BSD 4.4 Lite Kernel Sources

1 files changed, 2626 insertions, 0 deletions

diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
new file mode 100644
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--- /dev/null
+++ b/sys/vm/vm_map.c
@@ -0,0 +1,2626 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ *
+ *	@(#)vm_map.c	8.3 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Virtual memory mapping module.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_object.h>
+
+/*
+ *	Virtual memory maps provide for the mapping, protection,
+ *	and sharing of virtual memory objects.  In addition,
+ *	this module provides for an efficient virtual copy of
+ *	memory from one map to another.
+ *
+ *	Synchronization is required prior to most operations.
+ *
+ *	Maps consist of an ordered doubly-linked list of simple
+ *	entries; a single hint is used to speed up lookups.
+ *
+ *	In order to properly represent the sharing of virtual
+ *	memory regions among maps, the map structure is bi-level.
+ *	Top-level ("address") maps refer to regions of sharable
+ *	virtual memory.  These regions are implemented as
+ *	("sharing") maps, which then refer to the actual virtual
+ *	memory objects.  When two address maps "share" memory,
+ *	their top-level maps both have references to the same
+ *	sharing map.  When memory is virtual-copied from one
+ *	address map to another, the references in the sharing
+ *	maps are actually copied -- no copying occurs at the
+ *	virtual memory object level.
+ *
+ *	Since portions of maps are specified by start/end addreses,
+ *	which may not align with existing map entries, all
+ *	routines merely "clip" entries to these start/end values.
+ *	[That is, an entry is split into two, bordering at a
+ *	start or end value.]  Note that these clippings may not
+ *	always be necessary (as the two resulting entries are then
+ *	not changed); however, the clipping is done for convenience.
+ *	No attempt is currently made to "glue back together" two
+ *	abutting entries.
+ *
+ *	As mentioned above, virtual copy operations are performed
+ *	by copying VM object references from one sharing map to
+ *	another, and then marking both regions as copy-on-write.
+ *	It is important to note that only one writeable reference
+ *	to a VM object region exists in any map -- this means that
+ *	shadow object creation can be delayed until a write operation
+ *	occurs.
+ */
+
+/*
+ *	vm_map_startup:
+ *
+ *	Initialize the vm_map module.  Must be called before
+ *	any other vm_map routines.
+ *
+ *	Map and entry structures are allocated from the general
+ *	purpose memory pool with some exceptions:
+ *
+ *	- The kernel map and kmem submap are allocated statically.
+ *	- Kernel map entries are allocated out of a static pool.
+ *
+ *	These restrictions are necessary since malloc() uses the
+ *	maps and requires map entries.
+ */
+
+vm_offset_t	kentry_data;
+vm_size_t	kentry_data_size;
+vm_map_entry_t	kentry_free;
+vm_map_t	kmap_free;
+
+static void	_vm_map_clip_end __P((vm_map_t, vm_map_entry_t, vm_offset_t));
+static void	_vm_map_clip_start __P((vm_map_t, vm_map_entry_t, vm_offset_t));
+
+void vm_map_startup()
+{
+	register int i;
+	register vm_map_entry_t mep;
+	vm_map_t mp;
+
+	/*
+	 * Static map structures for allocation before initialization of
+	 * kernel map or kmem map.  vm_map_create knows how to deal with them.
+	 */
+	kmap_free = mp = (vm_map_t) kentry_data;
+	i = MAX_KMAP;
+	while (--i > 0) {
+		mp->header.next = (vm_map_entry_t) (mp + 1);
+		mp++;
+	}
+	mp++->header.next = NULL;
+
+	/*
+	 * Form a free list of statically allocated kernel map entries
+	 * with the rest.
+	 */
+	kentry_free = mep = (vm_map_entry_t) mp;
+	i = (kentry_data_size - MAX_KMAP * sizeof *mp) / sizeof *mep;
+	while (--i > 0) {
+		mep->next = mep + 1;
+		mep++;
+	}
+	mep->next = NULL;
+}
+
+/*
+ * Allocate a vmspace structure, including a vm_map and pmap,
+ * and initialize those structures.  The refcnt is set to 1.
+ * The remaining fields must be initialized by the caller.
+ */
+struct vmspace *
+vmspace_alloc(min, max, pageable)
+	vm_offset_t min, max;
+	int pageable;
+{
+	register struct vmspace *vm;
+
+	MALLOC(vm, struct vmspace *, sizeof(struct vmspace), M_VMMAP, M_WAITOK);
+	bzero(vm, (caddr_t) &vm->vm_startcopy - (caddr_t) vm);
+	vm_map_init(&vm->vm_map, min, max, pageable);
+	pmap_pinit(&vm->vm_pmap);
+	vm->vm_map.pmap = &vm->vm_pmap;		/* XXX */
+	vm->vm_refcnt = 1;
+	return (vm);
+}
+
+void
+vmspace_free(vm)
+	register struct vmspace *vm;
+{
+
+	if (--vm->vm_refcnt == 0) {
+		/*
+		 * Lock the map, to wait out all other references to it.
+		 * Delete all of the mappings and pages they hold,
+		 * then call the pmap module to reclaim anything left.
+		 */
+		vm_map_lock(&vm->vm_map);
+		(void) vm_map_delete(&vm->vm_map, vm->vm_map.min_offset,
+		    vm->vm_map.max_offset);
+		pmap_release(&vm->vm_pmap);
+		FREE(vm, M_VMMAP);
+	}
+}
+
+/*
+ *	vm_map_create:
+ *
+ *	Creates and returns a new empty VM map with
+ *	the given physical map structure, and having
+ *	the given lower and upper address bounds.
+ */
+vm_map_t vm_map_create(pmap, min, max, pageable)
+	pmap_t		pmap;
+	vm_offset_t	min, max;
+	boolean_t	pageable;
+{
+	register vm_map_t	result;
+	extern vm_map_t		kmem_map;
+
+	if (kmem_map == NULL) {
+		result = kmap_free;
+		kmap_free = (vm_map_t) result->header.next;
+		if (result == NULL)
+			panic("vm_map_create: out of maps");
+	} else
+		MALLOC(result, vm_map_t, sizeof(struct vm_map),
+		       M_VMMAP, M_WAITOK);
+
+	vm_map_init(result, min, max, pageable);
+	result->pmap = pmap;
+	return(result);
+}
+
+/*
+ * Initialize an existing vm_map structure
+ * such as that in the vmspace structure.
+ * The pmap is set elsewhere.
+ */
+void
+vm_map_init(map, min, max, pageable)
+	register struct vm_map *map;
+	vm_offset_t	min, max;
+	boolean_t	pageable;
+{
+	map->header.next = map->header.prev = &map->header;
+	map->nentries = 0;
+	map->size = 0;
+	map->ref_count = 1;
+	map->is_main_map = TRUE;
+	map->min_offset = min;
+	map->max_offset = max;
+	map->entries_pageable = pageable;
+	map->first_free = &map->header;
+	map->hint = &map->header;
+	map->timestamp = 0;
+	lock_init(&map->lock, TRUE);
+	simple_lock_init(&map->ref_lock);
+	simple_lock_init(&map->hint_lock);
+}
+
+/*
+ *	vm_map_entry_create:	[ internal use only ]
+ *
+ *	Allocates a VM map entry for insertion.
+ *	No entry fields are filled in.  This routine is
+ */
+vm_map_entry_t vm_map_entry_create(map)
+	vm_map_t	map;
+{
+	vm_map_entry_t	entry;
+#ifdef DEBUG
+	extern vm_map_t		kernel_map, kmem_map, mb_map, pager_map;
+	boolean_t		isspecial;
+
+	isspecial = (map == kernel_map || map == kmem_map ||
+		     map == mb_map || map == pager_map);
+	if (isspecial && map->entries_pageable ||
+	    !isspecial && !map->entries_pageable)
+		panic("vm_map_entry_create: bogus map");
+#endif
+	if (map->entries_pageable) {
+		MALLOC(entry, vm_map_entry_t, sizeof(struct vm_map_entry),
+		       M_VMMAPENT, M_WAITOK);
+	} else {
+		if (entry = kentry_free)
+			kentry_free = kentry_free->next;
+	}
+	if (entry == NULL)
+		panic("vm_map_entry_create: out of map entries");
+
+	return(entry);
+}
+
+/*
+ *	vm_map_entry_dispose:	[ internal use only ]
+ *
+ *	Inverse of vm_map_entry_create.
+ */
+void vm_map_entry_dispose(map, entry)
+	vm_map_t	map;
+	vm_map_entry_t	entry;
+{
+#ifdef DEBUG
+	extern vm_map_t		kernel_map, kmem_map, mb_map, pager_map;
+	boolean_t		isspecial;
+
+	isspecial = (map == kernel_map || map == kmem_map ||
+		     map == mb_map || map == pager_map);
+	if (isspecial && map->entries_pageable ||
+	    !isspecial && !map->entries_pageable)
+		panic("vm_map_entry_dispose: bogus map");
+#endif
+	if (map->entries_pageable) {
+		FREE(entry, M_VMMAPENT);
+	} else {
+		entry->next = kentry_free;
+		kentry_free = entry;
+	}
+}
+
+/*
+ *	vm_map_entry_{un,}link:
+ *
+ *	Insert/remove entries from maps.
