xref: /freebsd/sys/vm/vm_map.c (revision 98c15d4dc28450688dcee6c6082d3a4d417b5d5d)
1 /*-
2  * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
3  *
4  * Copyright (c) 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * The Mach Operating System project at Carnegie-Mellon University.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	from: @(#)vm_map.c	8.3 (Berkeley) 1/12/94
35  *
36  *
37  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
38  * All rights reserved.
39  *
40  * Authors: Avadis Tevanian, Jr., Michael Wayne Young
41  *
42  * Permission to use, copy, modify and distribute this software and
43  * its documentation is hereby granted, provided that both the copyright
44  * notice and this permission notice appear in all copies of the
45  * software, derivative works or modified versions, and any portions
46  * thereof, and that both notices appear in supporting documentation.
47  *
48  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
49  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
50  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
51  *
52  * Carnegie Mellon requests users of this software to return to
53  *
54  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
55  *  School of Computer Science
56  *  Carnegie Mellon University
57  *  Pittsburgh PA 15213-3890
58  *
59  * any improvements or extensions that they make and grant Carnegie the
60  * rights to redistribute these changes.
61  */
62 
63 /*
64  *	Virtual memory mapping module.
65  */
66 
67 #include <sys/cdefs.h>
68 __FBSDID("$FreeBSD$");
69 
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/elf.h>
73 #include <sys/kernel.h>
74 #include <sys/ktr.h>
75 #include <sys/lock.h>
76 #include <sys/mutex.h>
77 #include <sys/proc.h>
78 #include <sys/vmmeter.h>
79 #include <sys/mman.h>
80 #include <sys/vnode.h>
81 #include <sys/racct.h>
82 #include <sys/resourcevar.h>
83 #include <sys/rwlock.h>
84 #include <sys/file.h>
85 #include <sys/sysctl.h>
86 #include <sys/sysent.h>
87 #include <sys/shm.h>
88 
89 #include <vm/vm.h>
90 #include <vm/vm_param.h>
91 #include <vm/pmap.h>
92 #include <vm/vm_map.h>
93 #include <vm/vm_page.h>
94 #include <vm/vm_pageout.h>
95 #include <vm/vm_object.h>
96 #include <vm/vm_pager.h>
97 #include <vm/vm_kern.h>
98 #include <vm/vm_extern.h>
99 #include <vm/vnode_pager.h>
100 #include <vm/swap_pager.h>
101 #include <vm/uma.h>
102 
103 /*
104  *	Virtual memory maps provide for the mapping, protection,
105  *	and sharing of virtual memory objects.  In addition,
106  *	this module provides for an efficient virtual copy of
107  *	memory from one map to another.
108  *
109  *	Synchronization is required prior to most operations.
110  *
111  *	Maps consist of an ordered doubly-linked list of simple
112  *	entries; a self-adjusting binary search tree of these
113  *	entries is used to speed up lookups.
114  *
115  *	Since portions of maps are specified by start/end addresses,
116  *	which may not align with existing map entries, all
117  *	routines merely "clip" entries to these start/end values.
118  *	[That is, an entry is split into two, bordering at a
119  *	start or end value.]  Note that these clippings may not
120  *	always be necessary (as the two resulting entries are then
121  *	not changed); however, the clipping is done for convenience.
122  *
123  *	As mentioned above, virtual copy operations are performed
124  *	by copying VM object references from one map to
125  *	another, and then marking both regions as copy-on-write.
126  */
127 
128 static struct mtx map_sleep_mtx;
129 static uma_zone_t mapentzone;
130 static uma_zone_t kmapentzone;
131 static uma_zone_t vmspace_zone;
132 static int vmspace_zinit(void *mem, int size, int flags);
133 static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min,
134     vm_offset_t max);
135 static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map);
136 static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry);
137 static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry);
138 static int vm_map_growstack(vm_map_t map, vm_offset_t addr,
139     vm_map_entry_t gap_entry);
140 static void vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot,
141     vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags);
142 #ifdef INVARIANTS
143 static void vmspace_zdtor(void *mem, int size, void *arg);
144 #endif
145 static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos,
146     vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max,
147     int cow);
148 static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry,
149     vm_offset_t failed_addr);
150 
151 #define	ENTRY_CHARGED(e) ((e)->cred != NULL || \
152     ((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \
153      !((e)->eflags & MAP_ENTRY_NEEDS_COPY)))
154 
155 /*
156  * PROC_VMSPACE_{UN,}LOCK() can be a noop as long as vmspaces are type
157  * stable.
158  */
159 #define PROC_VMSPACE_LOCK(p) do { } while (0)
160 #define PROC_VMSPACE_UNLOCK(p) do { } while (0)
161 
162 /*
163  *	VM_MAP_RANGE_CHECK:	[ internal use only ]
164  *
165  *	Asserts that the starting and ending region
166  *	addresses fall within the valid range of the map.
167  */
168 #define	VM_MAP_RANGE_CHECK(map, start, end)		\
169 		{					\
170 		if (start < vm_map_min(map))		\
171 			start = vm_map_min(map);	\
172 		if (end > vm_map_max(map))		\
173 			end = vm_map_max(map);		\
174 		if (start > end)			\
175 			start = end;			\
176 		}
177 
178 #ifndef UMA_MD_SMALL_ALLOC
179 
180 /*
181  * Allocate a new slab for kernel map entries.  The kernel map may be locked or
182  * unlocked, depending on whether the request is coming from the kernel map or a
183  * submap.  This function allocates a virtual address range directly from the
184  * kernel map instead of the kmem_* layer to avoid recursion on the kernel map
185  * lock and also to avoid triggering allocator recursion in the vmem boundary
186  * tag allocator.
187  */
188 static void *
189 kmapent_alloc(uma_zone_t zone, vm_size_t bytes, int domain, uint8_t *pflag,
190     int wait)
191 {
192 	vm_offset_t addr;
193 	int error, locked;
194 
195 	*pflag = UMA_SLAB_PRIV;
196 
197 	if (!(locked = vm_map_locked(kernel_map)))
198 		vm_map_lock(kernel_map);
199 	addr = vm_map_findspace(kernel_map, vm_map_min(kernel_map), bytes);
200 	if (addr + bytes < addr || addr + bytes > vm_map_max(kernel_map))
201 		panic("%s: kernel map is exhausted", __func__);
202 	error = vm_map_insert(kernel_map, NULL, 0, addr, addr + bytes,
203 	    VM_PROT_RW, VM_PROT_RW, MAP_NOFAULT);
204 	if (error != KERN_SUCCESS)
205 		panic("%s: vm_map_insert() failed: %d", __func__, error);
206 	if (!locked)
207 		vm_map_unlock(kernel_map);
208 	error = kmem_back_domain(domain, kernel_object, addr, bytes, M_NOWAIT |
209 	    M_USE_RESERVE | (wait & M_ZERO));
210 	if (error == KERN_SUCCESS) {
211 		return ((void *)addr);
212 	} else {
213 		if (!locked)
214 			vm_map_lock(kernel_map);
215 		vm_map_delete(kernel_map, addr, bytes);
216 		if (!locked)
217 			vm_map_unlock(kernel_map);
218 		return (NULL);
219 	}
220 }
221 
222 static void
223 kmapent_free(void *item, vm_size_t size, uint8_t pflag)
224 {
225 	vm_offset_t addr;
226 	int error;
227 
228 	if ((pflag & UMA_SLAB_PRIV) == 0)
229 		/* XXX leaked */
230 		return;
231 
232 	addr = (vm_offset_t)item;
233 	kmem_unback(kernel_object, addr, size);
234 	error = vm_map_remove(kernel_map, addr, addr + size);
235 	KASSERT(error == KERN_SUCCESS,
236 	    ("%s: vm_map_remove failed: %d", __func__, error));
237 }
238 
239 /*
240  * The worst-case upper bound on the number of kernel map entries that may be
241  * created before the zone must be replenished in _vm_map_unlock().
242  */
243 #define	KMAPENT_RESERVE		1
244 
245 #endif /* !UMD_MD_SMALL_ALLOC */
246 
247 /*
248  *	vm_map_startup:
249  *
250  *	Initialize the vm_map module.  Must be called before any other vm_map
251  *	routines.
252  *
253  *	User map and entry structures are allocated from the general purpose
254  *	memory pool.  Kernel maps are statically defined.  Kernel map entries
255  *	require special handling to avoid recursion; see the comments above
256  *	kmapent_alloc() and in vm_map_entry_create().
257  */
258 void
259 vm_map_startup(void)
260 {
261 	mtx_init(&map_sleep_mtx, "vm map sleep mutex", NULL, MTX_DEF);
262 
263 	/*
264 	 * Disable the use of per-CPU buckets: map entry allocation is
265 	 * serialized by the kernel map lock.
266 	 */
267 	kmapentzone = uma_zcreate("KMAP ENTRY", sizeof(struct vm_map_entry),
268 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
269 	    UMA_ZONE_VM | UMA_ZONE_NOBUCKET);
270 #ifndef UMA_MD_SMALL_ALLOC
271 	/* Reserve an extra map entry for use when replenishing the reserve. */
272 	uma_zone_reserve(kmapentzone, KMAPENT_RESERVE + 1);
273 	uma_prealloc(kmapentzone, KMAPENT_RESERVE + 1);
274 	uma_zone_set_allocf(kmapentzone, kmapent_alloc);
275 	uma_zone_set_freef(kmapentzone, kmapent_free);
276 #endif
277 
278 	mapentzone = uma_zcreate("MAP ENTRY", sizeof(struct vm_map_entry),
279 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
280 	vmspace_zone = uma_zcreate("VMSPACE", sizeof(struct vmspace), NULL,
281 #ifdef INVARIANTS
282 	    vmspace_zdtor,
283 #else
284 	    NULL,
285 #endif
286 	    vmspace_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
287 }
288 
289 static int
290 vmspace_zinit(void *mem, int size, int flags)
291 {
292 	struct vmspace *vm;
293 	vm_map_t map;
294 
295 	vm = (struct vmspace *)mem;
296 	map = &vm->vm_map;
297 
298 	memset(map, 0, sizeof(*map));
299 	mtx_init(&map->system_mtx, "vm map (system)", NULL,
300 	    MTX_DEF | MTX_DUPOK);
301 	sx_init(&map->lock, "vm map (user)");
302 	PMAP_LOCK_INIT(vmspace_pmap(vm));
303 	return (0);
304 }
305 
306 #ifdef INVARIANTS
307 static void
308 vmspace_zdtor(void *mem, int size, void *arg)
309 {
310 	struct vmspace *vm;
311 
312 	vm = (struct vmspace *)mem;
313 	KASSERT(vm->vm_map.nentries == 0,
314 	    ("vmspace %p nentries == %d on free", vm, vm->vm_map.nentries));
315 	KASSERT(vm->vm_map.size == 0,
316 	    ("vmspace %p size == %ju on free", vm, (uintmax_t)vm->vm_map.size));
317 }
318 #endif	/* INVARIANTS */
319 
320 /*
321  * Allocate a vmspace structure, including a vm_map and pmap,
322  * and initialize those structures.  The refcnt is set to 1.
323  */
324 struct vmspace *
325 vmspace_alloc(vm_offset_t min, vm_offset_t max, pmap_pinit_t pinit)
326 {
327 	struct vmspace *vm;
328 
329 	vm = uma_zalloc(vmspace_zone, M_WAITOK);
330 	KASSERT(vm->vm_map.pmap == NULL, ("vm_map.pmap must be NULL"));
331 	if (!pinit(vmspace_pmap(vm))) {
332 		uma_zfree(vmspace_zone, vm);
333 		return (NULL);
334 	}
335 	CTR1(KTR_VM, "vmspace_alloc: %p", vm);
336 	_vm_map_init(&vm->vm_map, vmspace_pmap(vm), min, max);
337 	refcount_init(&vm->vm_refcnt, 1);
338 	vm->vm_shm = NULL;
339 	vm->vm_swrss = 0;
340 	vm->vm_tsize = 0;
341 	vm->vm_dsize = 0;
342 	vm->vm_ssize = 0;
343 	vm->vm_taddr = 0;
344 	vm->vm_daddr = 0;
345 	vm->vm_maxsaddr = 0;
346 	return (vm);
347 }
348 
349 #ifdef RACCT
350 static void
351 vmspace_container_reset(struct proc *p)
352 {
353 
354 	PROC_LOCK(p);
355 	racct_set(p, RACCT_DATA, 0);
356 	racct_set(p, RACCT_STACK, 0);
357 	racct_set(p, RACCT_RSS, 0);
358 	racct_set(p, RACCT_MEMLOCK, 0);
359 	racct_set(p, RACCT_VMEM, 0);
360 	PROC_UNLOCK(p);
361 }
362 #endif
363 
364 static inline void
365 vmspace_dofree(struct vmspace *vm)
366 {
367 
368 	CTR1(KTR_VM, "vmspace_free: %p", vm);
369 
370 	/*
371 	 * Make sure any SysV shm is freed, it might not have been in
372 	 * exit1().
373 	 */
374 	shmexit(vm);
375 
376 	/*
377 	 * Lock the map, to wait out all other references to it.
378 	 * Delete all of the mappings and pages they hold, then call
379 	 * the pmap module to reclaim anything left.
380 	 */
381 	(void)vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map),
382 	    vm_map_max(&vm->vm_map));
383 
384 	pmap_release(vmspace_pmap(vm));
385 	vm->vm_map.pmap = NULL;
386 	uma_zfree(vmspace_zone, vm);
387 }
388 
389 void
390 vmspace_free(struct vmspace *vm)
391 {
392 
393 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
394 	    "vmspace_free() called");
395 
396 	if (refcount_release(&vm->vm_refcnt))
397 		vmspace_dofree(vm);
398 }
399 
400 void
401 vmspace_exitfree(struct proc *p)
402 {
403 	struct vmspace *vm;
404 
405 	PROC_VMSPACE_LOCK(p);
406 	vm = p->p_vmspace;
407 	p->p_vmspace = NULL;
408 	PROC_VMSPACE_UNLOCK(p);
409 	KASSERT(vm == &vmspace0, ("vmspace_exitfree: wrong vmspace"));
410 	vmspace_free(vm);
411 }
412 
413 void
414 vmspace_exit(struct thread *td)
415 {
416 	struct vmspace *vm;
417 	struct proc *p;
418 	bool released;
419 
420 	p = td->td_proc;
421 	vm = p->p_vmspace;
422 
423 	/*
424 	 * Prepare to release the vmspace reference.  The thread that releases
425 	 * the last reference is responsible for tearing down the vmspace.
426 	 * However, threads not releasing the final reference must switch to the
427 	 * kernel's vmspace0 before the decrement so that the subsequent pmap
428 	 * deactivation does not modify a freed vmspace.
429 	 */
430 	refcount_acquire(&vmspace0.vm_refcnt);
431 	if (!(released = refcount_release_if_last(&vm->vm_refcnt))) {
432 		if (p->p_vmspace != &vmspace0) {
433 			PROC_VMSPACE_LOCK(p);
434 			p->p_vmspace = &vmspace0;
435 			PROC_VMSPACE_UNLOCK(p);
436 			pmap_activate(td);
437 		}
438 		released = refcount_release(&vm->vm_refcnt);
439 	}
440 	if (released) {
441 		/*
442 		 * pmap_remove_pages() expects the pmap to be active, so switch
443 		 * back first if necessary.
444 		 */
445 		if (p->p_vmspace != vm) {
446 			PROC_VMSPACE_LOCK(p);
447 			p->p_vmspace = vm;
448 			PROC_VMSPACE_UNLOCK(p);
449 			pmap_activate(td);
450 		}
451 		pmap_remove_pages(vmspace_pmap(vm));
452 		PROC_VMSPACE_LOCK(p);
453 		p->p_vmspace = &vmspace0;
454 		PROC_VMSPACE_UNLOCK(p);
455 		pmap_activate(td);
456 		vmspace_dofree(vm);
457 	}
458 #ifdef RACCT
459 	if (racct_enable)
460 		vmspace_container_reset(p);
461 #endif
462 }
463 
464 /* Acquire reference to vmspace owned by another process. */
465 
466 struct vmspace *
467 vmspace_acquire_ref(struct proc *p)
468 {
469 	struct vmspace *vm;
470 
471 	PROC_VMSPACE_LOCK(p);
472 	vm = p->p_vmspace;
473 	if (vm == NULL || !refcount_acquire_if_not_zero(&vm->vm_refcnt)) {
474 		PROC_VMSPACE_UNLOCK(p);
475 		return (NULL);
476 	}
477 	if (vm != p->p_vmspace) {
478 		PROC_VMSPACE_UNLOCK(p);
479 		vmspace_free(vm);
480 		return (NULL);
481 	}
482 	PROC_VMSPACE_UNLOCK(p);
483 	return (vm);
484 }
485 
486 /*
487  * Switch between vmspaces in an AIO kernel process.
488  *
489  * The new vmspace is either the vmspace of a user process obtained
490  * from an active AIO request or the initial vmspace of the AIO kernel
491  * process (when it is idling).  Because user processes will block to
492  * drain any active AIO requests before proceeding in exit() or
493  * execve(), the reference count for vmspaces from AIO requests can
494  * never be 0.  Similarly, AIO kernel processes hold an extra
495  * reference on their initial vmspace for the life of the process.  As
496  * a result, the 'newvm' vmspace always has a non-zero reference
497  * count.  This permits an additional reference on 'newvm' to be
498  * acquired via a simple atomic increment rather than the loop in
499  * vmspace_acquire_ref() above.
500  */
501 void
502 vmspace_switch_aio(struct vmspace *newvm)
503 {
504 	struct vmspace *oldvm;
505 
506 	/* XXX: Need some way to assert that this is an aio daemon. */
507 
508 	KASSERT(refcount_load(&newvm->vm_refcnt) > 0,
509 	    ("vmspace_switch_aio: newvm unreferenced"));
510 
511 	oldvm = curproc->p_vmspace;
512 	if (oldvm == newvm)
513 		return;
514 
515 	/*
516 	 * Point to the new address space and refer to it.
517 	 */
518 	curproc->p_vmspace = newvm;
519 	refcount_acquire(&newvm->vm_refcnt);
520 
521 	/* Activate the new mapping. */
522 	pmap_activate(curthread);
523 
524 	vmspace_free(oldvm);
525 }
526 
527 void
528 _vm_map_lock(vm_map_t map, const char *file, int line)
529 {
530 
531 	if (map->system_map)
532 		mtx_lock_flags_(&map->system_mtx, 0, file, line);
533 	else
534 		sx_xlock_(&map->lock, file, line);
535 	map->timestamp++;
536 }
537 
538 void
539 vm_map_entry_set_vnode_text(vm_map_entry_t entry, bool add)
540 {
541 	vm_object_t object;
542 	struct vnode *vp;
543 	bool vp_held;
544 
545 	if ((entry->eflags & MAP_ENTRY_VN_EXEC) == 0)
546 		return;
547 	KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
548 	    ("Submap with execs"));
549 	object = entry->object.vm_object;
550 	KASSERT(object != NULL, ("No object for text, entry %p", entry));
551 	if ((object->flags & OBJ_ANON) != 0)
552 		object = object->handle;
553 	else
554 		KASSERT(object->backing_object == NULL,
555 		    ("non-anon object %p shadows", object));
556 	KASSERT(object != NULL, ("No content object for text, entry %p obj %p",
557 	    entry, entry->object.vm_object));
558 
559 	/*
560 	 * Mostly, we do not lock the backing object.  It is
561 	 * referenced by the entry we are processing, so it cannot go
562 	 * away.
563 	 */
564 	vp = NULL;
565 	vp_held = false;
566 	if (object->type == OBJT_DEAD) {
567 		/*
568 		 * For OBJT_DEAD objects, v_writecount was handled in
569 		 * vnode_pager_dealloc().
570 		 */
571 	} else if (object->type == OBJT_VNODE) {
572 		vp = object->handle;
573 	} else if (object->type == OBJT_SWAP) {
574 		KASSERT((object->flags & OBJ_TMPFS_NODE) != 0,
575 		    ("vm_map_entry_set_vnode_text: swap and !TMPFS "
576 		    "entry %p, object %p, add %d", entry, object, add));
577 		/*
578 		 * Tmpfs VREG node, which was reclaimed, has
579 		 * OBJ_TMPFS_NODE flag set, but not OBJ_TMPFS.  In
580 		 * this case there is no v_writecount to adjust.
581 		 */
582 		VM_OBJECT_RLOCK(object);
583 		if ((object->flags & OBJ_TMPFS) != 0) {
584 			vp = object->un_pager.swp.swp_tmpfs;
585 			if (vp != NULL) {
586 				vhold(vp);
587 				vp_held = true;
588 			}
589 		}
590 		VM_OBJECT_RUNLOCK(object);
591 	} else {
592 		KASSERT(0,
593 		    ("vm_map_entry_set_vnode_text: wrong object type, "
594 		    "entry %p, object %p, add %d", entry, object, add));
595 	}
596 	if (vp != NULL) {
597 		if (add) {
598 			VOP_SET_TEXT_CHECKED(vp);
599 		} else {
600 			vn_lock(vp, LK_SHARED | LK_RETRY);
601 			VOP_UNSET_TEXT_CHECKED(vp);
602 			VOP_UNLOCK(vp);
603 		}
604 		if (vp_held)
605 			vdrop(vp);
606 	}
607 }
608 
609 /*
610  * Use a different name for this vm_map_entry field when it's use
611  * is not consistent with its use as part of an ordered search tree.
612  */
613 #define defer_next right
614 
615 static void
616 vm_map_process_deferred(void)
617 {
618 	struct thread *td;
619 	vm_map_entry_t entry, next;
620 	vm_object_t object;
621 
622 	td = curthread;
623 	entry = td->td_map_def_user;
624 	td->td_map_def_user = NULL;
625 	while (entry != NULL) {
626 		next = entry->defer_next;
627 		MPASS((entry->eflags & (MAP_ENTRY_WRITECNT |
628 		    MAP_ENTRY_VN_EXEC)) != (MAP_ENTRY_WRITECNT |
629 		    MAP_ENTRY_VN_EXEC));
630 		if ((entry->eflags & MAP_ENTRY_WRITECNT) != 0) {
631 			/*
632 			 * Decrement the object's writemappings and
633 			 * possibly the vnode's v_writecount.
634 			 */
635 			KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
636 			    ("Submap with writecount"));
637 			object = entry->object.vm_object;
638 			KASSERT(object != NULL, ("No object for writecount"));
639 			vm_pager_release_writecount(object, entry->start,
640 			    entry->end);
641 		}
642 		vm_map_entry_set_vnode_text(entry, false);
643 		vm_map_entry_deallocate(entry, FALSE);
644 		entry = next;
645 	}
646 }
647 
648 #ifdef INVARIANTS
649 static void
650 _vm_map_assert_locked(vm_map_t map, const char *file, int line)
651 {
652 
653 	if (map->system_map)
654 		mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
655 	else
656 		sx_assert_(&map->lock, SA_XLOCKED, file, line);
657 }
658 
659 #define	VM_MAP_ASSERT_LOCKED(map) \
660     _vm_map_assert_locked(map, LOCK_FILE, LOCK_LINE)
661 
662 enum { VMMAP_CHECK_NONE, VMMAP_CHECK_UNLOCK, VMMAP_CHECK_ALL };
663 #ifdef DIAGNOSTIC
664 static int enable_vmmap_check = VMMAP_CHECK_UNLOCK;
665 #else
666 static int enable_vmmap_check = VMMAP_CHECK_NONE;
667 #endif
668 SYSCTL_INT(_debug, OID_AUTO, vmmap_check, CTLFLAG_RWTUN,
669     &enable_vmmap_check, 0, "Enable vm map consistency checking");
670 
671 static void _vm_map_assert_consistent(vm_map_t map, int check);
672 
673 #define VM_MAP_ASSERT_CONSISTENT(map) \
674     _vm_map_assert_consistent(map, VMMAP_CHECK_ALL)
675 #ifdef DIAGNOSTIC
676 #define VM_MAP_UNLOCK_CONSISTENT(map) do {				\
677 	if (map->nupdates > map->nentries) {				\
678 		_vm_map_assert_consistent(map, VMMAP_CHECK_UNLOCK);	\
679 		map->nupdates = 0;					\
680 	}								\
681 } while (0)
682 #else
683 #define VM_MAP_UNLOCK_CONSISTENT(map)
684 #endif
685 #else
686 #define	VM_MAP_ASSERT_LOCKED(map)
687 #define VM_MAP_ASSERT_CONSISTENT(map)
688 #define VM_MAP_UNLOCK_CONSISTENT(map)
689 #endif /* INVARIANTS */
690 
691 void
692 _vm_map_unlock(vm_map_t map, const char *file, int line)
693 {
694 
695 	VM_MAP_UNLOCK_CONSISTENT(map);
696 	if (map->system_map) {
697 #ifndef UMA_MD_SMALL_ALLOC
698 		if (map == kernel_map && (map->flags & MAP_REPLENISH) != 0) {
699 			uma_prealloc(kmapentzone, 1);
700 			map->flags &= ~MAP_REPLENISH;
701 		}
702 #endif
703 		mtx_unlock_flags_(&map->system_mtx, 0, file, line);
704 	} else {
705 		sx_xunlock_(&map->lock, file, line);
706 		vm_map_process_deferred();
707 	}
708 }
709 
710 void
711 _vm_map_lock_read(vm_map_t map, const char *file, int line)
712 {
713 
714 	if (map->system_map)
715 		mtx_lock_flags_(&map->system_mtx, 0, file, line);
716 	else
717 		sx_slock_(&map->lock, file, line);
718 }
719 
720 void
721 _vm_map_unlock_read(vm_map_t map, const char *file, int line)
722 {
723 
724 	if (map->system_map) {
725 		KASSERT((map->flags & MAP_REPLENISH) == 0,
726 		    ("%s: MAP_REPLENISH leaked", __func__));
727 		mtx_unlock_flags_(&map->system_mtx, 0, file, line);
728 	} else {
729 		sx_sunlock_(&map->lock, file, line);
730 		vm_map_process_deferred();
731 	}
732 }
733 
734 int
735 _vm_map_trylock(vm_map_t map, const char *file, int line)
736 {
737 	int error;
738 
739 	error = map->system_map ?
