The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_map.c

Version: -  FREEBSD  -  FREEBSD11  -  FREEBSD10  -  FREEBSD9  -  FREEBSD92  -  FREEBSD91  -  FREEBSD90  -  FREEBSD8  -  FREEBSD82  -  FREEBSD81  -  FREEBSD80  -  FREEBSD7  -  FREEBSD74  -  FREEBSD73  -  FREEBSD72  -  FREEBSD71  -  FREEBSD70  -  FREEBSD6  -  FREEBSD64  -  FREEBSD63  -  FREEBSD62  -  FREEBSD61  -  FREEBSD60  -  FREEBSD5  -  FREEBSD55  -  FREEBSD54  -  FREEBSD53  -  FREEBSD52  -  FREEBSD51  -  FREEBSD50  -  FREEBSD4  -  FREEBSD3  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * This code is derived from software contributed to Berkeley by
    6  * The Mach Operating System project at Carnegie-Mellon University.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 4. Neither the name of the University nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  *
   32  *      from: @(#)vm_map.c      8.3 (Berkeley) 1/12/94
   33  *
   34  *
   35  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
   36  * All rights reserved.
   37  *
   38  * Authors: Avadis Tevanian, Jr., Michael Wayne Young
   39  *
   40  * Permission to use, copy, modify and distribute this software and
   41  * its documentation is hereby granted, provided that both the copyright
   42  * notice and this permission notice appear in all copies of the
   43  * software, derivative works or modified versions, and any portions
   44  * thereof, and that both notices appear in supporting documentation.
   45  *
   46  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
   47  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
   48  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   49  *
   50  * Carnegie Mellon requests users of this software to return to
   51  *
   52  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   53  *  School of Computer Science
   54  *  Carnegie Mellon University
   55  *  Pittsburgh PA 15213-3890
   56  *
   57  * any improvements or extensions that they make and grant Carnegie the
   58  * rights to redistribute these changes.
   59  */
   60 
   61 /*
   62  *      Virtual memory mapping module.
   63  */
   64 
   65 #include <sys/cdefs.h>
   66 __FBSDID("$FreeBSD: src/sys/vm/vm_map.c,v 1.366.2.2 2005/11/13 21:45:49 alc Exp $");
   67 
   68 #include <sys/param.h>
   69 #include <sys/systm.h>
   70 #include <sys/ktr.h>
   71 #include <sys/lock.h>
   72 #include <sys/mutex.h>
   73 #include <sys/proc.h>
   74 #include <sys/vmmeter.h>
   75 #include <sys/mman.h>
   76 #include <sys/vnode.h>
   77 #include <sys/resourcevar.h>
   78 #include <sys/file.h>
   79 #include <sys/sysent.h>
   80 #include <sys/shm.h>
   81 
   82 #include <vm/vm.h>
   83 #include <vm/vm_param.h>
   84 #include <vm/pmap.h>
   85 #include <vm/vm_map.h>
   86 #include <vm/vm_page.h>
   87 #include <vm/vm_object.h>
   88 #include <vm/vm_pager.h>
   89 #include <vm/vm_kern.h>
   90 #include <vm/vm_extern.h>
   91 #include <vm/swap_pager.h>
   92 #include <vm/uma.h>
   93 
   94 /*
   95  *      Virtual memory maps provide for the mapping, protection,
   96  *      and sharing of virtual memory objects.  In addition,
   97  *      this module provides for an efficient virtual copy of
   98  *      memory from one map to another.
   99  *
  100  *      Synchronization is required prior to most operations.
  101  *
  102  *      Maps consist of an ordered doubly-linked list of simple
  103  *      entries; a single hint is used to speed up lookups.
  104  *
  105  *      Since portions of maps are specified by start/end addresses,
  106  *      which may not align with existing map entries, all
  107  *      routines merely "clip" entries to these start/end values.
  108  *      [That is, an entry is split into two, bordering at a
  109  *      start or end value.]  Note that these clippings may not
  110  *      always be necessary (as the two resulting entries are then
  111  *      not changed); however, the clipping is done for convenience.
  112  *
  113  *      As mentioned above, virtual copy operations are performed
  114  *      by copying VM object references from one map to
  115  *      another, and then marking both regions as copy-on-write.
  116  */
  117 
  118 /*
  119  *      vm_map_startup:
  120  *
  121  *      Initialize the vm_map module.  Must be called before
  122  *      any other vm_map routines.
  123  *
  124  *      Map and entry structures are allocated from the general
  125  *      purpose memory pool with some exceptions:
  126  *
  127  *      - The kernel map and kmem submap are allocated statically.
  128  *      - Kernel map entries are allocated out of a static pool.
  129  *
  130  *      These restrictions are necessary since malloc() uses the
  131  *      maps and requires map entries.
  132  */
  133 
  134 static struct mtx map_sleep_mtx;
  135 static uma_zone_t mapentzone;
  136 static uma_zone_t kmapentzone;
  137 static uma_zone_t mapzone;
  138 static uma_zone_t vmspace_zone;
  139 static struct vm_object kmapentobj;
  140 static int vmspace_zinit(void *mem, int size, int flags);
  141 static void vmspace_zfini(void *mem, int size);
  142 static int vm_map_zinit(void *mem, int ize, int flags);
  143 static void vm_map_zfini(void *mem, int size);
  144 static void _vm_map_init(vm_map_t map, vm_offset_t min, vm_offset_t max);
  145 
  146 #ifdef INVARIANTS
  147 static void vm_map_zdtor(void *mem, int size, void *arg);
  148 static void vmspace_zdtor(void *mem, int size, void *arg);
  149 #endif
  150 
  151 void
  152 vm_map_startup(void)
  153 {
  154         mtx_init(&map_sleep_mtx, "vm map sleep mutex", NULL, MTX_DEF);
  155         mapzone = uma_zcreate("MAP", sizeof(struct vm_map), NULL,
  156 #ifdef INVARIANTS
  157             vm_map_zdtor,
  158 #else
  159             NULL,
  160 #endif
  161             vm_map_zinit, vm_map_zfini, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  162         uma_prealloc(mapzone, MAX_KMAP);
  163         kmapentzone = uma_zcreate("KMAP ENTRY", sizeof(struct vm_map_entry),
  164             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
  165             UMA_ZONE_MTXCLASS | UMA_ZONE_VM);
  166         uma_prealloc(kmapentzone, MAX_KMAPENT);
  167         mapentzone = uma_zcreate("MAP ENTRY", sizeof(struct vm_map_entry),
  168             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
  169         uma_prealloc(mapentzone, MAX_MAPENT);
  170 }
  171 
  172 static void
  173 vmspace_zfini(void *mem, int size)
  174 {
  175         struct vmspace *vm;
  176 
  177         vm = (struct vmspace *)mem;
  178         pmap_release(vmspace_pmap(vm));
  179         vm_map_zfini(&vm->vm_map, sizeof(vm->vm_map));
  180 }
  181 
  182 static int
  183 vmspace_zinit(void *mem, int size, int flags)
  184 {
  185         struct vmspace *vm;
  186 
  187         vm = (struct vmspace *)mem;
  188 
  189         (void)vm_map_zinit(&vm->vm_map, sizeof(vm->vm_map), flags);
  190         pmap_pinit(vmspace_pmap(vm));
  191         return (0);
  192 }
  193 
  194 static void
  195 vm_map_zfini(void *mem, int size)
  196 {
  197         vm_map_t map;
  198 
  199         map = (vm_map_t)mem;
  200         mtx_destroy(&map->system_mtx);
  201         sx_destroy(&map->lock);
  202 }
  203 
  204 static int
  205 vm_map_zinit(void *mem, int size, int flags)
  206 {
  207         vm_map_t map;
  208 
  209         map = (vm_map_t)mem;
  210         map->nentries = 0;
  211         map->size = 0;
  212         mtx_init(&map->system_mtx, "system map", NULL, MTX_DEF | MTX_DUPOK);
  213         sx_init(&map->lock, "user map");
  214         return (0);
  215 }
  216 
  217 #ifdef INVARIANTS
  218 static void
  219 vmspace_zdtor(void *mem, int size, void *arg)
  220 {
  221         struct vmspace *vm;
  222 
  223         vm = (struct vmspace *)mem;
  224 
  225         vm_map_zdtor(&vm->vm_map, sizeof(vm->vm_map), arg);
  226 }
  227 static void
  228 vm_map_zdtor(void *mem, int size, void *arg)
  229 {
  230         vm_map_t map;
  231 
  232         map = (vm_map_t)mem;
  233         KASSERT(map->nentries == 0,
  234             ("map %p nentries == %d on free.",
  235             map, map->nentries));
  236         KASSERT(map->size == 0,
  237             ("map %p size == %lu on free.",
  238             map, (unsigned long)map->size));
  239 }
  240 #endif  /* INVARIANTS */
  241 
  242 /*
  243  * Allocate a vmspace structure, including a vm_map and pmap,
  244  * and initialize those structures.  The refcnt is set to 1.
  245  */
  246 struct vmspace *
  247 vmspace_alloc(min, max)
  248         vm_offset_t min, max;
  249 {
  250         struct vmspace *vm;
  251 
  252         vm = uma_zalloc(vmspace_zone, M_WAITOK);
  253         CTR1(KTR_VM, "vmspace_alloc: %p", vm);
  254         _vm_map_init(&vm->vm_map, min, max);
  255         vm->vm_map.pmap = vmspace_pmap(vm);             /* XXX */
  256         vm->vm_refcnt = 1;
  257         vm->vm_shm = NULL;
  258         vm->vm_swrss = 0;
  259         vm->vm_tsize = 0;
  260         vm->vm_dsize = 0;
  261         vm->vm_ssize = 0;
  262         vm->vm_taddr = 0;
  263         vm->vm_daddr = 0;
  264         vm->vm_maxsaddr = 0;
  265         vm->vm_exitingcnt = 0;
  266         return (vm);
  267 }
  268 
  269 void
  270 vm_init2(void)
  271 {
  272         uma_zone_set_obj(kmapentzone, &kmapentobj, lmin(cnt.v_page_count,
  273             (VM_MAX_KERNEL_ADDRESS - KERNBASE) / PAGE_SIZE) / 8 +
  274              maxproc * 2 + maxfiles);
  275         vmspace_zone = uma_zcreate("VMSPACE", sizeof(struct vmspace), NULL,
  276 #ifdef INVARIANTS
  277             vmspace_zdtor,
  278 #else
  279             NULL,
  280 #endif
  281             vmspace_zinit, vmspace_zfini, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  282         pmap_init2();
  283 }
  284 
  285 static __inline void
  286 vmspace_dofree(struct vmspace *vm)
  287 {
  288         CTR1(KTR_VM, "vmspace_free: %p", vm);
  289 
  290         /*
  291          * Make sure any SysV shm is freed, it might not have been in
  292          * exit1().
  293          */
  294         shmexit(vm);
  295 
  296         /*
  297          * Lock the map, to wait out all other references to it.
  298          * Delete all of the mappings and pages they hold, then call
  299          * the pmap module to reclaim anything left.
  300          */
  301         vm_map_lock(&vm->vm_map);
  302         (void) vm_map_delete(&vm->vm_map, vm->vm_map.min_offset,
  303             vm->vm_map.max_offset);
  304         vm_map_unlock(&vm->vm_map);
  305 
  306         uma_zfree(vmspace_zone, vm);
  307 }
  308 
  309 void
  310 vmspace_free(struct vmspace *vm)
  311 {
  312         int refcnt;
  313 
  314         if (vm->vm_refcnt == 0)
  315                 panic("vmspace_free: attempt to free already freed vmspace");
  316 
  317         do
  318                 refcnt = vm->vm_refcnt;
  319         while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1));
  320         if (refcnt == 1 && vm->vm_exitingcnt == 0)
  321                 vmspace_dofree(vm);
  322 }
  323 
  324 void
  325 vmspace_exitfree(struct proc *p)
  326 {
  327         struct vmspace *vm;
  328         int exitingcnt;
  329 
  330         vm = p->p_vmspace;
  331         p->p_vmspace = NULL;
  332 
  333         /*
  334          * cleanup by parent process wait()ing on exiting child.  vm_refcnt
  335          * may not be 0 (e.g. fork() and child exits without exec()ing).