+ */
+#define	vm_map_entry_link(map, after_where, entry) \
+		{ \
+		(map)->nentries++; \
+		(entry)->prev = (after_where); \
+		(entry)->next = (after_where)->next; \
+		(entry)->prev->next = (entry); \
+		(entry)->next->prev = (entry); \
+		}
+#define	vm_map_entry_unlink(map, entry) \
+		{ \
+		(map)->nentries--; \
+		(entry)->next->prev = (entry)->prev; \
+		(entry)->prev->next = (entry)->next; \
+		}
+
+/*
+ *	vm_map_reference:
+ *
+ *	Creates another valid reference to the given map.
+ *
+ */
+void vm_map_reference(map)
+	register vm_map_t	map;
+{
+	if (map == NULL)
+		return;
+
+	simple_lock(&map->ref_lock);
+	map->ref_count++;
+	simple_unlock(&map->ref_lock);
+}
+
+/*
+ *	vm_map_deallocate:
+ *
+ *	Removes a reference from the specified map,
+ *	destroying it if no references remain.
+ *	The map should not be locked.
+ */
+void vm_map_deallocate(map)
+	register vm_map_t	map;
+{
+	register int		c;
+
+	if (map == NULL)
+		return;
+
+	simple_lock(&map->ref_lock);
+	c = --map->ref_count;
+	simple_unlock(&map->ref_lock);
+
+	if (c > 0) {
+		return;
+	}
+
+	/*
+	 *	Lock the map, to wait out all other references
+	 *	to it.
+	 */
+
+	vm_map_lock(map);
+
+	(void) vm_map_delete(map, map->min_offset, map->max_offset);
+
+	pmap_destroy(map->pmap);
+
+	FREE(map, M_VMMAP);
+}
+
+/*
+ *	vm_map_insert:
+ *
+ *	Inserts the given whole VM object into the target
+ *	map at the specified address range.  The object's
+ *	size should match that of the address range.
+ *
+ *	Requires that the map be locked, and leaves it so.
+ */
+int
+vm_map_insert(map, object, offset, start, end)
+	vm_map_t	map;
+	vm_object_t	object;
+	vm_offset_t	offset;
+	vm_offset_t	start;
+	vm_offset_t	end;
+{
+	register vm_map_entry_t		new_entry;
+	register vm_map_entry_t		prev_entry;
+	vm_map_entry_t			temp_entry;
+
+	/*
+	 *	Check that the start and end points are not bogus.
+	 */
+
+	if ((start < map->min_offset) || (end > map->max_offset) ||
+			(start >= end))
+		return(KERN_INVALID_ADDRESS);
+
+	/*
+	 *	Find the entry prior to the proposed
+	 *	starting address; if it's part of an
+	 *	existing entry, this range is bogus.
+	 */
+
+	if (vm_map_lookup_entry(map, start, &temp_entry))
+		return(KERN_NO_SPACE);
+
+	prev_entry = temp_entry;
+
+	/*
+	 *	Assert that the next entry doesn't overlap the
+	 *	end point.
+	 */
+
+	if ((prev_entry->next != &map->header) &&
+			(prev_entry->next->start < end))
+		return(KERN_NO_SPACE);
+
+	/*
+	 *	See if we can avoid creating a new entry by
+	 *	extending one of our neighbors.
+	 */
+
+	if (object == NULL) {
+		if ((prev_entry != &map->header) &&
+		    (prev_entry->end == start) &&
+		    (map->is_main_map) &&
+		    (prev_entry->is_a_map == FALSE) &&
+		    (prev_entry->is_sub_map == FALSE) &&
+		    (prev_entry->inheritance == VM_INHERIT_DEFAULT) &&
+		    (prev_entry->protection == VM_PROT_DEFAULT) &&
+		    (prev_entry->max_protection == VM_PROT_DEFAULT) &&
+		    (prev_entry->wired_count == 0)) {
+
+			if (vm_object_coalesce(prev_entry->object.vm_object,
+					NULL,
+					prev_entry->offset,
+					(vm_offset_t) 0,
+					(vm_size_t)(prev_entry->end
+						     - prev_entry->start),
+					(vm_size_t)(end - prev_entry->end))) {
+				/*
+				 *	Coalesced the two objects - can extend
+				 *	the previous map entry to include the
+				 *	new range.
+				 */
+				map->size += (end - prev_entry->end);
+				prev_entry->end = end;
+				return(KERN_SUCCESS);
+			}
+		}
+	}
+
+	/*
+	 *	Create a new entry
+	 */
+
+	new_entry = vm_map_entry_create(map);
+	new_entry->start = start;
+	new_entry->end = end;
+
+	new_entry->is_a_map = FALSE;
+	new_entry->is_sub_map = FALSE;
+	new_entry->object.vm_object = object;
+	new_entry->offset = offset;
+
+	new_entry->copy_on_write = FALSE;
+	new_entry->needs_copy = FALSE;
+
+	if (map->is_main_map) {
+		new_entry->inheritance = VM_INHERIT_DEFAULT;
+		new_entry->protection = VM_PROT_DEFAULT;
+		new_entry->max_protection = VM_PROT_DEFAULT;
+		new_entry->wired_count = 0;
+	}
+
+	/*
+	 *	Insert the new entry into the list
+	 */
+
+	vm_map_entry_link(map, prev_entry, new_entry);
+	map->size += new_entry->end - new_entry->start;
+
+	/*
+	 *	Update the free space hint
+	 */
+
+	if ((map->first_free == prev_entry) && (prev_entry->end >= new_entry->start))
+		map->first_free = new_entry;
+
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	SAVE_HINT:
+ *
+ *	Saves the specified entry as the hint for
+ *	future lookups.  Performs necessary interlocks.
+ */
+#define	SAVE_HINT(map,value) \
+		simple_lock(&(map)->hint_lock); \
+		(map)->hint = (value); \
+		simple_unlock(&(map)->hint_lock);
+
+/*
+ *	vm_map_lookup_entry:	[ internal use only ]
+ *
+ *	Finds the map entry containing (or
+ *	immediately preceding) the specified address
+ *	in the given map; the entry is returned
+ *	in the "entry" parameter.  The boolean
+ *	result indicates whether the address is
+ *	actually contained in the map.
+ */
+boolean_t vm_map_lookup_entry(map, address, entry)
+	register vm_map_t	map;
+	register vm_offset_t	address;
+	vm_map_entry_t		*entry;		/* OUT */
+{
+	register vm_map_entry_t		cur;
+	register vm_map_entry_t		last;
+
+	/*
+	 *	Start looking either from the head of the
+	 *	list, or from the hint.
+	 */
+
+	simple_lock(&map->hint_lock);
+	cur = map->hint;
+	simple_unlock(&map->hint_lock);
+
+	if (cur == &map->header)
+		cur = cur->next;
+
+	if (address >= cur->start) {
+	    	/*
+		 *	Go from hint to end of list.
+		 *
+		 *	But first, make a quick check to see if
+		 *	we are already looking at the entry we
+		 *	want (which is usually the case).
+		 *	Note also that we don't need to save the hint
+		 *	here... it is the same hint (unless we are
+		 *	at the header, in which case the hint didn't
+		 *	buy us anything anyway).
+		 */
+		last = &map->header;
+		if ((cur != last) && (cur->end > address)) {
+			*entry = cur;
+			return(TRUE);
+		}
+	}
+	else {
+	    	/*
+		 *	Go from start to hint, *inclusively*
+		 */
+		last = cur->next;
+		cur = map->header.next;
+	}
+
+	/*
+	 *	Search linearly
+	 */
+
+	while (cur != last) {
+		if (cur->end > address) {
+			if (address >= cur->start) {
+			    	/*
+				 *	Save this lookup for future
+				 *	hints, and return
+				 */
+
+				*entry = cur;
+				SAVE_HINT(map, cur);
+				return(TRUE);
+			}
+			break;
+		}
+		cur = cur->next;
+	}
+	*entry = cur->prev;
+	SAVE_HINT(map, *entry);
+	return(FALSE);
+}
+
+/*
+ * Find sufficient space for `length' bytes in the given map, starting at
+ * `start'.  The map must be locked.  Returns 0 on success, 1 on no space.
+ */
+int
+vm_map_findspace(map, start, length, addr)
+	register vm_map_t map;
+	register vm_offset_t start;
+	vm_size_t length;
+	vm_offset_t *addr;
+{
+	register vm_map_entry_t entry, next;
+	register vm_offset_t end;
+
+	if (start < map->min_offset)
+		start = map->min_offset;
+	if (start > map->max_offset)
+		return (1);
+
+	/*
+	 * Look for the first possible address; if there's already
+	 * something at this address, we have to start after it.
+	 */
+	if (start == map->min_offset) {
+		if ((entry = map->first_free) != &map->header)
+			start = entry->end;
+	} else {
+		vm_map_entry_t tmp;
+		if (vm_map_lookup_entry(map, start, &tmp))
+			start = tmp->end;
+		entry = tmp;
+	}
+
+	/*
+	 * Look through the rest of the map, trying to fit a new region in
+	 * the gap between existing regions, or after the very last region.
+	 */
+	for (;; start = (entry = next)->end) {
+		/*
+		 * Find the end of the proposed new region.  Be sure we didn't
+		 * go beyond the end of the map, or wrap around the address;
+		 * if so, we lose.  Otherwise, if this is the last entry, or
+		 * if the proposed new region fits before the next entry, we
+		 * win.
+		 */
+		end = start + length;
+		if (end > map->max_offset || end < start)
+			return (1);
+		next = entry->next;
+		if (next == &map->header || next->start >= end)
+			break;
+	}
+	SAVE_HINT(map, entry);
+	*addr = start;
+	return (0);
+}
+
+/*
+ *	vm_map_find finds an unallocated region in the target address
+ *	map with the given length.  The search is defined to be
+ *	first-fit from the specified address; the region found is
+ *	returned in the same parameter.
