diff --git a/cmd/zpool/zpool_vdev.c b/cmd/zpool/zpool_vdev.c
index 9b5f4972f7..9aa09b18c4 100644
--- a/cmd/zpool/zpool_vdev.c
+++ b/cmd/zpool/zpool_vdev.c
@@ -624,7 +624,7 @@ get_replication(nvlist_t *nvroot, boolean_t fatal)
 				 */
 				if (!dontreport &&
 				    (vdev_size != -1LL &&
-				    (labs(size - vdev_size) >
+				    (llabs(size - vdev_size) >
 				    ZPOOL_FUZZ))) {
 					if (ret != NULL)
 						free(ret);
diff --git a/include/os/freebsd/spl/sys/byteorder.h b/include/os/freebsd/spl/sys/byteorder.h
index fd6b0269d8..ae767242bd 100644
--- a/include/os/freebsd/spl/sys/byteorder.h
+++ b/include/os/freebsd/spl/sys/byteorder.h
@@ -84,9 +84,23 @@
 #define	htonll(x)	BMASK_64(x)
 #define	ntohll(x)	BMASK_64(x)
 #else
+#ifndef __LP64__
+static __inline__ uint64_t
+htonll(uint64_t n)
+{
+	return ((((uint64_t)htonl(n)) << 32) + htonl(n >> 32));
+}
+
+static __inline__ uint64_t
+ntohll(uint64_t n)
+{
+	return ((((uint64_t)ntohl(n)) << 32) + ntohl(n >> 32));
+}
+#else
 #define	htonll(x)	BSWAP_64(x)
 #define	ntohll(x)	BSWAP_64(x)
 #endif
+#endif
 
 #define	BE_IN32(xa)	htonl(*((uint32_t *)(void *)(xa)))
 
diff --git a/include/os/freebsd/spl/sys/ccompile.h b/include/os/freebsd/spl/sys/ccompile.h
index c594c928f8..c90813b040 100644
--- a/include/os/freebsd/spl/sys/ccompile.h
+++ b/include/os/freebsd/spl/sys/ccompile.h
@@ -202,11 +202,14 @@ typedef int enum_t;
 #define	ENODATA EINVAL
 
 
-#define	__XSI_VISIBLE 1000
 #define	__BSD_VISIBLE 1
+#ifndef	IN_BASE
 #define	__POSIX_VISIBLE 201808
+#define	__XSI_VISIBLE 1000
+#endif
 #define	ARRAY_SIZE(a) (sizeof (a) / sizeof (a[0]))
 #define	open64 open
+#define	mmap64 mmap
 #define	pwrite64 pwrite
 #define	ftruncate64 ftruncate
 #define	lseek64 lseek
@@ -257,7 +260,9 @@ typedef int enum_t;
 
 #define	DIV_ROUND_UP(n, d)	(((n) + (d) - 1) / (d))
 #define	RLIM64_INFINITY RLIM_INFINITY
+#ifndef HAVE_ERESTART
 #define	ERESTART EAGAIN
+#endif
 #define	ABS(a)	((a) < 0 ? -(a) : (a))
 
 #endif
diff --git a/include/os/freebsd/spl/sys/kmem.h b/include/os/freebsd/spl/sys/kmem.h
index 943b18f039..6155ce6b07 100644
--- a/include/os/freebsd/spl/sys/kmem.h
+++ b/include/os/freebsd/spl/sys/kmem.h
@@ -32,7 +32,7 @@
 #include <sys/param.h>
 #include <sys/malloc.h>
 #include <sys/vmem.h>
-#include <sys/vmmeter.h>
+#include <sys/counter.h>
 