  336          * exitingcnt may increment above 0 and drop back down to zero
  337          * several times while vm_refcnt is held non-zero.  vm_refcnt
  338          * may also increment above 0 and drop back down to zero several
  339          * times while vm_exitingcnt is held non-zero.
  340          *
  341          * The last wait on the exiting child's vmspace will clean up
  342          * the remainder of the vmspace.
  343          */
  344         do
  345                 exitingcnt = vm->vm_exitingcnt;
  346         while (!atomic_cmpset_int(&vm->vm_exitingcnt, exitingcnt,
  347             exitingcnt - 1));
  348         if (vm->vm_refcnt == 0 && exitingcnt == 1)
  349                 vmspace_dofree(vm);
  350 }
  351 
  352 void
  353 _vm_map_lock(vm_map_t map, const char *file, int line)
  354 {
  355 
  356         if (map->system_map)
  357                 _mtx_lock_flags(&map->system_mtx, 0, file, line);
  358         else
  359                 _sx_xlock(&map->lock, file, line);
  360         map->timestamp++;
  361 }
  362 
  363 void
  364 _vm_map_unlock(vm_map_t map, const char *file, int line)
  365 {
  366 
  367         if (map->system_map)
  368                 _mtx_unlock_flags(&map->system_mtx, 0, file, line);
  369         else
  370                 _sx_xunlock(&map->lock, file, line);
  371 }
  372 
  373 void
  374 _vm_map_lock_read(vm_map_t map, const char *file, int line)
  375 {
  376 
  377         if (map->system_map)
  378                 _mtx_lock_flags(&map->system_mtx, 0, file, line);
  379         else
  380                 _sx_xlock(&map->lock, file, line);
  381 }
  382 
  383 void
  384 _vm_map_unlock_read(vm_map_t map, const char *file, int line)
  385 {
  386 
  387         if (map->system_map)
  388                 _mtx_unlock_flags(&map->system_mtx, 0, file, line);
  389         else
  390                 _sx_xunlock(&map->lock, file, line);
  391 }
  392 
  393 int
  394 _vm_map_trylock(vm_map_t map, const char *file, int line)
  395 {
  396         int error;
  397 
  398         error = map->system_map ?
  399             !_mtx_trylock(&map->system_mtx, 0, file, line) :
  400             !_sx_try_xlock(&map->lock, file, line);
  401         if (error == 0)
  402                 map->timestamp++;
  403         return (error == 0);
  404 }
  405 
  406 int
  407 _vm_map_trylock_read(vm_map_t map, const char *file, int line)
  408 {
  409         int error;
  410 
  411         error = map->system_map ?
  412             !_mtx_trylock(&map->system_mtx, 0, file, line) :
  413             !_sx_try_xlock(&map->lock, file, line);
  414         return (error == 0);
  415 }
  416 
  417 int
  418 _vm_map_lock_upgrade(vm_map_t map, const char *file, int line)
  419 {
  420 
  421 #ifdef INVARIANTS
  422         if (map->system_map) {
  423                 _mtx_assert(&map->system_mtx, MA_OWNED, file, line);
  424         } else
  425                 _sx_assert(&map->lock, SX_XLOCKED, file, line);
  426 #endif
  427         map->timestamp++;
  428         return (0);
  429 }
  430 
  431 void
  432 _vm_map_lock_downgrade(vm_map_t map, const char *file, int line)
  433 {
  434 
  435 #ifdef INVARIANTS
  436         if (map->system_map) {
  437                 _mtx_assert(&map->system_mtx, MA_OWNED, file, line);
  438         } else
  439                 _sx_assert(&map->lock, SX_XLOCKED, file, line);
  440 #endif
  441 }
  442 
  443 /*
  444  *      vm_map_unlock_and_wait:
  445  */
  446 int
  447 vm_map_unlock_and_wait(vm_map_t map, boolean_t user_wait)
  448 {
  449 
  450         mtx_lock(&map_sleep_mtx);
  451         vm_map_unlock(map);
  452         return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps", 0));
  453 }
  454 
  455 /*
  456  *      vm_map_wakeup:
  457  */
  458 void
  459 vm_map_wakeup(vm_map_t map)
  460 {
  461 
  462         /*
  463          * Acquire and release map_sleep_mtx to prevent a wakeup()
  464          * from being performed (and lost) between the vm_map_unlock()
  465          * and the msleep() in vm_map_unlock_and_wait().
  466          */
  467         mtx_lock(&map_sleep_mtx);
  468         mtx_unlock(&map_sleep_mtx);
  469         wakeup(&map->root);
  470 }
  471 
  472 long
  473 vmspace_resident_count(struct vmspace *vmspace)
  474 {
  475         return pmap_resident_count(vmspace_pmap(vmspace));
  476 }
  477 
  478 long
  479 vmspace_wired_count(struct vmspace *vmspace)
  480 {
  481         return pmap_wired_count(vmspace_pmap(vmspace));
  482 }
  483 
  484 /*
  485  *      vm_map_create:
  486  *
  487  *      Creates and returns a new empty VM map with
  488  *      the given physical map structure, and having
  489  *      the given lower and upper address bounds.
  490  */
  491 vm_map_t
  492 vm_map_create(pmap_t pmap, vm_offset_t min, vm_offset_t max)
  493 {
  494         vm_map_t result;
  495 
  496         result = uma_zalloc(mapzone, M_WAITOK);
  497         CTR1(KTR_VM, "vm_map_create: %p", result);
  498         _vm_map_init(result, min, max);
  499         result->pmap = pmap;
  500         return (result);
  501 }
  502 
  503 /*
  504  * Initialize an existing vm_map structure
  505  * such as that in the vmspace structure.
  506  * The pmap is set elsewhere.
  507  */
  508 static void
  509 _vm_map_init(vm_map_t map, vm_offset_t min, vm_offset_t max)
  510 {
  511 
  512         map->header.next = map->header.prev = &map->header;
  513         map->needs_wakeup = FALSE;
  514         map->system_map = 0;
  515         map->min_offset = min;
  516         map->max_offset = max;
  517         map->flags = 0;
  518         map->root = NULL;
  519         map->timestamp = 0;
  520 }
  521 
  522 void
  523 vm_map_init(vm_map_t map, vm_offset_t min, vm_offset_t max)
  524 {
  525         _vm_map_init(map, min, max);
  526         mtx_init(&map->system_mtx, "system map", NULL, MTX_DEF | MTX_DUPOK);
  527         sx_init(&map->lock, "user map");
  528 }
  529 
  530 /*
  531  *      vm_map_entry_dispose:   [ internal use only ]
  532  *
  533  *      Inverse of vm_map_entry_create.
  534  */
  535 static void
  536 vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry)
  537 {
  538         uma_zfree(map->system_map ? kmapentzone : mapentzone, entry);
  539 }
  540 
  541 /*
  542  *      vm_map_entry_create:    [ internal use only ]
  543  *
  544  *      Allocates a VM map entry for insertion.
  545  *      No entry fields are filled in.
  546  */
  547 static vm_map_entry_t
  548 vm_map_entry_create(vm_map_t map)
  549 {
  550         vm_map_entry_t new_entry;
  551 
  552         if (map->system_map)
  553                 new_entry = uma_zalloc(kmapentzone, M_NOWAIT);
  554         else
  555                 new_entry = uma_zalloc(mapentzone, M_WAITOK);
  556         if (new_entry == NULL)
  557                 panic("vm_map_entry_create: kernel resources exhausted");
  558         return (new_entry);
  559 }
  560 
  561 /*
  562  *      vm_map_entry_set_behavior:
  563  *
  564  *      Set the expected access behavior, either normal, random, or
  565  *      sequential.
  566  */
  567 static __inline void
  568 vm_map_entry_set_behavior(vm_map_entry_t entry, u_char behavior)
  569 {
  570         entry->eflags = (entry->eflags & ~MAP_ENTRY_BEHAV_MASK) |
  571             (behavior & MAP_ENTRY_BEHAV_MASK);
  572 }
  573 
  574 /*
  575  *      vm_map_entry_set_max_free:
  576  *
  577  *      Set the max_free field in a vm_map_entry.
  578  */
  579 static __inline void
  580 vm_map_entry_set_max_free(vm_map_entry_t entry)
  581 {
  582 
  583         entry->max_free = entry->adj_free;
  584         if (entry->left != NULL && entry->left->max_free > entry->max_free)
  585                 entry->max_free = entry->left->max_free;
  586         if (entry->right != NULL && entry->right->max_free > entry->max_free)
  587                 entry->max_free = entry->right->max_free;
  588 }
  589 
  590 /*
  591  *      vm_map_entry_splay:
  592  *
  593  *      The Sleator and Tarjan top-down splay algorithm with the
  594  *      following variation.  Max_free must be computed bottom-up, so
  595  *      on the downward pass, maintain the left and right spines in
  596  *      reverse order.  Then, make a second pass up each side to fix
  597  *      the pointers and compute max_free.  The time bound is O(log n)
  598  *      amortized.
  599  *
  600  *      The new root is the vm_map_entry containing "addr", or else an
  601  *      adjacent entry (lower or higher) if addr is not in the tree.
  602  *
  603  *      The map must be locked, and leaves it so.
  604  *
  605  *      Returns: the new root.
  606  */
  607 static vm_map_entry_t
  608 vm_map_entry_splay(vm_offset_t addr, vm_map_entry_t root)
  609 {
  610         vm_map_entry_t llist, rlist;
  611         vm_map_entry_t ltree, rtree;
  612         vm_map_entry_t y;
  613 
  614         /* Special case of empty tree. */
  615         if (root == NULL)
  616                 return (root);
  617 
  618         /*
  619          * Pass One: Splay down the tree until we find addr or a NULL
  620          * pointer where addr would go.  llist and rlist are the two
  621          * sides in reverse order (bottom-up), with llist linked by
  622          * the right pointer and rlist linked by the left pointer in
  623          * the vm_map_entry.  Wait until Pass Two to set max_free on
  624          * the two spines.
  625          */
  626         llist = NULL;
  627         rlist = NULL;
  628         for (;;) {
  629                 /* root is never NULL in here. */
  630                 if (addr < root->start) {
  631                         y = root->left;
  632                         if (y == NULL)
  633                                 break;
  634                         if (addr < y->start && y->left != NULL) {
  635                                 /* Rotate right and put y on rlist. */
  636                                 root->left = y->right;
  637                                 y->right = root;
  638                                 vm_map_entry_set_max_free(root);
  639                                 root = y->left;
  640                                 y->left = rlist;
  641                                 rlist = y;
  642                         } else {
  643                                 /* Put root on rlist. */
  644                                 root->left = rlist;
  645                                 rlist = root;
  646                                 root = y;
  647                         }
  648                 } else {
  649                         y = root->right;
  650                         if (addr < root->end || y == NULL)
  651                                 break;
  652                         if (addr >= y->end && y->right != NULL) {
  653                                 /* Rotate left and put y on llist. */
  654                                 root->right = y->left;
  655                                 y->left = root;
  656                                 vm_map_entry_set_max_free(root);
  657                                 root = y->right;
  658                                 y->right = llist;
  659                                 llist = y;
  660                         } else {
  661                                 /* Put root on llist. */
  662                                 root->right = llist;
  663                                 llist = root;
  664                                 root = y;
  665                         }
  666                 }
  667         }
  668 
  669         /*
  670          * Pass Two: Walk back up the two spines, flip the pointers
  671          * and set max_free.  The subtrees of the root go at the
  672          * bottom of llist and rlist.