+ *
+ */
+int
+vm_map_find(map, object, offset, addr, length, find_space)
+	vm_map_t	map;
+	vm_object_t	object;
+	vm_offset_t	offset;
+	vm_offset_t	*addr;		/* IN/OUT */
+	vm_size_t	length;
+	boolean_t	find_space;
+{
+	register vm_offset_t	start;
+	int			result;
+
+	start = *addr;
+	vm_map_lock(map);
+	if (find_space) {
+		if (vm_map_findspace(map, start, length, addr)) {
+			vm_map_unlock(map);
+			return (KERN_NO_SPACE);
+		}
+		start = *addr;
+	}
+	result = vm_map_insert(map, object, offset, start, start + length);
+	vm_map_unlock(map);
+	return (result);
+}
+
+/*
+ *	vm_map_simplify_entry:	[ internal use only ]
+ *
+ *	Simplify the given map entry by:
+ *		removing extra sharing maps
+ *		[XXX maybe later] merging with a neighbor
+ */
+void vm_map_simplify_entry(map, entry)
+	vm_map_t	map;
+	vm_map_entry_t	entry;
+{
+#ifdef	lint
+	map++;
+#endif
+
+	/*
+	 *	If this entry corresponds to a sharing map, then
+	 *	see if we can remove the level of indirection.
+	 *	If it's not a sharing map, then it points to
+	 *	a VM object, so see if we can merge with either
+	 *	of our neighbors.
+	 */
+
+	if (entry->is_sub_map)
+		return;
+	if (entry->is_a_map) {
+#if	0
+		vm_map_t	my_share_map;
+		int		count;
+
+		my_share_map = entry->object.share_map;	
+		simple_lock(&my_share_map->ref_lock);
+		count = my_share_map->ref_count;
+		simple_unlock(&my_share_map->ref_lock);
+		
+		if (count == 1) {
+			/* Can move the region from
+			 * entry->start to entry->end (+ entry->offset)
+			 * in my_share_map into place of entry.
+			 * Later.
+			 */
+		}
+#endif
+	}
+	else {
+		/*
+		 *	Try to merge with our neighbors.
+		 *
+		 *	Conditions for merge are:
+		 *
+		 *	1.  entries are adjacent.
+		 *	2.  both entries point to objects
+		 *	    with null pagers.
+		 *
+		 * 	If a merge is possible, we replace the two
+		 *	entries with a single entry, then merge
+		 *	the two objects into a single object.
+		 *
+		 *	Now, all that is left to do is write the
+		 *	code!
+		 */
+	}
+}
+
+/*
+ *	vm_map_clip_start:	[ internal use only ]
+ *
+ *	Asserts that the given entry begins at or after
+ *	the specified address; if necessary,
+ *	it splits the entry into two.
+ */
+#define vm_map_clip_start(map, entry, startaddr) \
+{ \
+	if (startaddr > entry->start) \
+		_vm_map_clip_start(map, entry, startaddr); \
+}
+
+/*
+ *	This routine is called only when it is known that
+ *	the entry must be split.
+ */
+static void _vm_map_clip_start(map, entry, start)
+	register vm_map_t	map;
+	register vm_map_entry_t	entry;
+	register vm_offset_t	start;
+{
+	register vm_map_entry_t	new_entry;
+
+	/*
+	 *	See if we can simplify this entry first
+	 */
+		 
+	vm_map_simplify_entry(map, entry);
+
+	/*
+	 *	Split off the front portion --
+	 *	note that we must insert the new
+	 *	entry BEFORE this one, so that
+	 *	this entry has the specified starting
+	 *	address.
+	 */
+
+	new_entry = vm_map_entry_create(map);
+	*new_entry = *entry;
+
+	new_entry->end = start;
+	entry->offset += (start - entry->start);
+	entry->start = start;
+
+	vm_map_entry_link(map, entry->prev, new_entry);
+
+	if (entry->is_a_map || entry->is_sub_map)
+	 	vm_map_reference(new_entry->object.share_map);
+	else
+		vm_object_reference(new_entry->object.vm_object);
+}
+
+/*
+ *	vm_map_clip_end:	[ internal use only ]
+ *
+ *	Asserts that the given entry ends at or before
+ *	the specified address; if necessary,
+ *	it splits the entry into two.
+ */
+
+#define vm_map_clip_end(map, entry, endaddr) \
+{ \
+	if (endaddr < entry->end) \
+		_vm_map_clip_end(map, entry, endaddr); \
+}
+
+/*
+ *	This routine is called only when it is known that
+ *	the entry must be split.
+ */
+static void _vm_map_clip_end(map, entry, end)
+	register vm_map_t	map;
+	register vm_map_entry_t	entry;
+	register vm_offset_t	end;
+{
+	register vm_map_entry_t	new_entry;
+
+	/*
+	 *	Create a new entry and insert it
+	 *	AFTER the specified entry
+	 */
+
+	new_entry = vm_map_entry_create(map);
+	*new_entry = *entry;
+
+	new_entry->start = entry->end = end;
+	new_entry->offset += (end - entry->start);
+
+	vm_map_entry_link(map, entry, new_entry);
+
+	if (entry->is_a_map || entry->is_sub_map)
+	 	vm_map_reference(new_entry->object.share_map);
+	else
+		vm_object_reference(new_entry->object.vm_object);
+}
+
+/*
+ *	VM_MAP_RANGE_CHECK:	[ internal use only ]
+ *
+ *	Asserts that the starting and ending region
+ *	addresses fall within the valid range of the map.
+ */
+#define	VM_MAP_RANGE_CHECK(map, start, end)		\
+		{					\
+		if (start < vm_map_min(map))		\
+			start = vm_map_min(map);	\
+		if (end > vm_map_max(map))		\
+			end = vm_map_max(map);		\
+		if (start > end)			\
+			start = end;			\
+		}
+
+/*
+ *	vm_map_submap:		[ kernel use only ]
+ *
+ *	Mark the given range as handled by a subordinate map.
+ *
+ *	This range must have been created with vm_map_find,
+ *	and no other operations may have been performed on this
+ *	range prior to calling vm_map_submap.
+ *
+ *	Only a limited number of operations can be performed
+ *	within this rage after calling vm_map_submap:
+ *		vm_fault
+ *	[Don't try vm_map_copy!]
+ *
+ *	To remove a submapping, one must first remove the
+ *	range from the superior map, and then destroy the
+ *	submap (if desired).  [Better yet, don't try it.]
+ */
+int
+vm_map_submap(map, start, end, submap)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	vm_map_t		submap;
+{
+	vm_map_entry_t		entry;
+	register int		result = KERN_INVALID_ARGUMENT;
+
+	vm_map_lock(map);
+
+	VM_MAP_RANGE_CHECK(map, start, end);
+
+	if (vm_map_lookup_entry(map, start, &entry)) {
+		vm_map_clip_start(map, entry, start);
+	}
+	 else
+		entry = entry->next;
+
+	vm_map_clip_end(map, entry, end);
+
+	if ((entry->start == start) && (entry->end == end) &&
+	    (!entry->is_a_map) &&
+	    (entry->object.vm_object == NULL) &&
+	    (!entry->copy_on_write)) {
+		entry->is_a_map = FALSE;
+		entry->is_sub_map = TRUE;
+		vm_map_reference(entry->object.sub_map = submap);
+		result = KERN_SUCCESS;
+	}
+	vm_map_unlock(map);
+
+	return(result);
+}
+
+/*
+ *	vm_map_protect:
+ *
+ *	Sets the protection of the specified address
+ *	region in the target map.  If "set_max" is
+ *	specified, the maximum protection is to be set;
+ *	otherwise, only the current protection is affected.
+ */
+int
+vm_map_protect(map, start, end, new_prot, set_max)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	register vm_prot_t	new_prot;
+	register boolean_t	set_max;
+{
+	register vm_map_entry_t		current;
+	vm_map_entry_t			entry;
+
+	vm_map_lock(map);
+
+	VM_MAP_RANGE_CHECK(map, start, end);
+
+	if (vm_map_lookup_entry(map, start, &entry)) {
+		vm_map_clip_start(map, entry, start);
+	}
+	 else
+		entry = entry->next;
+
+	/*
+	 *	Make a first pass to check for protection
+	 *	violations.
+	 */
+
+	current = entry;
+	while ((current != &map->header) && (current->start < end)) {
+		if (current->is_sub_map)
+			return(KERN_INVALID_ARGUMENT);
+		if ((new_prot & current->max_protection) != new_prot) {
+			vm_map_unlock(map);
+			return(KERN_PROTECTION_FAILURE);
+		}
+
+		current = current->next;
+	}
+
+	/*
+	 *	Go back and fix up protections.
+	 *	[Note that clipping is not necessary the second time.]
+	 */
+
+	current = entry;
+
+	while ((current != &map->header) && (current->start < end)) {
+		vm_prot_t	old_prot;
+
+		vm_map_clip_end(map, current, end);
+
+		old_prot = current->protection;
+		if (set_max)
+			current->protection =
+				(current->max_protection = new_prot) &
+					old_prot;
+		else
+			current->protection = new_prot;
+
+		/*
+		 *	Update physical map if necessary.
