xtensa: properly fix missing compiler barrier in simcall

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/platforms/iss/include/platform/simcall.h

@@ -74,13 +74,12 @@ static inline int __simc(int a, int b, int c, int d, int e, int f)
 			"mov %1, a3\n"
 			: "=a" (ret), "=a" (errno), "+r"(a1), "+r"(b1)
 			: "r"(c1), "r"(d1), "r"(e1), "r"(f1)
-			: );
+			: "memory");
 	return ret;
 }
 
 static inline int simc_open(const char *file, int flags, int mode)
 {
-	wmb();
 	return __simc(SYS_open, (int) file, flags, mode, 0, 0);
 }
 
@@ -91,19 +90,16 @@ static inline int simc_close(int fd)
 
 static inline int simc_ioctl(int fd, int request, void *arg)
 {
-	wmb();
 	return __simc(SYS_ioctl, fd, request, (int) arg, 0, 0);
 }
 
 static inline int simc_read(int fd, void *buf, size_t count)
 {
-	rmb();
 	return __simc(SYS_read, fd, (int) buf, count, 0, 0);
 }
 
 static inline int simc_write(int fd, const void *buf, size_t count)
 {
-	wmb();
 	return __simc(SYS_write, fd, (int) buf, count, 0, 0);
 }
 
@@ -111,7 +107,6 @@ static inline int simc_poll(int fd)
 {
 	struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
 
-	wmb();
 	return __simc(SYS_select_one, fd, XTISS_SELECT_ONE_READ, (int)&tv,
 			0, 0);
 }