  673          */
  674         ltree = root->left;
  675         while (llist != NULL) {
  676                 y = llist->right;
  677                 llist->right = ltree;
  678                 vm_map_entry_set_max_free(llist);
  679                 ltree = llist;
  680                 llist = y;
  681         }
  682         rtree = root->right;
  683         while (rlist != NULL) {
  684                 y = rlist->left;
  685                 rlist->left = rtree;
  686                 vm_map_entry_set_max_free(rlist);
  687                 rtree = rlist;
  688                 rlist = y;
  689         }
  690 
  691         /*
  692          * Final assembly: add ltree and rtree as subtrees of root.
  693          */
  694         root->left = ltree;
  695         root->right = rtree;
  696         vm_map_entry_set_max_free(root);
  697 
  698         return (root);
  699 }
  700 
  701 /*
  702  *      vm_map_entry_{un,}link:
  703  *
  704  *      Insert/remove entries from maps.
  705  */
  706 static void
  707 vm_map_entry_link(vm_map_t map,
  708                   vm_map_entry_t after_where,
  709                   vm_map_entry_t entry)
  710 {
  711 
  712         CTR4(KTR_VM,
  713             "vm_map_entry_link: map %p, nentries %d, entry %p, after %p", map,
  714             map->nentries, entry, after_where);
  715         map->nentries++;
  716         entry->prev = after_where;
  717         entry->next = after_where->next;
  718         entry->next->prev = entry;
  719         after_where->next = entry;
  720 
  721         if (after_where != &map->header) {
  722                 if (after_where != map->root)
  723                         vm_map_entry_splay(after_where->start, map->root);
  724                 entry->right = after_where->right;
  725                 entry->left = after_where;
  726                 after_where->right = NULL;
  727                 after_where->adj_free = entry->start - after_where->end;
  728                 vm_map_entry_set_max_free(after_where);
  729         } else {
  730                 entry->right = map->root;
  731                 entry->left = NULL;
  732         }
  733         entry->adj_free = (entry->next == &map->header ? map->max_offset :
  734             entry->next->start) - entry->end;
  735         vm_map_entry_set_max_free(entry);
  736         map->root = entry;
  737 }
  738 
  739 static void
  740 vm_map_entry_unlink(vm_map_t map,
  741                     vm_map_entry_t entry)
  742 {
  743         vm_map_entry_t next, prev, root;
  744 
  745         if (entry != map->root)
  746                 vm_map_entry_splay(entry->start, map->root);
  747         if (entry->left == NULL)
  748                 root = entry->right;
  749         else {
  750                 root = vm_map_entry_splay(entry->start, entry->left);
  751                 root->right = entry->right;
  752                 root->adj_free = (entry->next == &map->header ? map->max_offset :
  753                     entry->next->start) - root->end;
  754                 vm_map_entry_set_max_free(root);
  755         }
  756         map->root = root;
  757 
  758         prev = entry->prev;
  759         next = entry->next;
  760         next->prev = prev;
  761         prev->next = next;
  762         map->nentries--;
  763         CTR3(KTR_VM, "vm_map_entry_unlink: map %p, nentries %d, entry %p", map,
  764             map->nentries, entry);
  765 }
  766 
  767 /*
  768  *      vm_map_entry_resize_free:
  769  *
  770  *      Recompute the amount of free space following a vm_map_entry
  771  *      and propagate that value up the tree.  Call this function after
  772  *      resizing a map entry in-place, that is, without a call to
  773  *      vm_map_entry_link() or _unlink().
  774  *
  775  *      The map must be locked, and leaves it so.
  776  */
  777 static void
  778 vm_map_entry_resize_free(vm_map_t map, vm_map_entry_t entry)
  779 {
  780 
  781         /*
  782          * Using splay trees without parent pointers, propagating
  783          * max_free up the tree is done by moving the entry to the
  784          * root and making the change there.
  785          */
  786         if (entry != map->root)
  787                 map->root = vm_map_entry_splay(entry->start, map->root);
  788 
  789         entry->adj_free = (entry->next == &map->header ? map->max_offset :
  790             entry->next->start) - entry->end;
  791         vm_map_entry_set_max_free(entry);
  792 }
  793 
  794 /*
  795  *      vm_map_lookup_entry:    [ internal use only ]
  796  *
  797  *      Finds the map entry containing (or
  798  *      immediately preceding) the specified address
  799  *      in the given map; the entry is returned
  800  *      in the "entry" parameter.  The boolean
  801  *      result indicates whether the address is
  802  *      actually contained in the map.
  803  */
  804 boolean_t
  805 vm_map_lookup_entry(
  806         vm_map_t map,
  807         vm_offset_t address,
  808         vm_map_entry_t *entry)  /* OUT */
  809 {
  810         vm_map_entry_t cur;
  811 
  812         cur = vm_map_entry_splay(address, map->root);
  813         if (cur == NULL)
  814                 *entry = &map->header;
  815         else {
  816                 map->root = cur;
  817 
  818                 if (address >= cur->start) {
  819                         *entry = cur;
  820                         if (cur->end > address)
  821                                 return (TRUE);
  822                 } else
  823                         *entry = cur->prev;
  824         }
  825         return (FALSE);
  826 }
  827 
  828 /*
  829  *      vm_map_insert:
  830  *
  831  *      Inserts the given whole VM object into the target
  832  *      map at the specified address range.  The object's
  833  *      size should match that of the address range.
  834  *
  835  *      Requires that the map be locked, and leaves it so.
  836  *
  837  *      If object is non-NULL, ref count must be bumped by caller
  838  *      prior to making call to account for the new entry.
  839  */
  840 int
  841 vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
  842               vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max,
  843               int cow)
  844 {
  845         vm_map_entry_t new_entry;
  846         vm_map_entry_t prev_entry;
  847         vm_map_entry_t temp_entry;
  848         vm_eflags_t protoeflags;
  849 
  850         /*
  851          * Check that the start and end points are not bogus.
  852          */
  853         if ((start < map->min_offset) || (end > map->max_offset) ||
  854             (start >= end))
  855                 return (KERN_INVALID_ADDRESS);
  856 
  857         /*
  858          * Find the entry prior to the proposed starting address; if it's part
  859          * of an existing entry, this range is bogus.
  860          */
  861         if (vm_map_lookup_entry(map, start, &temp_entry))
  862                 return (KERN_NO_SPACE);
  863 
  864         prev_entry = temp_entry;
  865 
  866         /*
  867          * Assert that the next entry doesn't overlap the end point.
  868          */
  869         if ((prev_entry->next != &map->header) &&
  870             (prev_entry->next->start < end))
  871                 return (KERN_NO_SPACE);
  872 
  873         protoeflags = 0;
  874 
  875         if (cow & MAP_COPY_ON_WRITE)
  876                 protoeflags |= MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY;
  877 
  878         if (cow & MAP_NOFAULT) {
  879                 protoeflags |= MAP_ENTRY_NOFAULT;
  880 
  881                 KASSERT(object == NULL,
  882                         ("vm_map_insert: paradoxical MAP_NOFAULT request"));
  883         }
  884         if (cow & MAP_DISABLE_SYNCER)
  885                 protoeflags |= MAP_ENTRY_NOSYNC;
  886         if (cow & MAP_DISABLE_COREDUMP)
  887                 protoeflags |= MAP_ENTRY_NOCOREDUMP;
  888 
  889         if (object != NULL) {
  890                 /*
  891                  * OBJ_ONEMAPPING must be cleared unless this mapping
  892                  * is trivially proven to be the only mapping for any
  893                  * of the object's pages.  (Object granularity
  894                  * reference counting is insufficient to recognize
  895                  * aliases with precision.)
  896                  */
  897                 VM_OBJECT_LOCK(object);
  898                 if (object->ref_count > 1 || object->shadow_count != 0)
  899                         vm_object_clear_flag(object, OBJ_ONEMAPPING);
  900                 VM_OBJECT_UNLOCK(object);
  901         }
  902         else if ((prev_entry != &map->header) &&
  903                  (prev_entry->eflags == protoeflags) &&
  904                  (prev_entry->end == start) &&
  905                  (prev_entry->wired_count == 0) &&
  906                  ((prev_entry->object.vm_object == NULL) ||
  907                   vm_object_coalesce(prev_entry->object.vm_object,
  908                                      prev_entry->offset,
  909                                      (vm_size_t)(prev_entry->end - prev_entry->start),
  910                                      (vm_size_t)(end - prev_entry->end)))) {
  911                 /*
  912                  * We were able to extend the object.  Determine if we
  913                  * can extend the previous map entry to include the
  914                  * new range as well.
  915                  */
  916                 if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) &&
  917                     (prev_entry->protection == prot) &&
  918                     (prev_entry->max_protection == max)) {
  919                         map->size += (end - prev_entry->end);
  920                         prev_entry->end = end;
  921                         vm_map_entry_resize_free(map, prev_entry);
  922                         vm_map_simplify_entry(map, prev_entry);
  923                         return (KERN_SUCCESS);
  924                 }
  925 
  926                 /*
  927                  * If we can extend the object but cannot extend the
  928                  * map entry, we have to create a new map entry.  We
  929                  * must bump the ref count on the extended object to
  930                  * account for it.  object may be NULL.
  931                  */
  932                 object = prev_entry->object.vm_object;
  933                 offset = prev_entry->offset +
  934                         (prev_entry->end - prev_entry->start);
  935                 vm_object_reference(object);
  936         }
  937 
  938         /*
  939          * NOTE: if conditionals fail, object can be NULL here.  This occurs
  940          * in things like the buffer map where we manage kva but do not manage
  941          * backing objects.
  942          */
  943 
  944         /*
  945          * Create a new entry
  946          */
  947         new_entry = vm_map_entry_create(map);
  948         new_entry->start = start;
  949         new_entry->end = end;
  950 
  951         new_entry->eflags = protoeflags;
  952         new_entry->object.vm_object = object;
  953         new_entry->offset = offset;
  954         new_entry->avail_ssize = 0;
  955 
  956         new_entry->inheritance = VM_INHERIT_DEFAULT;
  957         new_entry->protection = prot;
  958         new_entry->max_protection = max;
  959         new_entry->wired_count = 0;
  960 
  961         /*
  962          * Insert the new entry into the list
  963          */
  964         vm_map_entry_link(map, prev_entry, new_entry);
  965         map->size += new_entry->end - new_entry->start;
  966 
  967 #if 0
  968         /*
  969          * Temporarily removed to avoid MAP_STACK panic, due to
  970          * MAP_STACK being a huge hack.  Will be added back in
  971          * when MAP_STACK (and the user stack mapping) is fixed.
  972          */
  973         /*
  974          * It may be possible to simplify the entry
  975          */
  976         vm_map_simplify_entry(map, new_entry);
  977 #endif
  978 
  979         if (cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) {
  980                 vm_map_pmap_enter(map, start, prot,
  981                                     object, OFF_TO_IDX(offset), end - start,
  982                                     cow & MAP_PREFAULT_PARTIAL);
  983         }
  984 
  985         return (KERN_SUCCESS);
  986 }
  987 
  988 /*
  989  *      vm_map_findspace:
  990  *
  991  *      Find the first fit (lowest VM address) for "length" free bytes
  992  *      beginning at address >= start in the given map.
  993  *
  994  *      In a vm_map_entry, "adj_free" is the amount of free space
  995  *      adjacent (higher address) to this entry, and "max_free" is the
  996  *      maximum amount of contiguous free space in its subtree.  This
  997  *      allows finding a free region in one path down the tree, so
  998  *      O(log n) amortized with splay trees.
  999  *
 1000  *      The map must be locked, and leaves it so.
 1001  *
 1002  *      Returns: 0 on success, and starting address in *addr,
 1003  *               1 if insufficient space.
 1004  */
 1005 int
 1006 vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length,
 1007     vm_offset_t *addr)  /* OUT */
 1008 {
 1009         vm_map_entry_t entry;
 1010         vm_offset_t end, st;
 1011 
 1012         /*
 1013          * Request must fit within min/max VM address and must avoid
 1014          * address wrap.
