Index: sys/compat/common/vfs_syscalls_50.c
===================================================================
RCS file: /cvsroot/src/sys/compat/common/vfs_syscalls_50.c,v
retrieving revision 1.22
diff -u -r1.22 vfs_syscalls_50.c
--- sys/compat/common/vfs_syscalls_50.c	17 Jun 2019 14:59:15 -0000	1.22
+++ sys/compat/common/vfs_syscalls_50.c	18 Jun 2019 15:08:25 -0000
@@ -343,7 +343,7 @@
 		syscallarg(uint32_t) dev;
 	} */
 	return do_sys_mknod(l, SCARG(uap, path), SCARG(uap, mode),
-	    SCARG(uap, dev), retval, UIO_USERSPACE);
+	    SCARG(uap, dev), UIO_USERSPACE);
 }
 
 #ifdef QUOTA
Index: sys/compat/linux/common/linux_file.c
===================================================================
RCS file: /cvsroot/src/sys/compat/linux/common/linux_file.c,v
retrieving revision 1.115
diff -u -r1.115 linux_file.c
--- sys/compat/linux/common/linux_file.c	1 Mar 2015 13:19:39 -0000	1.115
+++ sys/compat/linux/common/linux_file.c	18 Jun 2019 15:08:25 -0000
@@ -675,8 +675,7 @@
 		 */
 
 		return do_sys_mknodat(l, SCARG(uap, fd), SCARG(uap, path),
-		    SCARG(uap, mode), SCARG(uap, dev) & 0xffff, retval,
-		    UIO_USERSPACE);
+		    SCARG(uap, mode), SCARG(uap, dev) & 0xffff, UIO_USERSPACE);
 	}
 }
 
Index: sys/compat/netbsd32/netbsd32_compat_50.c
===================================================================
RCS file: /cvsroot/src/sys/compat/netbsd32/netbsd32_compat_50.c,v
retrieving revision 1.36
diff -u -r1.36 netbsd32_compat_50.c
--- sys/compat/netbsd32/netbsd32_compat_50.c	1 Mar 2019 11:06:56 -0000	1.36
+++ sys/compat/netbsd32/netbsd32_compat_50.c	18 Jun 2019 15:08:25 -0000
@@ -116,7 +116,7 @@
 		syscallarg(uint32_t) dev;
 	} */
 	return do_sys_mknod(l, SCARG_P32(uap, path), SCARG(uap, mode),
-	    SCARG(uap, dev), retval, UIO_USERSPACE);
+	    SCARG(uap, dev), UIO_USERSPACE);
 }
 
 int
Index: sys/compat/netbsd32/netbsd32_netbsd.c
===================================================================
RCS file: /cvsroot/src/sys/compat/netbsd32/netbsd32_netbsd.c,v
retrieving revision 1.223
diff -u -r1.223 netbsd32_netbsd.c
--- sys/compat/netbsd32/netbsd32_netbsd.c	27 Jan 2019 02:08:40 -0000	1.223
+++ sys/compat/netbsd32/netbsd32_netbsd.c	18 Jun 2019 15:08:25 -0000
@@ -297,7 +297,7 @@
 	} */
 
 	return do_sys_mknod(l, SCARG_P32(uap, path), SCARG(uap, mode),
-	    SCARG(uap, dev), retval, UIO_USERSPACE);
+	    SCARG(uap, dev), UIO_USERSPACE);
 }
 
 int
Index: sys/kern/vfs_syscalls.c
===================================================================
RCS file: /cvsroot/src/sys/kern/vfs_syscalls.c,v
retrieving revision 1.528
diff -u -r1.528 vfs_syscalls.c
--- sys/kern/vfs_syscalls.c	13 May 2019 08:17:30 -0000	1.528
+++ sys/kern/vfs_syscalls.c	18 Jun 2019 15:08:26 -0000
@@ -2151,6 +2151,20 @@
 	return error;
 }
 