740 	    !mtx_trylock_flags_(&map->system_mtx, 0, file, line) :
741 	    !sx_try_xlock_(&map->lock, file, line);
742 	if (error == 0)
743 		map->timestamp++;
744 	return (error == 0);
745 }
746 
747 int
748 _vm_map_trylock_read(vm_map_t map, const char *file, int line)
749 {
750 	int error;
751 
752 	error = map->system_map ?
753 	    !mtx_trylock_flags_(&map->system_mtx, 0, file, line) :
754 	    !sx_try_slock_(&map->lock, file, line);
755 	return (error == 0);
756 }
757 
758 /*
759  *	_vm_map_lock_upgrade:	[ internal use only ]
760  *
761  *	Tries to upgrade a read (shared) lock on the specified map to a write
762  *	(exclusive) lock.  Returns the value "0" if the upgrade succeeds and a
763  *	non-zero value if the upgrade fails.  If the upgrade fails, the map is
764  *	returned without a read or write lock held.
765  *
766  *	Requires that the map be read locked.
767  */
768 int
769 _vm_map_lock_upgrade(vm_map_t map, const char *file, int line)
770 {
771 	unsigned int last_timestamp;
772 
773 	if (map->system_map) {
774 		mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
775 	} else {
776 		if (!sx_try_upgrade_(&map->lock, file, line)) {
777 			last_timestamp = map->timestamp;
778 			sx_sunlock_(&map->lock, file, line);
779 			vm_map_process_deferred();
780 			/*
781 			 * If the map's timestamp does not change while the
782 			 * map is unlocked, then the upgrade succeeds.
783 			 */
784 			sx_xlock_(&map->lock, file, line);
785 			if (last_timestamp != map->timestamp) {
786 				sx_xunlock_(&map->lock, file, line);
787 				return (1);
788 			}
789 		}
790 	}
791 	map->timestamp++;
792 	return (0);
793 }
794 
795 void
796 _vm_map_lock_downgrade(vm_map_t map, const char *file, int line)
797 {
798 
799 	if (map->system_map) {
800 		KASSERT((map->flags & MAP_REPLENISH) == 0,
801 		    ("%s: MAP_REPLENISH leaked", __func__));
802 		mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
803 	} else {
804 		VM_MAP_UNLOCK_CONSISTENT(map);
805 		sx_downgrade_(&map->lock, file, line);
806 	}
807 }
808 
809 /*
810  *	vm_map_locked:
811  *
812  *	Returns a non-zero value if the caller holds a write (exclusive) lock
813  *	on the specified map and the value "0" otherwise.
814  */
815 int
816 vm_map_locked(vm_map_t map)
817 {
818 
819 	if (map->system_map)
820 		return (mtx_owned(&map->system_mtx));
821 	else
822 		return (sx_xlocked(&map->lock));
823 }
824 
825 /*
826  *	_vm_map_unlock_and_wait:
827  *
828  *	Atomically releases the lock on the specified map and puts the calling
829  *	thread to sleep.  The calling thread will remain asleep until either
830  *	vm_map_wakeup() is performed on the map or the specified timeout is
831  *	exceeded.
832  *
833  *	WARNING!  This function does not perform deferred deallocations of
834  *	objects and map	entries.  Therefore, the calling thread is expected to
835  *	reacquire the map lock after reawakening and later perform an ordinary
836  *	unlock operation, such as vm_map_unlock(), before completing its
837  *	operation on the map.
838  */
839 int
840 _vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line)
841 {
842 
843 	VM_MAP_UNLOCK_CONSISTENT(map);
844 	mtx_lock(&map_sleep_mtx);
845 	if (map->system_map) {
846 		KASSERT((map->flags & MAP_REPLENISH) == 0,
847 		    ("%s: MAP_REPLENISH leaked", __func__));
848 		mtx_unlock_flags_(&map->system_mtx, 0, file, line);
849 	} else {
850 		sx_xunlock_(&map->lock, file, line);
851 	}
852 	return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps",
853 	    timo));
854 }
855 
856 /*
857  *	vm_map_wakeup:
858  *
859  *	Awaken any threads that have slept on the map using
860  *	vm_map_unlock_and_wait().
861  */
862 void
863 vm_map_wakeup(vm_map_t map)
864 {
865 
866 	/*
867 	 * Acquire and release map_sleep_mtx to prevent a wakeup()
868 	 * from being performed (and lost) between the map unlock
869 	 * and the msleep() in _vm_map_unlock_and_wait().
870 	 */
871 	mtx_lock(&map_sleep_mtx);
872 	mtx_unlock(&map_sleep_mtx);
873 	wakeup(&map->root);
874 }
875 
876 void
877 vm_map_busy(vm_map_t map)
878 {
879 
880 	VM_MAP_ASSERT_LOCKED(map);
881 	map->busy++;
882 }
883 
884 void
885 vm_map_unbusy(vm_map_t map)
886 {
887 
888 	VM_MAP_ASSERT_LOCKED(map);
889 	KASSERT(map->busy, ("vm_map_unbusy: not busy"));
890 	if (--map->busy == 0 && (map->flags & MAP_BUSY_WAKEUP)) {
891 		vm_map_modflags(map, 0, MAP_BUSY_WAKEUP);
892 		wakeup(&map->busy);
893 	}
894 }
895 
896 void
897 vm_map_wait_busy(vm_map_t map)
898 {
899 
900 	VM_MAP_ASSERT_LOCKED(map);
901 	while (map->busy) {
902 		vm_map_modflags(map, MAP_BUSY_WAKEUP, 0);
903 		if (map->system_map)
904 			msleep(&map->busy, &map->system_mtx, 0, "mbusy", 0);
905 		else
906 			sx_sleep(&map->busy, &map->lock, 0, "mbusy", 0);
907 	}
908 	map->timestamp++;
909 }
910 
911 long
912 vmspace_resident_count(struct vmspace *vmspace)
913 {
914 	return pmap_resident_count(vmspace_pmap(vmspace));
915 }
916 
917 /*
918  * Initialize an existing vm_map structure
919  * such as that in the vmspace structure.
920  */
921 static void
922 _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max)
923 {
924 
925 	map->header.eflags = MAP_ENTRY_HEADER;
926 	map->needs_wakeup = FALSE;
927 	map->system_map = 0;
928 	map->pmap = pmap;
929 	map->header.end = min;
930 	map->header.start = max;
931 	map->flags = 0;
932 	map->header.left = map->header.right = &map->header;
933 	map->root = NULL;
934 	map->timestamp = 0;
935 	map->busy = 0;
936 	map->anon_loc = 0;
937 #ifdef DIAGNOSTIC
938 	map->nupdates = 0;
939 #endif
940 }
941 
942 void
943 vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max)
944 {
945 
946 	_vm_map_init(map, pmap, min, max);
947 	mtx_init(&map->system_mtx, "vm map (system)", NULL,
948 	    MTX_DEF | MTX_DUPOK);
949 	sx_init(&map->lock, "vm map (user)");
950 }
951 
952 /*
953  *	vm_map_entry_dispose:	[ internal use only ]
954  *
955  *	Inverse of vm_map_entry_create.
956  */
957 static void
958 vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry)
959 {
960 	uma_zfree(map->system_map ? kmapentzone : mapentzone, entry);
961 }
962 
963 /*
964  *	vm_map_entry_create:	[ internal use only ]
965  *
966  *	Allocates a VM map entry for insertion.
967  *	No entry fields are filled in.
968  */
969 static vm_map_entry_t
970 vm_map_entry_create(vm_map_t map)
971 {
972 	vm_map_entry_t new_entry;
973 
974 #ifndef UMA_MD_SMALL_ALLOC
975 	if (map == kernel_map) {
976 		VM_MAP_ASSERT_LOCKED(map);
977 
978 		/*
979 		 * A new slab of kernel map entries cannot be allocated at this
980 		 * point because the kernel map has not yet been updated to
981 		 * reflect the caller's request.  Therefore, we allocate a new
982 		 * map entry, dipping into the reserve if necessary, and set a
983 		 * flag indicating that the reserve must be replenished before
984 		 * the map is unlocked.
985 		 */
986 		new_entry = uma_zalloc(kmapentzone, M_NOWAIT | M_NOVM);
987 		if (new_entry == NULL) {
988 			new_entry = uma_zalloc(kmapentzone,
989 			    M_NOWAIT | M_NOVM | M_USE_RESERVE);
990 			kernel_map->flags |= MAP_REPLENISH;
991 		}
992 	} else
993 #endif
994 	if (map->system_map) {
995 		new_entry = uma_zalloc(kmapentzone, M_NOWAIT);
996 	} else {
997 		new_entry = uma_zalloc(mapentzone, M_WAITOK);
998 	}
999 	KASSERT(new_entry != NULL,
1000 	    ("vm_map_entry_create: kernel resources exhausted"));
1001 	return (new_entry);
1002 }
1003 
1004 /*
1005  *	vm_map_entry_set_behavior:
1006  *
1007  *	Set the expected access behavior, either normal, random, or
1008  *	sequential.
1009  */
1010 static inline void
1011 vm_map_entry_set_behavior(vm_map_entry_t entry, u_char behavior)
1012 {
1013 	entry->eflags = (entry->eflags & ~MAP_ENTRY_BEHAV_MASK) |
1014 	    (behavior & MAP_ENTRY_BEHAV_MASK);
1015 }
1016 
1017 /*
1018  *	vm_map_entry_max_free_{left,right}:
1019  *
1020  *	Compute the size of the largest free gap between two entries,
1021  *	one the root of a tree and the other the ancestor of that root
1022  *	that is the least or greatest ancestor found on the search path.
1023  */
1024 static inline vm_size_t
1025 vm_map_entry_max_free_left(vm_map_entry_t root, vm_map_entry_t left_ancestor)
1026 {
1027 
1028 	return (root->left != left_ancestor ?
1029 	    root->left->max_free : root->start - left_ancestor->end);
1030 }
1031 
1032 static inline vm_size_t
1033 vm_map_entry_max_free_right(vm_map_entry_t root, vm_map_entry_t right_ancestor)
1034 {
1035 
1036 	return (root->right != right_ancestor ?
1037 	    root->right->max_free : right_ancestor->start - root->end);
1038 }
1039 
1040 /*
1041  *	vm_map_entry_{pred,succ}:
1042  *
1043  *	Find the {predecessor, successor} of the entry by taking one step
1044  *	in the appropriate direction and backtracking as much as necessary.
1045  *	vm_map_entry_succ is defined in vm_map.h.
1046  */
1047 static inline vm_map_entry_t
1048 vm_map_entry_pred(vm_map_entry_t entry)
1049 {
1050 	vm_map_entry_t prior;
1051 
1052 	prior = entry->left;
1053 	if (prior->right->start < entry->start) {
1054 		do
1055 			prior = prior->right;
1056 		while (prior->right != entry);
1057 	}
1058 	return (prior);
1059 }
1060 
1061 static inline vm_size_t
1062 vm_size_max(vm_size_t a, vm_size_t b)
1063 {
1064 
1065 	return (a > b ? a : b);
1066 }
1067 
1068 #define SPLAY_LEFT_STEP(root, y, llist, rlist, test) do {		\
1069 	vm_map_entry_t z;						\
1070 	vm_size_t max_free;						\
1071 									\
1072 	/*								\
1073 	 * Infer root->right->max_free == root->max_free when		\
1074 	 * y->max_free < root->max_free || root->max_free == 0.		\
1075 	 * Otherwise, look right to find it.				\
1076 	 */								\
1077 	y = root->left;							\
1078 	max_free = root->max_free;					\
1079 	KASSERT(max_free == vm_size_max(				\
1080 	    vm_map_entry_max_free_left(root, llist),			\
1081 	    vm_map_entry_max_free_right(root, rlist)),			\
1082 	    ("%s: max_free invariant fails", __func__));		\
1083 	if (max_free - 1 < vm_map_entry_max_free_left(root, llist))	\
1084 		max_free = vm_map_entry_max_free_right(root, rlist);	\
1085 	if (y != llist && (test)) {					\
1086 		/* Rotate right and make y root. */			\
1087 		z = y->right;						\
1088 		if (z != root) {					\
1089 			root->left = z;					\
1090 			y->right = root;				\
1091 			if (max_free < y->max_free)			\
1092 			    root->max_free = max_free =			\
1093 			    vm_size_max(max_free, z->max_free);		\
1094 		} else if (max_free < y->max_free)			\
1095 			root->max_free = max_free =			\
1096 			    vm_size_max(max_free, root->start - y->end);\
1097 		root = y;						\
1098 		y = root->left;						\
1099 	}								\
1100 	/* Copy right->max_free.  Put root on rlist. */			\
1101 	root->max_free = max_free;					\
1102 	KASSERT(max_free == vm_map_entry_max_free_right(root, rlist),	\
1103 	    ("%s: max_free not copied from right", __func__));		\
1104 	root->left = rlist;						\
1105 	rlist = root;							\
1106 	root = y != llist ? y : NULL;					\
1107 } while (0)
1108 
1109 #define SPLAY_RIGHT_STEP(root, y, llist, rlist, test) do {		\
1110 	vm_map_entry_t z;						\
1111 	vm_size_t max_free;						\
1112 									\
1113 	/*								\
1114 	 * Infer root->left->max_free == root->max_free when		\
1115 	 * y->max_free < root->max_free || root->max_free == 0.		\
1116 	 * Otherwise, look left to find it.				\
1117 	 */								\
1118 	y = root->right;						\
1119 	max_free = root->max_free;					\
1120 	KASSERT(max_free == vm_size_max(				\
1121 	    vm_map_entry_max_free_left(root, llist),			\
1122 	    vm_map_entry_max_free_right(root, rlist)),			\
1123 	    ("%s: max_free invariant fails", __func__));		\
1124 	if (max_free - 1 < vm_map_entry_max_free_right(root, rlist))	\
1125 		max_free = vm_map_entry_max_free_left(root, llist);	\
1126 	if (y != rlist && (test)) {					\
1127 		/* Rotate left and make y root. */			\
1128 		z = y->left;						\
1129 		if (z != root) {					\
1130 			root->right = z;				\
1131 			y->left = root;					\
1132 			if (max_free < y->max_free)			\
1133 			    root->max_free = max_free =			\
1134 			    vm_size_max(max_free, z->max_free);		\
1135 		} else if (max_free < y->max_free)			\
1136 			root->max_free = max_free =			\
1137 			    vm_size_max(max_free, y->start - root->end);\
1138 		root = y;						\
1139 		y = root->right;					\
1140 	}								\
1141 	/* Copy left->max_free.  Put root on llist. */			\
1142 	root->max_free = max_free;					\
1143 	KASSERT(max_free == vm_map_entry_max_free_left(root, llist),	\
1144 	    ("%s: max_free not copied from left", __func__));		\
1145 	root->right = llist;						\
1146 	llist = root;							\
1147 	root = y != rlist ? y : NULL;					\
1148 } while (0)
1149 
1150 /*
1151  * Walk down the tree until we find addr or a gap where addr would go, breaking
1152  * off left and right subtrees of nodes less than, or greater than addr.  Treat
1153  * subtrees with root->max_free < length as empty trees.  llist and rlist are
1154  * the two sides in reverse order (bottom-up), with llist linked by the right
1155  * pointer and rlist linked by the left pointer in the vm_map_entry, and both
1156  * lists terminated by &map->header.  This function, and the subsequent call to
1157  * vm_map_splay_merge_{left,right,pred,succ}, rely on the start and end address
1158  * values in &map->header.
1159  */
1160 static __always_inline vm_map_entry_t
1161 vm_map_splay_split(vm_map_t map, vm_offset_t addr, vm_size_t length,
1162     vm_map_entry_t *llist, vm_map_entry_t *rlist)
1163 {
1164 	vm_map_entry_t left, right, root, y;
1165 
1166 	left = right = &map->header;
1167 	root = map->root;
1168 	while (root != NULL && root->max_free >= length) {
1169 		KASSERT(left->end <= root->start &&
1170 		    root->end <= right->start,
1171 		    ("%s: root not within tree bounds", __func__));
1172 		if (addr < root->start) {
1173 			SPLAY_LEFT_STEP(root, y, left, right,
1174 			    y->max_free >= length && addr < y->start);
1175 		} else if (addr >= root->end) {
1176 			SPLAY_RIGHT_STEP(root, y, left, right,
1177 			    y->max_free >= length && addr >= y->end);
1178 		} else
1179 			break;
1180 	}
1181 	*llist = left;
1182 	*rlist = right;
1183 	return (root);
1184 }
1185 
1186 static __always_inline void
1187 vm_map_splay_findnext(vm_map_entry_t root, vm_map_entry_t *rlist)
1188 {
1189 	vm_map_entry_t hi, right, y;
1190 
1191 	right = *rlist;
1192 	hi = root->right == right ? NULL : root->right;
1193 	if (hi == NULL)
1194 		return;
1195 	do
1196 		SPLAY_LEFT_STEP(hi, y, root, right, true);
1197 	while (hi != NULL);
1198 	*rlist = right;
1199 }
1200 
1201 static __always_inline void
1202 vm_map_splay_findprev(vm_map_entry_t root, vm_map_entry_t *llist)
1203 {
1204 	vm_map_entry_t left, lo, y;
1205 
1206 	left = *llist;
1207 	lo = root->left == left ? NULL : root->left;
1208 	if (lo == NULL)
1209 		return;
1210 	do
1211 		SPLAY_RIGHT_STEP(lo, y, left, root, true);
1212 	while (lo != NULL);
1213 	*llist = left;
1214 }
1215 
1216 static inline void
1217 vm_map_entry_swap(vm_map_entry_t *a, vm_map_entry_t *b)
1218 {
1219 	vm_map_entry_t tmp;
1220 
1221 	tmp = *b;
1222 	*b = *a;
1223 	*a = tmp;
1224 }
1225 
1226 /*
1227  * Walk back up the two spines, flip the pointers and set max_free.  The
1228  * subtrees of the root go at the bottom of llist and rlist.
1229  */
1230 static vm_size_t
1231 vm_map_splay_merge_left_walk(vm_map_entry_t header, vm_map_entry_t root,
1232     vm_map_entry_t tail, vm_size_t max_free, vm_map_entry_t llist)
1233 {
1234 	do {
1235 		/*
1236 		 * The max_free values of the children of llist are in
1237 		 * llist->max_free and max_free.  Update with the
1238 		 * max value.
1239 		 */
1240 		llist->max_free = max_free =
1241 		    vm_size_max(llist->max_free, max_free);
1242 		vm_map_entry_swap(&llist->right, &tail);
1243 		vm_map_entry_swap(&tail, &llist);
1244 	} while (llist != header);
1245 	root->left = tail;
1246 	return (max_free);
1247 }
1248 
1249 /*
1250  * When llist is known to be the predecessor of root.
1251  */
1252 static inline vm_size_t
1253 vm_map_splay_merge_pred(vm_map_entry_t header, vm_map_entry_t root,
1254     vm_map_entry_t llist)
1255 {
1256 	vm_size_t max_free;
1257 
1258 	max_free = root->start - llist->end;
1259 	if (llist != header) {
1260 		max_free = vm_map_splay_merge_left_walk(header, root,
1261 		    root, max_free, llist);
1262 	} else {
1263 		root->left = header;
1264 		header->right = root;
1265 	}
1266 	return (max_free);
1267 }
1268 
1269 /*
1270  * When llist may or may not be the predecessor of root.
1271  */
1272 static inline vm_size_t
1273 vm_map_splay_merge_left(vm_map_entry_t header, vm_map_entry_t root,
1274     vm_map_entry_t llist)
1275 {
1276 	vm_size_t max_free;
1277 
1278 	max_free = vm_map_entry_max_free_left(root, llist);
1279 	if (llist != header) {
1280 		max_free = vm_map_splay_merge_left_walk(header, root,
1281 		    root->left == llist ? root : root->left,
1282 		    max_free, llist);
1283 	}
1284 	return (max_free);
1285 }
1286 
1287 static vm_size_t
1288 vm_map_splay_merge_right_walk(vm_map_entry_t header, vm_map_entry_t root,
1289     vm_map_entry_t tail, vm_size_t max_free, vm_map_entry_t rlist)
1290 {
1291 	do {
1292 		/*
1293 		 * The max_free values of the children of rlist are in
1294 		 * rlist->max_free and max_free.  Update with the
1295 		 * max value.
1296 		 */
1297 		rlist->max_free = max_free =
1298 		    vm_size_max(rlist->max_free, max_free);
1299 		vm_map_entry_swap(&rlist->left, &tail);
1300 		vm_map_entry_swap(&tail, &rlist);
1301 	} while (rlist != header);
1302 	root->right = tail;
1303 	return (max_free);
1304 }
1305 
1306 /*
1307  * When rlist is known to be the succecessor of root.
1308  */
1309 static inline vm_size_t
1310 vm_map_splay_merge_succ(vm_map_entry_t header, vm_map_entry_t root,
1311     vm_map_entry_t rlist)
1312 {
1313 	vm_size_t max_free;
1314 
1315 	max_free = rlist->start - root->end;
1316 	if (rlist != header) {
1317 		max_free = vm_map_splay_merge_right_walk(header, root,
1318 		    root, max_free, rlist);
1319 	} else {
1320 		root->right = header;
1321 		header->left = root;
1322 	}
1323 	return (max_free);
1324 }
1325 
1326 /*
1327  * When rlist may or may not be the succecessor of root.
1328  */
1329 static inline vm_size_t
1330 vm_map_splay_merge_right(vm_map_entry_t header, vm_map_entry_t root,
1331     vm_map_entry_t rlist)
1332 {
1333 	vm_size_t max_free;
1334 
1335 	max_free = vm_map_entry_max_free_right(root, rlist);
1336 	if (rlist != header) {
1337 		max_free = vm_map_splay_merge_right_walk(header, root,
1338 		    root->right == rlist ? root : root->right,
1339 		    max_free, rlist);
1340 	}
1341 	return (max_free);
1342 }
1343 
1344 /*
1345  *	vm_map_splay:
1346  *
1347  *	The Sleator and Tarjan top-down splay algorithm with the
1348  *	following variation.  Max_free must be computed bottom-up, so
1349  *	on the downward pass, maintain the left and right spines in
1350  *	reverse order.  Then, make a second pass up each side to fix
1351  *	the pointers and compute max_free.  The time bound is O(log n)
1352  *	amortized.
1353  *
1354  *	The tree is threaded, which means that there are no null pointers.
1355  *	When a node has no left child, its left pointer points to its
1356  *	predecessor, which the last ancestor on the search path from the root
1357  *	where the search branched right.  Likewise, when a node has no right
1358  *	child, its right pointer points to its successor.  The map header node
1359  *	is the predecessor of the first map entry, and the successor of the
1360  *	last.
1361  *
1362  *	The new root is the vm_map_entry containing "addr", or else an
1363  *	adjacent entry (lower if possible) if addr is not in the tree.
1364  *
1365  *	The map must be locked, and leaves it so.
1366  *
1367  *	Returns: the new root.
1368  */
1369 static vm_map_entry_t
1370 vm_map_splay(vm_map_t map, vm_offset_t addr)
1371 {
1372 	vm_map_entry_t header, llist, rlist, root;
1373 	vm_size_t max_free_left, max_free_right;
1374 
1375 	header = &map->header;
1376 	root = vm_map_splay_split(map, addr, 0, &llist, &rlist);
1377 	if (root != NULL) {
1378 		max_free_left = vm_map_splay_merge_left(header, root, llist);
1379 		max_free_right = vm_map_splay_merge_right(header, root, rlist);
1380 	} else if (llist != header) {
1381 		/*
1382 		 * Recover the greatest node in the left
1383 		 * subtree and make it the root.
1384 		 */
1385 		root = llist;
1386 		llist = root->right;
1387 		max_free_left = vm_map_splay_merge_left(header, root, llist);
1388 		max_free_right = vm_map_splay_merge_succ(header, root, rlist);
1389 	} else if (rlist != header) {
1390 		/*
1391 		 * Recover the least node in the right
1392 		 * subtree and make it the root.
1393 		 */
1394 		root = rlist;
1395 		rlist = root->left;
1396 		max_free_left = vm_map_splay_merge_pred(header, root, llist);
1397 		max_free_right = vm_map_splay_merge_right(header, root, rlist);
1398 	} else {
1399 		/* There is no root. */
1400 		return (NULL);
1401 	}
1402 	root->max_free = vm_size_max(max_free_left, max_free_right);
1403 	map->root = root;
1404 	VM_MAP_ASSERT_CONSISTENT(map);
1405 	return (root);
1406 }
1407 
1408 /*
1409  *	vm_map_entry_{un,}link:
1410  *
1411  *	Insert/remove entries from maps.  On linking, if new entry clips
1412  *	existing entry, trim existing entry to avoid overlap, and manage
1413  *	offsets.  On unlinking, merge disappearing entry with neighbor, if
1414  *	called for, and manage offsets.  Callers should not modify fields in
1415  *	entries already mapped.
1416  */
1417 static void
1418 vm_map_entry_link(vm_map_t map, vm_map_entry_t entry)
1419 {
1420 	vm_map_entry_t header, llist, rlist, root;
1421 	vm_size_t max_free_left, max_free_right;
1422 
1423 	CTR3(KTR_VM,
1424 	    "vm_map_entry_link: map %p, nentries %d, entry %p", map,
1425 	    map->nentries, entry);
1426 	VM_MAP_ASSERT_LOCKED(map);
1427 	map->nentries++;
1428 	header = &map->header;
1429 	root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist);
1430 	if (root == NULL) {
1431 		/*
1432 		 * The new entry does not overlap any existing entry in the
1433 		 * map, so it becomes the new root of the map tree.
1434 		 */
1435 		max_free_left = vm_map_splay_merge_pred(header, entry, llist);
1436 		max_free_right = vm_map_splay_merge_succ(header, entry, rlist);
1437 	} else if (entry->start == root->start) {
1438 		/*
1439 		 * The new entry is a clone of root, with only the end field
1440 		 * changed.  The root entry will be shrunk to abut the new
1441 		 * entry, and will be the right child of the new root entry in
1442 		 * the modified map.