 1015          */
 1016         if (start < map->min_offset)
 1017                 start = map->min_offset;
 1018         if (start + length > map->max_offset || start + length < start)
 1019                 return (1);
 1020 
 1021         /* Empty tree means wide open address space. */
 1022         if (map->root == NULL) {
 1023                 *addr = start;
 1024                 goto found;
 1025         }
 1026 
 1027         /*
 1028          * After splay, if start comes before root node, then there
 1029          * must be a gap from start to the root.
 1030          */
 1031         map->root = vm_map_entry_splay(start, map->root);
 1032         if (start + length <= map->root->start) {
 1033                 *addr = start;
 1034                 goto found;
 1035         }
 1036 
 1037         /*
 1038          * Root is the last node that might begin its gap before
 1039          * start, and this is the last comparison where address
 1040          * wrap might be a problem.
 1041          */
 1042         st = (start > map->root->end) ? start : map->root->end;
 1043         if (length <= map->root->end + map->root->adj_free - st) {
 1044                 *addr = st;
 1045                 goto found;
 1046         }
 1047 
 1048         /* With max_free, can immediately tell if no solution. */
 1049         entry = map->root->right;
 1050         if (entry == NULL || length > entry->max_free)
 1051                 return (1);
 1052 
 1053         /*
 1054          * Search the right subtree in the order: left subtree, root,
 1055          * right subtree (first fit).  The previous splay implies that
 1056          * all regions in the right subtree have addresses > start.
 1057          */
 1058         while (entry != NULL) {
 1059                 if (entry->left != NULL && entry->left->max_free >= length)
 1060                         entry = entry->left;
 1061                 else if (entry->adj_free >= length) {
 1062                         *addr = entry->end;
 1063                         goto found;
 1064                 } else
 1065                         entry = entry->right;
 1066         }
 1067 
 1068         /* Can't get here, so panic if we do. */
 1069         panic("vm_map_findspace: max_free corrupt");
 1070 
 1071 found:
 1072         /* Expand the kernel pmap, if necessary. */
 1073         if (map == kernel_map) {
 1074                 end = round_page(*addr + length);
 1075                 if (end > kernel_vm_end)
 1076                         pmap_growkernel(end);
 1077         }
 1078         return (0);
 1079 }
 1080 
 1081 /*
 1082  *      vm_map_find finds an unallocated region in the target address
 1083  *      map with the given length.  The search is defined to be
 1084  *      first-fit from the specified address; the region found is
 1085  *      returned in the same parameter.
 1086  *
 1087  *      If object is non-NULL, ref count must be bumped by caller
 1088  *      prior to making call to account for the new entry.
 1089  */
 1090 int
 1091 vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
 1092             vm_offset_t *addr,  /* IN/OUT */
 1093             vm_size_t length, boolean_t find_space, vm_prot_t prot,
 1094             vm_prot_t max, int cow)
 1095 {
 1096         vm_offset_t start;
 1097         int result;
 1098 
 1099         start = *addr;
 1100         vm_map_lock(map);
 1101         if (find_space) {
 1102                 if (vm_map_findspace(map, start, length, addr)) {
 1103                         vm_map_unlock(map);
 1104                         return (KERN_NO_SPACE);
 1105                 }
 1106                 start = *addr;
 1107         }
 1108         result = vm_map_insert(map, object, offset,
 1109                 start, start + length, prot, max, cow);
 1110         vm_map_unlock(map);
 1111         return (result);
 1112 }
 1113 
 1114 /*
 1115  *      vm_map_simplify_entry:
 1116  *
 1117  *      Simplify the given map entry by merging with either neighbor.  This
 1118  *      routine also has the ability to merge with both neighbors.
 1119  *
 1120  *      The map must be locked.
 1121  *
 1122  *      This routine guarentees that the passed entry remains valid (though
 1123  *      possibly extended).  When merging, this routine may delete one or
 1124  *      both neighbors.
 1125  */
 1126 void
 1127 vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry)
 1128 {
 1129         vm_map_entry_t next, prev;
 1130         vm_size_t prevsize, esize;
 1131 
 1132         if (entry->eflags & (MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP))
 1133                 return;
 1134 
 1135         prev = entry->prev;
 1136         if (prev != &map->header) {
 1137                 prevsize = prev->end - prev->start;
 1138                 if ( (prev->end == entry->start) &&
 1139                      (prev->object.vm_object == entry->object.vm_object) &&
 1140                      (!prev->object.vm_object ||
 1141                         (prev->offset + prevsize == entry->offset)) &&
 1142                      (prev->eflags == entry->eflags) &&
 1143                      (prev->protection == entry->protection) &&
 1144                      (prev->max_protection == entry->max_protection) &&
 1145                      (prev->inheritance == entry->inheritance) &&
 1146                      (prev->wired_count == entry->wired_count)) {
 1147                         vm_map_entry_unlink(map, prev);
 1148                         entry->start = prev->start;
 1149                         entry->offset = prev->offset;
 1150                         if (entry->prev != &map->header)
 1151                                 vm_map_entry_resize_free(map, entry->prev);
 1152                         if (prev->object.vm_object)
 1153                                 vm_object_deallocate(prev->object.vm_object);
 1154                         vm_map_entry_dispose(map, prev);
 1155                 }
 1156         }
 1157 
 1158         next = entry->next;
 1159         if (next != &map->header) {
 1160                 esize = entry->end - entry->start;
 1161                 if ((entry->end == next->start) &&
 1162                     (next->object.vm_object == entry->object.vm_object) &&
 1163                      (!entry->object.vm_object ||
 1164                         (entry->offset + esize == next->offset)) &&
 1165                     (next->eflags == entry->eflags) &&
 1166                     (next->protection == entry->protection) &&
 1167                     (next->max_protection == entry->max_protection) &&
 1168                     (next->inheritance == entry->inheritance) &&
 1169                     (next->wired_count == entry->wired_count)) {
 1170                         vm_map_entry_unlink(map, next);
 1171                         entry->end = next->end;
 1172                         vm_map_entry_resize_free(map, entry);
 1173                         if (next->object.vm_object)
 1174                                 vm_object_deallocate(next->object.vm_object);
 1175                         vm_map_entry_dispose(map, next);
 1176                 }
 1177         }
 1178 }
 1179 /*
 1180  *      vm_map_clip_start:      [ internal use only ]
 1181  *
 1182  *      Asserts that the given entry begins at or after
 1183  *      the specified address; if necessary,
 1184  *      it splits the entry into two.
 1185  */
 1186 #define vm_map_clip_start(map, entry, startaddr) \
 1187 { \
 1188         if (startaddr > entry->start) \
 1189                 _vm_map_clip_start(map, entry, startaddr); \
 1190 }
 1191 
 1192 /*
 1193  *      This routine is called only when it is known that
 1194  *      the entry must be split.
 1195  */
 1196 static void
 1197 _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start)
 1198 {
 1199         vm_map_entry_t new_entry;
 1200 
 1201         /*
 1202          * Split off the front portion -- note that we must insert the new
 1203          * entry BEFORE this one, so that this entry has the specified
 1204          * starting address.
 1205          */
 1206         vm_map_simplify_entry(map, entry);
 1207 
 1208         /*
 1209          * If there is no object backing this entry, we might as well create
 1210          * one now.  If we defer it, an object can get created after the map
 1211          * is clipped, and individual objects will be created for the split-up
 1212          * map.  This is a bit of a hack, but is also about the best place to
 1213          * put this improvement.
 1214          */
 1215         if (entry->object.vm_object == NULL && !map->system_map) {
 1216                 vm_object_t object;
 1217                 object = vm_object_allocate(OBJT_DEFAULT,
 1218                                 atop(entry->end - entry->start));
 1219                 entry->object.vm_object = object;
 1220                 entry->offset = 0;
 1221         }
 1222 
 1223         new_entry = vm_map_entry_create(map);
 1224         *new_entry = *entry;
 1225 
 1226         new_entry->end = start;
 1227         entry->offset += (start - entry->start);
 1228         entry->start = start;
 1229 
 1230         vm_map_entry_link(map, entry->prev, new_entry);
 1231 
 1232         if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
 1233                 vm_object_reference(new_entry->object.vm_object);
 1234         }
 1235 }
 1236 
 1237 /*
 1238  *      vm_map_clip_end:        [ internal use only ]
 1239  *
 1240  *      Asserts that the given entry ends at or before
 1241  *      the specified address; if necessary,
 1242  *      it splits the entry into two.
 1243  */
 1244 #define vm_map_clip_end(map, entry, endaddr) \
 1245 { \
 1246         if ((endaddr) < (entry->end)) \
 1247                 _vm_map_clip_end((map), (entry), (endaddr)); \
 1248 }
 1249 
 1250 /*
 1251  *      This routine is called only when it is known that
 1252  *      the entry must be split.
 1253  */
 1254 static void
 1255 _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end)
 1256 {
 1257         vm_map_entry_t new_entry;
 1258 
 1259         /*
 1260          * If there is no object backing this entry, we might as well create
 1261          * one now.  If we defer it, an object can get created after the map
 1262          * is clipped, and individual objects will be created for the split-up
 1263          * map.  This is a bit of a hack, but is also about the best place to
 1264          * put this improvement.
 1265          */
 1266         if (entry->object.vm_object == NULL && !map->system_map) {
 1267                 vm_object_t object;
 1268                 object = vm_object_allocate(OBJT_DEFAULT,
 1269                                 atop(entry->end - entry->start));
 1270                 entry->object.vm_object = object;
 1271                 entry->offset = 0;
 1272         }
 1273 
 1274         /*
 1275          * Create a new entry and insert it AFTER the specified entry
 1276          */
 1277         new_entry = vm_map_entry_create(map);
 1278         *new_entry = *entry;
 1279 
 1280         new_entry->start = entry->end = end;
 1281         new_entry->offset += (end - entry->start);
 1282 
 1283         vm_map_entry_link(map, entry, new_entry);
 1284 
 1285         if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
 1286                 vm_object_reference(new_entry->object.vm_object);
 1287         }
 1288 }
 1289 
 1290 /*
 1291  *      VM_MAP_RANGE_CHECK:     [ internal use only ]
 1292  *
 1293  *      Asserts that the starting and ending region
 1294  *      addresses fall within the valid range of the map.
 1295  */
 1296 #define VM_MAP_RANGE_CHECK(map, start, end)             \
 1297                 {                                       \
 1298                 if (start < vm_map_min(map))            \
 1299                         start = vm_map_min(map);        \
 1300                 if (end > vm_map_max(map))              \
 1301                         end = vm_map_max(map);          \
 1302                 if (start > end)                        \
 1303                         start = end;                    \
 1304                 }
 1305 
 1306 /*
 1307  *      vm_map_submap:          [ kernel use only ]
 1308  *
 1309  *      Mark the given range as handled by a subordinate map.
 1310  *
 1311  *      This range must have been created with vm_map_find,
 1312  *      and no other operations may have been performed on this
 1313  *      range prior to calling vm_map_submap.
 1314  *
 1315  *      Only a limited number of operations can be performed
 1316  *      within this rage after calling vm_map_submap:
 1317  *              vm_fault
 1318  *      [Don't try vm_map_copy!]
 1319  *
 1320  *      To remove a submapping, one must first remove the
 1321  *      range from the superior map, and then destroy the
 1322  *      submap (if desired).  [Better yet, don't try it.]