 #include <vm/uma.h>
 #include <vm/vm.h>
diff --git a/include/os/freebsd/spl/sys/simd_x86.h b/include/os/freebsd/spl/sys/simd_x86.h
index da846fcbe6..a35e205d5a 100644
--- a/include/os/freebsd/spl/sys/simd_x86.h
+++ b/include/os/freebsd/spl/sys/simd_x86.h
@@ -29,7 +29,11 @@
 #include <sys/cdefs.h>
 #include <sys/types.h>
 #include <sys/systm.h>
+#ifdef __i386__
+#include <x86/fpu.h>
+#else
 #include <machine/fpu.h>
+#endif
 #include <x86/x86_var.h>
 #include <x86/specialreg.h>
 
diff --git a/include/os/freebsd/spl/sys/types.h b/include/os/freebsd/spl/sys/types.h
index c06c963d64..3f89536288 100644
--- a/include/os/freebsd/spl/sys/types.h
+++ b/include/os/freebsd/spl/sys/types.h
@@ -73,7 +73,7 @@ typedef off_t		off64_t;
 typedef id_t		taskid_t;
 typedef id_t		projid_t;
 typedef id_t		poolid_t;
-typedef id_t		zoneid_t;
+typedef uint_t		zoneid_t;
 typedef id_t		ctid_t;
 typedef	mode_t		o_mode_t;
 typedef	uint64_t	pgcnt_t;
diff --git a/include/os/freebsd/spl/sys/vnode.h b/include/os/freebsd/spl/sys/vnode.h
index b9fae99ad2..6a61461327 100644
--- a/include/os/freebsd/spl/sys/vnode.h
+++ b/include/os/freebsd/spl/sys/vnode.h
@@ -49,7 +49,9 @@ enum symfollow { NO_FOLLOW = NOFOLLOW };
 
 #include <sys/proc.h>
 #include <sys/vnode_impl.h>
+#ifndef IN_BASE
 #include_next <sys/vnode.h>
+#endif
 #include <sys/mount.h>
 #include <sys/cred.h>
 #include <sys/fcntl.h>
@@ -70,11 +72,14 @@ typedef	struct vop_vector	vnodeops_t;
 
 #define	rootvfs		(rootvnode == NULL ? NULL : rootvnode->v_mount)
 
+
+#ifndef IN_BASE
 static __inline int
 vn_is_readonly(vnode_t *vp)
 {
 	return (vp->v_mount->mnt_flag & MNT_RDONLY);
 }
+#endif
 #define	vn_vfswlock(vp)		(0)
 #define	vn_vfsunlock(vp)	do { } while (0)
 #define	vn_ismntpt(vp)	   \
@@ -166,6 +171,7 @@ vn_is_readonly(vnode_t *vp)
 #define	AT_NOSET	(AT_NLINK|AT_RDEV|AT_FSID|AT_NODEID|\
 			AT_BLKSIZE|AT_NBLOCKS|AT_SEQ)
 
+#ifndef IN_BASE
 static __inline void
 vattr_init_mask(vattr_t *vap)
 {
@@ -187,6 +193,7 @@ vattr_init_mask(vattr_t *vap)
 	if (vap->va_flags != VNOVAL)
 		vap->va_mask |= AT_XVATTR;
 }
+#endif
 