1443 		 */
1444 		KASSERT(entry->end < root->end,
1445 		    ("%s: clip_start not within entry", __func__));
1446 		vm_map_splay_findprev(root, &llist);
1447 		root->offset += entry->end - root->start;
1448 		root->start = entry->end;
1449 		max_free_left = vm_map_splay_merge_pred(header, entry, llist);
1450 		max_free_right = root->max_free = vm_size_max(
1451 		    vm_map_splay_merge_pred(entry, root, entry),
1452 		    vm_map_splay_merge_right(header, root, rlist));
1453 	} else {
1454 		/*
1455 		 * The new entry is a clone of root, with only the start field
1456 		 * changed.  The root entry will be shrunk to abut the new
1457 		 * entry, and will be the left child of the new root entry in
1458 		 * the modified map.
1459 		 */
1460 		KASSERT(entry->end == root->end,
1461 		    ("%s: clip_start not within entry", __func__));
1462 		vm_map_splay_findnext(root, &rlist);
1463 		entry->offset += entry->start - root->start;
1464 		root->end = entry->start;
1465 		max_free_left = root->max_free = vm_size_max(
1466 		    vm_map_splay_merge_left(header, root, llist),
1467 		    vm_map_splay_merge_succ(entry, root, entry));
1468 		max_free_right = vm_map_splay_merge_succ(header, entry, rlist);
1469 	}
1470 	entry->max_free = vm_size_max(max_free_left, max_free_right);
1471 	map->root = entry;
1472 	VM_MAP_ASSERT_CONSISTENT(map);
1473 }
1474 
1475 enum unlink_merge_type {
1476 	UNLINK_MERGE_NONE,
1477 	UNLINK_MERGE_NEXT
1478 };
1479 
1480 static void
1481 vm_map_entry_unlink(vm_map_t map, vm_map_entry_t entry,
1482     enum unlink_merge_type op)
1483 {
1484 	vm_map_entry_t header, llist, rlist, root;
1485 	vm_size_t max_free_left, max_free_right;
1486 
1487 	VM_MAP_ASSERT_LOCKED(map);
1488 	header = &map->header;
1489 	root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist);
1490 	KASSERT(root != NULL,
1491 	    ("vm_map_entry_unlink: unlink object not mapped"));
1492 
1493 	vm_map_splay_findprev(root, &llist);
1494 	vm_map_splay_findnext(root, &rlist);
1495 	if (op == UNLINK_MERGE_NEXT) {
1496 		rlist->start = root->start;
1497 		rlist->offset = root->offset;
1498 	}
1499 	if (llist != header) {
1500 		root = llist;
1501 		llist = root->right;
1502 		max_free_left = vm_map_splay_merge_left(header, root, llist);
1503 		max_free_right = vm_map_splay_merge_succ(header, root, rlist);
1504 	} else if (rlist != header) {
1505 		root = rlist;
1506 		rlist = root->left;
1507 		max_free_left = vm_map_splay_merge_pred(header, root, llist);
1508 		max_free_right = vm_map_splay_merge_right(header, root, rlist);
1509 	} else {
1510 		header->left = header->right = header;
1511 		root = NULL;
1512 	}
1513 	if (root != NULL)
1514 		root->max_free = vm_size_max(max_free_left, max_free_right);
1515 	map->root = root;
1516 	VM_MAP_ASSERT_CONSISTENT(map);
1517 	map->nentries--;
1518 	CTR3(KTR_VM, "vm_map_entry_unlink: map %p, nentries %d, entry %p", map,
1519 	    map->nentries, entry);
1520 }
1521 
1522 /*
1523  *	vm_map_entry_resize:
1524  *
1525  *	Resize a vm_map_entry, recompute the amount of free space that
1526  *	follows it and propagate that value up the tree.
1527  *
1528  *	The map must be locked, and leaves it so.
1529  */
1530 static void
1531 vm_map_entry_resize(vm_map_t map, vm_map_entry_t entry, vm_size_t grow_amount)
1532 {
1533 	vm_map_entry_t header, llist, rlist, root;
1534 
1535 	VM_MAP_ASSERT_LOCKED(map);
1536 	header = &map->header;
1537 	root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist);
1538 	KASSERT(root != NULL, ("%s: resize object not mapped", __func__));
1539 	vm_map_splay_findnext(root, &rlist);
1540 	entry->end += grow_amount;
1541 	root->max_free = vm_size_max(
1542 	    vm_map_splay_merge_left(header, root, llist),
1543 	    vm_map_splay_merge_succ(header, root, rlist));
1544 	map->root = root;
1545 	VM_MAP_ASSERT_CONSISTENT(map);
1546 	CTR4(KTR_VM, "%s: map %p, nentries %d, entry %p",
1547 	    __func__, map, map->nentries, entry);
1548 }
1549 
1550 /*
1551  *	vm_map_lookup_entry:	[ internal use only ]
1552  *
1553  *	Finds the map entry containing (or
1554  *	immediately preceding) the specified address
1555  *	in the given map; the entry is returned
1556  *	in the "entry" parameter.  The boolean
1557  *	result indicates whether the address is
1558  *	actually contained in the map.
1559  */
1560 boolean_t
1561 vm_map_lookup_entry(
1562 	vm_map_t map,
1563 	vm_offset_t address,
1564 	vm_map_entry_t *entry)	/* OUT */
1565 {
1566 	vm_map_entry_t cur, header, lbound, ubound;
1567 	boolean_t locked;
1568 
1569 	/*
1570 	 * If the map is empty, then the map entry immediately preceding
1571 	 * "address" is the map's header.
1572 	 */
1573 	header = &map->header;
1574 	cur = map->root;
1575 	if (cur == NULL) {
1576 		*entry = header;
1577 		return (FALSE);
1578 	}
1579 	if (address >= cur->start && cur->end > address) {
1580 		*entry = cur;
1581 		return (TRUE);
1582 	}
1583 	if ((locked = vm_map_locked(map)) ||
1584 	    sx_try_upgrade(&map->lock)) {
1585 		/*
1586 		 * Splay requires a write lock on the map.  However, it only
1587 		 * restructures the binary search tree; it does not otherwise
1588 		 * change the map.  Thus, the map's timestamp need not change
1589 		 * on a temporary upgrade.
1590 		 */
1591 		cur = vm_map_splay(map, address);
1592 		if (!locked) {
1593 			VM_MAP_UNLOCK_CONSISTENT(map);
1594 			sx_downgrade(&map->lock);
1595 		}
1596 
1597 		/*
1598 		 * If "address" is contained within a map entry, the new root
1599 		 * is that map entry.  Otherwise, the new root is a map entry
1600 		 * immediately before or after "address".
1601 		 */
1602 		if (address < cur->start) {
1603 			*entry = header;
1604 			return (FALSE);
1605 		}
1606 		*entry = cur;
1607 		return (address < cur->end);
1608 	}
1609 	/*
1610 	 * Since the map is only locked for read access, perform a
1611 	 * standard binary search tree lookup for "address".
1612 	 */
1613 	lbound = ubound = header;
1614 	for (;;) {
1615 		if (address < cur->start) {
1616 			ubound = cur;
1617 			cur = cur->left;
1618 			if (cur == lbound)
1619 				break;
1620 		} else if (cur->end <= address) {
1621 			lbound = cur;
1622 			cur = cur->right;
1623 			if (cur == ubound)
1624 				break;
1625 		} else {
1626 			*entry = cur;
1627 			return (TRUE);
1628 		}
1629 	}
1630 	*entry = lbound;
1631 	return (FALSE);
1632 }
1633 
1634 /*
1635  *	vm_map_insert:
1636  *
1637  *	Inserts the given whole VM object into the target
1638  *	map at the specified address range.  The object's
1639  *	size should match that of the address range.
1640  *
1641  *	Requires that the map be locked, and leaves it so.
1642  *
1643  *	If object is non-NULL, ref count must be bumped by caller
1644  *	prior to making call to account for the new entry.
1645  */
1646 int
1647 vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
1648     vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow)
1649 {
1650 	vm_map_entry_t new_entry, next_entry, prev_entry;
1651 	struct ucred *cred;
1652 	vm_eflags_t protoeflags;
1653 	vm_inherit_t inheritance;
1654 	u_long bdry;
1655 	u_int bidx;
1656 
1657 	VM_MAP_ASSERT_LOCKED(map);
1658 	KASSERT(object != kernel_object ||
1659 	    (cow & MAP_COPY_ON_WRITE) == 0,
1660 	    ("vm_map_insert: kernel object and COW"));
1661 	KASSERT(object == NULL || (cow & MAP_NOFAULT) == 0 ||
1662 	    (cow & MAP_SPLIT_BOUNDARY_MASK) != 0,
1663 	    ("vm_map_insert: paradoxical MAP_NOFAULT request, obj %p cow %#x",
1664 	    object, cow));
1665 	KASSERT((prot & ~max) == 0,
1666 	    ("prot %#x is not subset of max_prot %#x", prot, max));
1667 
1668 	/*
1669 	 * Check that the start and end points are not bogus.
1670 	 */
1671 	if (start == end || !vm_map_range_valid(map, start, end))
1672 		return (KERN_INVALID_ADDRESS);
1673 
1674 	if ((map->flags & MAP_WXORX) != 0 && (prot & (VM_PROT_WRITE |
1675 	    VM_PROT_EXECUTE)) == (VM_PROT_WRITE | VM_PROT_EXECUTE))
1676 		return (KERN_PROTECTION_FAILURE);
1677 
1678 	/*
1679 	 * Find the entry prior to the proposed starting address; if it's part
1680 	 * of an existing entry, this range is bogus.
1681 	 */
1682 	if (vm_map_lookup_entry(map, start, &prev_entry))
1683 		return (KERN_NO_SPACE);
1684 
1685 	/*
1686 	 * Assert that the next entry doesn't overlap the end point.
1687 	 */
1688 	next_entry = vm_map_entry_succ(prev_entry);
1689 	if (next_entry->start < end)
1690 		return (KERN_NO_SPACE);
1691 
1692 	if ((cow & MAP_CREATE_GUARD) != 0 && (object != NULL ||
1693 	    max != VM_PROT_NONE))
1694 		return (KERN_INVALID_ARGUMENT);
1695 
1696 	protoeflags = 0;
1697 	if (cow & MAP_COPY_ON_WRITE)
1698 		protoeflags |= MAP_ENTRY_COW | MAP_ENTRY_NEEDS_COPY;
1699 	if (cow & MAP_NOFAULT)
1700 		protoeflags |= MAP_ENTRY_NOFAULT;
1701 	if (cow & MAP_DISABLE_SYNCER)
1702 		protoeflags |= MAP_ENTRY_NOSYNC;
1703 	if (cow & MAP_DISABLE_COREDUMP)
1704 		protoeflags |= MAP_ENTRY_NOCOREDUMP;
1705 	if (cow & MAP_STACK_GROWS_DOWN)
1706 		protoeflags |= MAP_ENTRY_GROWS_DOWN;
1707 	if (cow & MAP_STACK_GROWS_UP)
1708 		protoeflags |= MAP_ENTRY_GROWS_UP;
1709 	if (cow & MAP_WRITECOUNT)
1710 		protoeflags |= MAP_ENTRY_WRITECNT;
1711 	if (cow & MAP_VN_EXEC)
1712 		protoeflags |= MAP_ENTRY_VN_EXEC;
1713 	if ((cow & MAP_CREATE_GUARD) != 0)
1714 		protoeflags |= MAP_ENTRY_GUARD;
1715 	if ((cow & MAP_CREATE_STACK_GAP_DN) != 0)
1716 		protoeflags |= MAP_ENTRY_STACK_GAP_DN;
1717 	if ((cow & MAP_CREATE_STACK_GAP_UP) != 0)
1718 		protoeflags |= MAP_ENTRY_STACK_GAP_UP;
1719 	if (cow & MAP_INHERIT_SHARE)
1720 		inheritance = VM_INHERIT_SHARE;
1721 	else
1722 		inheritance = VM_INHERIT_DEFAULT;
1723 	if ((cow & MAP_SPLIT_BOUNDARY_MASK) != 0) {
1724 		/* This magically ignores index 0, for usual page size. */
1725 		bidx = (cow & MAP_SPLIT_BOUNDARY_MASK) >>
1726 		    MAP_SPLIT_BOUNDARY_SHIFT;
1727 		if (bidx >= MAXPAGESIZES)
1728 			return (KERN_INVALID_ARGUMENT);
1729 		bdry = pagesizes[bidx] - 1;
1730 		if ((start & bdry) != 0 || (end & bdry) != 0)
1731 			return (KERN_INVALID_ARGUMENT);
1732 		protoeflags |= bidx << MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
1733 	}
1734 
1735 	cred = NULL;
1736 	if ((cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT | MAP_CREATE_GUARD)) != 0)
1737 		goto charged;
1738 	if ((cow & MAP_ACC_CHARGED) || ((prot & VM_PROT_WRITE) &&
1739 	    ((protoeflags & MAP_ENTRY_NEEDS_COPY) || object == NULL))) {
1740 		if (!(cow & MAP_ACC_CHARGED) && !swap_reserve(end - start))
1741 			return (KERN_RESOURCE_SHORTAGE);
1742 		KASSERT(object == NULL ||
1743 		    (protoeflags & MAP_ENTRY_NEEDS_COPY) != 0 ||
1744 		    object->cred == NULL,
1745 		    ("overcommit: vm_map_insert o %p", object));
1746 		cred = curthread->td_ucred;
1747 	}
1748 
1749 charged:
1750 	/* Expand the kernel pmap, if necessary. */
1751 	if (map == kernel_map && end > kernel_vm_end)
1752 		pmap_growkernel(end);
1753 	if (object != NULL) {
1754 		/*
1755 		 * OBJ_ONEMAPPING must be cleared unless this mapping
1756 		 * is trivially proven to be the only mapping for any
1757 		 * of the object's pages.  (Object granularity
1758 		 * reference counting is insufficient to recognize
1759 		 * aliases with precision.)
1760 		 */
1761 		if ((object->flags & OBJ_ANON) != 0) {
1762 			VM_OBJECT_WLOCK(object);
1763 			if (object->ref_count > 1 || object->shadow_count != 0)
1764 				vm_object_clear_flag(object, OBJ_ONEMAPPING);
1765 			VM_OBJECT_WUNLOCK(object);
1766 		}
1767 	} else if ((prev_entry->eflags & ~MAP_ENTRY_USER_WIRED) ==
1768 	    protoeflags &&
1769 	    (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP |
1770 	    MAP_VN_EXEC)) == 0 &&
1771 	    prev_entry->end == start && (prev_entry->cred == cred ||
1772 	    (prev_entry->object.vm_object != NULL &&
1773 	    prev_entry->object.vm_object->cred == cred)) &&
1774 	    vm_object_coalesce(prev_entry->object.vm_object,
1775 	    prev_entry->offset,
1776 	    (vm_size_t)(prev_entry->end - prev_entry->start),
1777 	    (vm_size_t)(end - prev_entry->end), cred != NULL &&
1778 	    (protoeflags & MAP_ENTRY_NEEDS_COPY) == 0)) {
1779 		/*
1780 		 * We were able to extend the object.  Determine if we
1781 		 * can extend the previous map entry to include the
1782 		 * new range as well.
1783 		 */
1784 		if (prev_entry->inheritance == inheritance &&
1785 		    prev_entry->protection == prot &&
1786 		    prev_entry->max_protection == max &&
1787 		    prev_entry->wired_count == 0) {
1788 			KASSERT((prev_entry->eflags & MAP_ENTRY_USER_WIRED) ==
1789 			    0, ("prev_entry %p has incoherent wiring",
1790 			    prev_entry));
1791 			if ((prev_entry->eflags & MAP_ENTRY_GUARD) == 0)
1792 				map->size += end - prev_entry->end;
1793 			vm_map_entry_resize(map, prev_entry,
1794 			    end - prev_entry->end);
1795 			vm_map_try_merge_entries(map, prev_entry, next_entry);
1796 			return (KERN_SUCCESS);
1797 		}
1798 
1799 		/*
1800 		 * If we can extend the object but cannot extend the
1801 		 * map entry, we have to create a new map entry.  We
1802 		 * must bump the ref count on the extended object to
1803 		 * account for it.  object may be NULL.
1804 		 */
1805 		object = prev_entry->object.vm_object;
1806 		offset = prev_entry->offset +
1807 		    (prev_entry->end - prev_entry->start);
1808 		vm_object_reference(object);
1809 		if (cred != NULL && object != NULL && object->cred != NULL &&
1810 		    !(prev_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
1811 			/* Object already accounts for this uid. */
1812 			cred = NULL;
1813 		}
1814 	}
1815 	if (cred != NULL)
1816 		crhold(cred);
1817 
1818 	/*
1819 	 * Create a new entry
1820 	 */
1821 	new_entry = vm_map_entry_create(map);
1822 	new_entry->start = start;
1823 	new_entry->end = end;
1824 	new_entry->cred = NULL;
1825 
1826 	new_entry->eflags = protoeflags;
1827 	new_entry->object.vm_object = object;
1828 	new_entry->offset = offset;
1829 
1830 	new_entry->inheritance = inheritance;
1831 	new_entry->protection = prot;
1832 	new_entry->max_protection = max;
1833 	new_entry->wired_count = 0;
1834 	new_entry->wiring_thread = NULL;
1835 	new_entry->read_ahead = VM_FAULT_READ_AHEAD_INIT;
1836 	new_entry->next_read = start;
1837 
1838 	KASSERT(cred == NULL || !ENTRY_CHARGED(new_entry),
1839 	    ("overcommit: vm_map_insert leaks vm_map %p", new_entry));
1840 	new_entry->cred = cred;
1841 
1842 	/*
1843 	 * Insert the new entry into the list
1844 	 */
1845 	vm_map_entry_link(map, new_entry);
1846 	if ((new_entry->eflags & MAP_ENTRY_GUARD) == 0)
1847 		map->size += new_entry->end - new_entry->start;
1848 
1849 	/*
1850 	 * Try to coalesce the new entry with both the previous and next
1851 	 * entries in the list.  Previously, we only attempted to coalesce
1852 	 * with the previous entry when object is NULL.  Here, we handle the
1853 	 * other cases, which are less common.
1854 	 */
1855 	vm_map_try_merge_entries(map, prev_entry, new_entry);
1856 	vm_map_try_merge_entries(map, new_entry, next_entry);
1857 
1858 	if ((cow & (MAP_PREFAULT | MAP_PREFAULT_PARTIAL)) != 0) {
1859 		vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset),
1860 		    end - start, cow & MAP_PREFAULT_PARTIAL);
1861 	}
1862 
1863 	return (KERN_SUCCESS);
1864 }
1865 
1866 /*
1867  *	vm_map_findspace:
1868  *
1869  *	Find the first fit (lowest VM address) for "length" free bytes
1870  *	beginning at address >= start in the given map.
1871  *
1872  *	In a vm_map_entry, "max_free" is the maximum amount of
1873  *	contiguous free space between an entry in its subtree and a
1874  *	neighbor of that entry.  This allows finding a free region in
1875  *	one path down the tree, so O(log n) amortized with splay
1876  *	trees.
1877  *
1878  *	The map must be locked, and leaves it so.
1879  *
1880  *	Returns: starting address if sufficient space,
1881  *		 vm_map_max(map)-length+1 if insufficient space.
1882  */
1883 vm_offset_t
1884 vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length)
1885 {
1886 	vm_map_entry_t header, llist, rlist, root, y;
1887 	vm_size_t left_length, max_free_left, max_free_right;
1888 	vm_offset_t gap_end;
1889 
1890 	VM_MAP_ASSERT_LOCKED(map);
1891 
1892 	/*
1893 	 * Request must fit within min/max VM address and must avoid
1894 	 * address wrap.
1895 	 */
1896 	start = MAX(start, vm_map_min(map));
1897 	if (start >= vm_map_max(map) || length > vm_map_max(map) - start)
1898 		return (vm_map_max(map) - length + 1);
1899 
1900 	/* Empty tree means wide open address space. */
1901 	if (map->root == NULL)
1902 		return (start);
1903 
1904 	/*
1905 	 * After splay_split, if start is within an entry, push it to the start
1906 	 * of the following gap.  If rlist is at the end of the gap containing
1907 	 * start, save the end of that gap in gap_end to see if the gap is big
1908 	 * enough; otherwise set gap_end to start skip gap-checking and move
1909 	 * directly to a search of the right subtree.
1910 	 */
1911 	header = &map->header;
1912 	root = vm_map_splay_split(map, start, length, &llist, &rlist);
1913 	gap_end = rlist->start;
1914 	if (root != NULL) {
1915 		start = root->end;
1916 		if (root->right != rlist)
1917 			gap_end = start;
1918 		max_free_left = vm_map_splay_merge_left(header, root, llist);
1919 		max_free_right = vm_map_splay_merge_right(header, root, rlist);
1920 	} else if (rlist != header) {
1921 		root = rlist;
1922 		rlist = root->left;
1923 		max_free_left = vm_map_splay_merge_pred(header, root, llist);
1924 		max_free_right = vm_map_splay_merge_right(header, root, rlist);
1925 	} else {
1926 		root = llist;
1927 		llist = root->right;
1928 		max_free_left = vm_map_splay_merge_left(header, root, llist);
1929 		max_free_right = vm_map_splay_merge_succ(header, root, rlist);
1930 	}
1931 	root->max_free = vm_size_max(max_free_left, max_free_right);
1932 	map->root = root;
1933 	VM_MAP_ASSERT_CONSISTENT(map);
1934 	if (length <= gap_end - start)
1935 		return (start);
1936 
1937 	/* With max_free, can immediately tell if no solution. */
1938 	if (root->right == header || length > root->right->max_free)
1939 		return (vm_map_max(map) - length + 1);
1940 
1941 	/*
1942 	 * Splay for the least large-enough gap in the right subtree.
1943 	 */
1944 	llist = rlist = header;
1945 	for (left_length = 0;;
1946 	    left_length = vm_map_entry_max_free_left(root, llist)) {
1947 		if (length <= left_length)
1948 			SPLAY_LEFT_STEP(root, y, llist, rlist,
1949 			    length <= vm_map_entry_max_free_left(y, llist));
1950 		else
1951 			SPLAY_RIGHT_STEP(root, y, llist, rlist,
1952 			    length > vm_map_entry_max_free_left(y, root));
1953 		if (root == NULL)
1954 			break;
1955 	}
1956 	root = llist;
1957 	llist = root->right;
1958 	max_free_left = vm_map_splay_merge_left(header, root, llist);
1959 	if (rlist == header) {
1960 		root->max_free = vm_size_max(max_free_left,
1961 		    vm_map_splay_merge_succ(header, root, rlist));
1962 	} else {
1963 		y = rlist;
1964 		rlist = y->left;
1965 		y->max_free = vm_size_max(
1966 		    vm_map_splay_merge_pred(root, y, root),
1967 		    vm_map_splay_merge_right(header, y, rlist));
1968 		root->max_free = vm_size_max(max_free_left, y->max_free);
1969 	}
1970 	map->root = root;
1971 	VM_MAP_ASSERT_CONSISTENT(map);
1972 	return (root->end);
1973 }
1974 
1975 int
1976 vm_map_fixed(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
1977     vm_offset_t start, vm_size_t length, vm_prot_t prot,
1978     vm_prot_t max, int cow)
1979 {
1980 	vm_offset_t end;
1981 	int result;
1982 
1983 	end = start + length;
1984 	KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 ||
1985 	    object == NULL,
1986 	    ("vm_map_fixed: non-NULL backing object for stack"));
1987 	vm_map_lock(map);
1988 	VM_MAP_RANGE_CHECK(map, start, end);
1989 	if ((cow & MAP_CHECK_EXCL) == 0) {
1990 		result = vm_map_delete(map, start, end);
1991 		if (result != KERN_SUCCESS)
1992 			goto out;
1993 	}
1994 	if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) {
1995 		result = vm_map_stack_locked(map, start, length, sgrowsiz,
1996 		    prot, max, cow);
1997 	} else {
1998 		result = vm_map_insert(map, object, offset, start, end,
1999 		    prot, max, cow);
2000 	}
2001 out:
2002 	vm_map_unlock(map);
2003 	return (result);
2004 }
2005 
2006 static const int aslr_pages_rnd_64[2] = {0x1000, 0x10};
2007 static const int aslr_pages_rnd_32[2] = {0x100, 0x4};
2008 
2009 static int cluster_anon = 1;
2010 SYSCTL_INT(_vm, OID_AUTO, cluster_anon, CTLFLAG_RW,
2011     &cluster_anon, 0,
2012     "Cluster anonymous mappings: 0 = no, 1 = yes if no hint, 2 = always");
2013 
2014 static bool
2015 clustering_anon_allowed(vm_offset_t addr)
2016 {
2017 
2018 	switch (cluster_anon) {
2019 	case 0:
2020 		return (false);
2021 	case 1:
2022 		return (addr == 0);
2023 	case 2:
2024 	default:
2025 		return (true);
2026 	}
2027 }
2028 
2029 static long aslr_restarts;
2030 SYSCTL_LONG(_vm, OID_AUTO, aslr_restarts, CTLFLAG_RD,
2031     &aslr_restarts, 0,
2032     "Number of aslr failures");
2033 
2034 /*
2035  * Searches for the specified amount of free space in the given map with the
2036  * specified alignment.  Performs an address-ordered, first-fit search from
2037  * the given address "*addr", with an optional upper bound "max_addr".  If the
2038  * parameter "alignment" is zero, then the alignment is computed from the
2039  * given (object, offset) pair so as to enable the greatest possible use of
2040  * superpage mappings.  Returns KERN_SUCCESS and the address of the free space
2041  * in "*addr" if successful.  Otherwise, returns KERN_NO_SPACE.
2042  *
2043  * The map must be locked.  Initially, there must be at least "length" bytes
2044  * of free space at the given address.
2045  */
2046 static int
2047 vm_map_alignspace(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
2048     vm_offset_t *addr, vm_size_t length, vm_offset_t max_addr,
2049     vm_offset_t alignment)
2050 {
2051 	vm_offset_t aligned_addr, free_addr;
2052 
2053 	VM_MAP_ASSERT_LOCKED(map);
2054 	free_addr = *addr;
2055 	KASSERT(free_addr == vm_map_findspace(map, free_addr, length),
2056 	    ("caller failed to provide space %#jx at address %p",
2057 	     (uintmax_t)length, (void *)free_addr));
2058 	for (;;) {
2059 		/*
2060 		 * At the start of every iteration, the free space at address
2061 		 * "*addr" is at least "length" bytes.