 1323  */
 1324 int
 1325 vm_map_submap(
 1326         vm_map_t map,
 1327         vm_offset_t start,
 1328         vm_offset_t end,
 1329         vm_map_t submap)
 1330 {
 1331         vm_map_entry_t entry;
 1332         int result = KERN_INVALID_ARGUMENT;
 1333 
 1334         vm_map_lock(map);
 1335 
 1336         VM_MAP_RANGE_CHECK(map, start, end);
 1337 
 1338         if (vm_map_lookup_entry(map, start, &entry)) {
 1339                 vm_map_clip_start(map, entry, start);
 1340         } else
 1341                 entry = entry->next;
 1342 
 1343         vm_map_clip_end(map, entry, end);
 1344 
 1345         if ((entry->start == start) && (entry->end == end) &&
 1346             ((entry->eflags & MAP_ENTRY_COW) == 0) &&
 1347             (entry->object.vm_object == NULL)) {
 1348                 entry->object.sub_map = submap;
 1349                 entry->eflags |= MAP_ENTRY_IS_SUB_MAP;
 1350                 result = KERN_SUCCESS;
 1351         }
 1352         vm_map_unlock(map);
 1353 
 1354         return (result);
 1355 }
 1356 
 1357 /*
 1358  * The maximum number of pages to map
 1359  */
 1360 #define MAX_INIT_PT     96
 1361 
 1362 /*
 1363  *      vm_map_pmap_enter:
 1364  *
 1365  *      Preload read-only mappings for the given object into the specified
 1366  *      map.  This eliminates the soft faults on process startup and
 1367  *      immediately after an mmap(2).
 1368  */
 1369 void
 1370 vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot,
 1371     vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags)
 1372 {
 1373         vm_offset_t tmpidx;
 1374         int psize;
 1375         vm_page_t p, mpte;
 1376         boolean_t are_queues_locked;
 1377 
 1378         if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL)
 1379                 return;
 1380         VM_OBJECT_LOCK(object);
 1381         if (object->type == OBJT_DEVICE) {
 1382                 pmap_object_init_pt(map->pmap, addr, object, pindex, size);
 1383                 goto unlock_return;
 1384         }
 1385 
 1386         psize = atop(size);
 1387 
 1388         if (object->type != OBJT_VNODE ||
 1389             ((flags & MAP_PREFAULT_PARTIAL) && (psize > MAX_INIT_PT) &&
 1390              (object->resident_page_count > MAX_INIT_PT))) {
 1391                 goto unlock_return;
 1392         }
 1393 
 1394         if (psize + pindex > object->size) {
 1395                 if (object->size < pindex)
 1396                         goto unlock_return;
 1397                 psize = object->size - pindex;
 1398         }
 1399 
 1400         are_queues_locked = FALSE;
 1401         mpte = NULL;
 1402 
 1403         if ((p = TAILQ_FIRST(&object->memq)) != NULL) {
 1404                 if (p->pindex < pindex) {
 1405                         p = vm_page_splay(pindex, object->root);
 1406                         if ((object->root = p)->pindex < pindex)
 1407                                 p = TAILQ_NEXT(p, listq);
 1408                 }
 1409         }
 1410         /*
 1411          * Assert: the variable p is either (1) the page with the
 1412          * least pindex greater than or equal to the parameter pindex
 1413          * or (2) NULL.
 1414          */
 1415         for (;
 1416              p != NULL && (tmpidx = p->pindex - pindex) < psize;
 1417              p = TAILQ_NEXT(p, listq)) {
 1418                 /*
 1419                  * don't allow an madvise to blow away our really
 1420                  * free pages allocating pv entries.
 1421                  */
 1422                 if ((flags & MAP_PREFAULT_MADVISE) &&
 1423                     cnt.v_free_count < cnt.v_free_reserved) {
 1424                         break;
 1425                 }
 1426                 if ((p->valid & VM_PAGE_BITS_ALL) == VM_PAGE_BITS_ALL &&
 1427                     (p->busy == 0) &&
 1428                     (p->flags & (PG_BUSY | PG_FICTITIOUS)) == 0) {
 1429                         if (!are_queues_locked) {
 1430                                 are_queues_locked = TRUE;
 1431                                 vm_page_lock_queues();
 1432                         }
 1433                         if ((p->queue - p->pc) == PQ_CACHE)
 1434                                 vm_page_deactivate(p);
 1435                         mpte = pmap_enter_quick(map->pmap,
 1436                             addr + ptoa(tmpidx), p, prot, mpte);
 1437                 }
 1438         }
 1439         if (are_queues_locked)
 1440                 vm_page_unlock_queues();
 1441 unlock_return:
 1442         VM_OBJECT_UNLOCK(object);
 1443 }
 1444 
 1445 /*
 1446  *      vm_map_protect:
 1447  *
 1448  *      Sets the protection of the specified address
 1449  *      region in the target map.  If "set_max" is
 1450  *      specified, the maximum protection is to be set;
 1451  *      otherwise, only the current protection is affected.
 1452  */
 1453 int
 1454 vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
 1455                vm_prot_t new_prot, boolean_t set_max)
 1456 {
 1457         vm_map_entry_t current;
 1458         vm_map_entry_t entry;
 1459 
 1460         vm_map_lock(map);
 1461 
 1462         VM_MAP_RANGE_CHECK(map, start, end);
 1463 
 1464         if (vm_map_lookup_entry(map, start, &entry)) {
 1465                 vm_map_clip_start(map, entry, start);
 1466         } else {
 1467                 entry = entry->next;
 1468         }
 1469 
 1470         /*
 1471          * Make a first pass to check for protection violations.
 1472          */
 1473         current = entry;
 1474         while ((current != &map->header) && (current->start < end)) {
 1475                 if (current->eflags & MAP_ENTRY_IS_SUB_MAP) {
 1476                         vm_map_unlock(map);
 1477                         return (KERN_INVALID_ARGUMENT);
 1478                 }
 1479                 if ((new_prot & current->max_protection) != new_prot) {
 1480                         vm_map_unlock(map);
 1481                         return (KERN_PROTECTION_FAILURE);
 1482                 }
 1483                 current = current->next;
 1484         }
 1485 
 1486         /*
 1487          * Go back and fix up protections. [Note that clipping is not
 1488          * necessary the second time.]
 1489          */
 1490         current = entry;
 1491         while ((current != &map->header) && (current->start < end)) {
 1492                 vm_prot_t old_prot;
 1493 
 1494                 vm_map_clip_end(map, current, end);
 1495 
 1496                 old_prot = current->protection;
 1497                 if (set_max)
 1498                         current->protection =
 1499                             (current->max_protection = new_prot) &
 1500                             old_prot;
 1501                 else
 1502                         current->protection = new_prot;
 1503 
 1504                 /*
 1505                  * Update physical map if necessary. Worry about copy-on-write
 1506                  * here -- CHECK THIS XXX
 1507                  */
 1508                 if (current->protection != old_prot) {
 1509 #define MASK(entry)     (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \
 1510                                                         VM_PROT_ALL)
 1511                         pmap_protect(map->pmap, current->start,
 1512                             current->end,
 1513                             current->protection & MASK(current));
 1514 #undef  MASK
 1515                 }
 1516                 vm_map_simplify_entry(map, current);
 1517                 current = current->next;
 1518         }
 1519         vm_map_unlock(map);
 1520         return (KERN_SUCCESS);
 1521 }
 1522 
 1523 /*
 1524  *      vm_map_madvise:
 1525  *
 1526  *      This routine traverses a processes map handling the madvise
 1527  *      system call.  Advisories are classified as either those effecting
 1528  *      the vm_map_entry structure, or those effecting the underlying
 1529  *      objects.
 1530  */
 1531 int
 1532 vm_map_madvise(
 1533         vm_map_t map,
 1534         vm_offset_t start,
 1535         vm_offset_t end,
 1536         int behav)
 1537 {
 1538         vm_map_entry_t current, entry;
 1539         int modify_map = 0;
 1540 
 1541         /*
 1542          * Some madvise calls directly modify the vm_map_entry, in which case
 1543          * we need to use an exclusive lock on the map and we need to perform
 1544          * various clipping operations.  Otherwise we only need a read-lock
 1545          * on the map.
 1546          */
 1547         switch(behav) {
 1548         case MADV_NORMAL:
 1549         case MADV_SEQUENTIAL:
 1550         case MADV_RANDOM:
 1551         case MADV_NOSYNC:
 1552         case MADV_AUTOSYNC:
 1553         case MADV_NOCORE:
 1554         case MADV_CORE:
 1555                 modify_map = 1;
 1556                 vm_map_lock(map);
 1557                 break;
 1558         case MADV_WILLNEED:
 1559         case MADV_DONTNEED:
 1560         case MADV_FREE:
 1561                 vm_map_lock_read(map);
 1562                 break;
 1563         default:
 1564                 return (KERN_INVALID_ARGUMENT);
 1565         }
 1566 
 1567         /*
 1568          * Locate starting entry and clip if necessary.
 1569          */
 1570         VM_MAP_RANGE_CHECK(map, start, end);
 1571 
 1572         if (vm_map_lookup_entry(map, start, &entry)) {
 1573                 if (modify_map)
 1574                         vm_map_clip_start(map, entry, start);
 1575         } else {
 1576                 entry = entry->next;
 1577         }
 1578 
 1579         if (modify_map) {
 1580                 /*
 1581                  * madvise behaviors that are implemented in the vm_map_entry.
 1582                  *
 1583                  * We clip the vm_map_entry so that behavioral changes are
 1584                  * limited to the specified address range.
 1585                  */
 1586                 for (current = entry;
 1587                      (current != &map->header) && (current->start < end);
 1588                      current = current->next
 1589                 ) {
 1590                         if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
 1591                                 continue;
 1592 
 1593                         vm_map_clip_end(map, current, end);
 1594 
 1595                         switch (behav) {
 1596                         case MADV_NORMAL:
 1597                                 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL);
 1598                                 break;
 1599                         case MADV_SEQUENTIAL:
 1600                                 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL);
 1601                                 break;
 1602                         case MADV_RANDOM:
 1603                                 vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM);
 1604                                 break;
 1605                         case MADV_NOSYNC:
 1606                                 current->eflags |= MAP_ENTRY_NOSYNC;
 1607                                 break;
 1608                         case MADV_AUTOSYNC:
 1609                                 current->eflags &= ~MAP_ENTRY_NOSYNC;
 1610                                 break;
 1611                         case MADV_NOCORE:
 1612                                 current->eflags |= MAP_ENTRY_NOCOREDUMP;
 1613                                 break;
 1614                         case MADV_CORE:
 1615                                 current->eflags &= ~MAP_ENTRY_NOCOREDUMP;
 1616                                 break;
 1617                         default:
 1618                                 break;
 1619                         }
 1620                         vm_map_simplify_entry(map, current);
 1621                 }
 1622                 vm_map_unlock(map);
 1623         } else {
 1624                 vm_pindex_t pindex;
 1625                 int count;
 1626 
 1627                 /*
 1628                  * madvise behaviors that are implemented in the underlying
 1629                  * vm_object.
 1630                  *
 1631                  * Since we don't clip the vm_map_entry, we have to clip
 1632                  * the vm_object pindex and count.
 1633                  */
 1634                 for (current = entry;
 1635                      (current != &map->header) && (current->start < end);
 1636                      current = current->next
 1637                 ) {
 1638                         vm_offset_t useStart;
 1639 
 1640                         if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
 1641                                 continue;
 1642 
 1643                         pindex = OFF_TO_IDX(current->offset);
 1644                         count = atop(current->end - current->start);
 1645                         useStart = current->start;
 1646 
 1647                         if (current->start < start) {
 1648                                 pindex += atop(start - current->start);
 1649                                 count -= atop(start - current->start);
 1650                                 useStart = start;
 1651                         }
 1652                         if (current->end > end)
 1653                                 count -= atop(current->end - end);
 1654 
 1655                         if (count <= 0)
 1656                                 continue;
 1657 
 1658                         vm_object_madvise(current->object.vm_object,
 1659                                           pindex, count, behav);
 1660                         if (behav == MADV_WILLNEED) {
 1661                                 vm_map_pmap_enter(map,
 1662                                     useStart,
 1663                                     current->protection,
 1664                                     current->object.vm_object,
 1665                                     pindex,
 1666                                     (count << PAGE_SHIFT),
 1667                                     MAP_PREFAULT_MADVISE
 1668                                 );
 1669                         }
 1670                 }
 1671                 vm_map_unlock_read(map);
 1672         }
 1673         return (0);
 1674 }
 1675 
 1676 
 1677 /*
 1678  *      vm_map_inherit:
 1679  *
 1680  *      Sets the inheritance of the specified address
 1681  *      range in the target map.  Inheritance
 1682  *      affects how the map will be shared with
 1683  *      child maps at the time of vm_map_fork.