+		 *	Worry about copy-on-write here -- CHECK THIS XXX
+		 */
+
+		if (current->protection != old_prot) {
+
+#define MASK(entry)	((entry)->copy_on_write ? ~VM_PROT_WRITE : \
+							VM_PROT_ALL)
+#define	max(a,b)	((a) > (b) ? (a) : (b))
+
+			if (current->is_a_map) {
+				vm_map_entry_t	share_entry;
+				vm_offset_t	share_end;
+
+				vm_map_lock(current->object.share_map);
+				(void) vm_map_lookup_entry(
+						current->object.share_map,
+						current->offset,
+						&share_entry);
+				share_end = current->offset +
+					(current->end - current->start);
+				while ((share_entry !=
+					&current->object.share_map->header) &&
+					(share_entry->start < share_end)) {
+
+					pmap_protect(map->pmap,
+						(max(share_entry->start,
+							current->offset) -
+							current->offset +
+							current->start),
+						min(share_entry->end,
+							share_end) -
+						current->offset +
+						current->start,
+						current->protection &
+							MASK(share_entry));
+
+					share_entry = share_entry->next;
+				}
+				vm_map_unlock(current->object.share_map);
+			}
+			else
+			 	pmap_protect(map->pmap, current->start,
+					current->end,
+					current->protection & MASK(entry));
+#undef	max
+#undef	MASK
+		}
+		current = current->next;
+	}
+
+	vm_map_unlock(map);
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	vm_map_inherit:
+ *
+ *	Sets the inheritance of the specified address
+ *	range in the target map.  Inheritance
+ *	affects how the map will be shared with
+ *	child maps at the time of vm_map_fork.
+ */
+int
+vm_map_inherit(map, start, end, new_inheritance)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	register vm_inherit_t	new_inheritance;
+{
+	register vm_map_entry_t	entry;
+	vm_map_entry_t	temp_entry;
+
+	switch (new_inheritance) {
+	case VM_INHERIT_NONE:
+	case VM_INHERIT_COPY:
+	case VM_INHERIT_SHARE:
+		break;
+	default:
+		return(KERN_INVALID_ARGUMENT);
+	}
+
+	vm_map_lock(map);
+
+	VM_MAP_RANGE_CHECK(map, start, end);
+
+	if (vm_map_lookup_entry(map, start, &temp_entry)) {
+		entry = temp_entry;
+		vm_map_clip_start(map, entry, start);
+	}
+	else
+		entry = temp_entry->next;
+
+	while ((entry != &map->header) && (entry->start < end)) {
+		vm_map_clip_end(map, entry, end);
+
+		entry->inheritance = new_inheritance;
+
+		entry = entry->next;
+	}
+
+	vm_map_unlock(map);
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	vm_map_pageable:
+ *
+ *	Sets the pageability of the specified address
+ *	range in the target map.  Regions specified
+ *	as not pageable require locked-down physical
+ *	memory and physical page maps.
+ *
+ *	The map must not be locked, but a reference
+ *	must remain to the map throughout the call.
+ */
+int
+vm_map_pageable(map, start, end, new_pageable)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	register boolean_t	new_pageable;
+{
+	register vm_map_entry_t	entry;
+	vm_map_entry_t		start_entry;
+	register vm_offset_t	failed;
+	int			rv;
+
+	vm_map_lock(map);
+
+	VM_MAP_RANGE_CHECK(map, start, end);
+
+	/*
+	 *	Only one pageability change may take place at one
+	 *	time, since vm_fault assumes it will be called
+	 *	only once for each wiring/unwiring.  Therefore, we
+	 *	have to make sure we're actually changing the pageability
+	 *	for the entire region.  We do so before making any changes.
+	 */
+
+	if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) {
+		vm_map_unlock(map);
+		return(KERN_INVALID_ADDRESS);
+	}
+	entry = start_entry;
+
+	/*
+	 *	Actions are rather different for wiring and unwiring,
+	 *	so we have two separate cases.
+	 */
+
+	if (new_pageable) {
+
+		vm_map_clip_start(map, entry, start);
+
+		/*
+		 *	Unwiring.  First ensure that the range to be
+		 *	unwired is really wired down and that there
+		 *	are no holes.
+		 */
+		while ((entry != &map->header) && (entry->start < end)) {
+
+		    if (entry->wired_count == 0 ||
+			(entry->end < end &&
+			 (entry->next == &map->header ||
+			  entry->next->start > entry->end))) {
+			vm_map_unlock(map);
+			return(KERN_INVALID_ARGUMENT);
+		    }
+		    entry = entry->next;
+		}
+
+		/*
+		 *	Now decrement the wiring count for each region.
+		 *	If a region becomes completely unwired,
+		 *	unwire its physical pages and mappings.
+		 */
+		lock_set_recursive(&map->lock);
+
+		entry = start_entry;
+		while ((entry != &map->header) && (entry->start < end)) {
+		    vm_map_clip_end(map, entry, end);
+
+		    entry->wired_count--;
+		    if (entry->wired_count == 0)
+			vm_fault_unwire(map, entry->start, entry->end);
+
+		    entry = entry->next;
+		}
+		lock_clear_recursive(&map->lock);
+	}
+
+	else {
+		/*
+		 *	Wiring.  We must do this in two passes:
+		 *
+		 *	1.  Holding the write lock, we create any shadow
+		 *	    or zero-fill objects that need to be created.
+		 *	    Then we clip each map entry to the region to be
+		 *	    wired and increment its wiring count.  We
+		 *	    create objects before clipping the map entries
+		 *	    to avoid object proliferation.
+		 *
+		 *	2.  We downgrade to a read lock, and call
+		 *	    vm_fault_wire to fault in the pages for any
+		 *	    newly wired area (wired_count is 1).
+		 *
+		 *	Downgrading to a read lock for vm_fault_wire avoids
+		 *	a possible deadlock with another thread that may have
+		 *	faulted on one of the pages to be wired (it would mark
+		 *	the page busy, blocking us, then in turn block on the
+		 *	map lock that we hold).  Because of problems in the
+		 *	recursive lock package, we cannot upgrade to a write
+		 *	lock in vm_map_lookup.  Thus, any actions that require
+		 *	the write lock must be done beforehand.  Because we
+		 *	keep the read lock on the map, the copy-on-write status
+		 *	of the entries we modify here cannot change.
+		 */
+
+		/*
+		 *	Pass 1.
+		 */
+		while ((entry != &map->header) && (entry->start < end)) {
+		    if (entry->wired_count == 0) {
+
+			/*
+			 *	Perform actions of vm_map_lookup that need
+			 *	the write lock on the map: create a shadow
+			 *	object for a copy-on-write region, or an
+			 *	object for a zero-fill region.
+			 *
+			 *	We don't have to do this for entries that
+			 *	point to sharing maps, because we won't hold
+			 *	the lock on the sharing map.
+			 */
+			if (!entry->is_a_map) {
+			    if (entry->needs_copy &&
+				((entry->protection & VM_PROT_WRITE) != 0)) {
+
+				vm_object_shadow(&entry->object.vm_object,
+						&entry->offset,
+						(vm_size_t)(entry->end
+							- entry->start));
+				entry->needs_copy = FALSE;
+			    }
+			    else if (entry->object.vm_object == NULL) {
+				entry->object.vm_object =
+				    vm_object_allocate((vm_size_t)(entry->end
+				    			- entry->start));
+				entry->offset = (vm_offset_t)0;
+			    }
+			}
+		    }
+		    vm_map_clip_start(map, entry, start);
+		    vm_map_clip_end(map, entry, end);
+		    entry->wired_count++;
+
+		    /*
+		     * Check for holes
+		     */
+		    if (entry->end < end &&
+			(entry->next == &map->header ||
+			 entry->next->start > entry->end)) {
+			/*
+			 *	Found one.  Object creation actions
+			 *	do not need to be undone, but the
+			 *	wired counts need to be restored.
+			 */
+			while (entry != &map->header && entry->end > start) {
+			    entry->wired_count--;
+			    entry = entry->prev;
+			}
+			vm_map_unlock(map);
+			return(KERN_INVALID_ARGUMENT);
+		    }
+		    entry = entry->next;
+		}
+
+		/*
+		 *	Pass 2.
+		 */
+
+		/*
+		 * HACK HACK HACK HACK
+		 *
+		 * If we are wiring in the kernel map or a submap of it,
+		 * unlock the map to avoid deadlocks.  We trust that the
+		 * kernel threads are well-behaved, and therefore will
+		 * not do anything destructive to this region of the map
+		 * while we have it unlocked.  We cannot trust user threads
+		 * to do the same.
+		 *
+		 * HACK HACK HACK HACK
+		 */
+		if (vm_map_pmap(map) == kernel_pmap) {
+		    vm_map_unlock(map);		/* trust me ... */
+		}
+		else {
+		    lock_set_recursive(&map->lock);
+		    lock_write_to_read(&map->lock);
+		}
+
+		rv = 0;
+		entry = start_entry;
+		while (entry != &map->header && entry->start < end) {
+		    /*
+		     * If vm_fault_wire fails for any page we need to
+		     * undo what has been done.  We decrement the wiring
+		     * count for those pages which have not yet been
+		     * wired (now) and unwire those that have (later).
+		     *
+		     * XXX this violates the locking protocol on the map,
+		     * needs to be fixed.
