diff --git a/stand/kboot/host_syscall.h b/stand/kboot/host_syscall.h
index 061f82b062b0..b867cd9f0d99 100644
--- a/stand/kboot/host_syscall.h
+++ b/stand/kboot/host_syscall.h
@@ -1,152 +1,167 @@
 /*-
  * Copyright (C) 2014 Nathan Whitehorn
  * All rights reserved.
  *
  * 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 ``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 TOOLS GMBH 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.
  *
  * $FreeBSD$
  */
 
 #ifndef _HOST_SYSCALL_H
 #define _HOST_SYSCALL_H
 
 #include <stand.h>
 
 long host_syscall(int number, ...);
 
 /*
  * Sizes taken from musl's include/alltypes.h.in and expanded for LP64 hosts
  */
 typedef uint64_t host_dev_t;
 typedef uint64_t host_ino_t;
 typedef int64_t host_nlink_t;
 typedef unsigned int host_mode_t;
 typedef unsigned int host_uid_t;
 typedef unsigned int host_gid_t;
 typedef int64_t host_off_t;
 typedef long host_blksize_t;
 typedef int64_t host_blkcnt_t;
 
 #include "stat_arch.h"
 
 /*
  * Constants for open, fcntl, etc
  *
  * Note: Some of these are arch dependent on Linux, but are the same for
  * powerpc, x86, arm*, and riscv. We should be futureproof, though, since these
  * are the 'generic' values and only older architectures (no longer supported by
  * FreeBSD) vary.
  *
  * These are from tools/include/uapi/asm-generic/fcntl.h and use the octal
  * notation. Beware, hex is used in other places creating potential confsion.
  */
 #define HOST_O_RDONLY		    0
 #define HOST_O_WRONLY		    1
 #define HOST_O_RDWR		    2
 #define HOST_O_CREAT		00100
 #define HOST_O_EXCL		00200
 #define HOST_O_NOCTTY		00400
 #define HOST_O_TRUNC		01000
 #define HOST_O_APPEND		02000
 #define HOST_O_NONBLOCK		04000
 
 #define HOST_AT_FDCWD		-100            /* Relative to current directory */
 
 /*
  * Data types
  */
 struct old_utsname {
 	char sysname[65];
 	char nodename[65];
 	char release[65];
 	char version[65];
 	char machine[65];
 };
 
 struct host_timeval {
 	time_t tv_sec;
 	long tv_usec;
 };
 
-#define HOST_AT_FDCWD		-100		/* Relative to current directory */
+/*
+ * Must match Linux's values see linux/tools/include/uapi/asm-generic/mman-common.h
+ * and linux/tools/include/linux/mman.h
+ *
+ * And pre-pend HOST_ here.
+ */
+#define HOST_PROT_READ	0x1
+#define HOST_PROT_WRITE	0x2
+#define HOST_PROT_EXEC	0x4
+
+#define HOST_MAP_SHARED		0x01
+#define	HOST_MAP_PRIVATE	0x02
+#define HOST_MAP_FIXED		0x10
+#define HOST_MAP_ANONYMOUS	0x20
 
 /* Mount flags from uapi */
 #define MS_RELATIME (1 << 21)
 
 #define HOST_REBOOT_MAGIC1	0xfee1dead
 #define HOST_REBOOT_MAGIC2	672274793
 #define HOST_REBOOT_CMD_KEXEC	0x45584543
 
 /*
  * Values from linux/tools/include/uapi/linux/kexec.h
  */
 
 /*
  * Values match ELF architecture types.
  */
 #define HOST_KEXEC_ARCH_X86_64  (62 << 16)
 #define HOST_KEXEC_ARCH_PPC64   (21 << 16)
 #define HOST_KEXEC_ARCH_ARM     (40 << 16)
 #define HOST_KEXEC_ARCH_AARCH64 (183 << 16)
 #define HOST_KEXEC_ARCH_RISCV   (243 << 16)
 
 /* Arbitrary cap on segments */
 #define HOST_KEXEC_SEGMENT_MAX 16
 
 struct host_kexec_segment {
 	void *buf;
 	int bufsz;
 	void *mem;
 	int memsz;
 };
 
 /*
  * System Calls
  */
 int host_close(int fd);
 int host_dup(int fd);
 int host_fstat(int fd, struct host_kstat *sb);
 int host_getdents(int fd, void *dirp, int count);
 int host_getpid(void);
 int host_gettimeofday(struct host_timeval *a, void *b);
 int host_kexec_load(unsigned long entry, unsigned long nsegs, struct host_kexec_segment *segs, unsigned long flags);
 ssize_t host_llseek(int fd, int32_t offset_high, int32_t offset_lo, uint64_t *result, int whence);
 int host_mkdir(const char *, host_mode_t);
 void *host_mmap(void *addr, size_t len, int prot, int flags, int fd, off_t off);
 int host_mount(const char *src, const char *target, const char *type,
     unsigned long flags, void *data);
 int host_munmap(void *addr, size_t len);
 int host_open(const char *path, int flags, int mode);
 ssize_t host_read(int fd, void *buf, size_t nbyte);
 int host_reboot(int, int, int, uintptr_t);
 int host_select(int nfds, long *readfds, long *writefds, long *exceptfds,
     struct host_timeval *timeout);
 int host_stat(const char *path, struct host_kstat *sb);
 int host_symlink(const char *path1, const char *path2);
 int host_uname(struct old_utsname *);
 ssize_t host_write(int fd, const void *buf, size_t nbyte);
 
 /*
  * Wrappers / one-liners
  */
-#define host_getmem(size) host_mmap(0, size, 3 /* RW */, 0x22 /* ANON */, -1, 0);
+#define host_getmem(size) \
+	host_mmap(0, size, HOST_PROT_READ | HOST_PROT_WRITE, \
+	    HOST_MAP_PRIVATE | HOST_MAP_ANONYMOUS, -1, 0);
 
 #endif