 1684  */
 1685 int
 1686 vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
 1687                vm_inherit_t new_inheritance)
 1688 {
 1689         vm_map_entry_t entry;
 1690         vm_map_entry_t temp_entry;
 1691 
 1692         switch (new_inheritance) {
 1693         case VM_INHERIT_NONE:
 1694         case VM_INHERIT_COPY:
 1695         case VM_INHERIT_SHARE:
 1696                 break;
 1697         default:
 1698                 return (KERN_INVALID_ARGUMENT);
 1699         }
 1700         vm_map_lock(map);
 1701         VM_MAP_RANGE_CHECK(map, start, end);
 1702         if (vm_map_lookup_entry(map, start, &temp_entry)) {
 1703                 entry = temp_entry;
 1704                 vm_map_clip_start(map, entry, start);
 1705         } else
 1706                 entry = temp_entry->next;
 1707         while ((entry != &map->header) && (entry->start < end)) {
 1708                 vm_map_clip_end(map, entry, end);
 1709                 entry->inheritance = new_inheritance;
 1710                 vm_map_simplify_entry(map, entry);
 1711                 entry = entry->next;
 1712         }
 1713         vm_map_unlock(map);
 1714         return (KERN_SUCCESS);
 1715 }
 1716 
 1717 /*
 1718  *      vm_map_unwire:
 1719  *
 1720  *      Implements both kernel and user unwiring.
 1721  */
 1722 int
 1723 vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
 1724     int flags)
 1725 {
 1726         vm_map_entry_t entry, first_entry, tmp_entry;
 1727         vm_offset_t saved_start;
 1728         unsigned int last_timestamp;
 1729         int rv;
 1730         boolean_t need_wakeup, result, user_unwire;
 1731 
 1732         user_unwire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE;
 1733         vm_map_lock(map);
 1734         VM_MAP_RANGE_CHECK(map, start, end);
 1735         if (!vm_map_lookup_entry(map, start, &first_entry)) {
 1736                 if (flags & VM_MAP_WIRE_HOLESOK)
 1737                         first_entry = first_entry->next;
 1738                 else {
 1739                         vm_map_unlock(map);
 1740                         return (KERN_INVALID_ADDRESS);
 1741                 }
 1742         }
 1743         last_timestamp = map->timestamp;
 1744         entry = first_entry;
 1745         while (entry != &map->header && entry->start < end) {
 1746                 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
 1747                         /*
 1748                          * We have not yet clipped the entry.
 1749                          */
 1750                         saved_start = (start >= entry->start) ? start :
 1751                             entry->start;
 1752                         entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
 1753                         if (vm_map_unlock_and_wait(map, user_unwire)) {
 1754                                 /*
 1755                                  * Allow interruption of user unwiring?
 1756                                  */
 1757                         }
 1758                         vm_map_lock(map);
 1759                         if (last_timestamp+1 != map->timestamp) {
 1760                                 /*
 1761                                  * Look again for the entry because the map was
 1762                                  * modified while it was unlocked.
 1763                                  * Specifically, the entry may have been
 1764                                  * clipped, merged, or deleted.
 1765                                  */
 1766                                 if (!vm_map_lookup_entry(map, saved_start,
 1767                                     &tmp_entry)) {
 1768                                         if (flags & VM_MAP_WIRE_HOLESOK)
 1769                                                 tmp_entry = tmp_entry->next;
 1770                                         else {
 1771                                                 if (saved_start == start) {
 1772                                                         /*
 1773                                                          * First_entry has been deleted.
 1774                                                          */
 1775                                                         vm_map_unlock(map);
 1776                                                         return (KERN_INVALID_ADDRESS);
 1777                                                 }
 1778                                                 end = saved_start;
 1779                                                 rv = KERN_INVALID_ADDRESS;
 1780                                                 goto done;
 1781                                         }
 1782                                 }
 1783                                 if (entry == first_entry)
 1784                                         first_entry = tmp_entry;
 1785                                 else
 1786                                         first_entry = NULL;
 1787                                 entry = tmp_entry;
 1788                         }
 1789                         last_timestamp = map->timestamp;
 1790                         continue;
 1791                 }
 1792                 vm_map_clip_start(map, entry, start);
 1793                 vm_map_clip_end(map, entry, end);
 1794                 /*
 1795                  * Mark the entry in case the map lock is released.  (See
 1796                  * above.)
 1797                  */
 1798                 entry->eflags |= MAP_ENTRY_IN_TRANSITION;
 1799                 /*
 1800                  * Check the map for holes in the specified region.
 1801                  * If VM_MAP_WIRE_HOLESOK was specified, skip this check.
 1802                  */
 1803                 if (((flags & VM_MAP_WIRE_HOLESOK) == 0) &&
 1804                     (entry->end < end && (entry->next == &map->header ||
 1805                     entry->next->start > entry->end))) {
 1806                         end = entry->end;
 1807                         rv = KERN_INVALID_ADDRESS;
 1808                         goto done;
 1809                 }
 1810                 /*
 1811                  * If system unwiring, require that the entry is system wired.
 1812                  */
 1813                 if (!user_unwire &&
 1814                     vm_map_entry_system_wired_count(entry) == 0) {
 1815                         end = entry->end;
 1816                         rv = KERN_INVALID_ARGUMENT;
 1817                         goto done;
 1818                 }
 1819                 entry = entry->next;
 1820         }
 1821         rv = KERN_SUCCESS;
 1822 done:
 1823         need_wakeup = FALSE;
 1824         if (first_entry == NULL) {
 1825                 result = vm_map_lookup_entry(map, start, &first_entry);
 1826                 if (!result && (flags & VM_MAP_WIRE_HOLESOK))
 1827                         first_entry = first_entry->next;
 1828                 else
 1829                         KASSERT(result, ("vm_map_unwire: lookup failed"));
 1830         }
 1831         entry = first_entry;
 1832         while (entry != &map->header && entry->start < end) {
 1833                 if (rv == KERN_SUCCESS && (!user_unwire ||
 1834                     (entry->eflags & MAP_ENTRY_USER_WIRED))) {
 1835                         if (user_unwire)
 1836                                 entry->eflags &= ~MAP_ENTRY_USER_WIRED;
 1837                         entry->wired_count--;
 1838                         if (entry->wired_count == 0) {
 1839                                 /*
 1840                                  * Retain the map lock.
 1841                                  */
 1842                                 vm_fault_unwire(map, entry->start, entry->end,
 1843                                     entry->object.vm_object != NULL &&
 1844                                     entry->object.vm_object->type == OBJT_DEVICE);
 1845                         }
 1846                 }
 1847                 KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION,
 1848                         ("vm_map_unwire: in-transition flag missing"));
 1849                 entry->eflags &= ~MAP_ENTRY_IN_TRANSITION;
 1850                 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
 1851                         entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
 1852                         need_wakeup = TRUE;
 1853                 }
 1854                 vm_map_simplify_entry(map, entry);
 1855                 entry = entry->next;
 1856         }
 1857         vm_map_unlock(map);
 1858         if (need_wakeup)
 1859                 vm_map_wakeup(map);
 1860         return (rv);
 1861 }
 1862 
 1863 /*
 1864  *      vm_map_wire:
 1865  *
 1866  *      Implements both kernel and user wiring.
 1867  */
 1868 int
 1869 vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end,
 1870     int flags)
 1871 {
 1872         vm_map_entry_t entry, first_entry, tmp_entry;
 1873         vm_offset_t saved_end, saved_start;
 1874         unsigned int last_timestamp;
 1875         int rv;
 1876         boolean_t fictitious, need_wakeup, result, user_wire;
 1877 
 1878         user_wire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE;
 1879         vm_map_lock(map);
 1880         VM_MAP_RANGE_CHECK(map, start, end);
 1881         if (!vm_map_lookup_entry(map, start, &first_entry)) {
 1882                 if (flags & VM_MAP_WIRE_HOLESOK)
 1883                         first_entry = first_entry->next;
 1884                 else {
 1885                         vm_map_unlock(map);
 1886                         return (KERN_INVALID_ADDRESS);
 1887                 }
 1888         }
 1889         last_timestamp = map->timestamp;
 1890         entry = first_entry;
 1891         while (entry != &map->header && entry->start < end) {
 1892                 if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
 1893                         /*
 1894                          * We have not yet clipped the entry.
 1895                          */
 1896                         saved_start = (start >= entry->start) ? start :
 1897                             entry->start;
 1898                         entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
 1899                         if (vm_map_unlock_and_wait(map, user_wire)) {
 1900                                 /*
 1901                                  * Allow interruption of user wiring?
 1902                                  */
 1903                         }
 1904                         vm_map_lock(map);
 1905                         if (last_timestamp + 1 != map->timestamp) {
 1906                                 /*
 1907                                  * Look again for the entry because the map was
 1908                                  * modified while it was unlocked.
 1909                                  * Specifically, the entry may have been
 1910                                  * clipped, merged, or deleted.
 1911                                  */
 1912                                 if (!vm_map_lookup_entry(map, saved_start,
 1913                                     &tmp_entry)) {
 1914                                         if (flags & VM_MAP_WIRE_HOLESOK)
 1915                                                 tmp_entry = tmp_entry->next;
 1916                                         else {
 1917                                                 if (saved_start == start) {
 1918                                                         /*
 1919                                                          * first_entry has been deleted.
 1920                                                          */
 1921                                                         vm_map_unlock(map);
 1922                                                         return (KERN_INVALID_ADDRESS);
 1923                                                 }
 1924                                                 end = saved_start;
 1925                                                 rv = KERN_INVALID_ADDRESS;
 1926                                                 goto done;
 1927                                         }
 1928                                 }
 1929                                 if (entry == first_entry)
 1930                                         first_entry = tmp_entry;
 1931                                 else
 1932                                         first_entry = NULL;
 1933                                 entry = tmp_entry;
 1934                         }
 1935                         last_timestamp = map->timestamp;
 1936                         continue;
 1937                 }
 1938                 vm_map_clip_start(map, entry, start);
 1939                 vm_map_clip_end(map, entry, end);
 1940                 /*
 1941                  * Mark the entry in case the map lock is released.  (See
 1942                  * above.)
 1943                  */
 1944                 entry->eflags |= MAP_ENTRY_IN_TRANSITION;
 1945                 /*
 1946                  *
 1947                  */
 1948                 if (entry->wired_count == 0) {
 1949                         entry->wired_count++;
 1950                         saved_start = entry->start;
 1951                         saved_end = entry->end;
 1952                         fictitious = entry->object.vm_object != NULL &&
 1953                             entry->object.vm_object->type == OBJT_DEVICE;
 1954                         /*
 1955                          * Release the map lock, relying on the in-transition
 1956                          * mark.
 1957                          */
 1958                         vm_map_unlock(map);
 1959                         rv = vm_fault_wire(map, saved_start, saved_end,
 1960                             user_wire, fictitious);
 1961                         vm_map_lock(map);
 1962                         if (last_timestamp + 1 != map->timestamp) {
 1963                                 /*
 1964                                  * Look again for the entry because the map was
 1965                                  * modified while it was unlocked.  The entry
 1966                                  * may have been clipped, but NOT merged or
 1967                                  * deleted.
 1968                                  */
 1969                                 result = vm_map_lookup_entry(map, saved_start,
 1970                                     &tmp_entry);
 1971                                 KASSERT(result, ("vm_map_wire: lookup failed"));
 1972                                 if (entry == first_entry)
 1973                                         first_entry = tmp_entry;
 1974                                 else
 1975                                         first_entry = NULL;
 1976                                 entry = tmp_entry;
 1977                                 while (entry->end < saved_end) {
 1978                                         if (rv != KERN_SUCCESS) {
 1979                                                 KASSERT(entry->wired_count == 1,
 1980                                                     ("vm_map_wire: bad count"));
 1981                                                 entry->wired_count = -1;
 1982                                         }
 1983                                         entry = entry->next;
 1984                                 }
 1985                         }
 1986                         last_timestamp = map->timestamp;
 1987                         if (rv != KERN_SUCCESS) {
 1988                                 KASSERT(entry->wired_count == 1,
 1989                                     ("vm_map_wire: bad count"));
 1990                                 /*
 1991                                  * Assign an out-of-range value to represent
 1992                                  * the failure to wire this entry.