+		     */
+		    if (rv)
+			entry->wired_count--;
+		    else if (entry->wired_count == 1) {
+			rv = vm_fault_wire(map, entry->start, entry->end);
+			if (rv) {
+			    failed = entry->start;
+			    entry->wired_count--;
+			}
+		    }
+		    entry = entry->next;
+		}
+
+		if (vm_map_pmap(map) == kernel_pmap) {
+		    vm_map_lock(map);
+		}
+		else {
+		    lock_clear_recursive(&map->lock);
+		}
+		if (rv) {
+		    vm_map_unlock(map);
+		    (void) vm_map_pageable(map, start, failed, TRUE);
+		    return(rv);
+		}
+	}
+
+	vm_map_unlock(map);
+
+	return(KERN_SUCCESS);
+}
+
+/*
+ * vm_map_clean
+ *
+ * Push any dirty cached pages in the address range to their pager.
+ * If syncio is TRUE, dirty pages are written synchronously.
+ * If invalidate is TRUE, any cached pages are freed as well.
+ *
+ * Returns an error if any part of the specified range is not mapped.
+ */
+int
+vm_map_clean(map, start, end, syncio, invalidate)
+	vm_map_t	map;
+	vm_offset_t	start;
+	vm_offset_t	end;
+	boolean_t	syncio;
+	boolean_t	invalidate;
+{
+	register vm_map_entry_t current;
+	vm_map_entry_t entry;
+	vm_size_t size;
+	vm_object_t object;
+	vm_offset_t offset;
+
+	vm_map_lock_read(map);
+	VM_MAP_RANGE_CHECK(map, start, end);
+	if (!vm_map_lookup_entry(map, start, &entry)) {
+		vm_map_unlock_read(map);
+		return(KERN_INVALID_ADDRESS);
+	}
+
+	/*
+	 * Make a first pass to check for holes.
+	 */
+	for (current = entry; current->start < end; current = current->next) {
+		if (current->is_sub_map) {
+			vm_map_unlock_read(map);
+			return(KERN_INVALID_ARGUMENT);
+		}
+		if (end > current->end &&
+		    (current->next == &map->header ||
+		     current->end != current->next->start)) {
+			vm_map_unlock_read(map);
+			return(KERN_INVALID_ADDRESS);
+		}
+	}
+
+	/*
+	 * Make a second pass, cleaning/uncaching pages from the indicated
+	 * objects as we go.
+	 */
+	for (current = entry; current->start < end; current = current->next) {
+		offset = current->offset + (start - current->start);
+		size = (end <= current->end ? end : current->end) - start;
+		if (current->is_a_map) {
+			register vm_map_t smap;
+			vm_map_entry_t tentry;
+			vm_size_t tsize;
+
+			smap = current->object.share_map;
+			vm_map_lock_read(smap);
+			(void) vm_map_lookup_entry(smap, offset, &tentry);
+			tsize = tentry->end - offset;
+			if (tsize < size)
+				size = tsize;
+			object = tentry->object.vm_object;
+			offset = tentry->offset + (offset - tentry->start);
+			vm_object_lock(object);
+			vm_map_unlock_read(smap);
+		} else {
+			object = current->object.vm_object;
+			vm_object_lock(object);
+		}
+		/*
+		 * Flush pages if writing is allowed.
+		 * XXX should we continue on an error?
+		 */
+		if ((current->protection & VM_PROT_WRITE) &&
+		    !vm_object_page_clean(object, offset, offset+size,
+					  syncio, FALSE)) {
+			vm_object_unlock(object);
+			vm_map_unlock_read(map);
+			return(KERN_FAILURE);
+		}
+		if (invalidate)
+			vm_object_page_remove(object, offset, offset+size);
+		vm_object_unlock(object);
+		start += size;
+	}
+
+	vm_map_unlock_read(map);
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	vm_map_entry_unwire:	[ internal use only ]
+ *
+ *	Make the region specified by this entry pageable.
+ *
+ *	The map in question should be locked.
+ *	[This is the reason for this routine's existence.]
+ */
+void vm_map_entry_unwire(map, entry)
+	vm_map_t		map;
+	register vm_map_entry_t	entry;
+{
+	vm_fault_unwire(map, entry->start, entry->end);
+	entry->wired_count = 0;
+}
+
+/*
+ *	vm_map_entry_delete:	[ internal use only ]
+ *
+ *	Deallocate the given entry from the target map.
+ */		
+void vm_map_entry_delete(map, entry)
+	register vm_map_t	map;
+	register vm_map_entry_t	entry;
+{
+	if (entry->wired_count != 0)
+		vm_map_entry_unwire(map, entry);
+		
+	vm_map_entry_unlink(map, entry);
+	map->size -= entry->end - entry->start;
+
+	if (entry->is_a_map || entry->is_sub_map)
+		vm_map_deallocate(entry->object.share_map);
+	else
+	 	vm_object_deallocate(entry->object.vm_object);
+
+	vm_map_entry_dispose(map, entry);
+}
+
+/*
+ *	vm_map_delete:	[ internal use only ]
+ *
+ *	Deallocates the given address range from the target
+ *	map.
+ *
+ *	When called with a sharing map, removes pages from
+ *	that region from all physical maps.
+ */
+int
+vm_map_delete(map, start, end)
+	register vm_map_t	map;
+	vm_offset_t		start;
+	register vm_offset_t	end;
+{
+	register vm_map_entry_t	entry;
+	vm_map_entry_t		first_entry;
+
+	/*
+	 *	Find the start of the region, and clip it
+	 */
+
+	if (!vm_map_lookup_entry(map, start, &first_entry))
+		entry = first_entry->next;
+	else {
+		entry = first_entry;
+		vm_map_clip_start(map, entry, start);
+
+		/*
+		 *	Fix the lookup hint now, rather than each
+		 *	time though the loop.
+		 */
+
+		SAVE_HINT(map, entry->prev);
+	}
+
+	/*
+	 *	Save the free space hint
+	 */
+
+	if (map->first_free->start >= start)
+		map->first_free = entry->prev;
+
+	/*
+	 *	Step through all entries in this region
+	 */
+
+	while ((entry != &map->header) && (entry->start < end)) {
+		vm_map_entry_t		next;
+		register vm_offset_t	s, e;
+		register vm_object_t	object;
+
+		vm_map_clip_end(map, entry, end);
+
+		next = entry->next;
+		s = entry->start;
+		e = entry->end;
+
+		/*
+		 *	Unwire before removing addresses from the pmap;
+		 *	otherwise, unwiring will put the entries back in
+		 *	the pmap.
+		 */
+
+		object = entry->object.vm_object;
+		if (entry->wired_count != 0)
+			vm_map_entry_unwire(map, entry);
+
+		/*
+		 *	If this is a sharing map, we must remove
+		 *	*all* references to this data, since we can't
+		 *	find all of the physical maps which are sharing
+		 *	it.
+		 */
+
+		if (object == kernel_object || object == kmem_object)
+			vm_object_page_remove(object, entry->offset,
+					entry->offset + (e - s));
+		else if (!map->is_main_map)
+			vm_object_pmap_remove(object,
+					 entry->offset,
+					 entry->offset + (e - s));
+		else
+			pmap_remove(map->pmap, s, e);
+
+		/*
+		 *	Delete the entry (which may delete the object)
+		 *	only after removing all pmap entries pointing
+		 *	to its pages.  (Otherwise, its page frames may
+		 *	be reallocated, and any modify bits will be
+		 *	set in the wrong object!)
+		 */
+
+		vm_map_entry_delete(map, entry);
+		entry = next;
+	}
+	return(KERN_SUCCESS);
+}
+
+/*
+ *	vm_map_remove:
+ *
+ *	Remove the given address range from the target map.
+ *	This is the exported form of vm_map_delete.
+ */
+int
+vm_map_remove(map, start, end)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+{
+	register int		result;
+
+	vm_map_lock(map);
+	VM_MAP_RANGE_CHECK(map, start, end);
+	result = vm_map_delete(map, start, end);
+	vm_map_unlock(map);
+
+	return(result);
+}
+
+/*
+ *	vm_map_check_protection:
+ *
+ *	Assert that the target map allows the specified
+ *	privilege on the entire address region given.
+ *	The entire region must be allocated.
+ */
+boolean_t vm_map_check_protection(map, start, end, protection)
+	register vm_map_t	map;
+	register vm_offset_t	start;
+	register vm_offset_t	end;
+	register vm_prot_t	protection;
+{
+	register vm_map_entry_t	entry;
+	vm_map_entry_t		tmp_entry;
+
+	if (!vm_map_lookup_entry(map, start, &tmp_entry)) {
+		return(FALSE);
+	}
+
+	entry = tmp_entry;
+
+	while (start < end) {
+		if (entry == &map->header) {
+			return(FALSE);
+		}
+
+		/*
+		 *	No holes allowed!
+		 */
+
+		if (start < entry->start) {
+			return(FALSE);
+		}
+
+		/*
+		 * Check protection associated with entry.
+		 */
+
+		if ((entry->protection & protection) != protection) {
+			return(FALSE);
+		}
+
+		/* go to next entry */
+
+		start = entry->end;
+		entry = entry->next;
+	}
+	return(TRUE);
+}
+
+/*
+ *	vm_map_copy_entry:
+ *
+ *	Copies the contents of the source entry to the destination
+ *	entry.  The entries *must* be aligned properly.
+ */
+void vm_map_copy_entry(src_map, dst_map, src_entry, dst_entry)
+	vm_map_t		src_map, dst_map;
+	register vm_map_entry_t	src_entry, dst_entry;
+{
+	vm_object_t	temp_object;
+
+	if (src_entry->is_sub_map || dst_entry->is_sub_map)
+		return;
+
+	if (dst_entry->object.vm_object != NULL &&
+	    (dst_entry->object.vm_object->flags & OBJ_INTERNAL) == 0)
+		printf("vm_map_copy_entry: copying over permanent data!\n");
+
+	/*
+	 *	If our destination map was wired down,
+	 *	unwire it now.