+int
+do_posix_mknodat(struct lwp *l, int fdat, const char *pathname, mode_t mode,
+    dev_t dev)
+{
+
+	if ((mode & S_IFIFO) && dev == 0)
+		return do_sys_mkfifoat(l, fdat, pathname, mode);
+	else if (mode & (S_IFCHR | S_IFBLK))
+		return do_sys_mknodat(l, fdat, pathname, mode, dev,
+		    UIO_USERSPACE);
+	else
+		return EINVAL;
+}
+
 /*
  * Create a special file.
  */
@@ -2164,8 +2178,8 @@
 		syscallarg(mode_t) mode;
 		syscallarg(dev_t) dev;
 	} */
-	return do_sys_mknodat(l, AT_FDCWD, SCARG(uap, path), SCARG(uap, mode),
-	    SCARG(uap, dev), retval, UIO_USERSPACE);
+	return do_posix_mknodat(l,  AT_FDCWD, SCARG(uap, path),
+	    SCARG(uap, mode), SCARG(uap, dev));
 }
 
 int
@@ -2180,20 +2194,20 @@
 		syscallarg(dev_t) dev;
 	} */
 
-	return do_sys_mknodat(l, SCARG(uap, fd), SCARG(uap, path), 
-	    SCARG(uap, mode), SCARG(uap, dev), retval, UIO_USERSPACE);
+	return do_posix_mknodat(l, SCARG(uap, fd), SCARG(uap, path),
+	    SCARG(uap, mode), SCARG(uap, dev));
 }
 
 int
 do_sys_mknod(struct lwp *l, const char *pathname, mode_t mode, dev_t dev,
-    register_t *retval, enum uio_seg seg)
+    enum uio_seg seg)
 {
-	return do_sys_mknodat(l, AT_FDCWD, pathname, mode, dev, retval, seg);
+	return do_sys_mknodat(l, AT_FDCWD, pathname, mode, dev, seg);
 }
 
 int
 do_sys_mknodat(struct lwp *l, int fdat, const char *pathname, mode_t mode,
-    dev_t dev, register_t *retval, enum uio_seg seg)
+    dev_t dev, enum uio_seg seg)
 {
 	struct proc *p = l->l_proc;
 	struct vnode *vp;
Index: sys/rump/librump/rumpvfs/devnodes.c
===================================================================
RCS file: /cvsroot/src/sys/rump/librump/rumpvfs/devnodes.c,v
retrieving revision 1.12
diff -u -r1.12 devnodes.c
--- sys/rump/librump/rumpvfs/devnodes.c	26 Jan 2016 23:12:18 -0000	1.12
+++ sys/rump/librump/rumpvfs/devnodes.c	18 Jun 2019 15:08:26 -0000
@@ -44,11 +44,10 @@
 makeonedevnode(dev_t devtype, const char *devname,
 	devmajor_t majnum, devminor_t minnum)
 {
-	register_t retval;
 	int error;
 
 	error = do_sys_mknod(curlwp, devname, 0666 | devtype,
-	    makedev(majnum, minnum), &retval, UIO_SYSSPACE);
+	    makedev(majnum, minnum), UIO_SYSSPACE);
 	if (error == EEXIST) /* XXX: should check it's actually the same */
 		error = 0;
 
@@ -62,7 +61,6 @@
 	int error = 0;
 	char *devname, *p;
 	size_t devlen;
-	register_t retval;
 
 	devlen = strlen(basename) + 1 + 1; /* +letter +0 */
 	devname = kmem_zalloc(devlen, KM_SLEEP);
@@ -74,7 +72,7 @@
 		*p = minchar;
 