2062 		 */
2063 		if (alignment == 0)
2064 			pmap_align_superpage(object, offset, addr, length);
2065 		else if ((*addr & (alignment - 1)) != 0) {
2066 			*addr &= ~(alignment - 1);
2067 			*addr += alignment;
2068 		}
2069 		aligned_addr = *addr;
2070 		if (aligned_addr == free_addr) {
2071 			/*
2072 			 * Alignment did not change "*addr", so "*addr" must
2073 			 * still provide sufficient free space.
2074 			 */
2075 			return (KERN_SUCCESS);
2076 		}
2077 
2078 		/*
2079 		 * Test for address wrap on "*addr".  A wrapped "*addr" could
2080 		 * be a valid address, in which case vm_map_findspace() cannot
2081 		 * be relied upon to fail.
2082 		 */
2083 		if (aligned_addr < free_addr)
2084 			return (KERN_NO_SPACE);
2085 		*addr = vm_map_findspace(map, aligned_addr, length);
2086 		if (*addr + length > vm_map_max(map) ||
2087 		    (max_addr != 0 && *addr + length > max_addr))
2088 			return (KERN_NO_SPACE);
2089 		free_addr = *addr;
2090 		if (free_addr == aligned_addr) {
2091 			/*
2092 			 * If a successful call to vm_map_findspace() did not
2093 			 * change "*addr", then "*addr" must still be aligned
2094 			 * and provide sufficient free space.
2095 			 */
2096 			return (KERN_SUCCESS);
2097 		}
2098 	}
2099 }
2100 
2101 int
2102 vm_map_find_aligned(vm_map_t map, vm_offset_t *addr, vm_size_t length,
2103     vm_offset_t max_addr, vm_offset_t alignment)
2104 {
2105 	/* XXXKIB ASLR eh ? */
2106 	*addr = vm_map_findspace(map, *addr, length);
2107 	if (*addr + length > vm_map_max(map) ||
2108 	    (max_addr != 0 && *addr + length > max_addr))
2109 		return (KERN_NO_SPACE);
2110 	return (vm_map_alignspace(map, NULL, 0, addr, length, max_addr,
2111 	    alignment));
2112 }
2113 
2114 /*
2115  *	vm_map_find finds an unallocated region in the target address
2116  *	map with the given length.  The search is defined to be
2117  *	first-fit from the specified address; the region found is
2118  *	returned in the same parameter.
2119  *
2120  *	If object is non-NULL, ref count must be bumped by caller
2121  *	prior to making call to account for the new entry.
2122  */
2123 int
2124 vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
2125 	    vm_offset_t *addr,	/* IN/OUT */
2126 	    vm_size_t length, vm_offset_t max_addr, int find_space,
2127 	    vm_prot_t prot, vm_prot_t max, int cow)
2128 {
2129 	vm_offset_t alignment, curr_min_addr, min_addr;
2130 	int gap, pidx, rv, try;
2131 	bool cluster, en_aslr, update_anon;
2132 
2133 	KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 ||
2134 	    object == NULL,
2135 	    ("vm_map_find: non-NULL backing object for stack"));
2136 	MPASS((cow & MAP_REMAP) == 0 || (find_space == VMFS_NO_SPACE &&
2137 	    (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0));
2138 	if (find_space == VMFS_OPTIMAL_SPACE && (object == NULL ||
2139 	    (object->flags & OBJ_COLORED) == 0))
2140 		find_space = VMFS_ANY_SPACE;
2141 	if (find_space >> 8 != 0) {
2142 		KASSERT((find_space & 0xff) == 0, ("bad VMFS flags"));
2143 		alignment = (vm_offset_t)1 << (find_space >> 8);
2144 	} else
2145 		alignment = 0;
2146 	en_aslr = (map->flags & MAP_ASLR) != 0;
2147 	update_anon = cluster = clustering_anon_allowed(*addr) &&
2148 	    (map->flags & MAP_IS_SUB_MAP) == 0 && max_addr == 0 &&
2149 	    find_space != VMFS_NO_SPACE && object == NULL &&
2150 	    (cow & (MAP_INHERIT_SHARE | MAP_STACK_GROWS_UP |
2151 	    MAP_STACK_GROWS_DOWN)) == 0 && prot != PROT_NONE;
2152 	curr_min_addr = min_addr = *addr;
2153 	if (en_aslr && min_addr == 0 && !cluster &&
2154 	    find_space != VMFS_NO_SPACE &&
2155 	    (map->flags & MAP_ASLR_IGNSTART) != 0)
2156 		curr_min_addr = min_addr = vm_map_min(map);
2157 	try = 0;
2158 	vm_map_lock(map);
2159 	if (cluster) {
2160 		curr_min_addr = map->anon_loc;
2161 		if (curr_min_addr == 0)
2162 			cluster = false;
2163 	}
2164 	if (find_space != VMFS_NO_SPACE) {
2165 		KASSERT(find_space == VMFS_ANY_SPACE ||
2166 		    find_space == VMFS_OPTIMAL_SPACE ||
2167 		    find_space == VMFS_SUPER_SPACE ||
2168 		    alignment != 0, ("unexpected VMFS flag"));
2169 again:
2170 		/*
2171 		 * When creating an anonymous mapping, try clustering
2172 		 * with an existing anonymous mapping first.
2173 		 *
2174 		 * We make up to two attempts to find address space
2175 		 * for a given find_space value. The first attempt may
2176 		 * apply randomization or may cluster with an existing
2177 		 * anonymous mapping. If this first attempt fails,
2178 		 * perform a first-fit search of the available address
2179 		 * space.
2180 		 *
2181 		 * If all tries failed, and find_space is
2182 		 * VMFS_OPTIMAL_SPACE, fallback to VMFS_ANY_SPACE.
2183 		 * Again enable clustering and randomization.
2184 		 */
2185 		try++;
2186 		MPASS(try <= 2);
2187 
2188 		if (try == 2) {
2189 			/*
2190 			 * Second try: we failed either to find a
2191 			 * suitable region for randomizing the
2192 			 * allocation, or to cluster with an existing
2193 			 * mapping.  Retry with free run.
2194 			 */
2195 			curr_min_addr = (map->flags & MAP_ASLR_IGNSTART) != 0 ?
2196 			    vm_map_min(map) : min_addr;
2197 			atomic_add_long(&aslr_restarts, 1);
2198 		}
2199 
2200 		if (try == 1 && en_aslr && !cluster) {
2201 			/*
2202 			 * Find space for allocation, including
2203 			 * gap needed for later randomization.
2204 			 */
2205 			pidx = MAXPAGESIZES > 1 && pagesizes[1] != 0 &&
2206 			    (find_space == VMFS_SUPER_SPACE || find_space ==
2207 			    VMFS_OPTIMAL_SPACE) ? 1 : 0;
2208 			gap = vm_map_max(map) > MAP_32BIT_MAX_ADDR &&
2209 			    (max_addr == 0 || max_addr > MAP_32BIT_MAX_ADDR) ?
2210 			    aslr_pages_rnd_64[pidx] : aslr_pages_rnd_32[pidx];
2211 			*addr = vm_map_findspace(map, curr_min_addr,
2212 			    length + gap * pagesizes[pidx]);
2213 			if (*addr + length + gap * pagesizes[pidx] >
2214 			    vm_map_max(map))
2215 				goto again;
2216 			/* And randomize the start address. */
2217 			*addr += (arc4random() % gap) * pagesizes[pidx];
2218 			if (max_addr != 0 && *addr + length > max_addr)
2219 				goto again;
2220 		} else {
2221 			*addr = vm_map_findspace(map, curr_min_addr, length);
2222 			if (*addr + length > vm_map_max(map) ||
2223 			    (max_addr != 0 && *addr + length > max_addr)) {
2224 				if (cluster) {
2225 					cluster = false;
2226 					MPASS(try == 1);
2227 					goto again;
2228 				}
2229 				rv = KERN_NO_SPACE;
2230 				goto done;
2231 			}
2232 		}
2233 
2234 		if (find_space != VMFS_ANY_SPACE &&
2235 		    (rv = vm_map_alignspace(map, object, offset, addr, length,
2236 		    max_addr, alignment)) != KERN_SUCCESS) {
2237 			if (find_space == VMFS_OPTIMAL_SPACE) {
2238 				find_space = VMFS_ANY_SPACE;
2239 				curr_min_addr = min_addr;
2240 				cluster = update_anon;
2241 				try = 0;
2242 				goto again;
2243 			}
2244 			goto done;
2245 		}
2246 	} else if ((cow & MAP_REMAP) != 0) {
2247 		if (!vm_map_range_valid(map, *addr, *addr + length)) {
2248 			rv = KERN_INVALID_ADDRESS;
2249 			goto done;
2250 		}
2251 		rv = vm_map_delete(map, *addr, *addr + length);
2252 		if (rv != KERN_SUCCESS)
2253 			goto done;
2254 	}
2255 	if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) {
2256 		rv = vm_map_stack_locked(map, *addr, length, sgrowsiz, prot,
2257 		    max, cow);
2258 	} else {
2259 		rv = vm_map_insert(map, object, offset, *addr, *addr + length,
2260 		    prot, max, cow);
2261 	}
2262 	if (rv == KERN_SUCCESS && update_anon)
2263 		map->anon_loc = *addr + length;
2264 done:
2265 	vm_map_unlock(map);
2266 	return (rv);
2267 }
2268 
2269 /*
2270  *	vm_map_find_min() is a variant of vm_map_find() that takes an
2271  *	additional parameter (min_addr) and treats the given address
2272  *	(*addr) differently.  Specifically, it treats *addr as a hint
2273  *	and not as the minimum address where the mapping is created.
2274  *
2275  *	This function works in two phases.  First, it tries to
2276  *	allocate above the hint.  If that fails and the hint is
2277  *	greater than min_addr, it performs a second pass, replacing
2278  *	the hint with min_addr as the minimum address for the
2279  *	allocation.
2280  */
2281 int
2282 vm_map_find_min(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
2283     vm_offset_t *addr, vm_size_t length, vm_offset_t min_addr,
2284     vm_offset_t max_addr, int find_space, vm_prot_t prot, vm_prot_t max,
2285     int cow)
2286 {
2287 	vm_offset_t hint;
2288 	int rv;
2289 
2290 	hint = *addr;
2291 	for (;;) {
2292 		rv = vm_map_find(map, object, offset, addr, length, max_addr,
2293 		    find_space, prot, max, cow);
2294 		if (rv == KERN_SUCCESS || min_addr >= hint)
2295 			return (rv);
2296 		*addr = hint = min_addr;
2297 	}
2298 }
2299 
2300 /*
2301  * A map entry with any of the following flags set must not be merged with
2302  * another entry.
2303  */
2304 #define	MAP_ENTRY_NOMERGE_MASK	(MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP | \
2305 	    MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP | MAP_ENTRY_VN_EXEC)
2306 
2307 static bool
2308 vm_map_mergeable_neighbors(vm_map_entry_t prev, vm_map_entry_t entry)
2309 {
2310 
2311 	KASSERT((prev->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 ||
2312 	    (entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0,
2313 	    ("vm_map_mergeable_neighbors: neither %p nor %p are mergeable",
2314 	    prev, entry));
2315 	return (prev->end == entry->start &&
2316 	    prev->object.vm_object == entry->object.vm_object &&
2317 	    (prev->object.vm_object == NULL ||
2318 	    prev->offset + (prev->end - prev->start) == entry->offset) &&
2319 	    prev->eflags == entry->eflags &&
2320 	    prev->protection == entry->protection &&
2321 	    prev->max_protection == entry->max_protection &&
2322 	    prev->inheritance == entry->inheritance &&
2323 	    prev->wired_count == entry->wired_count &&
2324 	    prev->cred == entry->cred);
2325 }
2326 
2327 static void
2328 vm_map_merged_neighbor_dispose(vm_map_t map, vm_map_entry_t entry)
2329 {
2330 
2331 	/*
2332 	 * If the backing object is a vnode object, vm_object_deallocate()
2333 	 * calls vrele().  However, vrele() does not lock the vnode because
2334 	 * the vnode has additional references.  Thus, the map lock can be
2335 	 * kept without causing a lock-order reversal with the vnode lock.
2336 	 *
2337 	 * Since we count the number of virtual page mappings in
2338 	 * object->un_pager.vnp.writemappings, the writemappings value
2339 	 * should not be adjusted when the entry is disposed of.
2340 	 */
2341 	if (entry->object.vm_object != NULL)
2342 		vm_object_deallocate(entry->object.vm_object);
2343 	if (entry->cred != NULL)
2344 		crfree(entry->cred);
2345 	vm_map_entry_dispose(map, entry);
2346 }
2347 
2348 /*
2349  *	vm_map_try_merge_entries:
2350  *
2351  *	Compare the given map entry to its predecessor, and merge its precessor
2352  *	into it if possible.  The entry remains valid, and may be extended.
2353  *	The predecessor may be deleted.
2354  *
2355  *	The map must be locked.
2356  */
2357 void
2358 vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev_entry,
2359     vm_map_entry_t entry)
2360 {
2361 
2362 	VM_MAP_ASSERT_LOCKED(map);
2363 	if ((entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 &&
2364 	    vm_map_mergeable_neighbors(prev_entry, entry)) {
2365 		vm_map_entry_unlink(map, prev_entry, UNLINK_MERGE_NEXT);
2366 		vm_map_merged_neighbor_dispose(map, prev_entry);
2367 	}
2368 }
2369 
2370 /*
2371  *	vm_map_entry_back:
2372  *
2373  *	Allocate an object to back a map entry.
2374  */
2375 static inline void
2376 vm_map_entry_back(vm_map_entry_t entry)
2377 {
2378 	vm_object_t object;
2379 
2380 	KASSERT(entry->object.vm_object == NULL,
2381 	    ("map entry %p has backing object", entry));
2382 	KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
2383 	    ("map entry %p is a submap", entry));
2384 	object = vm_object_allocate_anon(atop(entry->end - entry->start), NULL,
2385 	    entry->cred, entry->end - entry->start);
2386 	entry->object.vm_object = object;
2387 	entry->offset = 0;
2388 	entry->cred = NULL;
2389 }
2390 
2391 /*
2392  *	vm_map_entry_charge_object
2393  *
2394  *	If there is no object backing this entry, create one.  Otherwise, if
2395  *	the entry has cred, give it to the backing object.
2396  */
2397 static inline void
2398 vm_map_entry_charge_object(vm_map_t map, vm_map_entry_t entry)
2399 {
2400 
2401 	VM_MAP_ASSERT_LOCKED(map);
2402 	KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
2403 	    ("map entry %p is a submap", entry));
2404 	if (entry->object.vm_object == NULL && !map->system_map &&
2405 	    (entry->eflags & MAP_ENTRY_GUARD) == 0)
2406 		vm_map_entry_back(entry);
2407 	else if (entry->object.vm_object != NULL &&
2408 	    ((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) &&
2409 	    entry->cred != NULL) {
2410 		VM_OBJECT_WLOCK(entry->object.vm_object);
2411 		KASSERT(entry->object.vm_object->cred == NULL,
2412 		    ("OVERCOMMIT: %s: both cred e %p", __func__, entry));
2413 		entry->object.vm_object->cred = entry->cred;
2414 		entry->object.vm_object->charge = entry->end - entry->start;
2415 		VM_OBJECT_WUNLOCK(entry->object.vm_object);
2416 		entry->cred = NULL;
2417 	}
2418 }
2419 
2420 /*
2421  *	vm_map_entry_clone
2422  *
2423  *	Create a duplicate map entry for clipping.
2424  */
2425 static vm_map_entry_t
2426 vm_map_entry_clone(vm_map_t map, vm_map_entry_t entry)
2427 {
2428 	vm_map_entry_t new_entry;
2429 
2430 	VM_MAP_ASSERT_LOCKED(map);
2431 
2432 	/*
2433 	 * Create a backing object now, if none exists, so that more individual
2434 	 * objects won't be created after the map entry is split.
2435 	 */
2436 	vm_map_entry_charge_object(map, entry);
2437 
2438 	/* Clone the entry. */
2439 	new_entry = vm_map_entry_create(map);
2440 	*new_entry = *entry;
2441 	if (new_entry->cred != NULL)
2442 		crhold(entry->cred);
2443 	if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
2444 		vm_object_reference(new_entry->object.vm_object);
2445 		vm_map_entry_set_vnode_text(new_entry, true);
2446 		/*
2447 		 * The object->un_pager.vnp.writemappings for the object of
2448 		 * MAP_ENTRY_WRITECNT type entry shall be kept as is here.  The
2449 		 * virtual pages are re-distributed among the clipped entries,
2450 		 * so the sum is left the same.
2451 		 */
2452 	}
2453 	return (new_entry);
2454 }
2455 
2456 /*
2457  *	vm_map_clip_start:	[ internal use only ]
2458  *
2459  *	Asserts that the given entry begins at or after
2460  *	the specified address; if necessary,
2461  *	it splits the entry into two.
2462  */
2463 static int
2464 vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t startaddr)
2465 {
2466 	vm_map_entry_t new_entry;
2467 	int bdry_idx;
2468 
2469 	if (!map->system_map)
2470 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
2471 		    "%s: map %p entry %p start 0x%jx", __func__, map, entry,
2472 		    (uintmax_t)startaddr);
2473 
2474 	if (startaddr <= entry->start)
2475 		return (KERN_SUCCESS);
2476 
2477 	VM_MAP_ASSERT_LOCKED(map);
2478 	KASSERT(entry->end > startaddr && entry->start < startaddr,
2479 	    ("%s: invalid clip of entry %p", __func__, entry));
2480 
2481 	bdry_idx = (entry->eflags & MAP_ENTRY_SPLIT_BOUNDARY_MASK) >>
2482 	    MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
2483 	if (bdry_idx != 0) {
2484 		if ((startaddr & (pagesizes[bdry_idx] - 1)) != 0)
2485 			return (KERN_INVALID_ARGUMENT);
2486 	}
2487 
2488 	new_entry = vm_map_entry_clone(map, entry);
2489 
2490 	/*
2491 	 * Split off the front portion.  Insert the new entry BEFORE this one,
2492 	 * so that this entry has the specified starting address.
2493 	 */
2494 	new_entry->end = startaddr;
2495 	vm_map_entry_link(map, new_entry);
2496 	return (KERN_SUCCESS);
2497 }
2498 
2499 /*
2500  *	vm_map_lookup_clip_start:
2501  *
2502  *	Find the entry at or just after 'start', and clip it if 'start' is in
2503  *	the interior of the entry.  Return entry after 'start', and in
2504  *	prev_entry set the entry before 'start'.
2505  */
2506 static int
2507 vm_map_lookup_clip_start(vm_map_t map, vm_offset_t start,
2508     vm_map_entry_t *res_entry, vm_map_entry_t *prev_entry)
2509 {
2510 	vm_map_entry_t entry;
2511 	int rv;
2512 
2513 	if (!map->system_map)
2514 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
2515 		    "%s: map %p start 0x%jx prev %p", __func__, map,
2516 		    (uintmax_t)start, prev_entry);
2517 
2518 	if (vm_map_lookup_entry(map, start, prev_entry)) {
2519 		entry = *prev_entry;
2520 		rv = vm_map_clip_start(map, entry, start);
2521 		if (rv != KERN_SUCCESS)
2522 			return (rv);
2523 		*prev_entry = vm_map_entry_pred(entry);
2524 	} else
2525 		entry = vm_map_entry_succ(*prev_entry);
2526 	*res_entry = entry;
2527 	return (KERN_SUCCESS);
2528 }
2529 
2530 /*
2531  *	vm_map_clip_end:	[ internal use only ]
2532  *
2533  *	Asserts that the given entry ends at or before
2534  *	the specified address; if necessary,
2535  *	it splits the entry into two.
2536  */
2537 static int
2538 vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t endaddr)
2539 {
2540 	vm_map_entry_t new_entry;
2541 	int bdry_idx;
2542 
2543 	if (!map->system_map)
2544 		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
2545 		    "%s: map %p entry %p end 0x%jx", __func__, map, entry,
2546 		    (uintmax_t)endaddr);
2547 
2548 	if (endaddr >= entry->end)
2549 		return (KERN_SUCCESS);
2550 
2551 	VM_MAP_ASSERT_LOCKED(map);
2552 	KASSERT(entry->start < endaddr && entry->end > endaddr,
2553 	    ("%s: invalid clip of entry %p", __func__, entry));
2554 
2555 	bdry_idx = (entry->eflags & MAP_ENTRY_SPLIT_BOUNDARY_MASK) >>
2556 	    MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
2557 	if (bdry_idx != 0) {
2558 		if ((endaddr & (pagesizes[bdry_idx] - 1)) != 0)
2559 			return (KERN_INVALID_ARGUMENT);
2560 	}
2561 
2562 	new_entry = vm_map_entry_clone(map, entry);
2563 
2564 	/*
2565 	 * Split off the back portion.  Insert the new entry AFTER this one,
2566 	 * so that this entry has the specified ending address.
2567 	 */
2568 	new_entry->start = endaddr;
2569 	vm_map_entry_link(map, new_entry);
2570 
2571 	return (KERN_SUCCESS);
2572 }
2573 
2574 /*
2575  *	vm_map_submap:		[ kernel use only ]
2576  *
2577  *	Mark the given range as handled by a subordinate map.
2578  *
2579  *	This range must have been created with vm_map_find,
2580  *	and no other operations may have been performed on this
2581  *	range prior to calling vm_map_submap.
2582  *
2583  *	Only a limited number of operations can be performed
2584  *	within this rage after calling vm_map_submap:
2585  *		vm_fault
2586  *	[Don't try vm_map_copy!]
2587  *
2588  *	To remove a submapping, one must first remove the
2589  *	range from the superior map, and then destroy the
2590  *	submap (if desired).  [Better yet, don't try it.]
2591  */
2592 int
2593 vm_map_submap(
2594 	vm_map_t map,
2595 	vm_offset_t start,
2596 	vm_offset_t end,
2597 	vm_map_t submap)
2598 {
2599 	vm_map_entry_t entry;
2600 	int result;
2601 
2602 	result = KERN_INVALID_ARGUMENT;
2603 
2604 	vm_map_lock(submap);
2605 	submap->flags |= MAP_IS_SUB_MAP;
2606 	vm_map_unlock(submap);
2607 
2608 	vm_map_lock(map);
2609 	VM_MAP_RANGE_CHECK(map, start, end);
2610 	if (vm_map_lookup_entry(map, start, &entry) && entry->end >= end &&
2611 	    (entry->eflags & MAP_ENTRY_COW) == 0 &&
2612 	    entry->object.vm_object == NULL) {
2613 		result = vm_map_clip_start(map, entry, start);
2614 		if (result != KERN_SUCCESS)
2615 			goto unlock;
2616 		result = vm_map_clip_end(map, entry, end);
2617 		if (result != KERN_SUCCESS)
2618 			goto unlock;
2619 		entry->object.sub_map = submap;
2620 		entry->eflags |= MAP_ENTRY_IS_SUB_MAP;
2621 		result = KERN_SUCCESS;
2622 	}
2623 unlock:
2624 	vm_map_unlock(map);
2625 
2626 	if (result != KERN_SUCCESS) {
2627 		vm_map_lock(submap);
2628 		submap->flags &= ~MAP_IS_SUB_MAP;
2629 		vm_map_unlock(submap);
2630 	}
2631 	return (result);
2632 }
2633 
2634 /*
2635  * The maximum number of pages to map if MAP_PREFAULT_PARTIAL is specified
2636  */
2637 #define	MAX_INIT_PT	96
2638 
2639 /*
2640  *	vm_map_pmap_enter:
2641  *
2642  *	Preload the specified map's pmap with mappings to the specified
2643  *	object's memory-resident pages.  No further physical pages are
2644  *	allocated, and no further virtual pages are retrieved from secondary
2645  *	storage.  If the specified flags include MAP_PREFAULT_PARTIAL, then a
2646  *	limited number of page mappings are created at the low-end of the
2647  *	specified address range.  (For this purpose, a superpage mapping
2648  *	counts as one page mapping.)  Otherwise, all resident pages within
2649  *	the specified address range are mapped.
2650  */
2651 static void
2652 vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot,
2653     vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags)
2654 {
2655 	vm_offset_t start;
2656 	vm_page_t p, p_start;
2657 	vm_pindex_t mask, psize, threshold, tmpidx;
2658 
2659 	if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL)
2660 		return;
2661 	if (object->type == OBJT_DEVICE || object->type == OBJT_SG) {
2662 		VM_OBJECT_WLOCK(object);
2663 		if (object->type == OBJT_DEVICE || object->type == OBJT_SG) {
2664 			pmap_object_init_pt(map->pmap, addr, object, pindex,
2665 			    size);
2666 			VM_OBJECT_WUNLOCK(object);
2667 			return;
2668 		}
2669 		VM_OBJECT_LOCK_DOWNGRADE(object);
2670 	} else
2671 		VM_OBJECT_RLOCK(object);
2672 
2673 	psize = atop(size);
2674 	if (psize + pindex > object->size) {
2675 		if (pindex >= object->size) {
2676 			VM_OBJECT_RUNLOCK(object);
2677 			return;
2678 		}
2679 		psize = object->size - pindex;
2680 	}
2681 
2682 	start = 0;
2683 	p_start = NULL;
2684 	threshold = MAX_INIT_PT;
2685 
2686 	p = vm_page_find_least(object, pindex);
2687 	/*
2688 	 * Assert: the variable p is either (1) the page with the
2689 	 * least pindex greater than or equal to the parameter pindex
2690 	 * or (2) NULL.
2691 	 */
2692 	for (;
2693 	     p != NULL && (tmpidx = p->pindex - pindex) < psize;
2694 	     p = TAILQ_NEXT(p, listq)) {
2695 		/*
2696 		 * don't allow an madvise to blow away our really
2697 		 * free pages allocating pv entries.