+	 */
+
+	if (dst_entry->wired_count != 0)
+		vm_map_entry_unwire(dst_map, dst_entry);
+
+	/*
+	 *	If we're dealing with a sharing map, we
+	 *	must remove the destination pages from
+	 *	all maps (since we cannot know which maps
+	 *	this sharing map belongs in).
+	 */
+
+	if (dst_map->is_main_map)
+		pmap_remove(dst_map->pmap, dst_entry->start, dst_entry->end);
+	else
+		vm_object_pmap_remove(dst_entry->object.vm_object,
+			dst_entry->offset,
+			dst_entry->offset +
+				(dst_entry->end - dst_entry->start));
+
+	if (src_entry->wired_count == 0) {
+
+		boolean_t	src_needs_copy;
+
+		/*
+		 *	If the source entry is marked needs_copy,
+		 *	it is already write-protected.
+		 */
+		if (!src_entry->needs_copy) {
+
+			boolean_t	su;
+
+			/*
+			 *	If the source entry has only one mapping,
+			 *	we can just protect the virtual address
+			 *	range.
+			 */
+			if (!(su = src_map->is_main_map)) {
+				simple_lock(&src_map->ref_lock);
+				su = (src_map->ref_count == 1);
+				simple_unlock(&src_map->ref_lock);
+			}
+
+			if (su) {
+				pmap_protect(src_map->pmap,
+					src_entry->start,
+					src_entry->end,
+					src_entry->protection & ~VM_PROT_WRITE);
+			}
+			else {
+				vm_object_pmap_copy(src_entry->object.vm_object,
+					src_entry->offset,
+					src_entry->offset + (src_entry->end
+							    -src_entry->start));
+			}
+		}
+
+		/*
+		 *	Make a copy of the object.
+		 */
+		temp_object = dst_entry->object.vm_object;
+		vm_object_copy(src_entry->object.vm_object,
+				src_entry->offset,
+				(vm_size_t)(src_entry->end -
+					    src_entry->start),
+				&dst_entry->object.vm_object,
+				&dst_entry->offset,
+				&src_needs_copy);
+		/*
+		 *	If we didn't get a copy-object now, mark the
+		 *	source map entry so that a shadow will be created
+		 *	to hold its changed pages.
+		 */
+		if (src_needs_copy)
+			src_entry->needs_copy = TRUE;
+
+		/*
+		 *	The destination always needs to have a shadow
+		 *	created.
+		 */
+		dst_entry->needs_copy = TRUE;
+
+		/*
+		 *	Mark the entries copy-on-write, so that write-enabling
+		 *	the entry won't make copy-on-write pages writable.
+		 */
+		src_entry->copy_on_write = TRUE;
+		dst_entry->copy_on_write = TRUE;
+		/*
+		 *	Get rid of the old object.
+		 */
+		vm_object_deallocate(temp_object);
+
+		pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start,
+			dst_entry->end - dst_entry->start, src_entry->start);
+	}
+	else {
+		/*
+		 *	Of course, wired down pages can't be set copy-on-write.
+		 *	Cause wired pages to be copied into the new
+		 *	map by simulating faults (the new pages are
+		 *	pageable)
+		 */
+		vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry);
+	}
+}
+
+/*
+ *	vm_map_copy:
+ *
+ *	Perform a virtual memory copy from the source
+ *	address map/range to the destination map/range.
+ *
+ *	If src_destroy or dst_alloc is requested,
+ *	the source and destination regions should be
+ *	disjoint, not only in the top-level map, but
+ *	in the sharing maps as well.  [The best way
+ *	to guarantee this is to use a new intermediate
+ *	map to make copies.  This also reduces map
+ *	fragmentation.]
+ */
+int
+vm_map_copy(dst_map, src_map,
+			  dst_addr, len, src_addr,
+			  dst_alloc, src_destroy)
+	vm_map_t	dst_map;
+	vm_map_t	src_map;
+	vm_offset_t	dst_addr;
+	vm_size_t	len;
+	vm_offset_t	src_addr;
+	boolean_t	dst_alloc;
+	boolean_t	src_destroy;
+{
+	register
+	vm_map_entry_t	src_entry;
+	register
+	vm_map_entry_t	dst_entry;
+	vm_map_entry_t	tmp_entry;
+	vm_offset_t	src_start;
+	vm_offset_t	src_end;
+	vm_offset_t	dst_start;
+	vm_offset_t	dst_end;
+	vm_offset_t	src_clip;
+	vm_offset_t	dst_clip;
+	int		result;
+	boolean_t	old_src_destroy;
+
+	/*
+	 *	XXX While we figure out why src_destroy screws up,
+	 *	we'll do it by explicitly vm_map_delete'ing at the end.
+	 */
+
+	old_src_destroy = src_destroy;
+	src_destroy = FALSE;
+
+	/*
+	 *	Compute start and end of region in both maps
+	 */
+
+	src_start = src_addr;
+	src_end = src_start + len;
+	dst_start = dst_addr;
+	dst_end = dst_start + len;
+
+	/*
+	 *	Check that the region can exist in both source
+	 *	and destination.
+	 */
+
+	if ((dst_end < dst_start) || (src_end < src_start))
+		return(KERN_NO_SPACE);
+
+	/*
+	 *	Lock the maps in question -- we avoid deadlock
+	 *	by ordering lock acquisition by map value
+	 */
+
+	if (src_map == dst_map) {
+		vm_map_lock(src_map);
+	}
+	else if ((int) src_map < (int) dst_map) {
+	 	vm_map_lock(src_map);
+		vm_map_lock(dst_map);
+	} else {
+		vm_map_lock(dst_map);
+	 	vm_map_lock(src_map);
+	}
+
+	result = KERN_SUCCESS;
+
+	/*
+	 *	Check protections... source must be completely readable and
+	 *	destination must be completely writable.  [Note that if we're
+	 *	allocating the destination region, we don't have to worry
+	 *	about protection, but instead about whether the region
+	 *	exists.]
+	 */
+
+	if (src_map->is_main_map && dst_map->is_main_map) {
+		if (!vm_map_check_protection(src_map, src_start, src_end,
+					VM_PROT_READ)) {
+			result = KERN_PROTECTION_FAILURE;
+			goto Return;
+		}
+
+		if (dst_alloc) {
+			/* XXX Consider making this a vm_map_find instead */
+			if ((result = vm_map_insert(dst_map, NULL,
+					(vm_offset_t) 0, dst_start, dst_end)) != KERN_SUCCESS)
+				goto Return;
+		}
+		else if (!vm_map_check_protection(dst_map, dst_start, dst_end,
+					VM_PROT_WRITE)) {
+			result = KERN_PROTECTION_FAILURE;
+			goto Return;
+		}
+	}
+
+	/*
+	 *	Find the start entries and clip.
+	 *
+	 *	Note that checking protection asserts that the
+	 *	lookup cannot fail.
+	 *
+	 *	Also note that we wait to do the second lookup
+	 *	until we have done the first clip, as the clip
+	 *	may affect which entry we get!
+	 */
+
+	(void) vm_map_lookup_entry(src_map, src_addr, &tmp_entry);
+	src_entry = tmp_entry;
+	vm_map_clip_start(src_map, src_entry, src_start);
+
+	(void) vm_map_lookup_entry(dst_map, dst_addr, &tmp_entry);
+	dst_entry = tmp_entry;
+	vm_map_clip_start(dst_map, dst_entry, dst_start);
+
+	/*
+	 *	If both source and destination entries are the same,
+	 *	retry the first lookup, as it may have changed.
+	 */
+
+	if (src_entry == dst_entry) {
+		(void) vm_map_lookup_entry(src_map, src_addr, &tmp_entry);
+		src_entry = tmp_entry;
+	}
+
+	/*
+	 *	If source and destination entries are still the same,
+	 *	a null copy is being performed.
+	 */
+
+	if (src_entry == dst_entry)
+		goto Return;
+
+	/*
+	 *	Go through entries until we get to the end of the
+	 *	region.
+	 */
+
+	while (src_start < src_end) {
+		/*
+		 *	Clip the entries to the endpoint of the entire region.
+		 */
+
+		vm_map_clip_end(src_map, src_entry, src_end);
+		vm_map_clip_end(dst_map, dst_entry, dst_end);
+
+		/*
+		 *	Clip each entry to the endpoint of the other entry.
+		 */
+
+		src_clip = src_entry->start + (dst_entry->end - dst_entry->start);
+		vm_map_clip_end(src_map, src_entry, src_clip);
+
+		dst_clip = dst_entry->start + (src_entry->end - src_entry->start);
+		vm_map_clip_end(dst_map, dst_entry, dst_clip);
+
+		/*
+		 *	Both entries now match in size and relative endpoints.
+		 *
+		 *	If both entries refer to a VM object, we can
+		 *	deal with them now.
+		 */
+
+		if (!src_entry->is_a_map && !dst_entry->is_a_map) {
+			vm_map_copy_entry(src_map, dst_map, src_entry,
+						dst_entry);
+		}
+		else {
+			register vm_map_t	new_dst_map;
+			vm_offset_t		new_dst_start;
+			vm_size_t		new_size;
+			vm_map_t		new_src_map;
+			vm_offset_t		new_src_start;
+
+			/*
+			 *	We have to follow at least one sharing map.
