Index: head/lib/libc/sys/Makefile.inc
===================================================================
--- head/lib/libc/sys/Makefile.inc
+++ head/lib/libc/sys/Makefile.inc
@@ -46,6 +46,7 @@
 PSEUDO+= _getdirentries.o
 
 SRCS+= pipe.c
+SRCS+= vadvise.c
 
 INTERPOSED = \
 	accept \
Index: head/lib/libc/sys/Symbol.map
===================================================================
--- head/lib/libc/sys/Symbol.map
+++ head/lib/libc/sys/Symbol.map
@@ -1010,8 +1010,6 @@
 	__sys_utrace;
 	_uuidgen;
 	__sys_uuidgen;
-	_vadvise;
-	__sys_vadvise;
 	_wait4;
 	__sys_wait4;
 	_wait6;
Index: head/lib/libc/sys/vadvise.c
===================================================================
--- head/lib/libc/sys/vadvise.c
+++ head/lib/libc/sys/vadvise.c
@@ -0,0 +1,46 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2018 SRI International
+ * All rights reserved.
+ *
+ * This software was developed by SRI International and the University of
+ * Cambridge Computer Laboratory (Department of Computer Science and
+ * Technology) under DARPA contract HR0011-18-C-0016 ("ECATS"), as part of the
+ * DARPA SSITH research programme.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/cdefs.h>
+#include <sys/errno.h>
+
+int vadvise(int);
+
+int
+vadvise(int arg __unused)
+{
+
+	return (EINVAL);
+}
Index: head/sys/compat/freebsd32/syscalls.master
===================================================================
--- head/sys/compat/freebsd32/syscalls.master
+++ head/sys/compat/freebsd32/syscalls.master
@@ -173,8 +173,7 @@
 70	AUE_SSTK	NOPROTO	{ int sstk(int incr); }
 71	AUE_MMAP	COMPAT|NOPROTO	{ int mmap(void *addr, int len, \
 				    int prot, int flags, int fd, int pos); }
-72	AUE_O_VADVISE	NOPROTO	{ int ovadvise(int anom); } vadvise \
-				    ovadvise_args int
+72	AUE_O_VADVISE	COMPAT11|NOPROTO	{ int vadvise(int anom); }
 73	AUE_MUNMAP	NOPROTO	{ int munmap(void *addr, size_t len); }
 74	AUE_MPROTECT	STD	{ int freebsd32_mprotect(void *addr, \
 				    size_t len, int prot); }
Index: head/sys/kern/syscalls.master
===================================================================
--- head/sys/kern/syscalls.master
+++ head/sys/kern/syscalls.master
@@ -229,8 +229,7 @@
 70	AUE_SSTK	STD	{ int sstk(int incr); }
 71	AUE_MMAP	COMPAT	{ int mmap(_In_ void *addr, int len, int prot, \
 				    int flags, int fd, long pos); }
-72	AUE_O_VADVISE	STD	{ int ovadvise(int anom); } vadvise \
-				    ovadvise_args int
+72	AUE_O_VADVISE	COMPAT11	{ int vadvise(int anom); }
 73	AUE_MUNMAP	STD	{ int munmap(_In_ void *addr, size_t len); }
 74	AUE_MPROTECT	STD	{ int mprotect(_In_ void *addr, \
 				    size_t len, int prot); }
Index: head/sys/vm/vm_unix.c
===================================================================
--- head/sys/vm/vm_unix.c
+++ head/sys/vm/vm_unix.c
@@ -231,20 +231,11 @@
 #endif /* defined(__aarch64__) || defined(__riscv__) */
 }
 
-#ifndef _SYS_SYSPROTO_H_
-struct ovadvise_args {
-	int anom;
-};
-#endif
-
-/*
- * MPSAFE
- */
-/* ARGSUSED */
+#ifdef COMPAT_FREEBSD11
 int
-sys_ovadvise(struct thread *td, struct ovadvise_args *uap)
+freebsd11_vadvise(struct thread *td, struct freebsd11_vadvise_args *uap)
 {
-	/* START_GIANT_OPTIONAL */
-	/* END_GIANT_OPTIONAL */
+
 	return (EINVAL);
 }
+#endif