2698 		 */
2699 		if (((flags & MAP_PREFAULT_MADVISE) != 0 &&
2700 		    vm_page_count_severe()) ||
2701 		    ((flags & MAP_PREFAULT_PARTIAL) != 0 &&
2702 		    tmpidx >= threshold)) {
2703 			psize = tmpidx;
2704 			break;
2705 		}
2706 		if (vm_page_all_valid(p)) {
2707 			if (p_start == NULL) {
2708 				start = addr + ptoa(tmpidx);
2709 				p_start = p;
2710 			}
2711 			/* Jump ahead if a superpage mapping is possible. */
2712 			if (p->psind > 0 && ((addr + ptoa(tmpidx)) &
2713 			    (pagesizes[p->psind] - 1)) == 0) {
2714 				mask = atop(pagesizes[p->psind]) - 1;
2715 				if (tmpidx + mask < psize &&
2716 				    vm_page_ps_test(p, PS_ALL_VALID, NULL)) {
2717 					p += mask;
2718 					threshold += mask;
2719 				}
2720 			}
2721 		} else if (p_start != NULL) {
2722 			pmap_enter_object(map->pmap, start, addr +
2723 			    ptoa(tmpidx), p_start, prot);
2724 			p_start = NULL;
2725 		}
2726 	}
2727 	if (p_start != NULL)
2728 		pmap_enter_object(map->pmap, start, addr + ptoa(psize),
2729 		    p_start, prot);
2730 	VM_OBJECT_RUNLOCK(object);
2731 }
2732 
2733 /*
2734  *	vm_map_protect:
2735  *
2736  *	Sets the protection and/or the maximum protection of the
2737  *	specified address region in the target map.
2738  */
2739 int
2740 vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
2741     vm_prot_t new_prot, vm_prot_t new_maxprot, int flags)
2742 {
2743 	vm_map_entry_t entry, first_entry, in_tran, prev_entry;
2744 	vm_object_t obj;
2745 	struct ucred *cred;
2746 	vm_prot_t old_prot;
2747 	int rv;
2748 
2749 	if (start == end)
2750 		return (KERN_SUCCESS);
2751 
2752 	if ((flags & (VM_MAP_PROTECT_SET_PROT | VM_MAP_PROTECT_SET_MAXPROT)) ==
2753 	    (VM_MAP_PROTECT_SET_PROT | VM_MAP_PROTECT_SET_MAXPROT) &&
2754 	    (new_prot & new_maxprot) != new_prot)
2755 		return (KERN_OUT_OF_BOUNDS);
2756 
2757 again:
2758 	in_tran = NULL;
2759 	vm_map_lock(map);
2760 
2761 	if ((map->flags & MAP_WXORX) != 0 &&
2762 	    (flags & VM_MAP_PROTECT_SET_PROT) != 0 &&
2763 	    (new_prot & (VM_PROT_WRITE | VM_PROT_EXECUTE)) == (VM_PROT_WRITE |
2764 	    VM_PROT_EXECUTE)) {
2765 		vm_map_unlock(map);
2766 		return (KERN_PROTECTION_FAILURE);
2767 	}
2768 
2769 	/*
2770 	 * Ensure that we are not concurrently wiring pages.  vm_map_wire() may
2771 	 * need to fault pages into the map and will drop the map lock while
2772 	 * doing so, and the VM object may end up in an inconsistent state if we
2773 	 * update the protection on the map entry in between faults.
2774 	 */
2775 	vm_map_wait_busy(map);
2776 
2777 	VM_MAP_RANGE_CHECK(map, start, end);
2778 
2779 	if (!vm_map_lookup_entry(map, start, &first_entry))
2780 		first_entry = vm_map_entry_succ(first_entry);
2781 
2782 	/*
2783 	 * Make a first pass to check for protection violations.
2784 	 */
2785 	for (entry = first_entry; entry->start < end;
2786 	    entry = vm_map_entry_succ(entry)) {
2787 		if ((entry->eflags & MAP_ENTRY_GUARD) != 0)
2788 			continue;
2789 		if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
2790 			vm_map_unlock(map);
2791 			return (KERN_INVALID_ARGUMENT);
2792 		}
2793 		if ((flags & VM_MAP_PROTECT_SET_PROT) == 0)
2794 			new_prot = entry->protection;
2795 		if ((flags & VM_MAP_PROTECT_SET_MAXPROT) == 0)
2796 			new_maxprot = entry->max_protection;
2797 		if ((new_prot & entry->max_protection) != new_prot ||
2798 		    (new_maxprot & entry->max_protection) != new_maxprot) {
2799 			vm_map_unlock(map);
2800 			return (KERN_PROTECTION_FAILURE);
2801 		}
2802 		if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0)
2803 			in_tran = entry;
2804 	}
2805 
2806 	/*
2807 	 * Postpone the operation until all in-transition map entries have
2808 	 * stabilized.  An in-transition entry might already have its pages
2809 	 * wired and wired_count incremented, but not yet have its
2810 	 * MAP_ENTRY_USER_WIRED flag set.  In which case, we would fail to call
2811 	 * vm_fault_copy_entry() in the final loop below.
2812 	 */
2813 	if (in_tran != NULL) {
2814 		in_tran->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
2815 		vm_map_unlock_and_wait(map, 0);
2816 		goto again;
2817 	}
2818 
2819 	/*
2820 	 * Before changing the protections, try to reserve swap space for any
2821 	 * private (i.e., copy-on-write) mappings that are transitioning from
2822 	 * read-only to read/write access.  If a reservation fails, break out
2823 	 * of this loop early and let the next loop simplify the entries, since
2824 	 * some may now be mergeable.
2825 	 */
2826 	rv = vm_map_clip_start(map, first_entry, start);
2827 	if (rv != KERN_SUCCESS) {
2828 		vm_map_unlock(map);
2829 		return (rv);
2830 	}
2831 	for (entry = first_entry; entry->start < end;
2832 	    entry = vm_map_entry_succ(entry)) {
2833 		rv = vm_map_clip_end(map, entry, end);
2834 		if (rv != KERN_SUCCESS) {
2835 			vm_map_unlock(map);
2836 			return (rv);
2837 		}
2838 
2839 		if ((flags & VM_MAP_PROTECT_SET_PROT) == 0)
2840 			new_prot = entry->protection;
2841 		if ((flags & VM_MAP_PROTECT_SET_MAXPROT) == 0)
2842 			new_maxprot = entry->max_protection;
2843 
2844 		if ((flags & VM_MAP_PROTECT_SET_PROT) == 0 ||
2845 		    ((new_prot & ~entry->protection) & VM_PROT_WRITE) == 0 ||
2846 		    ENTRY_CHARGED(entry) ||
2847 		    (entry->eflags & MAP_ENTRY_GUARD) != 0)
2848 			continue;
2849 
2850 		cred = curthread->td_ucred;
2851 		obj = entry->object.vm_object;
2852 
2853 		if (obj == NULL ||
2854 		    (entry->eflags & MAP_ENTRY_NEEDS_COPY) != 0) {
2855 			if (!swap_reserve(entry->end - entry->start)) {
2856 				rv = KERN_RESOURCE_SHORTAGE;
2857 				end = entry->end;
2858 				break;
2859 			}
2860 			crhold(cred);
2861 			entry->cred = cred;
2862 			continue;
2863 		}
2864 
2865 		if (obj->type != OBJT_DEFAULT && obj->type != OBJT_SWAP)
2866 			continue;
2867 		VM_OBJECT_WLOCK(obj);
2868 		if (obj->type != OBJT_DEFAULT && obj->type != OBJT_SWAP) {
2869 			VM_OBJECT_WUNLOCK(obj);
2870 			continue;
2871 		}
2872 
2873 		/*
2874 		 * Charge for the whole object allocation now, since
2875 		 * we cannot distinguish between non-charged and
2876 		 * charged clipped mapping of the same object later.
2877 		 */
2878 		KASSERT(obj->charge == 0,
2879 		    ("vm_map_protect: object %p overcharged (entry %p)",
2880 		    obj, entry));
2881 		if (!swap_reserve(ptoa(obj->size))) {
2882 			VM_OBJECT_WUNLOCK(obj);
2883 			rv = KERN_RESOURCE_SHORTAGE;
2884 			end = entry->end;
2885 			break;
2886 		}
2887 
2888 		crhold(cred);
2889 		obj->cred = cred;
2890 		obj->charge = ptoa(obj->size);
2891 		VM_OBJECT_WUNLOCK(obj);
2892 	}
2893 
2894 	/*
2895 	 * If enough swap space was available, go back and fix up protections.
2896 	 * Otherwise, just simplify entries, since some may have been modified.
2897 	 * [Note that clipping is not necessary the second time.]
2898 	 */
2899 	for (prev_entry = vm_map_entry_pred(first_entry), entry = first_entry;
2900 	    entry->start < end;
2901 	    vm_map_try_merge_entries(map, prev_entry, entry),
2902 	    prev_entry = entry, entry = vm_map_entry_succ(entry)) {
2903 		if (rv != KERN_SUCCESS ||
2904 		    (entry->eflags & MAP_ENTRY_GUARD) != 0)
2905 			continue;
2906 
2907 		old_prot = entry->protection;
2908 
2909 		if ((flags & VM_MAP_PROTECT_SET_MAXPROT) != 0) {
2910 			entry->max_protection = new_maxprot;
2911 			entry->protection = new_maxprot & old_prot;
2912 		}
2913 		if ((flags & VM_MAP_PROTECT_SET_PROT) != 0)
2914 			entry->protection = new_prot;
2915 
2916 		/*
2917 		 * For user wired map entries, the normal lazy evaluation of
2918 		 * write access upgrades through soft page faults is
2919 		 * undesirable.  Instead, immediately copy any pages that are
2920 		 * copy-on-write and enable write access in the physical map.
2921 		 */
2922 		if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0 &&
2923 		    (entry->protection & VM_PROT_WRITE) != 0 &&
2924 		    (old_prot & VM_PROT_WRITE) == 0)
2925 			vm_fault_copy_entry(map, map, entry, entry, NULL);
2926 
2927 		/*
2928 		 * When restricting access, update the physical map.  Worry
2929 		 * about copy-on-write here.
2930 		 */
2931 		if ((old_prot & ~entry->protection) != 0) {
2932 #define MASK(entry)	(((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \
2933 							VM_PROT_ALL)
2934 			pmap_protect(map->pmap, entry->start,
2935 			    entry->end,
2936 			    entry->protection & MASK(entry));
2937 #undef	MASK
2938 		}
2939 	}
2940 	vm_map_try_merge_entries(map, prev_entry, entry);
2941 	vm_map_unlock(map);
2942 	return (rv);
2943 }
2944 
2945 /*
2946  *	vm_map_madvise:
2947  *
2948  *	This routine traverses a processes map handling the madvise
2949  *	system call.  Advisories are classified as either those effecting
2950  *	the vm_map_entry structure, or those effecting the underlying
2951  *	objects.
2952  */
2953 int
2954 vm_map_madvise(
2955 	vm_map_t map,
2956 	vm_offset_t start,
2957 	vm_offset_t end,
2958 	int behav)
2959 {
2960 	vm_map_entry_t entry, prev_entry;
2961 	int rv;
2962 	bool modify_map;
2963 
2964 	/*
2965 	 * Some madvise calls directly modify the vm_map_entry, in which case
2966 	 * we need to use an exclusive lock on the map and we need to perform
2967 	 * various clipping operations.  Otherwise we only need a read-lock
2968 	 * on the map.
2969 	 */
2970 	switch(behav) {
2971 	case MADV_NORMAL:
2972 	case MADV_SEQUENTIAL:
2973 	case MADV_RANDOM:
2974 	case MADV_NOSYNC:
2975 	case MADV_AUTOSYNC:
2976 	case MADV_NOCORE:
2977 	case MADV_CORE:
2978 		if (start == end)
2979 			return (0);
2980 		modify_map = true;
2981 		vm_map_lock(map);
2982 		break;
2983 	case MADV_WILLNEED:
2984 	case MADV_DONTNEED:
2985 	case MADV_FREE:
2986 		if (start == end)
2987 			return (0);
2988 		modify_map = false;
2989 		vm_map_lock_read(map);
2990 		break;
2991 	default:
2992 		return (EINVAL);
2993 	}
2994 
2995 	/*
2996 	 * Locate starting entry and clip if necessary.
2997 	 */
2998 	VM_MAP_RANGE_CHECK(map, start, end);
2999 
3000 	if (modify_map) {
3001 		/*
3002 		 * madvise behaviors that are implemented in the vm_map_entry.
3003 		 *
3004 		 * We clip the vm_map_entry so that behavioral changes are
3005 		 * limited to the specified address range.
3006 		 */
3007 		rv = vm_map_lookup_clip_start(map, start, &entry, &prev_entry);
3008 		if (rv != KERN_SUCCESS) {
3009 			vm_map_unlock(map);
3010 			return (vm_mmap_to_errno(rv));
3011 		}
3012 
3013 		for (; entry->start < end; prev_entry = entry,
3014 		    entry = vm_map_entry_succ(entry)) {
3015 			if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
3016 				continue;
3017 
3018 			rv = vm_map_clip_end(map, entry, end);
3019 			if (rv != KERN_SUCCESS) {
3020 				vm_map_unlock(map);
3021 				return (vm_mmap_to_errno(rv));
3022 			}
3023 
3024 			switch (behav) {
3025 			case MADV_NORMAL:
3026 				vm_map_entry_set_behavior(entry,
3027 				    MAP_ENTRY_BEHAV_NORMAL);
3028 				break;
3029 			case MADV_SEQUENTIAL:
3030 				vm_map_entry_set_behavior(entry,
3031 				    MAP_ENTRY_BEHAV_SEQUENTIAL);
3032 				break;
3033 			case MADV_RANDOM:
3034 				vm_map_entry_set_behavior(entry,
3035 				    MAP_ENTRY_BEHAV_RANDOM);
3036 				break;
3037 			case MADV_NOSYNC:
3038 				entry->eflags |= MAP_ENTRY_NOSYNC;
3039 				break;
3040 			case MADV_AUTOSYNC:
3041 				entry->eflags &= ~MAP_ENTRY_NOSYNC;
3042 				break;
3043 			case MADV_NOCORE:
3044 				entry->eflags |= MAP_ENTRY_NOCOREDUMP;
3045 				break;
3046 			case MADV_CORE:
3047 				entry->eflags &= ~MAP_ENTRY_NOCOREDUMP;
3048 				break;
3049 			default:
3050 				break;
3051 			}
3052 			vm_map_try_merge_entries(map, prev_entry, entry);
3053 		}
3054 		vm_map_try_merge_entries(map, prev_entry, entry);
3055 		vm_map_unlock(map);
3056 	} else {
3057 		vm_pindex_t pstart, pend;
3058 
3059 		/*
3060 		 * madvise behaviors that are implemented in the underlying
3061 		 * vm_object.
3062 		 *
3063 		 * Since we don't clip the vm_map_entry, we have to clip
3064 		 * the vm_object pindex and count.
3065 		 */
3066 		if (!vm_map_lookup_entry(map, start, &entry))
3067 			entry = vm_map_entry_succ(entry);
3068 		for (; entry->start < end;
3069 		    entry = vm_map_entry_succ(entry)) {
3070 			vm_offset_t useEnd, useStart;
3071 
3072 			if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
3073 				continue;
3074 
3075 			/*
3076 			 * MADV_FREE would otherwise rewind time to
3077 			 * the creation of the shadow object.  Because
3078 			 * we hold the VM map read-locked, neither the
3079 			 * entry's object nor the presence of a
3080 			 * backing object can change.
3081 			 */
3082 			if (behav == MADV_FREE &&
3083 			    entry->object.vm_object != NULL &&
3084 			    entry->object.vm_object->backing_object != NULL)
3085 				continue;
3086 
3087 			pstart = OFF_TO_IDX(entry->offset);
3088 			pend = pstart + atop(entry->end - entry->start);
3089 			useStart = entry->start;
3090 			useEnd = entry->end;
3091 
3092 			if (entry->start < start) {
3093 				pstart += atop(start - entry->start);
3094 				useStart = start;
3095 			}
3096 			if (entry->end > end) {
3097 				pend -= atop(entry->end - end);
3098 				useEnd = end;
3099 			}
3100 
3101 			if (pstart >= pend)
3102 				continue;
3103 
3104 			/*
3105 			 * Perform the pmap_advise() before clearing
3106 			 * PGA_REFERENCED in vm_page_advise().  Otherwise, a
3107 			 * concurrent pmap operation, such as pmap_remove(),
3108 			 * could clear a reference in the pmap and set
3109 			 * PGA_REFERENCED on the page before the pmap_advise()
3110 			 * had completed.  Consequently, the page would appear
3111 			 * referenced based upon an old reference that
3112 			 * occurred before this pmap_advise() ran.
3113 			 */
3114 			if (behav == MADV_DONTNEED || behav == MADV_FREE)
3115 				pmap_advise(map->pmap, useStart, useEnd,
3116 				    behav);
3117 
3118 			vm_object_madvise(entry->object.vm_object, pstart,
3119 			    pend, behav);
3120 
3121 			/*
3122 			 * Pre-populate paging structures in the
3123 			 * WILLNEED case.  For wired entries, the
3124 			 * paging structures are already populated.
3125 			 */
3126 			if (behav == MADV_WILLNEED &&
3127 			    entry->wired_count == 0) {
3128 				vm_map_pmap_enter(map,
3129 				    useStart,
3130 				    entry->protection,
3131 				    entry->object.vm_object,
3132 				    pstart,
3133 				    ptoa(pend - pstart),
3134 				    MAP_PREFAULT_MADVISE
3135 				);
3136 			}
3137 		}
3138 		vm_map_unlock_read(map);
3139 	}
3140 	return (0);
3141 }
3142 
3143 /*
3144  *	vm_map_inherit:
3145  *
3146  *	Sets the inheritance of the specified address
3147  *	range in the target map.  Inheritance
3148  *	affects how the map will be shared with
3149  *	child maps at the time of vmspace_fork.
3150  */
3151 int
3152 vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
3153 	       vm_inherit_t new_inheritance)
3154 {
3155 	vm_map_entry_t entry, lentry, prev_entry, start_entry;
3156 	int rv;
3157 
3158 	switch (new_inheritance) {
3159 	case VM_INHERIT_NONE:
3160 	case VM_INHERIT_COPY:
3161 	case VM_INHERIT_SHARE:
3162 	case VM_INHERIT_ZERO:
3163 		break;
3164 	default:
3165 		return (KERN_INVALID_ARGUMENT);
3166 	}
3167 	if (start == end)
3168 		return (KERN_SUCCESS);
3169 	vm_map_lock(map);
3170 	VM_MAP_RANGE_CHECK(map, start, end);
3171 	rv = vm_map_lookup_clip_start(map, start, &start_entry, &prev_entry);
3172 	if (rv != KERN_SUCCESS)
3173 		goto unlock;
3174 	if (vm_map_lookup_entry(map, end - 1, &lentry)) {
3175 		rv = vm_map_clip_end(map, lentry, end);
3176 		if (rv != KERN_SUCCESS)
3177 			goto unlock;
3178 	}
3179 	if (new_inheritance == VM_INHERIT_COPY) {
3180 		for (entry = start_entry; entry->start < end;
3181 		    prev_entry = entry, entry = vm_map_entry_succ(entry)) {
3182 			if ((entry->eflags & MAP_ENTRY_SPLIT_BOUNDARY_MASK)
3183 			    != 0) {
3184 				rv = KERN_INVALID_ARGUMENT;
3185 				goto unlock;
3186 			}
3187 		}
3188 	}
3189 	for (entry = start_entry; entry->start < end; prev_entry = entry,
3190 	    entry = vm_map_entry_succ(entry)) {
3191 		KASSERT(entry->end <= end, ("non-clipped entry %p end %jx %jx",
3192 		    entry, (uintmax_t)entry->end, (uintmax_t)end));
3193 		if ((entry->eflags & MAP_ENTRY_GUARD) == 0 ||
3194 		    new_inheritance != VM_INHERIT_ZERO)
3195 			entry->inheritance = new_inheritance;
3196 		vm_map_try_merge_entries(map, prev_entry, entry);
3197 	}
3198 	vm_map_try_merge_entries(map, prev_entry, entry);
3199 unlock:
3200 	vm_map_unlock(map);
3201 	return (rv);
3202 }
3203 
3204 /*
3205  *	vm_map_entry_in_transition:
3206  *
3207  *	Release the map lock, and sleep until the entry is no longer in
3208  *	transition.  Awake and acquire the map lock.  If the map changed while
3209  *	another held the lock, lookup a possibly-changed entry at or after the
3210  *	'start' position of the old entry.
3211  */
3212 static vm_map_entry_t
3213 vm_map_entry_in_transition(vm_map_t map, vm_offset_t in_start,
3214     vm_offset_t *io_end, bool holes_ok, vm_map_entry_t in_entry)
3215 {
3216 	vm_map_entry_t entry;
3217 	vm_offset_t start;
3218 	u_int last_timestamp;
3219 
3220 	VM_MAP_ASSERT_LOCKED(map);
3221 	KASSERT((in_entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0,
3222 	    ("not in-tranition map entry %p", in_entry));
3223 	/*
3224 	 * We have not yet clipped the entry.
3225 	 */
3226 	start = MAX(in_start, in_entry->start);
3227 	in_entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
3228 	last_timestamp = map->timestamp;
3229 	if (vm_map_unlock_and_wait(map, 0)) {
3230 		/*
3231 		 * Allow interruption of user wiring/unwiring?
3232 		 */
3233 	}
3234 	vm_map_lock(map);
3235 	if (last_timestamp + 1 == map->timestamp)
3236 		return (in_entry);
3237 
3238 	/*
3239 	 * Look again for the entry because the map was modified while it was
3240 	 * unlocked.  Specifically, the entry may have been clipped, merged, or
3241 	 * deleted.
3242 	 */
3243 	if (!vm_map_lookup_entry(map, start, &entry)) {
3244 		if (!holes_ok) {
3245 			*io_end = start;
3246 			return (NULL);
3247 		}
3248 		entry = vm_map_entry_succ(entry);
3249 	}
3250 	return (entry);
3251 }
3252 
3253 /*
3254  *	vm_map_unwire:
3255  *
3256  *	Implements both kernel and user unwiring.
3257  */
3258 int
3259 vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
3260     int flags)
3261 {
3262 	vm_map_entry_t entry, first_entry, next_entry, prev_entry;
3263 	int rv;
3264 	bool holes_ok, need_wakeup, user_unwire;
3265 
3266 	if (start == end)
3267 		return (KERN_SUCCESS);
3268 	holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0;
3269 	user_unwire = (flags & VM_MAP_WIRE_USER) != 0;
3270 	vm_map_lock(map);
3271 	VM_MAP_RANGE_CHECK(map, start, end);
3272 	if (!vm_map_lookup_entry(map, start, &first_entry)) {
3273 		if (holes_ok)
3274 			first_entry = vm_map_entry_succ(first_entry);
3275 		else {
3276 			vm_map_unlock(map);
3277 			return (KERN_INVALID_ADDRESS);
3278 		}
3279 	}
3280 	rv = KERN_SUCCESS;
3281 	for (entry = first_entry; entry->start < end; entry = next_entry) {
3282 		if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
3283 			/*
3284 			 * We have not yet clipped the entry.
3285 			 */
3286 			next_entry = vm_map_entry_in_transition(map, start,
3287 			    &end, holes_ok, entry);
3288 			if (next_entry == NULL) {
3289 				if (entry == first_entry) {
3290 					vm_map_unlock(map);
3291 					return (KERN_INVALID_ADDRESS);
3292 				}
3293 				rv = KERN_INVALID_ADDRESS;
3294 				break;
3295 			}
3296 			first_entry = (entry == first_entry) ?
3297 			    next_entry : NULL;
3298 			continue;
3299 		}
3300 		rv = vm_map_clip_start(map, entry, start);
3301 		if (rv != KERN_SUCCESS)
3302 			break;
3303 		rv = vm_map_clip_end(map, entry, end);
3304 		if (rv != KERN_SUCCESS)
3305 			break;
3306 
3307 		/*
3308 		 * Mark the entry in case the map lock is released.  (See
3309 		 * above.)
3310 		 */
3311 		KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 &&
3312 		    entry->wiring_thread == NULL,
3313 		    ("owned map entry %p", entry));
3314 		entry->eflags |= MAP_ENTRY_IN_TRANSITION;
3315 		entry->wiring_thread = curthread;
3316 		next_entry = vm_map_entry_succ(entry);
3317 		/*
3318 		 * Check the map for holes in the specified region.
3319 		 * If holes_ok, skip this check.
3320 		 */
3321 		if (!holes_ok &&
3322 		    entry->end < end && next_entry->start > entry->end) {
3323 			end = entry->end;
3324 			rv = KERN_INVALID_ADDRESS;
3325 			break;
3326 		}
3327 		/*
3328 		 * If system unwiring, require that the entry is system wired.
3329 		 */
3330 		if (!user_unwire &&
3331 		    vm_map_entry_system_wired_count(entry) == 0) {
3332 			end = entry->end;
3333 			rv = KERN_INVALID_ARGUMENT;
3334 			break;
3335 		}
3336 	}
3337 	need_wakeup = false;
3338 	if (first_entry == NULL &&
3339 	    !vm_map_lookup_entry(map, start, &first_entry)) {
3340 		KASSERT(holes_ok, ("vm_map_unwire: lookup failed"));
3341 		prev_entry = first_entry;
3342 		entry = vm_map_entry_succ(first_entry);
3343 	} else {
3344 		prev_entry = vm_map_entry_pred(first_entry);
3345 		entry = first_entry;
3346 	}
3347 	for (; entry->start < end;
3348 	    prev_entry = entry, entry = vm_map_entry_succ(entry)) {
3349 		/*
3350 		 * If holes_ok was specified, an empty
3351 		 * space in the unwired region could have been mapped
3352 		 * while the map lock was dropped for draining
3353 		 * MAP_ENTRY_IN_TRANSITION.  Moreover, another thread
3354 		 * could be simultaneously wiring this new mapping
3355 		 * entry.  Detect these cases and skip any entries
3356 		 * marked as in transition by us.