 #define		RLIM64_INFINITY 0
 
diff --git a/include/os/freebsd/zfs/sys/sha2.h b/include/os/freebsd/zfs/sys/sha2.h
index 9d848e1fc2..e3923e4ca3 100644
--- a/include/os/freebsd/zfs/sys/sha2.h
+++ b/include/os/freebsd/zfs/sys/sha2.h
@@ -116,7 +116,7 @@ SHA2Init(uint64_t mech, SHA2_CTX *c)
 			SHA512_256_Init(&c->SHA512_ctx);
 			break;
 		default:
-			panic("unknown mechanism %lu", mech);
+			panic("unknown mechanism %ju", (uintmax_t)mech);
 	}
 	c->algotype = (uint32_t)mech;
 }
diff --git a/include/os/freebsd/zfs/sys/zfs_context_os.h b/include/os/freebsd/zfs/sys/zfs_context_os.h
index 8da3374a6f..7dd298564d 100644
--- a/include/os/freebsd/zfs/sys/zfs_context_os.h
+++ b/include/os/freebsd/zfs/sys/zfs_context_os.h
@@ -88,8 +88,4 @@ typedef int fstrans_cookie_t;
 typedef struct opensolaris_utsname	utsname_t;
 extern utsname_t *utsname(void);
 extern int spa_import_rootpool(const char *name);
-#else
-#if BYTE_ORDER != BIG_ENDIAN
-#undef _BIG_ENDIAN
-#endif
 #endif
diff --git a/lib/libspl/asm-i386/atomic.S b/lib/libspl/asm-i386/atomic.S
index 3086d55439..7a574b0d17 100644
--- a/lib/libspl/asm-i386/atomic.S
+++ b/lib/libspl/asm-i386/atomic.S
@@ -28,8 +28,12 @@
 	.file	"%M%"
 
 #define _ASM
+#ifdef __linux__
 #include <ia32/sys/asm_linkage.h>
-
+#elif __FreeBSD__
+#include <machine/asmacros.h>
+#define SET_SIZE(x)
+#endif
 	ENTRY(atomic_inc_8)
 	ALTENTRY(atomic_inc_uchar)
 	movl	4(%esp), %eax
diff --git a/lib/libspl/include/os/freebsd/sys/param.h b/lib/libspl/include/os/freebsd/sys/param.h
index e2abef1896..7c23b67059 100644
--- a/lib/libspl/include/os/freebsd/sys/param.h
+++ b/lib/libspl/include/os/freebsd/sys/param.h
@@ -45,8 +45,10 @@
  */
 #define	MAXNAMELEN	256
 
+#ifndef IN_BASE
 #define	UID_NOBODY	60001		/* user ID no body */
 #define	GID_NOBODY	UID_NOBODY
+#endif
 #define	UID_NOACCESS	60002		/* user ID no access */
 
 #define	MAXUID		UINT32_MAX	/* max user id */
diff --git a/lib/libspl/include/rpc/xdr.h b/lib/libspl/include/rpc/xdr.h
index 27e4395c73..51d71f693b 100644
--- a/lib/libspl/include/rpc/xdr.h
+++ b/lib/libspl/include/rpc/xdr.h
@@ -40,10 +40,13 @@
 
 #define	XDR_GET_BYTES_AVAIL 1
 
-typedef struct xdr_bytesrec {
+#ifndef HAVE_XDR_BYTESREC
+struct xdr_bytesrec {
 	bool_t xc_is_last_record;
 	size_t xc_num_avail;
-} xdr_bytesrec_t;
+};
+#endif
+typedef struct xdr_bytesrec  xdr_bytesrec_t;
 
 /*
  * This functionality is not required and is disabled in user space.
diff --git a/lib/libspl/include/sys/isa_defs.h b/lib/libspl/include/sys/isa_defs.h
index 6f242ea77e..8c0932f576 100644
--- a/lib/libspl/include/sys/isa_defs.h
+++ b/lib/libspl/include/sys/isa_defs.h
@@ -208,7 +208,7 @@ extern "C" {
 #error MIPS no endian specified
 #endif
 