+			 */
+
+			new_size = (dst_entry->end - dst_entry->start);
+
+			if (src_entry->is_a_map) {
+				new_src_map = src_entry->object.share_map;
+				new_src_start = src_entry->offset;
+			}
+			else {
+			 	new_src_map = src_map;
+				new_src_start = src_entry->start;
+				lock_set_recursive(&src_map->lock);
+			}
+
+			if (dst_entry->is_a_map) {
+			    	vm_offset_t	new_dst_end;
+
+				new_dst_map = dst_entry->object.share_map;
+				new_dst_start = dst_entry->offset;
+
+				/*
+				 *	Since the destination sharing entries
+				 *	will be merely deallocated, we can
+				 *	do that now, and replace the region
+				 *	with a null object.  [This prevents
+				 *	splitting the source map to match
+				 *	the form of the destination map.]
+				 *	Note that we can only do so if the
+				 *	source and destination do not overlap.
+				 */
+
+				new_dst_end = new_dst_start + new_size;
+
+				if (new_dst_map != new_src_map) {
+					vm_map_lock(new_dst_map);
+					(void) vm_map_delete(new_dst_map,
+							new_dst_start,
+							new_dst_end);
+					(void) vm_map_insert(new_dst_map,
+							NULL,
+							(vm_offset_t) 0,
+							new_dst_start,
+							new_dst_end);
+					vm_map_unlock(new_dst_map);
+				}
+			}
+			else {
+			 	new_dst_map = dst_map;
+				new_dst_start = dst_entry->start;
+				lock_set_recursive(&dst_map->lock);
+			}
+
+			/*
+			 *	Recursively copy the sharing map.
+			 */
+
+			(void) vm_map_copy(new_dst_map, new_src_map,
+				new_dst_start, new_size, new_src_start,
+				FALSE, FALSE);
+
+			if (dst_map == new_dst_map)
+				lock_clear_recursive(&dst_map->lock);
+			if (src_map == new_src_map)
+				lock_clear_recursive(&src_map->lock);
+		}
+
+		/*
+		 *	Update variables for next pass through the loop.
+		 */
+
+		src_start = src_entry->end;
+		src_entry = src_entry->next;
+		dst_start = dst_entry->end;
+		dst_entry = dst_entry->next;
+
+		/*
+		 *	If the source is to be destroyed, here is the
+		 *	place to do it.
+		 */
+
+		if (src_destroy && src_map->is_main_map &&
+						dst_map->is_main_map)
+			vm_map_entry_delete(src_map, src_entry->prev);
+	}
+
+	/*
+	 *	Update the physical maps as appropriate
+	 */
+
+	if (src_map->is_main_map && dst_map->is_main_map) {
+		if (src_destroy)
+			pmap_remove(src_map->pmap, src_addr, src_addr + len);
+	}
+
+	/*
+	 *	Unlock the maps
+	 */
+
+	Return: ;
+
+	if (old_src_destroy)
+		vm_map_delete(src_map, src_addr, src_addr + len);
+
+	vm_map_unlock(src_map);
+	if (src_map != dst_map)
+		vm_map_unlock(dst_map);
+
+	return(result);
+}
+
+/*
+ * vmspace_fork:
+ * Create a new process vmspace structure and vm_map
+ * based on those of an existing process.  The new map
+ * is based on the old map, according to the inheritance
+ * values on the regions in that map.
+ *
+ * The source map must not be locked.
+ */
+struct vmspace *
+vmspace_fork(vm1)
+	register struct vmspace *vm1;
+{
+	register struct vmspace *vm2;
+	vm_map_t	old_map = &vm1->vm_map;
+	vm_map_t	new_map;
+	vm_map_entry_t	old_entry;
+	vm_map_entry_t	new_entry;
+	pmap_t		new_pmap;
+
+	vm_map_lock(old_map);
+
+	vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset,
+	    old_map->entries_pageable);
+	bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy,
+	    (caddr_t) (vm1 + 1) - (caddr_t) &vm1->vm_startcopy);
+	new_pmap = &vm2->vm_pmap;		/* XXX */
+	new_map = &vm2->vm_map;			/* XXX */
+
+	old_entry = old_map->header.next;
+
+	while (old_entry != &old_map->header) {
+		if (old_entry->is_sub_map)
+			panic("vm_map_fork: encountered a submap");
+
+		switch (old_entry->inheritance) {
+		case VM_INHERIT_NONE:
+			break;
+
+		case VM_INHERIT_SHARE:
+			/*
+			 *	If we don't already have a sharing map:
+			 */
+
+			if (!old_entry->is_a_map) {
+			 	vm_map_t	new_share_map;
+				vm_map_entry_t	new_share_entry;
+				
+				/*
+				 *	Create a new sharing map
+				 */
+				 
+				new_share_map = vm_map_create(NULL,
+							old_entry->start,
+							old_entry->end,
+							TRUE);
+				new_share_map->is_main_map = FALSE;
+
+				/*
+				 *	Create the only sharing entry from the
+				 *	old task map entry.
+				 */
+
+				new_share_entry =
+					vm_map_entry_create(new_share_map);
+				*new_share_entry = *old_entry;
+				new_share_entry->wired_count = 0;
+
+				/*
+				 *	Insert the entry into the new sharing
+				 *	map
+				 */
+
+				vm_map_entry_link(new_share_map,
+						new_share_map->header.prev,
+						new_share_entry);
+
+				/*
+				 *	Fix up the task map entry to refer
+				 *	to the sharing map now.
+				 */
+
+				old_entry->is_a_map = TRUE;
+				old_entry->object.share_map = new_share_map;
+				old_entry->offset = old_entry->start;
+			}
+
+			/*
+			 *	Clone the entry, referencing the sharing map.
+			 */
+
+			new_entry = vm_map_entry_create(new_map);
+			*new_entry = *old_entry;
+			new_entry->wired_count = 0;
+			vm_map_reference(new_entry->object.share_map);
+
+			/*
+			 *	Insert the entry into the new map -- we
+			 *	know we're inserting at the end of the new
+			 *	map.
+			 */
+
+			vm_map_entry_link(new_map, new_map->header.prev,
+						new_entry);
+
+			/*
+			 *	Update the physical map
+			 */
+
+			pmap_copy(new_map->pmap, old_map->pmap,
+				new_entry->start,
+				(old_entry->end - old_entry->start),
+				old_entry->start);
+			break;
+
+		case VM_INHERIT_COPY:
+			/*
+			 *	Clone the entry and link into the map.
+			 */
+
+			new_entry = vm_map_entry_create(new_map);
+			*new_entry = *old_entry;
+			new_entry->wired_count = 0;
+			new_entry->object.vm_object = NULL;
+			new_entry->is_a_map = FALSE;
+			vm_map_entry_link(new_map, new_map->header.prev,
+							new_entry);
+			if (old_entry->is_a_map) {
+				int	check;
+
+				check = vm_map_copy(new_map,
+						old_entry->object.share_map,
+						new_entry->start,
+						(vm_size_t)(new_entry->end -
+							new_entry->start),
+						old_entry->offset,
+						FALSE, FALSE);
+				if (check != KERN_SUCCESS)
+					printf("vm_map_fork: copy in share_map region failed\n");
+			}
+			else {
+				vm_map_copy_entry(old_map, new_map, old_entry,
+						new_entry);
+			}
+			break;
+		}
+		old_entry = old_entry->next;
+	}
+
+	new_map->size = old_map->size;
+	vm_map_unlock(old_map);
+
+	return(vm2);
+}
+
+/*
+ *	vm_map_lookup:
+ *
+ *	Finds the VM object, offset, and
+ *	protection for a given virtual address in the
+ *	specified map, assuming a page fault of the
+ *	type specified.
+ *
+ *	Leaves the map in question locked for read; return
+ *	values are guaranteed until a vm_map_lookup_done
+ *	call is performed.  Note that the map argument
+ *	is in/out; the returned map must be used in
+ *	the call to vm_map_lookup_done.
+ *
+ *	A handle (out_entry) is returned for use in
+ *	vm_map_lookup_done, to make that fast.
+ *
+ *	If a lookup is requested with "write protection"
+ *	specified, the map may be changed to perform virtual
+ *	copying operations, although the data referenced will
+ *	remain the same.
+ */
+int
+vm_map_lookup(var_map, vaddr, fault_type, out_entry,
+				object, offset, out_prot, wired, single_use)
+	vm_map_t		*var_map;	/* IN/OUT */
+	register vm_offset_t	vaddr;
+	register vm_prot_t	fault_type;
+
+	vm_map_entry_t		*out_entry;	/* OUT */
+	vm_object_t		*object;	/* OUT */
+	vm_offset_t		*offset;	/* OUT */
+	vm_prot_t		*out_prot;	/* OUT */
+	boolean_t		*wired;		/* OUT */
+	boolean_t		*single_use;	/* OUT */
+{
+	vm_map_t			share_map;
+	vm_offset_t			share_offset;
+	register vm_map_entry_t		entry;
+	register vm_map_t		map = *var_map;
+	register vm_prot_t		prot;
+	register boolean_t		su;
+
+	RetryLookup: ;
+
+	/*
+	 *	Lookup the faulting address.
+	 */
+
+	vm_map_lock_read(map);
+
+#define	RETURN(why) \
+		{ \
+		vm_map_unlock_read(map); \
+		return(why); \
+		}
+
+	/*
+	 *	If the map has an interesting hint, try it before calling
+	 *	full blown lookup routine.
