"
 	"2:\n"
 	"	.section .fixup,\"ax\"\n"
 	"	.align 4\n"
 	"	.literal_position\n"
-	"4:	movi	%1, 2b\n"
-	"	movi	%0, %7\n"
-	"	jx	%1\n"
+	"4:	movi	%[tmp], 2b\n"
+	"	movi	%[ret], %[fault]\n"
+	"	jx	%[tmp]\n"
 	"	.previous\n"
 	"	.section __ex_table,\"a\"\n"
-	"	.long 1b,4b\n"
+	"	.long 1b, 4b\n"
 	"	.previous\n"
-	: "+r" (ret), "+r" (newval), "+m" (*uaddr), "+m" (*uval)
-	: "r" (uaddr), "r" (oldval), "r" (uval), "I" (-EFAULT)
+	: [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp)
+	: [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval),
+	  [fault] "I" (-EFAULT)
 	: "memory");
 
 	return ret;
+#else
+	return -ENOSYS;
+#endif
 }
 
 #endif /* _ASM_XTENSA_FUTEX_H */