3357 		 */
3358 		if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 ||
3359 		    entry->wiring_thread != curthread) {
3360 			KASSERT(holes_ok,
3361 			    ("vm_map_unwire: !HOLESOK and new/changed entry"));
3362 			continue;
3363 		}
3364 
3365 		if (rv == KERN_SUCCESS && (!user_unwire ||
3366 		    (entry->eflags & MAP_ENTRY_USER_WIRED))) {
3367 			if (entry->wired_count == 1)
3368 				vm_map_entry_unwire(map, entry);
3369 			else
3370 				entry->wired_count--;
3371 			if (user_unwire)
3372 				entry->eflags &= ~MAP_ENTRY_USER_WIRED;
3373 		}
3374 		KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0,
3375 		    ("vm_map_unwire: in-transition flag missing %p", entry));
3376 		KASSERT(entry->wiring_thread == curthread,
3377 		    ("vm_map_unwire: alien wire %p", entry));
3378 		entry->eflags &= ~MAP_ENTRY_IN_TRANSITION;
3379 		entry->wiring_thread = NULL;
3380 		if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
3381 			entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
3382 			need_wakeup = true;
3383 		}
3384 		vm_map_try_merge_entries(map, prev_entry, entry);
3385 	}
3386 	vm_map_try_merge_entries(map, prev_entry, entry);
3387 	vm_map_unlock(map);
3388 	if (need_wakeup)
3389 		vm_map_wakeup(map);
3390 	return (rv);
3391 }
3392 
3393 static void
3394 vm_map_wire_user_count_sub(u_long npages)
3395 {
3396 
3397 	atomic_subtract_long(&vm_user_wire_count, npages);
3398 }
3399 
3400 static bool
3401 vm_map_wire_user_count_add(u_long npages)
3402 {
3403 	u_long wired;
3404 
3405 	wired = vm_user_wire_count;
3406 	do {
3407 		if (npages + wired > vm_page_max_user_wired)
3408 			return (false);
3409 	} while (!atomic_fcmpset_long(&vm_user_wire_count, &wired,
3410 	    npages + wired));
3411 
3412 	return (true);
3413 }
3414 
3415 /*
3416  *	vm_map_wire_entry_failure:
3417  *
3418  *	Handle a wiring failure on the given entry.
3419  *
3420  *	The map should be locked.
3421  */
3422 static void
3423 vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry,
3424     vm_offset_t failed_addr)
3425 {
3426 
3427 	VM_MAP_ASSERT_LOCKED(map);
3428 	KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 &&
3429 	    entry->wired_count == 1,
3430 	    ("vm_map_wire_entry_failure: entry %p isn't being wired", entry));
3431 	KASSERT(failed_addr < entry->end,
3432 	    ("vm_map_wire_entry_failure: entry %p was fully wired", entry));
3433 
3434 	/*
3435 	 * If any pages at the start of this entry were successfully wired,
3436 	 * then unwire them.
3437 	 */
3438 	if (failed_addr > entry->start) {
3439 		pmap_unwire(map->pmap, entry->start, failed_addr);
3440 		vm_object_unwire(entry->object.vm_object, entry->offset,
3441 		    failed_addr - entry->start, PQ_ACTIVE);
3442 	}
3443 
3444 	/*
3445 	 * Assign an out-of-range value to represent the failure to wire this
3446 	 * entry.
3447 	 */
3448 	entry->wired_count = -1;
3449 }
3450 
3451 int
3452 vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
3453 {
3454 	int rv;
3455 
3456 	vm_map_lock(map);
3457 	rv = vm_map_wire_locked(map, start, end, flags);
3458 	vm_map_unlock(map);
3459 	return (rv);
3460 }
3461 
3462 /*
3463  *	vm_map_wire_locked:
3464  *
3465  *	Implements both kernel and user wiring.  Returns with the map locked,
3466  *	the map lock may be dropped.
3467  */
3468 int
3469 vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
3470 {
3471 	vm_map_entry_t entry, first_entry, next_entry, prev_entry;
3472 	vm_offset_t faddr, saved_end, saved_start;
3473 	u_long incr, npages;
3474 	u_int bidx, last_timestamp;
3475 	int rv;
3476 	bool holes_ok, need_wakeup, user_wire;
3477 	vm_prot_t prot;
3478 
3479 	VM_MAP_ASSERT_LOCKED(map);
3480 
3481 	if (start == end)
3482 		return (KERN_SUCCESS);
3483 	prot = 0;
3484 	if (flags & VM_MAP_WIRE_WRITE)
3485 		prot |= VM_PROT_WRITE;
3486 	holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0;
3487 	user_wire = (flags & VM_MAP_WIRE_USER) != 0;
3488 	VM_MAP_RANGE_CHECK(map, start, end);
3489 	if (!vm_map_lookup_entry(map, start, &first_entry)) {
3490 		if (holes_ok)
3491 			first_entry = vm_map_entry_succ(first_entry);
3492 		else
3493 			return (KERN_INVALID_ADDRESS);
3494 	}
3495 	for (entry = first_entry; entry->start < end; entry = next_entry) {
3496 		if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
3497 			/*
3498 			 * We have not yet clipped the entry.
3499 			 */
3500 			next_entry = vm_map_entry_in_transition(map, start,
3501 			    &end, holes_ok, entry);
3502 			if (next_entry == NULL) {
3503 				if (entry == first_entry)
3504 					return (KERN_INVALID_ADDRESS);
3505 				rv = KERN_INVALID_ADDRESS;
3506 				goto done;
3507 			}
3508 			first_entry = (entry == first_entry) ?
3509 			    next_entry : NULL;
3510 			continue;
3511 		}
3512 		rv = vm_map_clip_start(map, entry, start);
3513 		if (rv != KERN_SUCCESS)
3514 			goto done;
3515 		rv = vm_map_clip_end(map, entry, end);
3516 		if (rv != KERN_SUCCESS)
3517 			goto done;
3518 
3519 		/*
3520 		 * Mark the entry in case the map lock is released.  (See
3521 		 * above.)
3522 		 */
3523 		KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 &&
3524 		    entry->wiring_thread == NULL,
3525 		    ("owned map entry %p", entry));
3526 		entry->eflags |= MAP_ENTRY_IN_TRANSITION;
3527 		entry->wiring_thread = curthread;
3528 		if ((entry->protection & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0
3529 		    || (entry->protection & prot) != prot) {
3530 			entry->eflags |= MAP_ENTRY_WIRE_SKIPPED;
3531 			if (!holes_ok) {
3532 				end = entry->end;
3533 				rv = KERN_INVALID_ADDRESS;
3534 				goto done;
3535 			}
3536 		} else if (entry->wired_count == 0) {
3537 			entry->wired_count++;
3538 
3539 			npages = atop(entry->end - entry->start);
3540 			if (user_wire && !vm_map_wire_user_count_add(npages)) {
3541 				vm_map_wire_entry_failure(map, entry,
3542 				    entry->start);
3543 				end = entry->end;
3544 				rv = KERN_RESOURCE_SHORTAGE;
3545 				goto done;
3546 			}
3547 
3548 			/*
3549 			 * Release the map lock, relying on the in-transition
3550 			 * mark.  Mark the map busy for fork.
3551 			 */
3552 			saved_start = entry->start;
3553 			saved_end = entry->end;
3554 			last_timestamp = map->timestamp;
3555 			bidx = (entry->eflags & MAP_ENTRY_SPLIT_BOUNDARY_MASK)
3556 			    >> MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
3557 			incr =  pagesizes[bidx];
3558 			vm_map_busy(map);
3559 			vm_map_unlock(map);
3560 
3561 			for (faddr = saved_start; faddr < saved_end;
3562 			    faddr += incr) {
3563 				/*
3564 				 * Simulate a fault to get the page and enter
3565 				 * it into the physical map.
3566 				 */
3567 				rv = vm_fault(map, faddr, VM_PROT_NONE,
3568 				    VM_FAULT_WIRE, NULL);
3569 				if (rv != KERN_SUCCESS)
3570 					break;
3571 			}
3572 			vm_map_lock(map);
3573 			vm_map_unbusy(map);
3574 			if (last_timestamp + 1 != map->timestamp) {
3575 				/*
3576 				 * Look again for the entry because the map was
3577 				 * modified while it was unlocked.  The entry
3578 				 * may have been clipped, but NOT merged or
3579 				 * deleted.
3580 				 */
3581 				if (!vm_map_lookup_entry(map, saved_start,
3582 				    &next_entry))
3583 					KASSERT(false,
3584 					    ("vm_map_wire: lookup failed"));
3585 				first_entry = (entry == first_entry) ?
3586 				    next_entry : NULL;
3587 				for (entry = next_entry; entry->end < saved_end;
3588 				    entry = vm_map_entry_succ(entry)) {
3589 					/*
3590 					 * In case of failure, handle entries
3591 					 * that were not fully wired here;
3592 					 * fully wired entries are handled
3593 					 * later.
3594 					 */
3595 					if (rv != KERN_SUCCESS &&
3596 					    faddr < entry->end)
3597 						vm_map_wire_entry_failure(map,
3598 						    entry, faddr);
3599 				}
3600 			}
3601 			if (rv != KERN_SUCCESS) {
3602 				vm_map_wire_entry_failure(map, entry, faddr);
3603 				if (user_wire)
3604 					vm_map_wire_user_count_sub(npages);
3605 				end = entry->end;
3606 				goto done;
3607 			}
3608 		} else if (!user_wire ||
3609 			   (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) {
3610 			entry->wired_count++;
3611 		}
3612 		/*
3613 		 * Check the map for holes in the specified region.
3614 		 * If holes_ok was specified, skip this check.
3615 		 */
3616 		next_entry = vm_map_entry_succ(entry);
3617 		if (!holes_ok &&
3618 		    entry->end < end && next_entry->start > entry->end) {
3619 			end = entry->end;
3620 			rv = KERN_INVALID_ADDRESS;
3621 			goto done;
3622 		}
3623 	}
3624 	rv = KERN_SUCCESS;
3625 done:
3626 	need_wakeup = false;
3627 	if (first_entry == NULL &&
3628 	    !vm_map_lookup_entry(map, start, &first_entry)) {
3629 		KASSERT(holes_ok, ("vm_map_wire: lookup failed"));
3630 		prev_entry = first_entry;
3631 		entry = vm_map_entry_succ(first_entry);
3632 	} else {
3633 		prev_entry = vm_map_entry_pred(first_entry);
3634 		entry = first_entry;
3635 	}
3636 	for (; entry->start < end;
3637 	    prev_entry = entry, entry = vm_map_entry_succ(entry)) {
3638 		/*
3639 		 * If holes_ok was specified, an empty
3640 		 * space in the unwired region could have been mapped
3641 		 * while the map lock was dropped for faulting in the
3642 		 * pages or draining MAP_ENTRY_IN_TRANSITION.
3643 		 * Moreover, another thread could be simultaneously
3644 		 * wiring this new mapping entry.  Detect these cases
3645 		 * and skip any entries marked as in transition not by us.
3646 		 *
3647 		 * Another way to get an entry not marked with
3648 		 * MAP_ENTRY_IN_TRANSITION is after failed clipping,
3649 		 * which set rv to KERN_INVALID_ARGUMENT.
3650 		 */
3651 		if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 ||
3652 		    entry->wiring_thread != curthread) {
3653 			KASSERT(holes_ok || rv == KERN_INVALID_ARGUMENT,
3654 			    ("vm_map_wire: !HOLESOK and new/changed entry"));
3655 			continue;
3656 		}
3657 
3658 		if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0) {
3659 			/* do nothing */
3660 		} else if (rv == KERN_SUCCESS) {
3661 			if (user_wire)
3662 				entry->eflags |= MAP_ENTRY_USER_WIRED;
3663 		} else if (entry->wired_count == -1) {
3664 			/*
3665 			 * Wiring failed on this entry.  Thus, unwiring is
3666 			 * unnecessary.
3667 			 */
3668 			entry->wired_count = 0;
3669 		} else if (!user_wire ||
3670 		    (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) {
3671 			/*
3672 			 * Undo the wiring.  Wiring succeeded on this entry
3673 			 * but failed on a later entry.
3674 			 */
3675 			if (entry->wired_count == 1) {
3676 				vm_map_entry_unwire(map, entry);
3677 				if (user_wire)
3678 					vm_map_wire_user_count_sub(
3679 					    atop(entry->end - entry->start));
3680 			} else
3681 				entry->wired_count--;
3682 		}
3683 		KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0,
3684 		    ("vm_map_wire: in-transition flag missing %p", entry));
3685 		KASSERT(entry->wiring_thread == curthread,
3686 		    ("vm_map_wire: alien wire %p", entry));
3687 		entry->eflags &= ~(MAP_ENTRY_IN_TRANSITION |
3688 		    MAP_ENTRY_WIRE_SKIPPED);
3689 		entry->wiring_thread = NULL;
3690 		if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
3691 			entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
3692 			need_wakeup = true;
3693 		}
3694 		vm_map_try_merge_entries(map, prev_entry, entry);
3695 	}
3696 	vm_map_try_merge_entries(map, prev_entry, entry);
3697 	if (need_wakeup)
3698 		vm_map_wakeup(map);
3699 	return (rv);
3700 }
3701 
3702 /*
3703  * vm_map_sync
3704  *
3705  * Push any dirty cached pages in the address range to their pager.
3706  * If syncio is TRUE, dirty pages are written synchronously.
3707  * If invalidate is TRUE, any cached pages are freed as well.
3708  *
3709  * If the size of the region from start to end is zero, we are
3710  * supposed to flush all modified pages within the region containing
3711  * start.  Unfortunately, a region can be split or coalesced with
3712  * neighboring regions, making it difficult to determine what the
3713  * original region was.  Therefore, we approximate this requirement by
3714  * flushing the current region containing start.
3715  *
3716  * Returns an error if any part of the specified range is not mapped.
3717  */
3718 int
3719 vm_map_sync(
3720 	vm_map_t map,
3721 	vm_offset_t start,
3722 	vm_offset_t end,
3723 	boolean_t syncio,
3724 	boolean_t invalidate)
3725 {
3726 	vm_map_entry_t entry, first_entry, next_entry;
3727 	vm_size_t size;
3728 	vm_object_t object;
3729 	vm_ooffset_t offset;
3730 	unsigned int last_timestamp;
3731 	int bdry_idx;
3732 	boolean_t failed;
3733 
3734 	vm_map_lock_read(map);
3735 	VM_MAP_RANGE_CHECK(map, start, end);
3736 	if (!vm_map_lookup_entry(map, start, &first_entry)) {
3737 		vm_map_unlock_read(map);
3738 		return (KERN_INVALID_ADDRESS);
3739 	} else if (start == end) {
3740 		start = first_entry->start;
3741 		end = first_entry->end;
3742 	}
3743 
3744 	/*
3745 	 * Make a first pass to check for user-wired memory, holes,
3746 	 * and partial invalidation of largepage mappings.
3747 	 */
3748 	for (entry = first_entry; entry->start < end; entry = next_entry) {
3749 		if (invalidate) {
3750 			if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0) {
3751 				vm_map_unlock_read(map);
3752 				return (KERN_INVALID_ARGUMENT);
3753 			}
3754 			bdry_idx = (entry->eflags &
3755 			    MAP_ENTRY_SPLIT_BOUNDARY_MASK) >>
3756 			    MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
3757 			if (bdry_idx != 0 &&
3758 			    ((start & (pagesizes[bdry_idx] - 1)) != 0 ||
3759 			    (end & (pagesizes[bdry_idx] - 1)) != 0)) {
3760 				vm_map_unlock_read(map);
3761 				return (KERN_INVALID_ARGUMENT);
3762 			}
3763 		}
3764 		next_entry = vm_map_entry_succ(entry);
3765 		if (end > entry->end &&
3766 		    entry->end != next_entry->start) {
3767 			vm_map_unlock_read(map);
3768 			return (KERN_INVALID_ADDRESS);
3769 		}
3770 	}
3771 
3772 	if (invalidate)
3773 		pmap_remove(map->pmap, start, end);
3774 	failed = FALSE;
3775 
3776 	/*
3777 	 * Make a second pass, cleaning/uncaching pages from the indicated
3778 	 * objects as we go.
3779 	 */
3780 	for (entry = first_entry; entry->start < end;) {
3781 		offset = entry->offset + (start - entry->start);
3782 		size = (end <= entry->end ? end : entry->end) - start;
3783 		if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
3784 			vm_map_t smap;
3785 			vm_map_entry_t tentry;
3786 			vm_size_t tsize;
3787 
3788 			smap = entry->object.sub_map;
3789 			vm_map_lock_read(smap);
3790 			(void) vm_map_lookup_entry(smap, offset, &tentry);
3791 			tsize = tentry->end - offset;
3792 			if (tsize < size)
3793 				size = tsize;
3794 			object = tentry->object.vm_object;
3795 			offset = tentry->offset + (offset - tentry->start);
3796 			vm_map_unlock_read(smap);
3797 		} else {
3798 			object = entry->object.vm_object;
3799 		}
3800 		vm_object_reference(object);
3801 		last_timestamp = map->timestamp;
3802 		vm_map_unlock_read(map);
3803 		if (!vm_object_sync(object, offset, size, syncio, invalidate))
3804 			failed = TRUE;
3805 		start += size;
3806 		vm_object_deallocate(object);
3807 		vm_map_lock_read(map);
3808 		if (last_timestamp == map->timestamp ||
3809 		    !vm_map_lookup_entry(map, start, &entry))
3810 			entry = vm_map_entry_succ(entry);
3811 	}
3812 
3813 	vm_map_unlock_read(map);
3814 	return (failed ? KERN_FAILURE : KERN_SUCCESS);
3815 }
3816 
3817 /*
3818  *	vm_map_entry_unwire:	[ internal use only ]
3819  *
3820  *	Make the region specified by this entry pageable.
3821  *
3822  *	The map in question should be locked.
3823  *	[This is the reason for this routine's existence.]
3824  */
3825 static void
3826 vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry)
3827 {
3828 	vm_size_t size;
3829 
3830 	VM_MAP_ASSERT_LOCKED(map);
3831 	KASSERT(entry->wired_count > 0,
3832 	    ("vm_map_entry_unwire: entry %p isn't wired", entry));
3833 
3834 	size = entry->end - entry->start;
3835 	if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0)
3836 		vm_map_wire_user_count_sub(atop(size));
3837 	pmap_unwire(map->pmap, entry->start, entry->end);
3838 	vm_object_unwire(entry->object.vm_object, entry->offset, size,
3839 	    PQ_ACTIVE);
3840 	entry->wired_count = 0;
3841 }
3842 
3843 static void
3844 vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map)
3845 {
3846 
3847 	if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
3848 		vm_object_deallocate(entry->object.vm_object);
3849 	uma_zfree(system_map ? kmapentzone : mapentzone, entry);
3850 }
3851 
3852 /*
3853  *	vm_map_entry_delete:	[ internal use only ]
3854  *
3855  *	Deallocate the given entry from the target map.
3856  */
3857 static void
3858 vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry)
3859 {
3860 	vm_object_t object;
3861 	vm_pindex_t offidxstart, offidxend, size1;
3862 	vm_size_t size;
3863 
3864 	vm_map_entry_unlink(map, entry, UNLINK_MERGE_NONE);
3865 	object = entry->object.vm_object;
3866 
3867 	if ((entry->eflags & MAP_ENTRY_GUARD) != 0) {
3868 		MPASS(entry->cred == NULL);
3869 		MPASS((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0);
3870 		MPASS(object == NULL);
3871 		vm_map_entry_deallocate(entry, map->system_map);
3872 		return;
3873 	}
3874 
3875 	size = entry->end - entry->start;
3876 	map->size -= size;
3877 
3878 	if (entry->cred != NULL) {
3879 		swap_release_by_cred(size, entry->cred);
3880 		crfree(entry->cred);
3881 	}
3882 
3883 	if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0 || object == NULL) {
3884 		entry->object.vm_object = NULL;
3885 	} else if ((object->flags & OBJ_ANON) != 0 ||
3886 	    object == kernel_object) {
3887 		KASSERT(entry->cred == NULL || object->cred == NULL ||
3888 		    (entry->eflags & MAP_ENTRY_NEEDS_COPY),
3889 		    ("OVERCOMMIT vm_map_entry_delete: both cred %p", entry));
3890 		offidxstart = OFF_TO_IDX(entry->offset);
3891 		offidxend = offidxstart + atop(size);
3892 		VM_OBJECT_WLOCK(object);
3893 		if (object->ref_count != 1 &&
3894 		    ((object->flags & OBJ_ONEMAPPING) != 0 ||
3895 		    object == kernel_object)) {
3896 			vm_object_collapse(object);
3897 
3898 			/*
3899 			 * The option OBJPR_NOTMAPPED can be passed here
3900 			 * because vm_map_delete() already performed
3901 			 * pmap_remove() on the only mapping to this range
3902 			 * of pages.
3903 			 */
3904 			vm_object_page_remove(object, offidxstart, offidxend,
3905 			    OBJPR_NOTMAPPED);
3906 			if (offidxend >= object->size &&
3907 			    offidxstart < object->size) {
3908 				size1 = object->size;
3909 				object->size = offidxstart;
3910 				if (object->cred != NULL) {
3911 					size1 -= object->size;
3912 					KASSERT(object->charge >= ptoa(size1),
3913 					    ("object %p charge < 0", object));
3914 					swap_release_by_cred(ptoa(size1),
3915 					    object->cred);
3916 					object->charge -= ptoa(size1);
3917 				}
3918 			}
3919 		}
3920 		VM_OBJECT_WUNLOCK(object);
3921 	}
3922 	if (map->system_map)
3923 		vm_map_entry_deallocate(entry, TRUE);
3924 	else {
3925 		entry->defer_next = curthread->td_map_def_user;
3926 		curthread->td_map_def_user = entry;
3927 	}
3928 }
3929 
3930 /*
3931  *	vm_map_delete:	[ internal use only ]
3932  *
3933  *	Deallocates the given address range from the target
3934  *	map.
3935  */
3936 int
3937 vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end)
3938 {
3939 	vm_map_entry_t entry, next_entry, scratch_entry;
3940 	int rv;
3941 
3942 	VM_MAP_ASSERT_LOCKED(map);
3943 
3944 	if (start == end)
3945 		return (KERN_SUCCESS);
3946 
3947 	/*
3948 	 * Find the start of the region, and clip it.
3949 	 * Step through all entries in this region.
3950 	 */
3951 	rv = vm_map_lookup_clip_start(map, start, &entry, &scratch_entry);
3952 	if (rv != KERN_SUCCESS)
3953 		return (rv);
3954 	for (; entry->start < end; entry = next_entry) {
3955 		/*
3956 		 * Wait for wiring or unwiring of an entry to complete.
3957 		 * Also wait for any system wirings to disappear on
3958 		 * user maps.
3959 		 */
3960 		if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 ||
3961 		    (vm_map_pmap(map) != kernel_pmap &&
3962 		    vm_map_entry_system_wired_count(entry) != 0)) {
3963 			unsigned int last_timestamp;
3964 			vm_offset_t saved_start;
3965 
3966 			saved_start = entry->start;
3967 			entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
3968 			last_timestamp = map->timestamp;
3969 			(void) vm_map_unlock_and_wait(map, 0);
3970 			vm_map_lock(map);
3971 			if (last_timestamp + 1 != map->timestamp) {
3972 				/*
3973 				 * Look again for the entry because the map was
3974 				 * modified while it was unlocked.
3975 				 * Specifically, the entry may have been
3976 				 * clipped, merged, or deleted.
3977 				 */
3978 				rv = vm_map_lookup_clip_start(map, saved_start,
3979 				    &next_entry, &scratch_entry);
3980 				if (rv != KERN_SUCCESS)
3981 					break;
3982 			} else
3983 				next_entry = entry;
3984 			continue;
3985 		}
3986 
3987 		/* XXXKIB or delete to the upper superpage boundary ? */
3988 		rv = vm_map_clip_end(map, entry, end);
3989 		if (rv != KERN_SUCCESS)
3990 			break;
3991 		next_entry = vm_map_entry_succ(entry);
3992 
3993 		/*
3994 		 * Unwire before removing addresses from the pmap; otherwise,
3995 		 * unwiring will put the entries back in the pmap.
3996 		 */
3997 		if (entry->wired_count != 0)
3998 			vm_map_entry_unwire(map, entry);
3999 
4000 		/*
4001 		 * Remove mappings for the pages, but only if the
4002 		 * mappings could exist.  For instance, it does not
4003 		 * make sense to call pmap_remove() for guard entries.
4004 		 */
4005 		if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0 ||
4006 		    entry->object.vm_object != NULL)
4007 			pmap_remove(map->pmap, entry->start, entry->end);
4008 
4009 		if (entry->end == map->anon_loc)
4010 			map->anon_loc = entry->start;
4011 
4012 		/*
4013 		 * Delete the entry only after removing all pmap
4014 		 * entries pointing to its pages.  (Otherwise, its
4015 		 * page frames may be reallocated, and any modify bits
4016 		 * will be set in the wrong object!)
4017 		 */
4018 		vm_map_entry_delete(map, entry);
4019 	}
4020 	return (rv);
4021 }
4022 
4023 /*
4024  *	vm_map_remove:
4025  *
4026  *	Remove the given address range from the target map.
4027  *	This is the exported form of vm_map_delete.
4028  */
4029 int
4030 vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end)
4031 {
4032 	int result;
4033 
4034 	vm_map_lock(map);
4035 	VM_MAP_RANGE_CHECK(map, start, end);
4036 	result = vm_map_delete(map, start, end);
4037 	vm_map_unlock(map);
4038 	return (result);
4039 }
4040 
4041 /*
4042  *	vm_map_check_protection:
4043  *
4044  *	Assert that the target map allows the specified privilege on the
4045  *	entire address region given.  The entire region must be allocated.
4046  *
4047  *	WARNING!  This code does not and should not check whether the
4048  *	contents of the region is accessible.  For example a smaller file
4049  *	might be mapped into a larger address space.
4050  *
4051  *	NOTE!  This code is also called by munmap().
4052  *
4053  *	The map must be locked.  A read lock is sufficient.
4054  */
4055 boolean_t
4056 vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end,
4057 			vm_prot_t protection)
4058 {
4059 	vm_map_entry_t entry;
4060 	vm_map_entry_t tmp_entry;
4061 
4062 	if (!vm_map_lookup_entry(map, start, &tmp_entry))
4063 		return (FALSE);
4064 	entry = tmp_entry;
4065 
4066 	while (start < end) {
4067 		/*
4068 		 * No holes allowed!
4069 		 */
4070 		if (start < entry->start)
4071 			return (FALSE);
4072 		/*
4073 		 * Check protection associated with entry.
4074 		 */
4075 		if ((entry->protection & protection) != protection)
4076 			return (FALSE);
4077 		/* go to next entry */
4078 		start = entry->end;
4079 		entry = vm_map_entry_succ(entry);
4080 	}
4081 	return (TRUE);
4082 }
4083 
4084 /*
4085  *
4086  *	vm_map_copy_swap_object:
4087  *
4088  *	Copies a swap-backed object from an existing map entry to a
4089  *	new one.  Carries forward the swap charge.  May change the
4090  *	src object on return.