-#ifndef _LP64
+#if !defined(_LP64) && !defined(_ILP32)
 #define	_ILP32
 #endif
 
diff --git a/lib/libspl/include/sys/uio.h b/lib/libspl/include/sys/uio.h
index 6d892dd3e2..3a834b996a 100644
--- a/lib/libspl/include/sys/uio.h
+++ b/lib/libspl/include/sys/uio.h
@@ -141,7 +141,8 @@ static inline offset_t
 uio_index_at_offset(uio_t *uio, offset_t off, uint_t *vec_idx)
 {
 	*vec_idx = 0;
-	while (*vec_idx < uio_iovcnt(uio) && off >= uio_iovlen(uio, *vec_idx)) {
+	while (*vec_idx < (uint_t)uio_iovcnt(uio) &&
+	    off >= (offset_t)uio_iovlen(uio, *vec_idx)) {
 		off -= uio_iovlen(uio, *vec_idx);
 		(*vec_idx)++;
 	}
diff --git a/module/os/freebsd/spl/spl_vm.c b/module/os/freebsd/spl/spl_vm.c
index b5649d5197..739ddb05e8 100644
--- a/module/os/freebsd/spl/spl_vm.c
+++ b/module/os/freebsd/spl/spl_vm.c
@@ -29,6 +29,8 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/types.h>
 #include <sys/param.h>
+#include <sys/counter.h>
+
 #include <sys/byteorder.h>
 #include <sys/lock.h>
 #include <sys/freebsd_rwlock.h>
diff --git a/module/os/freebsd/zfs/arc_os.c b/module/os/freebsd/zfs/arc_os.c
index 5f4b5df4a9..94df750035 100644
--- a/module/os/freebsd/zfs/arc_os.c
+++ b/module/os/freebsd/zfs/arc_os.c
@@ -22,6 +22,7 @@
 #include <sys/spa.h>
 #include <sys/zio.h>
 #include <sys/spa_impl.h>
+#include <sys/counter.h>
 #include <sys/zio_compress.h>
 #include <sys/zio_checksum.h>
 #include <sys/zfs_context.h>
@@ -47,6 +48,8 @@
 #include <sys/vnode.h>
 #include <cityhash.h>
 #include <machine/vmparam.h>
+#include <sys/vm.h>
+#include <sys/vmmeter.h>
 
 extern struct vfsops zfs_vfsops;
 
diff --git a/module/os/freebsd/zfs/kmod_core.c b/module/os/freebsd/zfs/kmod_core.c
index e6eceacb22..89f4996409 100644
--- a/module/os/freebsd/zfs/kmod_core.c
+++ b/module/os/freebsd/zfs/kmod_core.c
@@ -142,8 +142,8 @@ zfsdev_ioctl(struct cdev *dev, ulong_t zcmd, caddr_t arg, int flag,
 	zcl = NULL;
 
 	if (len != sizeof (zfs_iocparm_t)) {
-		printf("len %d vecnum: %d sizeof (zfs_cmd_t) %lu\n",
-		    len, vecnum, sizeof (zfs_cmd_t));
+		printf("len %d vecnum: %d sizeof (zfs_cmd_t) %ju\n",
+		    len, vecnum, (uintmax_t)sizeof (zfs_cmd_t));
 		return (EINVAL);
 	}
 
diff --git a/module/os/freebsd/zfs/sysctl_os.c b/module/os/freebsd/zfs/sysctl_os.c
index 945416ebcb..d76b49de9d 100644
--- a/module/os/freebsd/zfs/sysctl_os.c
+++ b/module/os/freebsd/zfs/sysctl_os.c
@@ -123,11 +123,10 @@ SYSCTL_NODE(_vfs_zfs_vdev, OID_AUTO, cache, CTLFLAG_RW, 0, "ZFS VDEV Cache");
 SYSCTL_NODE(_vfs_zfs_vdev, OID_AUTO, mirror, CTLFLAG_RD, 0,
     "ZFS VDEV mirror");
 
-#ifdef ZFS_META_VERSION
 SYSCTL_DECL(_vfs_zfs_version);
 SYSCTL_CONST_STRING(_vfs_zfs_version, OID_AUTO, module, CTLFLAG_RD,
     (ZFS_META_VERSION "-" ZFS_META_RELEASE), "OpenZFS module version");
-#endif
+
 extern arc_state_t ARC_anon;
 extern arc_state_t ARC_mru;
 extern arc_state_t ARC_mru_ghost;
@@ -143,12 +142,12 @@ extern arc_state_t ARC_l2c_only;
 /* arc.c */
 