+	 */
+
+	simple_lock(&map->hint_lock);
+	entry = map->hint;
+	simple_unlock(&map->hint_lock);
+
+	*out_entry = entry;
+
+	if ((entry == &map->header) ||
+	    (vaddr < entry->start) || (vaddr >= entry->end)) {
+		vm_map_entry_t	tmp_entry;
+
+		/*
+		 *	Entry was either not a valid hint, or the vaddr
+		 *	was not contained in the entry, so do a full lookup.
+		 */
+		if (!vm_map_lookup_entry(map, vaddr, &tmp_entry))
+			RETURN(KERN_INVALID_ADDRESS);
+
+		entry = tmp_entry;
+		*out_entry = entry;
+	}
+
+	/*
+	 *	Handle submaps.
+	 */
+
+	if (entry->is_sub_map) {
+		vm_map_t	old_map = map;
+
+		*var_map = map = entry->object.sub_map;
+		vm_map_unlock_read(old_map);
+		goto RetryLookup;
+	}
+		
+	/*
+	 *	Check whether this task is allowed to have
+	 *	this page.
+	 */
+
+	prot = entry->protection;
+	if ((fault_type & (prot)) != fault_type)
+		RETURN(KERN_PROTECTION_FAILURE);
+
+	/*
+	 *	If this page is not pageable, we have to get
+	 *	it for all possible accesses.
+	 */
+
+	if (*wired = (entry->wired_count != 0))
+		prot = fault_type = entry->protection;
+
+	/*
+	 *	If we don't already have a VM object, track
+	 *	it down.
+	 */
+
+	if (su = !entry->is_a_map) {
+	 	share_map = map;
+		share_offset = vaddr;
+	}
+	else {
+		vm_map_entry_t	share_entry;
+
+		/*
+		 *	Compute the sharing map, and offset into it.
+		 */
+
+		share_map = entry->object.share_map;
+		share_offset = (vaddr - entry->start) + entry->offset;
+
+		/*
+		 *	Look for the backing store object and offset
+		 */
+
+		vm_map_lock_read(share_map);
+
+		if (!vm_map_lookup_entry(share_map, share_offset,
+					&share_entry)) {
+			vm_map_unlock_read(share_map);
+			RETURN(KERN_INVALID_ADDRESS);
+		}
+		entry = share_entry;
+	}
+
+	/*
+	 *	If the entry was copy-on-write, we either ...
+	 */
+
+	if (entry->needs_copy) {
+	    	/*
+		 *	If we want to write the page, we may as well
+		 *	handle that now since we've got the sharing
+		 *	map locked.
+		 *
+		 *	If we don't need to write the page, we just
+		 *	demote the permissions allowed.
+		 */
+
+		if (fault_type & VM_PROT_WRITE) {
+			/*
+			 *	Make a new object, and place it in the
+			 *	object chain.  Note that no new references
+			 *	have appeared -- one just moved from the
+			 *	share map to the new object.
+			 */
+
+			if (lock_read_to_write(&share_map->lock)) {
+				if (share_map != map)
+					vm_map_unlock_read(map);
+				goto RetryLookup;
+			}
+
+			vm_object_shadow(
+				&entry->object.vm_object,
+				&entry->offset,
+				(vm_size_t) (entry->end - entry->start));
+				
+			entry->needs_copy = FALSE;
+			
+			lock_write_to_read(&share_map->lock);
+		}
+		else {
+			/*
+			 *	We're attempting to read a copy-on-write
+			 *	page -- don't allow writes.
+			 */
+
+			prot &= (~VM_PROT_WRITE);
+		}
+	}
+
+	/*
+	 *	Create an object if necessary.
+	 */
+	if (entry->object.vm_object == NULL) {
+
+		if (lock_read_to_write(&share_map->lock)) {
+			if (share_map != map)
+				vm_map_unlock_read(map);
+			goto RetryLookup;
+		}
+
+		entry->object.vm_object = vm_object_allocate(
+					(vm_size_t)(entry->end - entry->start));
+		entry->offset = 0;
+		lock_write_to_read(&share_map->lock);
+	}
+
+	/*
+	 *	Return the object/offset from this entry.  If the entry
+	 *	was copy-on-write or empty, it has been fixed up.
+	 */
+
+	*offset = (share_offset - entry->start) + entry->offset;
+	*object = entry->object.vm_object;
+
+	/*
+	 *	Return whether this is the only map sharing this data.
+	 */
+
+	if (!su) {
+		simple_lock(&share_map->ref_lock);
+		su = (share_map->ref_count == 1);
+		simple_unlock(&share_map->ref_lock);
+	}
+
+	*out_prot = prot;
+	*single_use = su;
+
+	return(KERN_SUCCESS);
+	
+#undef	RETURN
+}
+
+/*
+ *	vm_map_lookup_done:
+ *
+ *	Releases locks acquired by a vm_map_lookup
+ *	(according to the handle returned by that lookup).
+ */
+
+void vm_map_lookup_done(map, entry)
+	register vm_map_t	map;
+	vm_map_entry_t		entry;
+{
+	/*
+	 *	If this entry references a map, unlock it first.
+	 */
+
+	if (entry->is_a_map)
+		vm_map_unlock_read(entry->object.share_map);
+
+	/*
+	 *	Unlock the main-level map
+	 */
+
+	vm_map_unlock_read(map);
+}
+
+/*
+ *	Routine:	vm_map_simplify
+ *	Purpose:
+ *		Attempt to simplify the map representation in
+ *		the vicinity of the given starting address.
+ *	Note:
+ *		This routine is intended primarily to keep the
+ *		kernel maps more compact -- they generally don't
+ *		benefit from the "expand a map entry" technology
+ *		at allocation time because the adjacent entry
+ *		is often wired down.
+ */
+void vm_map_simplify(map, start)
+	vm_map_t	map;
+	vm_offset_t	start;
+{
+	vm_map_entry_t	this_entry;
+	vm_map_entry_t	prev_entry;
+
+	vm_map_lock(map);
+	if (
+		(vm_map_lookup_entry(map, start, &this_entry)) &&
+		((prev_entry = this_entry->prev) != &map->header) &&
+
+		(prev_entry->end == start) &&
+		(map->is_main_map) &&
+
+		(prev_entry->is_a_map == FALSE) &&
+		(prev_entry->is_sub_map == FALSE) &&
+
+		(this_entry->is_a_map == FALSE) &&
+		(this_entry->is_sub_map == FALSE) &&
+
+		(prev_entry->inheritance == this_entry->inheritance) &&
+		(prev_entry->protection == this_entry->protection) &&
+		(prev_entry->max_protection == this_entry->max_protection) &&
+		(prev_entry->wired_count == this_entry->wired_count) &&
+		
+		(prev_entry->copy_on_write == this_entry->copy_on_write) &&
+		(prev_entry->needs_copy == this_entry->needs_copy) &&
+		
+		(prev_entry->object.vm_object == this_entry->object.vm_object) &&
+		((prev_entry->offset + (prev_entry->end - prev_entry->start))
+		     == this_entry->offset)
+	) {
+		if (map->first_free == this_entry)
+			map->first_free = prev_entry;
+
+		SAVE_HINT(map, prev_entry);
+		vm_map_entry_unlink(map, this_entry);
+		prev_entry->end = this_entry->end;
+	 	vm_object_deallocate(this_entry->object.vm_object);
+		vm_map_entry_dispose(map, this_entry);
+	}
+	vm_map_unlock(map);
+}
+
+/*
+ *	vm_map_print:	[ debug ]
+ */
+void vm_map_print(map, full)
+	register vm_map_t	map;
+	boolean_t		full;
+{
+	register vm_map_entry_t	entry;
+	extern int indent;
+
+	iprintf("%s map 0x%x: pmap=0x%x,ref=%d,nentries=%d,version=%d\n",
+		(map->is_main_map ? "Task" : "Share"),
+ 		(int) map, (int) (map->pmap), map->ref_count, map->nentries,
+		map->timestamp);
+
+	if (!full && indent)
+		return;
+
+	indent += 2;
+	for (entry = map->header.next; entry != &map->header;
+				entry = entry->next) {
+		iprintf("map entry 0x%x: start=0x%x, end=0x%x, ",
+			(int) entry, (int) entry->start, (int) entry->end);
+		if (map->is_main_map) {
+		     	static char *inheritance_name[4] =
+				{ "share", "copy", "none", "donate_copy"};
+			printf("prot=%x/%x/%s, ",
+				entry->protection,
+				entry->max_protection,
+				inheritance_name[entry->inheritance]);
+			if (entry->wired_count != 0)
+				printf("wired, ");
+		}
+
+		if (entry->is_a_map || entry->is_sub_map) {
+		 	printf("share=0x%x, offset=0x%x\n",
+				(int) entry->object.share_map,
+				(int) entry->offset);
+			if ((entry->prev == &map->header) ||
+			    (!entry->prev->is_a_map) ||
+			    (entry->prev->object.share_map !=
+			     entry->object.share_map)) {
+				indent += 2;
+				vm_map_print(entry->object.share_map, full);
+				indent -= 2;
+			}
+				
+		}
+		else {
+			printf("object=0x%x, offset=0x%x",
+				(int) entry->object.vm_object,
+				(int) entry->offset);
+			if (entry->copy_on_write)
+				printf(", copy (%s)",
+				       entry->needs_copy ? "needed" : "done");
+			printf("\n");
+
+			if ((entry->prev == &map->header) ||
+			    (entry->prev->is_a_map) ||
+			    (entry->prev->object.vm_object !=
+			     entry->object.vm_object)) {
+				indent += 2;
+				vm_object_print(entry->object.vm_object, full);
+				indent -= 2;
+			}
+		}
+	}
+	indent -= 2;
+}