4091  */
4092 static void
4093 vm_map_copy_swap_object(vm_map_entry_t src_entry, vm_map_entry_t dst_entry,
4094     vm_offset_t size, vm_ooffset_t *fork_charge)
4095 {
4096 	vm_object_t src_object;
4097 	struct ucred *cred;
4098 	int charged;
4099 
4100 	src_object = src_entry->object.vm_object;
4101 	charged = ENTRY_CHARGED(src_entry);
4102 	if ((src_object->flags & OBJ_ANON) != 0) {
4103 		VM_OBJECT_WLOCK(src_object);
4104 		vm_object_collapse(src_object);
4105 		if ((src_object->flags & OBJ_ONEMAPPING) != 0) {
4106 			vm_object_split(src_entry);
4107 			src_object = src_entry->object.vm_object;
4108 		}
4109 		vm_object_reference_locked(src_object);
4110 		vm_object_clear_flag(src_object, OBJ_ONEMAPPING);
4111 		VM_OBJECT_WUNLOCK(src_object);
4112 	} else
4113 		vm_object_reference(src_object);
4114 	if (src_entry->cred != NULL &&
4115 	    !(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
4116 		KASSERT(src_object->cred == NULL,
4117 		    ("OVERCOMMIT: vm_map_copy_anon_entry: cred %p",
4118 		     src_object));
4119 		src_object->cred = src_entry->cred;
4120 		src_object->charge = size;
4121 	}
4122 	dst_entry->object.vm_object = src_object;
4123 	if (charged) {
4124 		cred = curthread->td_ucred;
4125 		crhold(cred);
4126 		dst_entry->cred = cred;
4127 		*fork_charge += size;
4128 		if (!(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
4129 			crhold(cred);
4130 			src_entry->cred = cred;
4131 			*fork_charge += size;
4132 		}
4133 	}
4134 }
4135 
4136 /*
4137  *	vm_map_copy_entry:
4138  *
4139  *	Copies the contents of the source entry to the destination
4140  *	entry.  The entries *must* be aligned properly.
4141  */
4142 static void
4143 vm_map_copy_entry(
4144 	vm_map_t src_map,
4145 	vm_map_t dst_map,
4146 	vm_map_entry_t src_entry,
4147 	vm_map_entry_t dst_entry,
4148 	vm_ooffset_t *fork_charge)
4149 {
4150 	vm_object_t src_object;
4151 	vm_map_entry_t fake_entry;
4152 	vm_offset_t size;
4153 
4154 	VM_MAP_ASSERT_LOCKED(dst_map);
4155 
4156 	if ((dst_entry->eflags|src_entry->eflags) & MAP_ENTRY_IS_SUB_MAP)
4157 		return;
4158 
4159 	if (src_entry->wired_count == 0 ||
4160 	    (src_entry->protection & VM_PROT_WRITE) == 0) {
4161 		/*
4162 		 * If the source entry is marked needs_copy, it is already
4163 		 * write-protected.
4164 		 */
4165 		if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0 &&
4166 		    (src_entry->protection & VM_PROT_WRITE) != 0) {
4167 			pmap_protect(src_map->pmap,
4168 			    src_entry->start,
4169 			    src_entry->end,
4170 			    src_entry->protection & ~VM_PROT_WRITE);
4171 		}
4172 
4173 		/*
4174 		 * Make a copy of the object.
4175 		 */
4176 		size = src_entry->end - src_entry->start;
4177 		if ((src_object = src_entry->object.vm_object) != NULL) {
4178 			if (src_object->type == OBJT_DEFAULT ||
4179 			    src_object->type == OBJT_SWAP) {
4180 				vm_map_copy_swap_object(src_entry, dst_entry,
4181 				    size, fork_charge);
4182 				/* May have split/collapsed, reload obj. */
4183 				src_object = src_entry->object.vm_object;
4184 			} else {
4185 				vm_object_reference(src_object);
4186 				dst_entry->object.vm_object = src_object;
4187 			}
4188 			src_entry->eflags |= MAP_ENTRY_COW |
4189 			    MAP_ENTRY_NEEDS_COPY;
4190 			dst_entry->eflags |= MAP_ENTRY_COW |
4191 			    MAP_ENTRY_NEEDS_COPY;
4192 			dst_entry->offset = src_entry->offset;
4193 			if (src_entry->eflags & MAP_ENTRY_WRITECNT) {
4194 				/*
4195 				 * MAP_ENTRY_WRITECNT cannot
4196 				 * indicate write reference from
4197 				 * src_entry, since the entry is
4198 				 * marked as needs copy.  Allocate a
4199 				 * fake entry that is used to
4200 				 * decrement object->un_pager writecount
4201 				 * at the appropriate time.  Attach
4202 				 * fake_entry to the deferred list.
4203 				 */
4204 				fake_entry = vm_map_entry_create(dst_map);
4205 				fake_entry->eflags = MAP_ENTRY_WRITECNT;
4206 				src_entry->eflags &= ~MAP_ENTRY_WRITECNT;
4207 				vm_object_reference(src_object);
4208 				fake_entry->object.vm_object = src_object;
4209 				fake_entry->start = src_entry->start;
4210 				fake_entry->end = src_entry->end;
4211 				fake_entry->defer_next =
4212 				    curthread->td_map_def_user;
4213 				curthread->td_map_def_user = fake_entry;
4214 			}
4215 
4216 			pmap_copy(dst_map->pmap, src_map->pmap,
4217 			    dst_entry->start, dst_entry->end - dst_entry->start,
4218 			    src_entry->start);
4219 		} else {
4220 			dst_entry->object.vm_object = NULL;
4221 			dst_entry->offset = 0;
4222 			if (src_entry->cred != NULL) {
4223 				dst_entry->cred = curthread->td_ucred;
4224 				crhold(dst_entry->cred);
4225 				*fork_charge += size;
4226 			}
4227 		}
4228 	} else {
4229 		/*
4230 		 * We don't want to make writeable wired pages copy-on-write.
4231 		 * Immediately copy these pages into the new map by simulating
4232 		 * page faults.  The new pages are pageable.
4233 		 */
4234 		vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry,
4235 		    fork_charge);
4236 	}
4237 }
4238 
4239 /*
4240  * vmspace_map_entry_forked:
4241  * Update the newly-forked vmspace each time a map entry is inherited
4242  * or copied.  The values for vm_dsize and vm_tsize are approximate
4243  * (and mostly-obsolete ideas in the face of mmap(2) et al.)
4244  */
4245 static void
4246 vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2,
4247     vm_map_entry_t entry)
4248 {
4249 	vm_size_t entrysize;
4250 	vm_offset_t newend;
4251 
4252 	if ((entry->eflags & MAP_ENTRY_GUARD) != 0)
4253 		return;
4254 	entrysize = entry->end - entry->start;
4255 	vm2->vm_map.size += entrysize;
4256 	if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) {
4257 		vm2->vm_ssize += btoc(entrysize);
4258 	} else if (entry->start >= (vm_offset_t)vm1->vm_daddr &&
4259 	    entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) {
4260 		newend = MIN(entry->end,
4261 		    (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize));
4262 		vm2->vm_dsize += btoc(newend - entry->start);
4263 	} else if (entry->start >= (vm_offset_t)vm1->vm_taddr &&
4264 	    entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) {
4265 		newend = MIN(entry->end,
4266 		    (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize));
4267 		vm2->vm_tsize += btoc(newend - entry->start);
4268 	}
4269 }
4270 
4271 /*
4272  * vmspace_fork:
4273  * Create a new process vmspace structure and vm_map
4274  * based on those of an existing process.  The new map
4275  * is based on the old map, according to the inheritance
4276  * values on the regions in that map.
4277  *
4278  * XXX It might be worth coalescing the entries added to the new vmspace.
4279  *
4280  * The source map must not be locked.
4281  */
4282 struct vmspace *
4283 vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
4284 {
4285 	struct vmspace *vm2;
4286 	vm_map_t new_map, old_map;
4287 	vm_map_entry_t new_entry, old_entry;
4288 	vm_object_t object;
4289 	int error, locked;
4290 	vm_inherit_t inh;
4291 
4292 	old_map = &vm1->vm_map;
4293 	/* Copy immutable fields of vm1 to vm2. */
4294 	vm2 = vmspace_alloc(vm_map_min(old_map), vm_map_max(old_map),
4295 	    pmap_pinit);
4296 	if (vm2 == NULL)
4297 		return (NULL);
4298 
4299 	vm2->vm_taddr = vm1->vm_taddr;
4300 	vm2->vm_daddr = vm1->vm_daddr;
4301 	vm2->vm_maxsaddr = vm1->vm_maxsaddr;
4302 	vm_map_lock(old_map);
4303 	if (old_map->busy)
4304 		vm_map_wait_busy(old_map);
4305 	new_map = &vm2->vm_map;
4306 	locked = vm_map_trylock(new_map); /* trylock to silence WITNESS */
4307 	KASSERT(locked, ("vmspace_fork: lock failed"));
4308 
4309 	error = pmap_vmspace_copy(new_map->pmap, old_map->pmap);
4310 	if (error != 0) {
4311 		sx_xunlock(&old_map->lock);
4312 		sx_xunlock(&new_map->lock);
4313 		vm_map_process_deferred();
4314 		vmspace_free(vm2);
4315 		return (NULL);
4316 	}
4317 
4318 	new_map->anon_loc = old_map->anon_loc;
4319 	new_map->flags |= old_map->flags & (MAP_ASLR | MAP_ASLR_IGNSTART |
4320 	    MAP_WXORX);
4321 
4322 	VM_MAP_ENTRY_FOREACH(old_entry, old_map) {
4323 		if ((old_entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
4324 			panic("vm_map_fork: encountered a submap");
4325 
4326 		inh = old_entry->inheritance;
4327 		if ((old_entry->eflags & MAP_ENTRY_GUARD) != 0 &&
4328 		    inh != VM_INHERIT_NONE)
4329 			inh = VM_INHERIT_COPY;
4330 
4331 		switch (inh) {
4332 		case VM_INHERIT_NONE:
4333 			break;
4334 
4335 		case VM_INHERIT_SHARE:
4336 			/*
4337 			 * Clone the entry, creating the shared object if
4338 			 * necessary.
4339 			 */
4340 			object = old_entry->object.vm_object;
4341 			if (object == NULL) {
4342 				vm_map_entry_back(old_entry);
4343 				object = old_entry->object.vm_object;
4344 			}
4345 
4346 			/*
4347 			 * Add the reference before calling vm_object_shadow
4348 			 * to insure that a shadow object is created.
4349 			 */
4350 			vm_object_reference(object);
4351 			if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) {
4352 				vm_object_shadow(&old_entry->object.vm_object,
4353 				    &old_entry->offset,
4354 				    old_entry->end - old_entry->start,
4355 				    old_entry->cred,
4356 				    /* Transfer the second reference too. */
4357 				    true);
4358 				old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
4359 				old_entry->cred = NULL;
4360 
4361 				/*
4362 				 * As in vm_map_merged_neighbor_dispose(),
4363 				 * the vnode lock will not be acquired in
4364 				 * this call to vm_object_deallocate().
4365 				 */
4366 				vm_object_deallocate(object);
4367 				object = old_entry->object.vm_object;
4368 			} else {
4369 				VM_OBJECT_WLOCK(object);
4370 				vm_object_clear_flag(object, OBJ_ONEMAPPING);
4371 				if (old_entry->cred != NULL) {
4372 					KASSERT(object->cred == NULL,
4373 					    ("vmspace_fork both cred"));
4374 					object->cred = old_entry->cred;
4375 					object->charge = old_entry->end -
4376 					    old_entry->start;
4377 					old_entry->cred = NULL;
4378 				}
4379 
4380 				/*
4381 				 * Assert the correct state of the vnode
4382 				 * v_writecount while the object is locked, to
4383 				 * not relock it later for the assertion
4384 				 * correctness.
4385 				 */
4386 				if (old_entry->eflags & MAP_ENTRY_WRITECNT &&
4387 				    object->type == OBJT_VNODE) {
4388 					KASSERT(((struct vnode *)object->
4389 					    handle)->v_writecount > 0,
4390 					    ("vmspace_fork: v_writecount %p",
4391 					    object));
4392 					KASSERT(object->un_pager.vnp.
4393 					    writemappings > 0,
4394 					    ("vmspace_fork: vnp.writecount %p",
4395 					    object));
4396 				}
4397 				VM_OBJECT_WUNLOCK(object);
4398 			}
4399 
4400 			/*
4401 			 * Clone the entry, referencing the shared object.
4402 			 */
4403 			new_entry = vm_map_entry_create(new_map);
4404 			*new_entry = *old_entry;
4405 			new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED |
4406 			    MAP_ENTRY_IN_TRANSITION);
4407 			new_entry->wiring_thread = NULL;
4408 			new_entry->wired_count = 0;
4409 			if (new_entry->eflags & MAP_ENTRY_WRITECNT) {
4410 				vm_pager_update_writecount(object,
4411 				    new_entry->start, new_entry->end);
4412 			}
4413 			vm_map_entry_set_vnode_text(new_entry, true);
4414 
4415 			/*
4416 			 * Insert the entry into the new map -- we know we're
4417 			 * inserting at the end of the new map.
4418 			 */
4419 			vm_map_entry_link(new_map, new_entry);
4420 			vmspace_map_entry_forked(vm1, vm2, new_entry);
4421 
4422 			/*
4423 			 * Update the physical map
4424 			 */
4425 			pmap_copy(new_map->pmap, old_map->pmap,
4426 			    new_entry->start,
4427 			    (old_entry->end - old_entry->start),
4428 			    old_entry->start);
4429 			break;
4430 
4431 		case VM_INHERIT_COPY:
4432 			/*
4433 			 * Clone the entry and link into the map.
4434 			 */
4435 			new_entry = vm_map_entry_create(new_map);
4436 			*new_entry = *old_entry;
4437 			/*
4438 			 * Copied entry is COW over the old object.
4439 			 */
4440 			new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED |
4441 			    MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_WRITECNT);
4442 			new_entry->wiring_thread = NULL;
4443 			new_entry->wired_count = 0;
4444 			new_entry->object.vm_object = NULL;
4445 			new_entry->cred = NULL;
4446 			vm_map_entry_link(new_map, new_entry);
4447 			vmspace_map_entry_forked(vm1, vm2, new_entry);
4448 			vm_map_copy_entry(old_map, new_map, old_entry,
4449 			    new_entry, fork_charge);
4450 			vm_map_entry_set_vnode_text(new_entry, true);
4451 			break;
4452 
4453 		case VM_INHERIT_ZERO:
4454 			/*
4455 			 * Create a new anonymous mapping entry modelled from
4456 			 * the old one.
4457 			 */
4458 			new_entry = vm_map_entry_create(new_map);
4459 			memset(new_entry, 0, sizeof(*new_entry));
4460 
4461 			new_entry->start = old_entry->start;
4462 			new_entry->end = old_entry->end;
4463 			new_entry->eflags = old_entry->eflags &
4464 			    ~(MAP_ENTRY_USER_WIRED | MAP_ENTRY_IN_TRANSITION |
4465 			    MAP_ENTRY_WRITECNT | MAP_ENTRY_VN_EXEC |
4466 			    MAP_ENTRY_SPLIT_BOUNDARY_MASK);
4467 			new_entry->protection = old_entry->protection;
4468 			new_entry->max_protection = old_entry->max_protection;
4469 			new_entry->inheritance = VM_INHERIT_ZERO;
4470 
4471 			vm_map_entry_link(new_map, new_entry);
4472 			vmspace_map_entry_forked(vm1, vm2, new_entry);
4473 
4474 			new_entry->cred = curthread->td_ucred;
4475 			crhold(new_entry->cred);
4476 			*fork_charge += (new_entry->end - new_entry->start);
4477 
4478 			break;
4479 		}
4480 	}
4481 	/*
4482 	 * Use inlined vm_map_unlock() to postpone handling the deferred
4483 	 * map entries, which cannot be done until both old_map and
4484 	 * new_map locks are released.
4485 	 */
4486 	sx_xunlock(&old_map->lock);
4487 	sx_xunlock(&new_map->lock);
4488 	vm_map_process_deferred();
4489 
4490 	return (vm2);
4491 }
4492 
4493 /*
4494  * Create a process's stack for exec_new_vmspace().  This function is never
4495  * asked to wire the newly created stack.
4496  */
4497 int
4498 vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
4499     vm_prot_t prot, vm_prot_t max, int cow)
4500 {
4501 	vm_size_t growsize, init_ssize;
4502 	rlim_t vmemlim;
4503 	int rv;
4504 
4505 	MPASS((map->flags & MAP_WIREFUTURE) == 0);
4506 	growsize = sgrowsiz;
4507 	init_ssize = (max_ssize < growsize) ? max_ssize : growsize;
4508 	vm_map_lock(map);
4509 	vmemlim = lim_cur(curthread, RLIMIT_VMEM);
4510 	/* If we would blow our VMEM resource limit, no go */
4511 	if (map->size + init_ssize > vmemlim) {
4512 		rv = KERN_NO_SPACE;
4513 		goto out;
4514 	}
4515 	rv = vm_map_stack_locked(map, addrbos, max_ssize, growsize, prot,
4516 	    max, cow);
4517 out:
4518 	vm_map_unlock(map);
4519 	return (rv);
4520 }
4521 
4522 static int stack_guard_page = 1;
4523 SYSCTL_INT(_security_bsd, OID_AUTO, stack_guard_page, CTLFLAG_RWTUN,
4524     &stack_guard_page, 0,
4525     "Specifies the number of guard pages for a stack that grows");
4526 
4527 static int
4528 vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
4529     vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow)
4530 {
4531 	vm_map_entry_t new_entry, prev_entry;
4532 	vm_offset_t bot, gap_bot, gap_top, top;
4533 	vm_size_t init_ssize, sgp;
4534 	int orient, rv;
4535 
4536 	/*
4537 	 * The stack orientation is piggybacked with the cow argument.
4538 	 * Extract it into orient and mask the cow argument so that we
4539 	 * don't pass it around further.
4540 	 */
4541 	orient = cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP);
4542 	KASSERT(orient != 0, ("No stack grow direction"));
4543 	KASSERT(orient != (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP),
4544 	    ("bi-dir stack"));
4545 
4546 	if (max_ssize == 0 ||
4547 	    !vm_map_range_valid(map, addrbos, addrbos + max_ssize))
4548 		return (KERN_INVALID_ADDRESS);
4549 	sgp = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ||
4550 	    (curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 :
4551 	    (vm_size_t)stack_guard_page * PAGE_SIZE;
4552 	if (sgp >= max_ssize)
4553 		return (KERN_INVALID_ARGUMENT);
4554 
4555 	init_ssize = growsize;
4556 	if (max_ssize < init_ssize + sgp)
4557 		init_ssize = max_ssize - sgp;
4558 
4559 	/* If addr is already mapped, no go */
4560 	if (vm_map_lookup_entry(map, addrbos, &prev_entry))
4561 		return (KERN_NO_SPACE);
4562 
4563 	/*
4564 	 * If we can't accommodate max_ssize in the current mapping, no go.
4565 	 */
4566 	if (vm_map_entry_succ(prev_entry)->start < addrbos + max_ssize)
4567 		return (KERN_NO_SPACE);
4568 
4569 	/*
4570 	 * We initially map a stack of only init_ssize.  We will grow as
4571 	 * needed later.  Depending on the orientation of the stack (i.e.
4572 	 * the grow direction) we either map at the top of the range, the
4573 	 * bottom of the range or in the middle.
4574 	 *
4575 	 * Note: we would normally expect prot and max to be VM_PROT_ALL,
4576 	 * and cow to be 0.  Possibly we should eliminate these as input
4577 	 * parameters, and just pass these values here in the insert call.
4578 	 */
4579 	if (orient == MAP_STACK_GROWS_DOWN) {
4580 		bot = addrbos + max_ssize - init_ssize;
4581 		top = bot + init_ssize;
4582 		gap_bot = addrbos;
4583 		gap_top = bot;
4584 	} else /* if (orient == MAP_STACK_GROWS_UP) */ {
4585 		bot = addrbos;
4586 		top = bot + init_ssize;
4587 		gap_bot = top;
4588 		gap_top = addrbos + max_ssize;
4589 	}
4590 	rv = vm_map_insert(map, NULL, 0, bot, top, prot, max, cow);
4591 	if (rv != KERN_SUCCESS)
4592 		return (rv);
4593 	new_entry = vm_map_entry_succ(prev_entry);
4594 	KASSERT(new_entry->end == top || new_entry->start == bot,
4595 	    ("Bad entry start/end for new stack entry"));
4596 	KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 ||
4597 	    (new_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 0,
4598 	    ("new entry lacks MAP_ENTRY_GROWS_DOWN"));
4599 	KASSERT((orient & MAP_STACK_GROWS_UP) == 0 ||
4600 	    (new_entry->eflags & MAP_ENTRY_GROWS_UP) != 0,
4601 	    ("new entry lacks MAP_ENTRY_GROWS_UP"));
4602 	if (gap_bot == gap_top)
4603 		return (KERN_SUCCESS);
4604 	rv = vm_map_insert(map, NULL, 0, gap_bot, gap_top, VM_PROT_NONE,
4605 	    VM_PROT_NONE, MAP_CREATE_GUARD | (orient == MAP_STACK_GROWS_DOWN ?
4606 	    MAP_CREATE_STACK_GAP_DN : MAP_CREATE_STACK_GAP_UP));
4607 	if (rv == KERN_SUCCESS) {
4608 		/*
4609 		 * Gap can never successfully handle a fault, so
4610 		 * read-ahead logic is never used for it.  Re-use
4611 		 * next_read of the gap entry to store
4612 		 * stack_guard_page for vm_map_growstack().
4613 		 */
4614 		if (orient == MAP_STACK_GROWS_DOWN)
4615 			vm_map_entry_pred(new_entry)->next_read = sgp;
4616 		else
4617 			vm_map_entry_succ(new_entry)->next_read = sgp;
4618 	} else {
4619 		(void)vm_map_delete(map, bot, top);
4620 	}
4621 	return (rv);
4622 }
4623 
4624 /*
4625  * Attempts to grow a vm stack entry.  Returns KERN_SUCCESS if we
4626  * successfully grow the stack.
4627  */
4628 static int
4629 vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_map_entry_t gap_entry)
4630 {
4631 	vm_map_entry_t stack_entry;
4632 	struct proc *p;
4633 	struct vmspace *vm;
4634 	struct ucred *cred;
4635 	vm_offset_t gap_end, gap_start, grow_start;
4636 	vm_size_t grow_amount, guard, max_grow;
4637 	rlim_t lmemlim, stacklim, vmemlim;
4638 	int rv, rv1;
4639 	bool gap_deleted, grow_down, is_procstack;
4640 #ifdef notyet
4641 	uint64_t limit;
4642 #endif
4643 #ifdef RACCT
4644 	int error;
4645 #endif
4646 
4647 	p = curproc;
4648 	vm = p->p_vmspace;
4649 
4650 	/*
4651 	 * Disallow stack growth when the access is performed by a
4652 	 * debugger or AIO daemon.  The reason is that the wrong
4653 	 * resource limits are applied.
4654 	 */
4655 	if (p != initproc && (map != &p->p_vmspace->vm_map ||
4656 	    p->p_textvp == NULL))
4657 		return (KERN_FAILURE);
4658 
4659 	MPASS(!map->system_map);
4660 
4661 	lmemlim = lim_cur(curthread, RLIMIT_MEMLOCK);
4662 	stacklim = lim_cur(curthread, RLIMIT_STACK);
4663 	vmemlim = lim_cur(curthread, RLIMIT_VMEM);
4664 retry:
4665 	/* If addr is not in a hole for a stack grow area, no need to grow. */
4666 	if (gap_entry == NULL && !vm_map_lookup_entry(map, addr, &gap_entry))
4667 		return (KERN_FAILURE);
4668 	if ((gap_entry->eflags & MAP_ENTRY_GUARD) == 0)
4669 		return (KERN_SUCCESS);
4670 	if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_DN) != 0) {
4671 		stack_entry = vm_map_entry_succ(gap_entry);
4672 		if ((stack_entry->eflags & MAP_ENTRY_GROWS_DOWN) == 0 ||
4673 		    stack_entry->start != gap_entry->end)
4674 			return (KERN_FAILURE);
4675 		grow_amount = round_page(stack_entry->start - addr);
4676 		grow_down = true;
4677 	} else if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_UP) != 0) {
4678 		stack_entry = vm_map_entry_pred(gap_entry);
4679 		if ((stack_entry->eflags & MAP_ENTRY_GROWS_UP) == 0 ||
4680 		    stack_entry->end != gap_entry->start)
4681 			return (KERN_FAILURE);
4682 		grow_amount = round_page(addr + 1 - stack_entry->end);
4683 		grow_down = false;
4684 	} else {
4685 		return (KERN_FAILURE);
4686 	}
4687 	guard = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ||
4688 	    (curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 :
4689 	    gap_entry->next_read;
4690 	max_grow = gap_entry->end - gap_entry->start;
4691 	if (guard > max_grow)
4692 		return (KERN_NO_SPACE);
4693 	max_grow -= guard;
4694 	if (grow_amount > max_grow)
4695 		return (KERN_NO_SPACE);
4696 
4697 	/*
4698 	 * If this is the main process stack, see if we're over the stack
4699 	 * limit.