 1993                                  */
 1994                                 entry->wired_count = -1;
 1995                                 end = entry->end;
 1996                                 goto done;
 1997                         }
 1998                 } else if (!user_wire ||
 1999                            (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) {
 2000                         entry->wired_count++;
 2001                 }
 2002                 /*
 2003                  * Check the map for holes in the specified region.
 2004                  * If VM_MAP_WIRE_HOLESOK was specified, skip this check.
 2005                  */
 2006                 if (((flags & VM_MAP_WIRE_HOLESOK) == 0) &&
 2007                     (entry->end < end && (entry->next == &map->header ||
 2008                     entry->next->start > entry->end))) {
 2009                         end = entry->end;
 2010                         rv = KERN_INVALID_ADDRESS;
 2011                         goto done;
 2012                 }
 2013                 entry = entry->next;
 2014         }
 2015         rv = KERN_SUCCESS;
 2016 done:
 2017         need_wakeup = FALSE;
 2018         if (first_entry == NULL) {
 2019                 result = vm_map_lookup_entry(map, start, &first_entry);
 2020                 if (!result && (flags & VM_MAP_WIRE_HOLESOK))
 2021                         first_entry = first_entry->next;
 2022                 else
 2023                         KASSERT(result, ("vm_map_wire: lookup failed"));
 2024         }
 2025         entry = first_entry;
 2026         while (entry != &map->header && entry->start < end) {
 2027                 if (rv == KERN_SUCCESS) {
 2028                         if (user_wire)
 2029                                 entry->eflags |= MAP_ENTRY_USER_WIRED;
 2030                 } else if (entry->wired_count == -1) {
 2031                         /*
 2032                          * Wiring failed on this entry.  Thus, unwiring is
 2033                          * unnecessary.
 2034                          */
 2035                         entry->wired_count = 0;
 2036                 } else {
 2037                         if (!user_wire ||
 2038                             (entry->eflags & MAP_ENTRY_USER_WIRED) == 0)
 2039                                 entry->wired_count--;
 2040                         if (entry->wired_count == 0) {
 2041                                 /*
 2042                                  * Retain the map lock.
 2043                                  */
 2044                                 vm_fault_unwire(map, entry->start, entry->end,
 2045                                     entry->object.vm_object != NULL &&
 2046                                     entry->object.vm_object->type == OBJT_DEVICE);
 2047                         }
 2048                 }
 2049                 KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION,
 2050                         ("vm_map_wire: in-transition flag missing"));
 2051                 entry->eflags &= ~MAP_ENTRY_IN_TRANSITION;
 2052                 if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
 2053                         entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
 2054                         need_wakeup = TRUE;
 2055                 }
 2056                 vm_map_simplify_entry(map, entry);
 2057                 entry = entry->next;
 2058         }
 2059         vm_map_unlock(map);
 2060         if (need_wakeup)
 2061                 vm_map_wakeup(map);
 2062         return (rv);
 2063 }
 2064 
 2065 /*
 2066  * vm_map_sync
 2067  *
 2068  * Push any dirty cached pages in the address range to their pager.
 2069  * If syncio is TRUE, dirty pages are written synchronously.
 2070  * If invalidate is TRUE, any cached pages are freed as well.
 2071  *
 2072  * If the size of the region from start to end is zero, we are
 2073  * supposed to flush all modified pages within the region containing
 2074  * start.  Unfortunately, a region can be split or coalesced with
 2075  * neighboring regions, making it difficult to determine what the
 2076  * original region was.  Therefore, we approximate this requirement by
 2077  * flushing the current region containing start.
 2078  *
 2079  * Returns an error if any part of the specified range is not mapped.
 2080  */
 2081 int
 2082 vm_map_sync(
 2083         vm_map_t map,
 2084         vm_offset_t start,
 2085         vm_offset_t end,
 2086         boolean_t syncio,
 2087         boolean_t invalidate)
 2088 {
 2089         vm_map_entry_t current;
 2090         vm_map_entry_t entry;
 2091         vm_size_t size;
 2092         vm_object_t object;
 2093         vm_ooffset_t offset;
 2094 
 2095         vm_map_lock_read(map);
 2096         VM_MAP_RANGE_CHECK(map, start, end);
 2097         if (!vm_map_lookup_entry(map, start, &entry)) {
 2098                 vm_map_unlock_read(map);
 2099                 return (KERN_INVALID_ADDRESS);
 2100         } else if (start == end) {
 2101                 start = entry->start;
 2102                 end = entry->end;
 2103         }
 2104         /*
 2105          * Make a first pass to check for user-wired memory and holes.
 2106          */
 2107         for (current = entry; current->start < end; current = current->next) {
 2108                 if (invalidate && (current->eflags & MAP_ENTRY_USER_WIRED)) {
 2109                         vm_map_unlock_read(map);
 2110                         return (KERN_INVALID_ARGUMENT);
 2111                 }
 2112                 if (end > current->end &&
 2113                     (current->next == &map->header ||
 2114                         current->end != current->next->start)) {
 2115                         vm_map_unlock_read(map);
 2116                         return (KERN_INVALID_ADDRESS);
 2117                 }
 2118         }
 2119 
 2120         if (invalidate) {
 2121                 VM_LOCK_GIANT();
 2122                 pmap_remove(map->pmap, start, end);
 2123                 VM_UNLOCK_GIANT();
 2124         }
 2125         /*
 2126          * Make a second pass, cleaning/uncaching pages from the indicated
 2127          * objects as we go.
 2128          */
 2129         for (current = entry; current->start < end; current = current->next) {
 2130                 offset = current->offset + (start - current->start);
 2131                 size = (end <= current->end ? end : current->end) - start;
 2132                 if (current->eflags & MAP_ENTRY_IS_SUB_MAP) {
 2133                         vm_map_t smap;
 2134                         vm_map_entry_t tentry;
 2135                         vm_size_t tsize;
 2136 
 2137                         smap = current->object.sub_map;
 2138                         vm_map_lock_read(smap);
 2139                         (void) vm_map_lookup_entry(smap, offset, &tentry);
 2140                         tsize = tentry->end - offset;
 2141                         if (tsize < size)
 2142                                 size = tsize;
 2143                         object = tentry->object.vm_object;
 2144                         offset = tentry->offset + (offset - tentry->start);
 2145                         vm_map_unlock_read(smap);
 2146                 } else {
 2147                         object = current->object.vm_object;
 2148                 }
 2149                 vm_object_sync(object, offset, size, syncio, invalidate);
 2150                 start += size;
 2151         }
 2152 
 2153         vm_map_unlock_read(map);
 2154         return (KERN_SUCCESS);
 2155 }
 2156 
 2157 /*
 2158  *      vm_map_entry_unwire:    [ internal use only ]
 2159  *
 2160  *      Make the region specified by this entry pageable.
 2161  *
 2162  *      The map in question should be locked.
 2163  *      [This is the reason for this routine's existence.]
 2164  */
 2165 static void
 2166 vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry)
 2167 {
 2168         vm_fault_unwire(map, entry->start, entry->end,
 2169             entry->object.vm_object != NULL &&
 2170             entry->object.vm_object->type == OBJT_DEVICE);
 2171         entry->wired_count = 0;
 2172 }
 2173 
 2174 /*
 2175  *      vm_map_entry_delete:    [ internal use only ]
 2176  *
 2177  *      Deallocate the given entry from the target map.
 2178  */
 2179 static void
 2180 vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry)
 2181 {
 2182         vm_object_t object;
 2183         vm_pindex_t offidxstart, offidxend, count;
 2184 
 2185         vm_map_entry_unlink(map, entry);
 2186         map->size -= entry->end - entry->start;
 2187 
 2188         if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0 &&
 2189             (object = entry->object.vm_object) != NULL) {
 2190                 count = OFF_TO_IDX(entry->end - entry->start);
 2191                 offidxstart = OFF_TO_IDX(entry->offset);
 2192                 offidxend = offidxstart + count;
 2193                 VM_OBJECT_LOCK(object);
 2194                 if (object->ref_count != 1 &&
 2195                     ((object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING ||
 2196                      object == kernel_object || object == kmem_object) &&
 2197                     (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
 2198                         vm_object_collapse(object);
 2199                         vm_object_page_remove(object, offidxstart, offidxend, FALSE);
 2200                         if (object->type == OBJT_SWAP)
 2201                                 swap_pager_freespace(object, offidxstart, count);
 2202                         if (offidxend >= object->size &&
 2203                             offidxstart < object->size)
 2204                                 object->size = offidxstart;
 2205                 }
 2206                 VM_OBJECT_UNLOCK(object);
 2207                 vm_object_deallocate(object);
 2208         }
 2209 
 2210         vm_map_entry_dispose(map, entry);
 2211 }
 2212 
 2213 /*
 2214  *      vm_map_delete:  [ internal use only ]
 2215  *
 2216  *      Deallocates the given address range from the target
 2217  *      map.
 2218  */
 2219 int
 2220 vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end)
 2221 {
 2222         vm_map_entry_t entry;
 2223         vm_map_entry_t first_entry;
 2224 
 2225         /*
 2226          * Find the start of the region, and clip it
 2227          */
 2228         if (!vm_map_lookup_entry(map, start, &first_entry))
 2229                 entry = first_entry->next;
 2230         else {
 2231                 entry = first_entry;
 2232                 vm_map_clip_start(map, entry, start);
 2233         }
 2234 
 2235         /*
 2236          * Step through all entries in this region
 2237          */
 2238         while ((entry != &map->header) && (entry->start < end)) {
 2239                 vm_map_entry_t next;
 2240 
 2241                 /*
 2242                  * Wait for wiring or unwiring of an entry to complete.
 2243                  * Also wait for any system wirings to disappear on
 2244                  * user maps.
 2245                  */
 2246                 if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 ||
 2247                     (vm_map_pmap(map) != kernel_pmap &&
 2248                     vm_map_entry_system_wired_count(entry) != 0)) {
 2249                         unsigned int last_timestamp;
 2250                         vm_offset_t saved_start;
 2251                         vm_map_entry_t tmp_entry;
 2252 
 2253                         saved_start = entry->start;
 2254                         entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
 2255                         last_timestamp = map->timestamp;
 2256                         (void) vm_map_unlock_and_wait(map, FALSE);
 2257                         vm_map_lock(map);
 2258                         if (last_timestamp + 1 != map->timestamp) {
 2259                                 /*
 2260                                  * Look again for the entry because the map was
 2261                                  * modified while it was unlocked.
 2262                                  * Specifically, the entry may have been
 2263                                  * clipped, merged, or deleted.
 2264                                  */
 2265                                 if (!vm_map_lookup_entry(map, saved_start,
 2266                                                          &tmp_entry))
 2267                                         entry = tmp_entry->next;
 2268                                 else {
 2269                                         entry = tmp_entry;
 2270                                         vm_map_clip_start(map, entry,
 2271                                                           saved_start);
 2272                                 }
 2273                         }
 2274                         continue;
 2275                 }
 2276                 vm_map_clip_end(map, entry, end);
 2277 
 2278                 next = entry->next;
 2279 
 2280                 /*
 2281                  * Unwire before removing addresses from the pmap; otherwise,
 2282                  * unwiring will put the entries back in the pmap.