 		if ((error = do_sys_mknod(curlwp, devname, 0666 | devtype,
-		    makedev(maj, minnum), &retval, UIO_SYSSPACE))) {
+		    makedev(maj, minnum), UIO_SYSSPACE))) {
 			if (error == EEXIST)
 				error = 0;
 			else
@@ -121,7 +119,6 @@
     devminor_t dmin, const char *base, int c1, int c2)
 {
 	char cstr1[2] = {0,0}, cstr2[2] = {0,0};
-	register_t rv;
 	int error;
 
 	if (c1 != -1) {
@@ -145,7 +142,7 @@
 			break;
 		case NOTEXIST:
 			if ((error = do_sys_mknod(curlwp, buf, 0600 | S_IFBLK,
-			    makedev(blk, dmin), &rv, UIO_SYSSPACE)) != 0)
+			    makedev(blk, dmin), UIO_SYSSPACE)) != 0)
 				aprint_verbose("mkdevnodes: failed to "
 				    "create %s: %d\n", buf, error);
 			break;
@@ -163,7 +160,7 @@
 		break;
 	case NOTEXIST:
 		if ((error = do_sys_mknod(curlwp, buf, 0600 | S_IFCHR,
-		    makedev(chr, dmin), &rv, UIO_SYSSPACE)) != 0)
+		    makedev(chr, dmin), UIO_SYSSPACE)) != 0)
 			aprint_verbose("mkdevnodes: failed to "
 			    "create %s: %d\n", buf, error);
 		break;
Index: sys/sys/vfs_syscalls.h
===================================================================
RCS file: /cvsroot/src/sys/sys/vfs_syscalls.h,v
retrieving revision 1.23
diff -u -r1.23 vfs_syscalls.h
--- sys/sys/vfs_syscalls.h	29 Jul 2017 04:02:49 -0000	1.23
+++ sys/sys/vfs_syscalls.h	18 Jun 2019 15:08:26 -0000
@@ -70,8 +70,9 @@
 int	do_sys_linkat(struct lwp *, int, const char *, int, const char *, int, register_t *);
 int	do_sys_unlink(const char *, enum uio_seg);
 int	do_sys_rename(const char *, const char *, enum uio_seg, int);
-int	do_sys_mknod(struct lwp *, const char *, mode_t, dev_t, register_t *, enum uio_seg);
-int	do_sys_mknodat(struct lwp *, int, const char *, mode_t, dev_t, register_t *, enum uio_seg);
+int	do_posix_mknodat(struct lwp *, int, const char *, mode_t, dev_t);
+int	do_sys_mknod(struct lwp *, const char *, mode_t, dev_t, enum uio_seg);
+int	do_sys_mknodat(struct lwp *, int, const char *, mode_t, dev_t, enum uio_seg);
 int	do_sys_chmodat(struct lwp *, int, const char *, int, int);
 int	do_sys_chownat(struct lwp *, int, const char *, uid_t, gid_t, int);
 int	do_sys_accessat(struct lwp *, int, const char *, int ,int);
Index: external/cddl/osnet/sys/kern/ddi.c
===================================================================
RCS file: /cvsroot/src/external/cddl/osnet/sys/kern/ddi.c,v
retrieving revision 1.7
diff -u -r1.7 ddi.c
--- external/cddl/osnet/sys/kern/ddi.c	22 May 2019 08:44:48 -0000	1.7
+++ external/cddl/osnet/sys/kern/ddi.c	18 Jun 2019 15:09:05 -0000
@@ -613,7 +613,6 @@
 	char *pn;
 	dev_t dev;
 	int error;
-	register_t ret;
 
 	pn = PNBUF_GET();
 	if (spec_type == S_IFCHR) {
@@ -649,7 +648,7 @@
 		(void)do_sys_unlink(pn, UIO_SYSSPACE);
 	}
 
-	error = do_sys_mknod(l, pn, spec_type, dev, &ret, UIO_SYSSPACE);
+	error = do_sys_mknod(l, pn, spec_type, dev, UIO_SYSSPACE);
 
 exit:
 	PNBUF_PUT(pn);