 /* legacy compat */
-extern unsigned long l2arc_write_max;	/* def max write size */
-extern unsigned long l2arc_write_boost;	/* extra warmup write */
-extern unsigned long l2arc_headroom;		/* # of dev writes */
-extern unsigned long l2arc_headroom_boost;
-extern unsigned long l2arc_feed_secs;	/* interval seconds */
-extern unsigned long l2arc_feed_min_ms;	/* min interval msecs */
+extern uint64_t l2arc_write_max;	/* def max write size */
+extern uint64_t l2arc_write_boost;	/* extra warmup write */
+extern uint64_t l2arc_headroom;		/* # of dev writes */
+extern uint64_t l2arc_headroom_boost;
+extern uint64_t l2arc_feed_secs;	/* interval seconds */
+extern uint64_t l2arc_feed_min_ms;	/* min interval msecs */
 extern int l2arc_noprefetch;			/* don't cache prefetch bufs */
 extern int l2arc_feed_again;			/* turbo warmup */
 extern int l2arc_norw;			/* no reads during writes */
diff --git a/module/os/freebsd/zfs/zfs_ioctl_compat.c b/module/os/freebsd/zfs/zfs_ioctl_compat.c
index 18ab587563..8dec8644c0 100644
--- a/module/os/freebsd/zfs/zfs_ioctl_compat.c
+++ b/module/os/freebsd/zfs/zfs_ioctl_compat.c
@@ -31,15 +31,12 @@ __FBSDID("$FreeBSD$");
 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/conf.h>
-#include <sys/eventhandler.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
 #include <sys/malloc.h>
 #include <sys/mutex.h>
 #include <sys/errno.h>
-#include <sys/uio.h>
 #include <sys/cmn_err.h>
-#include <sys/stat.h>
 #include <sys/zfs_ioctl_compat.h>
 
 enum zfs_ioc_legacy {
diff --git a/module/os/freebsd/zfs/zfs_vfsops.c b/module/os/freebsd/zfs/zfs_vfsops.c
index 92a53afc2b..cf397ca297 100644
--- a/module/os/freebsd/zfs/zfs_vfsops.c
+++ b/module/os/freebsd/zfs/zfs_vfsops.c
@@ -2157,6 +2157,13 @@ zfs_freevfs(vfs_t *vfsp)
 
 #ifdef __i386__
 static int desiredvnodes_backup;
+#include <sys/vmmeter.h>
+
+
+#include <vm/vm_page.h>
+#include <vm/vm_object.h>
+#include <vm/vm_kern.h>
+#include <vm/vm_map.h>
 #endif
 
 static void
@@ -2321,8 +2328,8 @@ zfs_set_version(zfsvfs_t *zfsvfs, uint64_t newvers)
 	}
 
 	spa_history_log_internal_ds(dmu_objset_ds(os), "upgrade", tx,
-	    "from %lu to %lu", zfsvfs->z_version, newvers);
-
+	    "from %ju to %ju", (uintmax_t)zfsvfs->z_version,
+	    (uintmax_t)newvers);
 	dmu_tx_commit(tx);
 
 	zfsvfs->z_version = newvers;
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 3ec98917d1..9399f97218 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -7447,9 +7447,15 @@ arc_init(void)
 	 * zfs_dirty_data_max_percent (default 10%) with a cap at
 	 * zfs_dirty_data_max_max (default 4G or 25% of physical memory).
 	 */
+#ifdef __LP64__
 	if (zfs_dirty_data_max_max == 0)
 		zfs_dirty_data_max_max = MIN(4ULL * 1024 * 1024 * 1024,
 		    allmem * zfs_dirty_data_max_max_percent / 100);
+#else
+	if (zfs_dirty_data_max_max == 0)
+		zfs_dirty_data_max_max = MIN(1ULL * 1024 * 1024 * 1024,
+		    allmem * zfs_dirty_data_max_max_percent / 100);
+#endif
 
 	if (zfs_dirty_data_max == 0) {
 		zfs_dirty_data_max = allmem *