4700 	 */
4701 	is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr &&
4702 	    addr < (vm_offset_t)p->p_sysent->sv_usrstack;
4703 	if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim))
4704 		return (KERN_NO_SPACE);
4705 
4706 #ifdef RACCT
4707 	if (racct_enable) {
4708 		PROC_LOCK(p);
4709 		if (is_procstack && racct_set(p, RACCT_STACK,
4710 		    ctob(vm->vm_ssize) + grow_amount)) {
4711 			PROC_UNLOCK(p);
4712 			return (KERN_NO_SPACE);
4713 		}
4714 		PROC_UNLOCK(p);
4715 	}
4716 #endif
4717 
4718 	grow_amount = roundup(grow_amount, sgrowsiz);
4719 	if (grow_amount > max_grow)
4720 		grow_amount = max_grow;
4721 	if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) {
4722 		grow_amount = trunc_page((vm_size_t)stacklim) -
4723 		    ctob(vm->vm_ssize);
4724 	}
4725 
4726 #ifdef notyet
4727 	PROC_LOCK(p);
4728 	limit = racct_get_available(p, RACCT_STACK);
4729 	PROC_UNLOCK(p);
4730 	if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > limit))
4731 		grow_amount = limit - ctob(vm->vm_ssize);
4732 #endif
4733 
4734 	if (!old_mlock && (map->flags & MAP_WIREFUTURE) != 0) {
4735 		if (ptoa(pmap_wired_count(map->pmap)) + grow_amount > lmemlim) {
4736 			rv = KERN_NO_SPACE;
4737 			goto out;
4738 		}
4739 #ifdef RACCT
4740 		if (racct_enable) {
4741 			PROC_LOCK(p);
4742 			if (racct_set(p, RACCT_MEMLOCK,
4743 			    ptoa(pmap_wired_count(map->pmap)) + grow_amount)) {
4744 				PROC_UNLOCK(p);
4745 				rv = KERN_NO_SPACE;
4746 				goto out;
4747 			}
4748 			PROC_UNLOCK(p);
4749 		}
4750 #endif
4751 	}
4752 
4753 	/* If we would blow our VMEM resource limit, no go */
4754 	if (map->size + grow_amount > vmemlim) {
4755 		rv = KERN_NO_SPACE;
4756 		goto out;
4757 	}
4758 #ifdef RACCT
4759 	if (racct_enable) {
4760 		PROC_LOCK(p);
4761 		if (racct_set(p, RACCT_VMEM, map->size + grow_amount)) {
4762 			PROC_UNLOCK(p);
4763 			rv = KERN_NO_SPACE;
4764 			goto out;
4765 		}
4766 		PROC_UNLOCK(p);
4767 	}
4768 #endif
4769 
4770 	if (vm_map_lock_upgrade(map)) {
4771 		gap_entry = NULL;
4772 		vm_map_lock_read(map);
4773 		goto retry;
4774 	}
4775 
4776 	if (grow_down) {
4777 		grow_start = gap_entry->end - grow_amount;
4778 		if (gap_entry->start + grow_amount == gap_entry->end) {
4779 			gap_start = gap_entry->start;
4780 			gap_end = gap_entry->end;
4781 			vm_map_entry_delete(map, gap_entry);
4782 			gap_deleted = true;
4783 		} else {
4784 			MPASS(gap_entry->start < gap_entry->end - grow_amount);
4785 			vm_map_entry_resize(map, gap_entry, -grow_amount);
4786 			gap_deleted = false;
4787 		}
4788 		rv = vm_map_insert(map, NULL, 0, grow_start,
4789 		    grow_start + grow_amount,
4790 		    stack_entry->protection, stack_entry->max_protection,
4791 		    MAP_STACK_GROWS_DOWN);
4792 		if (rv != KERN_SUCCESS) {
4793 			if (gap_deleted) {
4794 				rv1 = vm_map_insert(map, NULL, 0, gap_start,
4795 				    gap_end, VM_PROT_NONE, VM_PROT_NONE,
4796 				    MAP_CREATE_GUARD | MAP_CREATE_STACK_GAP_DN);
4797 				MPASS(rv1 == KERN_SUCCESS);
4798 			} else
4799 				vm_map_entry_resize(map, gap_entry,
4800 				    grow_amount);
4801 		}
4802 	} else {
4803 		grow_start = stack_entry->end;
4804 		cred = stack_entry->cred;
4805 		if (cred == NULL && stack_entry->object.vm_object != NULL)
4806 			cred = stack_entry->object.vm_object->cred;
4807 		if (cred != NULL && !swap_reserve_by_cred(grow_amount, cred))
4808 			rv = KERN_NO_SPACE;
4809 		/* Grow the underlying object if applicable. */
4810 		else if (stack_entry->object.vm_object == NULL ||
4811 		    vm_object_coalesce(stack_entry->object.vm_object,
4812 		    stack_entry->offset,
4813 		    (vm_size_t)(stack_entry->end - stack_entry->start),
4814 		    grow_amount, cred != NULL)) {
4815 			if (gap_entry->start + grow_amount == gap_entry->end) {
4816 				vm_map_entry_delete(map, gap_entry);
4817 				vm_map_entry_resize(map, stack_entry,
4818 				    grow_amount);
4819 			} else {
4820 				gap_entry->start += grow_amount;
4821 				stack_entry->end += grow_amount;
4822 			}
4823 			map->size += grow_amount;
4824 			rv = KERN_SUCCESS;
4825 		} else
4826 			rv = KERN_FAILURE;
4827 	}
4828 	if (rv == KERN_SUCCESS && is_procstack)
4829 		vm->vm_ssize += btoc(grow_amount);
4830 
4831 	/*
4832 	 * Heed the MAP_WIREFUTURE flag if it was set for this process.
4833 	 */
4834 	if (rv == KERN_SUCCESS && (map->flags & MAP_WIREFUTURE) != 0) {
4835 		rv = vm_map_wire_locked(map, grow_start,
4836 		    grow_start + grow_amount,
4837 		    VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
4838 	}
4839 	vm_map_lock_downgrade(map);
4840 
4841 out:
4842 #ifdef RACCT
4843 	if (racct_enable && rv != KERN_SUCCESS) {
4844 		PROC_LOCK(p);
4845 		error = racct_set(p, RACCT_VMEM, map->size);
4846 		KASSERT(error == 0, ("decreasing RACCT_VMEM failed"));
4847 		if (!old_mlock) {
4848 			error = racct_set(p, RACCT_MEMLOCK,
4849 			    ptoa(pmap_wired_count(map->pmap)));
4850 			KASSERT(error == 0, ("decreasing RACCT_MEMLOCK failed"));
4851 		}
4852 	    	error = racct_set(p, RACCT_STACK, ctob(vm->vm_ssize));
4853 		KASSERT(error == 0, ("decreasing RACCT_STACK failed"));
4854 		PROC_UNLOCK(p);
4855 	}
4856 #endif
4857 
4858 	return (rv);
4859 }
4860 
4861 /*
4862  * Unshare the specified VM space for exec.  If other processes are
4863  * mapped to it, then create a new one.  The new vmspace is null.
4864  */
4865 int
4866 vmspace_exec(struct proc *p, vm_offset_t minuser, vm_offset_t maxuser)
4867 {
4868 	struct vmspace *oldvmspace = p->p_vmspace;
4869 	struct vmspace *newvmspace;
4870 
4871 	KASSERT((curthread->td_pflags & TDP_EXECVMSPC) == 0,
4872 	    ("vmspace_exec recursed"));
4873 	newvmspace = vmspace_alloc(minuser, maxuser, pmap_pinit);
4874 	if (newvmspace == NULL)
4875 		return (ENOMEM);
4876 	newvmspace->vm_swrss = oldvmspace->vm_swrss;
4877 	/*
4878 	 * This code is written like this for prototype purposes.  The
4879 	 * goal is to avoid running down the vmspace here, but let the
4880 	 * other process's that are still using the vmspace to finally
4881 	 * run it down.  Even though there is little or no chance of blocking
4882 	 * here, it is a good idea to keep this form for future mods.
4883 	 */
4884 	PROC_VMSPACE_LOCK(p);
4885 	p->p_vmspace = newvmspace;
4886 	PROC_VMSPACE_UNLOCK(p);
4887 	if (p == curthread->td_proc)
4888 		pmap_activate(curthread);
4889 	curthread->td_pflags |= TDP_EXECVMSPC;
4890 	return (0);
4891 }
4892 
4893 /*
4894  * Unshare the specified VM space for forcing COW.  This
4895  * is called by rfork, for the (RFMEM|RFPROC) == 0 case.
4896  */
4897 int
4898 vmspace_unshare(struct proc *p)
4899 {
4900 	struct vmspace *oldvmspace = p->p_vmspace;
4901 	struct vmspace *newvmspace;
4902 	vm_ooffset_t fork_charge;
4903 
4904 	if (refcount_load(&oldvmspace->vm_refcnt) == 1)
4905 		return (0);
4906 	fork_charge = 0;
4907 	newvmspace = vmspace_fork(oldvmspace, &fork_charge);
4908 	if (newvmspace == NULL)
4909 		return (ENOMEM);
4910 	if (!swap_reserve_by_cred(fork_charge, p->p_ucred)) {
4911 		vmspace_free(newvmspace);
4912 		return (ENOMEM);
4913 	}
4914 	PROC_VMSPACE_LOCK(p);
4915 	p->p_vmspace = newvmspace;
4916 	PROC_VMSPACE_UNLOCK(p);
4917 	if (p == curthread->td_proc)
4918 		pmap_activate(curthread);
4919 	vmspace_free(oldvmspace);
4920 	return (0);
4921 }
4922 
4923 /*
4924  *	vm_map_lookup:
4925  *
4926  *	Finds the VM object, offset, and
4927  *	protection for a given virtual address in the
4928  *	specified map, assuming a page fault of the
4929  *	type specified.
4930  *
4931  *	Leaves the map in question locked for read; return
4932  *	values are guaranteed until a vm_map_lookup_done
4933  *	call is performed.  Note that the map argument
4934  *	is in/out; the returned map must be used in
4935  *	the call to vm_map_lookup_done.
4936  *
4937  *	A handle (out_entry) is returned for use in
4938  *	vm_map_lookup_done, to make that fast.
4939  *
4940  *	If a lookup is requested with "write protection"
4941  *	specified, the map may be changed to perform virtual
4942  *	copying operations, although the data referenced will
4943  *	remain the same.
4944  */
4945 int
4946 vm_map_lookup(vm_map_t *var_map,		/* IN/OUT */
4947 	      vm_offset_t vaddr,
4948 	      vm_prot_t fault_typea,
4949 	      vm_map_entry_t *out_entry,	/* OUT */
4950 	      vm_object_t *object,		/* OUT */
4951 	      vm_pindex_t *pindex,		/* OUT */
4952 	      vm_prot_t *out_prot,		/* OUT */
4953 	      boolean_t *wired)			/* OUT */
4954 {
4955 	vm_map_entry_t entry;
4956 	vm_map_t map = *var_map;
4957 	vm_prot_t prot;
4958 	vm_prot_t fault_type;
4959 	vm_object_t eobject;
4960 	vm_size_t size;
4961 	struct ucred *cred;
4962 
4963 RetryLookup:
4964 
4965 	vm_map_lock_read(map);
4966 
4967 RetryLookupLocked:
4968 	/*
4969 	 * Lookup the faulting address.
4970 	 */
4971 	if (!vm_map_lookup_entry(map, vaddr, out_entry)) {
4972 		vm_map_unlock_read(map);
4973 		return (KERN_INVALID_ADDRESS);
4974 	}
4975 
4976 	entry = *out_entry;
4977 
4978 	/*
4979 	 * Handle submaps.
4980 	 */
4981 	if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
4982 		vm_map_t old_map = map;
4983 
4984 		*var_map = map = entry->object.sub_map;
4985 		vm_map_unlock_read(old_map);
4986 		goto RetryLookup;
4987 	}
4988 
4989 	/*
4990 	 * Check whether this task is allowed to have this page.
4991 	 */
4992 	prot = entry->protection;
4993 	if ((fault_typea & VM_PROT_FAULT_LOOKUP) != 0) {
4994 		fault_typea &= ~VM_PROT_FAULT_LOOKUP;
4995 		if (prot == VM_PROT_NONE && map != kernel_map &&
4996 		    (entry->eflags & MAP_ENTRY_GUARD) != 0 &&
4997 		    (entry->eflags & (MAP_ENTRY_STACK_GAP_DN |
4998 		    MAP_ENTRY_STACK_GAP_UP)) != 0 &&
4999 		    vm_map_growstack(map, vaddr, entry) == KERN_SUCCESS)
5000 			goto RetryLookupLocked;
5001 	}
5002 	fault_type = fault_typea & VM_PROT_ALL;
5003 	if ((fault_type & prot) != fault_type || prot == VM_PROT_NONE) {
5004 		vm_map_unlock_read(map);
5005 		return (KERN_PROTECTION_FAILURE);
5006 	}
5007 	KASSERT((prot & VM_PROT_WRITE) == 0 || (entry->eflags &
5008 	    (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY)) !=
5009 	    (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY),
5010 	    ("entry %p flags %x", entry, entry->eflags));
5011 	if ((fault_typea & VM_PROT_COPY) != 0 &&
5012 	    (entry->max_protection & VM_PROT_WRITE) == 0 &&
5013 	    (entry->eflags & MAP_ENTRY_COW) == 0) {
5014 		vm_map_unlock_read(map);
5015 		return (KERN_PROTECTION_FAILURE);
5016 	}
5017 
5018 	/*
5019 	 * If this page is not pageable, we have to get it for all possible
5020 	 * accesses.
5021 	 */
5022 	*wired = (entry->wired_count != 0);
5023 	if (*wired)
5024 		fault_type = entry->protection;
5025 	size = entry->end - entry->start;
5026 
5027 	/*
5028 	 * If the entry was copy-on-write, we either ...
5029 	 */
5030 	if (entry->eflags & MAP_ENTRY_NEEDS_COPY) {
5031 		/*
5032 		 * If we want to write the page, we may as well handle that
5033 		 * now since we've got the map locked.
5034 		 *
5035 		 * If we don't need to write the page, we just demote the
5036 		 * permissions allowed.
5037 		 */
5038 		if ((fault_type & VM_PROT_WRITE) != 0 ||
5039 		    (fault_typea & VM_PROT_COPY) != 0) {
5040 			/*
5041 			 * Make a new object, and place it in the object
5042 			 * chain.  Note that no new references have appeared
5043 			 * -- one just moved from the map to the new
5044 			 * object.
5045 			 */
5046 			if (vm_map_lock_upgrade(map))
5047 				goto RetryLookup;
5048 
5049 			if (entry->cred == NULL) {
5050 				/*
5051 				 * The debugger owner is charged for
5052 				 * the memory.
5053 				 */
5054 				cred = curthread->td_ucred;
5055 				crhold(cred);
5056 				if (!swap_reserve_by_cred(size, cred)) {
5057 					crfree(cred);
5058 					vm_map_unlock(map);
5059 					return (KERN_RESOURCE_SHORTAGE);
5060 				}
5061 				entry->cred = cred;
5062 			}
5063 			eobject = entry->object.vm_object;
5064 			vm_object_shadow(&entry->object.vm_object,
5065 			    &entry->offset, size, entry->cred, false);
5066 			if (eobject == entry->object.vm_object) {
5067 				/*
5068 				 * The object was not shadowed.
5069 				 */
5070 				swap_release_by_cred(size, entry->cred);
5071 				crfree(entry->cred);
5072 			}
5073 			entry->cred = NULL;
5074 			entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
5075 
5076 			vm_map_lock_downgrade(map);
5077 		} else {
5078 			/*
5079 			 * We're attempting to read a copy-on-write page --
5080 			 * don't allow writes.
5081 			 */
5082 			prot &= ~VM_PROT_WRITE;
5083 		}
5084 	}
5085 
5086 	/*
5087 	 * Create an object if necessary.
5088 	 */
5089 	if (entry->object.vm_object == NULL && !map->system_map) {
5090 		if (vm_map_lock_upgrade(map))
5091 			goto RetryLookup;
5092 		entry->object.vm_object = vm_object_allocate_anon(atop(size),
5093 		    NULL, entry->cred, entry->cred != NULL ? size : 0);
5094 		entry->offset = 0;
5095 		entry->cred = NULL;
5096 		vm_map_lock_downgrade(map);
5097 	}
5098 
5099 	/*
5100 	 * Return the object/offset from this entry.  If the entry was
5101 	 * copy-on-write or empty, it has been fixed up.
5102 	 */
5103 	*pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
5104 	*object = entry->object.vm_object;
5105 
5106 	*out_prot = prot;
5107 	return (KERN_SUCCESS);
5108 }
5109 
5110 /*
5111  *	vm_map_lookup_locked:
5112  *
5113  *	Lookup the faulting address.  A version of vm_map_lookup that returns
5114  *      KERN_FAILURE instead of blocking on map lock or memory allocation.
5115  */
5116 int
5117 vm_map_lookup_locked(vm_map_t *var_map,		/* IN/OUT */
5118 		     vm_offset_t vaddr,
5119 		     vm_prot_t fault_typea,
5120 		     vm_map_entry_t *out_entry,	/* OUT */
5121 		     vm_object_t *object,	/* OUT */
5122 		     vm_pindex_t *pindex,	/* OUT */
5123 		     vm_prot_t *out_prot,	/* OUT */
5124 		     boolean_t *wired)		/* OUT */
5125 {
5126 	vm_map_entry_t entry;
5127 	vm_map_t map = *var_map;
5128 	vm_prot_t prot;
5129 	vm_prot_t fault_type = fault_typea;
5130 
5131 	/*
5132 	 * Lookup the faulting address.
5133 	 */
5134 	if (!vm_map_lookup_entry(map, vaddr, out_entry))
5135 		return (KERN_INVALID_ADDRESS);
5136 
5137 	entry = *out_entry;
5138 
5139 	/*
5140 	 * Fail if the entry refers to a submap.
5141 	 */
5142 	if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
5143 		return (KERN_FAILURE);
5144 
5145 	/*
5146 	 * Check whether this task is allowed to have this page.
5147 	 */
5148 	prot = entry->protection;
5149 	fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
5150 	if ((fault_type & prot) != fault_type)
5151 		return (KERN_PROTECTION_FAILURE);
5152 
5153 	/*
5154 	 * If this page is not pageable, we have to get it for all possible
5155 	 * accesses.
5156 	 */
5157 	*wired = (entry->wired_count != 0);
5158 	if (*wired)
5159 		fault_type = entry->protection;
5160 
5161 	if (entry->eflags & MAP_ENTRY_NEEDS_COPY) {
5162 		/*
5163 		 * Fail if the entry was copy-on-write for a write fault.
5164 		 */
5165 		if (fault_type & VM_PROT_WRITE)
5166 			return (KERN_FAILURE);
5167 		/*
5168 		 * We're attempting to read a copy-on-write page --
5169 		 * don't allow writes.
5170 		 */
5171 		prot &= ~VM_PROT_WRITE;
5172 	}
5173 
5174 	/*
5175 	 * Fail if an object should be created.
5176 	 */
5177 	if (entry->object.vm_object == NULL && !map->system_map)
5178 		return (KERN_FAILURE);
5179 
5180 	/*
5181 	 * Return the object/offset from this entry.  If the entry was
5182 	 * copy-on-write or empty, it has been fixed up.
5183 	 */
5184 	*pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
5185 	*object = entry->object.vm_object;
5186 
5187 	*out_prot = prot;
5188 	return (KERN_SUCCESS);
5189 }
5190 
5191 /*
5192  *	vm_map_lookup_done:
5193  *
5194  *	Releases locks acquired by a vm_map_lookup
5195  *	(according to the handle returned by that lookup).
5196  */
5197 void
5198 vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry)
5199 {
5200 	/*
5201 	 * Unlock the main-level map
5202 	 */
5203 	vm_map_unlock_read(map);
5204 }
5205 
5206 vm_offset_t
5207 vm_map_max_KBI(const struct vm_map *map)
5208 {
5209 
5210 	return (vm_map_max(map));
5211 }
5212 
5213 vm_offset_t
5214 vm_map_min_KBI(const struct vm_map *map)
5215 {
5216 
5217 	return (vm_map_min(map));
5218 }
5219 
5220 pmap_t
5221 vm_map_pmap_KBI(vm_map_t map)
5222 {
5223 
5224 	return (map->pmap);
5225 }
5226 
5227 bool
5228 vm_map_range_valid_KBI(vm_map_t map, vm_offset_t start, vm_offset_t end)
5229 {
5230 
5231 	return (vm_map_range_valid(map, start, end));
5232 }
5233 
5234 #ifdef INVARIANTS
5235 static void
5236 _vm_map_assert_consistent(vm_map_t map, int check)
5237 {
5238 	vm_map_entry_t entry, prev;
5239 	vm_map_entry_t cur, header, lbound, ubound;
5240 	vm_size_t max_left, max_right;
5241 
5242 #ifdef DIAGNOSTIC
5243 	++map->nupdates;
5244 #endif
5245 	if (enable_vmmap_check != check)
5246 		return;
5247 
5248 	header = prev = &map->header;
5249 	VM_MAP_ENTRY_FOREACH(entry, map) {
5250 		KASSERT(prev->end <= entry->start,
5251 		    ("map %p prev->end = %jx, start = %jx", map,
5252 		    (uintmax_t)prev->end, (uintmax_t)entry->start));
5253 		KASSERT(entry->start < entry->end,
5254 		    ("map %p start = %jx, end = %jx", map,
5255 		    (uintmax_t)entry->start, (uintmax_t)entry->end));
5256 		KASSERT(entry->left == header ||
5257 		    entry->left->start < entry->start,
5258 		    ("map %p left->start = %jx, start = %jx", map,
5259 		    (uintmax_t)entry->left->start, (uintmax_t)entry->start));
5260 		KASSERT(entry->right == header ||
5261 		    entry->start < entry->right->start,
5262 		    ("map %p start = %jx, right->start = %jx", map,
5263 		    (uintmax_t)entry->start, (uintmax_t)entry->right->start));
5264 		cur = map->root;
5265 		lbound = ubound = header;
5266 		for (;;) {
5267 			if (entry->start < cur->start) {
5268 				ubound = cur;
5269 				cur = cur->left;
5270 				KASSERT(cur != lbound,
5271 				    ("map %p cannot find %jx",
5272 				    map, (uintmax_t)entry->start));
5273 			} else if (cur->end <= entry->start) {
5274 				lbound = cur;
5275 				cur = cur->right;
5276 				KASSERT(cur != ubound,
5277 				    ("map %p cannot find %jx",
5278 				    map, (uintmax_t)entry->start));
5279 			} else {
5280 				KASSERT(cur == entry,
5281 				    ("map %p cannot find %jx",
5282 				    map, (uintmax_t)entry->start));
5283 				break;
5284 			}
5285 		}
5286 		max_left = vm_map_entry_max_free_left(entry, lbound);
5287 		max_right = vm_map_entry_max_free_right(entry, ubound);
5288 		KASSERT(entry->max_free == vm_size_max(max_left, max_right),
5289 		    ("map %p max = %jx, max_left = %jx, max_right = %jx", map,
5290 		    (uintmax_t)entry->max_free,
5291 		    (uintmax_t)max_left, (uintmax_t)max_right));
5292 		prev = entry;
5293 	}
5294 	KASSERT(prev->end <= entry->start,
5295 	    ("map %p prev->end = %jx, start = %jx", map,
5296 	    (uintmax_t)prev->end, (uintmax_t)entry->start));
5297 }
5298 #endif
5299 
5300 #include "opt_ddb.h"
5301 #ifdef DDB
5302 #include <sys/kernel.h>
5303 
5304 #include <ddb/ddb.h>
5305 
5306 static void
5307 vm_map_print(vm_map_t map)
5308 {
5309 	vm_map_entry_t entry, prev;
5310 
5311 	db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n",
5312 	    (void *)map,
5313 	    (void *)map->pmap, map->nentries, map->timestamp);
5314 
5315 	db_indent += 2;
5316 	prev = &map->header;
5317 	VM_MAP_ENTRY_FOREACH(entry, map) {
5318 		db_iprintf("map entry %p: start=%p, end=%p, eflags=%#x, \n",
5319 		    (void *)entry, (void *)entry->start, (void *)entry->end,
5320 		    entry->eflags);
5321 		{
5322 			static const char * const inheritance_name[4] =
5323 			{"share", "copy", "none", "donate_copy"};
5324 
5325 			db_iprintf(" prot=%x/%x/%s",
5326 			    entry->protection,
5327 			    entry->max_protection,
5328 			    inheritance_name[(int)(unsigned char)
5329 			    entry->inheritance]);
5330 			if (entry->wired_count != 0)
5331 				db_printf(", wired");
5332 		}
5333 		if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
5334 			db_printf(", share=%p, offset=0x%jx\n",
5335 			    (void *)entry->object.sub_map,
5336 			    (uintmax_t)entry->offset);
5337 			if (prev == &map->header ||
5338 			    prev->object.sub_map !=
5339 				entry->object.sub_map) {
5340 				db_indent += 2;
5341 				vm_map_print((vm_map_t)entry->object.sub_map);
5342 				db_indent -= 2;
5343 			}
5344 		} else {
5345 			if (entry->cred != NULL)
5346 				db_printf(", ruid %d", entry->cred->cr_ruid);
5347 			db_printf(", object=%p, offset=0x%jx",
5348 			    (void *)entry->object.vm_object,
5349 			    (uintmax_t)entry->offset);
5350 			if (entry->object.vm_object && entry->object.vm_object->cred)
5351 				db_printf(", obj ruid %d charge %jx",
5352 				    entry->object.vm_object->cred->cr_ruid,
5353 				    (uintmax_t)entry->object.vm_object->charge);
5354 			if (entry->eflags & MAP_ENTRY_COW)
5355 				db_printf(", copy (%s)",
5356 				    (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done");
5357 			db_printf("\n");
5358 
5359 			if (prev == &map->header ||
5360 			    prev->object.vm_object !=
5361 				entry->object.vm_object) {
5362 				db_indent += 2;
5363 				vm_object_print((db_expr_t)(intptr_t)
5364 						entry->object.vm_object,
5365 						0, 0, (char *)0);
5366 				db_indent -= 2;
5367 			}
5368 		}
5369 		prev = entry;
5370 	}
5371 	db_indent -= 2;
5372 }
5373 
5374 DB_SHOW_COMMAND(map, map)
5375 {
5376 
5377 	if (!have_addr) {
5378 		db_printf("usage: show map <addr>\n");
5379 		return;
5380 	}
5381 	vm_map_print((vm_map_t)addr);
5382 }
5383 
5384 DB_SHOW_COMMAND(procvm, procvm)
5385 {
5386 	struct proc *p;
5387 
5388 	if (have_addr) {
5389 		p = db_lookup_proc(addr);
5390 	} else {
5391 		p = curproc;
5392 	}
5393 
5394 	db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n",
5395 	    (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map,
5396 	    (void *)vmspace_pmap(p->p_vmspace));
5397 
5398 	vm_map_print((vm_map_t)&p->p_vmspace->vm_map);
5399 }
5400 
5401 #endif /* DDB */
5402