 2283                  */
 2284                 if (entry->wired_count != 0) {
 2285                         vm_map_entry_unwire(map, entry);
 2286                 }
 2287 
 2288                 if (!map->system_map)
 2289                         VM_LOCK_GIANT();
 2290                 pmap_remove(map->pmap, entry->start, entry->end);
 2291                 if (!map->system_map)
 2292                         VM_UNLOCK_GIANT();
 2293 
 2294                 /*
 2295                  * Delete the entry (which may delete the object) only after
 2296                  * removing all pmap entries pointing to its pages.
 2297                  * (Otherwise, its page frames may be reallocated, and any
 2298                  * modify bits will be set in the wrong object!)
 2299                  */
 2300                 vm_map_entry_delete(map, entry);
 2301                 entry = next;
 2302         }
 2303         return (KERN_SUCCESS);
 2304 }
 2305 
 2306 /*
 2307  *      vm_map_remove:
 2308  *
 2309  *      Remove the given address range from the target map.
 2310  *      This is the exported form of vm_map_delete.
 2311  */
 2312 int
 2313 vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end)
 2314 {
 2315         int result;
 2316 
 2317         vm_map_lock(map);
 2318         VM_MAP_RANGE_CHECK(map, start, end);
 2319         result = vm_map_delete(map, start, end);
 2320         vm_map_unlock(map);
 2321         return (result);
 2322 }
 2323 
 2324 /*
 2325  *      vm_map_check_protection:
 2326  *
 2327  *      Assert that the target map allows the specified privilege on the
 2328  *      entire address region given.  The entire region must be allocated.
 2329  *
 2330  *      WARNING!  This code does not and should not check whether the
 2331  *      contents of the region is accessible.  For example a smaller file
 2332  *      might be mapped into a larger address space.
 2333  *
 2334  *      NOTE!  This code is also called by munmap().
 2335  *
 2336  *      The map must be locked.  A read lock is sufficient.
 2337  */
 2338 boolean_t
 2339 vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end,
 2340                         vm_prot_t protection)
 2341 {
 2342         vm_map_entry_t entry;
 2343         vm_map_entry_t tmp_entry;
 2344 
 2345         if (!vm_map_lookup_entry(map, start, &tmp_entry))
 2346                 return (FALSE);
 2347         entry = tmp_entry;
 2348 
 2349         while (start < end) {
 2350                 if (entry == &map->header)
 2351                         return (FALSE);
 2352                 /*
 2353                  * No holes allowed!
 2354                  */
 2355                 if (start < entry->start)
 2356                         return (FALSE);
 2357                 /*
 2358                  * Check protection associated with entry.
 2359                  */
 2360                 if ((entry->protection & protection) != protection)
 2361                         return (FALSE);
 2362                 /* go to next entry */
 2363                 start = entry->end;
 2364                 entry = entry->next;
 2365         }
 2366         return (TRUE);
 2367 }
 2368 
 2369 /*
 2370  *      vm_map_copy_entry:
 2371  *
 2372  *      Copies the contents of the source entry to the destination
 2373  *      entry.  The entries *must* be aligned properly.
 2374  */
 2375 static void
 2376 vm_map_copy_entry(
 2377         vm_map_t src_map,
 2378         vm_map_t dst_map,
 2379         vm_map_entry_t src_entry,
 2380         vm_map_entry_t dst_entry)
 2381 {
 2382         vm_object_t src_object;
 2383 
 2384         if ((dst_entry->eflags|src_entry->eflags) & MAP_ENTRY_IS_SUB_MAP)
 2385                 return;
 2386 
 2387         if (src_entry->wired_count == 0) {
 2388 
 2389                 /*
 2390                  * If the source entry is marked needs_copy, it is already
 2391                  * write-protected.
 2392                  */
 2393                 if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) {
 2394                         pmap_protect(src_map->pmap,
 2395                             src_entry->start,
 2396                             src_entry->end,
 2397                             src_entry->protection & ~VM_PROT_WRITE);
 2398                 }
 2399 
 2400                 /*
 2401                  * Make a copy of the object.
 2402                  */
 2403                 if ((src_object = src_entry->object.vm_object) != NULL) {
 2404                         VM_OBJECT_LOCK(src_object);
 2405                         if ((src_object->handle == NULL) &&
 2406                                 (src_object->type == OBJT_DEFAULT ||
 2407                                  src_object->type == OBJT_SWAP)) {
 2408                                 vm_object_collapse(src_object);
 2409                                 if ((src_object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) {
 2410                                         vm_object_split(src_entry);
 2411                                         src_object = src_entry->object.vm_object;
 2412                                 }
 2413                         }
 2414                         vm_object_reference_locked(src_object);
 2415                         vm_object_clear_flag(src_object, OBJ_ONEMAPPING);
 2416                         VM_OBJECT_UNLOCK(src_object);
 2417                         dst_entry->object.vm_object = src_object;
 2418                         src_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY);
 2419                         dst_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY);
 2420                         dst_entry->offset = src_entry->offset;
 2421                 } else {
 2422                         dst_entry->object.vm_object = NULL;
 2423                         dst_entry->offset = 0;
 2424                 }
 2425 
 2426                 pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start,
 2427                     dst_entry->end - dst_entry->start, src_entry->start);
 2428         } else {
 2429                 /*
 2430                  * Of course, wired down pages can't be set copy-on-write.
 2431                  * Cause wired pages to be copied into the new map by
 2432                  * simulating faults (the new pages are pageable)
 2433                  */
 2434                 vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry);
 2435         }
 2436 }
 2437 
 2438 /*
 2439  * vmspace_map_entry_forked:
 2440  * Update the newly-forked vmspace each time a map entry is inherited
 2441  * or copied.  The values for vm_dsize and vm_tsize are approximate
 2442  * (and mostly-obsolete ideas in the face of mmap(2) et al.)
 2443  */
 2444 static void
 2445 vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2,
 2446     vm_map_entry_t entry)
 2447 {
 2448         vm_size_t entrysize;
 2449         vm_offset_t newend;
 2450 
 2451         entrysize = entry->end - entry->start;
 2452         vm2->vm_map.size += entrysize;
 2453         if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) {
 2454                 vm2->vm_ssize += btoc(entrysize);
 2455         } else if (entry->start >= (vm_offset_t)vm1->vm_daddr &&
 2456             entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) {
 2457                 newend = MIN(entry->end,
 2458                     (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize));
 2459                 vm2->vm_dsize += btoc(newend - entry->start);
 2460         } else if (entry->start >= (vm_offset_t)vm1->vm_taddr &&
 2461             entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) {
 2462                 newend = MIN(entry->end,
 2463                     (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize));
 2464                 vm2->vm_tsize += btoc(newend - entry->start);
 2465         }
 2466 }
 2467 
 2468 /*
 2469  * vmspace_fork:
 2470  * Create a new process vmspace structure and vm_map
 2471  * based on those of an existing process.  The new map
 2472  * is based on the old map, according to the inheritance
 2473  * values on the regions in that map.
 2474  *
 2475  * XXX It might be worth coalescing the entries added to the new vmspace.
 2476  *
 2477  * The source map must not be locked.
 2478  */
 2479 struct vmspace *
 2480 vmspace_fork(struct vmspace *vm1)
 2481 {
 2482         struct vmspace *vm2;
 2483         vm_map_t old_map = &vm1->vm_map;
 2484         vm_map_t new_map;
 2485         vm_map_entry_t old_entry;
 2486         vm_map_entry_t new_entry;
 2487         vm_object_t object;
 2488 
 2489         vm_map_lock(old_map);
 2490 
 2491         vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset);
 2492         vm2->vm_taddr = vm1->vm_taddr;
 2493         vm2->vm_daddr = vm1->vm_daddr;
 2494         vm2->vm_maxsaddr = vm1->vm_maxsaddr;
 2495         new_map = &vm2->vm_map; /* XXX */
 2496         new_map->timestamp = 1;
 2497 
 2498         /* Do not inherit the MAP_WIREFUTURE property. */
 2499         if ((new_map->flags & MAP_WIREFUTURE) == MAP_WIREFUTURE)
 2500                 new_map->flags &= ~MAP_WIREFUTURE;
 2501 
 2502         old_entry = old_map->header.next;
 2503 
 2504         while (old_entry != &old_map->header) {
 2505                 if (old_entry->eflags & MAP_ENTRY_IS_SUB_MAP)
 2506                         panic("vm_map_fork: encountered a submap");
 2507 
 2508                 switch (old_entry->inheritance) {
 2509                 case VM_INHERIT_NONE:
 2510                         break;
 2511 
 2512                 case VM_INHERIT_SHARE:
 2513                         /*
 2514                          * Clone the entry, creating the shared object if necessary.
 2515                          */
 2516                         object = old_entry->object.vm_object;
 2517                         if (object == NULL) {
 2518                                 object = vm_object_allocate(OBJT_DEFAULT,
 2519                                         atop(old_entry->end - old_entry->start));
 2520                                 old_entry->object.vm_object = object;
 2521                                 old_entry->offset = 0;
 2522                         }
 2523 
 2524                         /*
 2525                          * Add the reference before calling vm_object_shadow
 2526                          * to insure that a shadow object is created.
 2527                          */
 2528                         vm_object_reference(object);
 2529                         if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) {
 2530                                 vm_object_shadow(&old_entry->object.vm_object,
 2531                                         &old_entry->offset,
 2532                                         atop(old_entry->end - old_entry->start));
 2533                                 old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
 2534                                 /* Transfer the second reference too. */
 2535                                 vm_object_reference(
 2536                                     old_entry->object.vm_object);
 2537                                 vm_object_deallocate(object);
 2538                                 object = old_entry->object.vm_object;
 2539                         }
 2540                         VM_OBJECT_LOCK(object);
 2541                         vm_object_clear_flag(object, OBJ_ONEMAPPING);
 2542                         VM_OBJECT_UNLOCK(object);
 2543 
 2544                         /*
 2545                          * Clone the entry, referencing the shared object.
 2546                          */
 2547                         new_entry = vm_map_entry_create(new_map);
 2548                         *new_entry = *old_entry;
 2549                         new_entry->eflags &= ~MAP_ENTRY_USER_WIRED;
 2550                         new_entry->wired_count = 0;
 2551 
 2552                         /*
 2553                          * Insert the entry into the new map -- we know we're
 2554                          * inserting at the end of the new map.
 2555                          */
 2556                         vm_map_entry_link(new_map, new_map->header.prev,
 2557                             new_entry);
 2558                         vmspace_map_entry_forked(vm1, vm2, new_entry);
 2559 
 2560                         /*
 2561                          * Update the physical map
 2562                          */
 2563                         pmap_copy(new_map->pmap, old_map->pmap,
 2564                             new_entry->start,
 2565                             (old_entry->end - old_entry->start),
 2566                             old_entry->start);
 2567                         break;
 2568 
 2569                 case VM_INHERIT_COPY:
 2570                         /*
 2571                          * Clone the entry and link into the map.
 2572                          */
 2573                         new_entry = vm_map_entry_create(new_map);
 2574                         *new_entry = *old_entry;
 2575                         new_entry->eflags &= ~MAP_ENTRY_USER_WIRED;
 2576                         new_entry->wired_count = 0;
 2577                         new_entry->object.vm_object = NULL;
 2578                         vm_map_entry_link(new_map, new_map->header.prev,
 2579                             new_entry);
 2580                         vmspace_map_entry_forked(vm1, vm2, new_entry);
 2581                         vm_map_copy_entry(old_map, new_map, old_entry,
 2582                             new_entry);
 2583                         break;
 2584                 }
 2585                 old_entry = old_entry->next;
 2586         }
 2587 
 2588         vm_map_unlock(old_map);
 2589 
 2590         return (vm2);
 2591 }
 2592 
 2593 int
 2594 vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
 2595     vm_prot_t prot, vm_prot_t max, int cow)
 2596 {
 2597         vm_map_entry_t new_entry, prev_entry;
 2598         vm_offset_t bot, top;
 2599         vm_size_t init_ssize;
 2600         int orient, rv;
 2601         rlim_t vmemlim;
 2602 
 2603         /*
 2604          * The stack orientation is piggybacked with the cow argument.
 2605          * Extract it into orient and mask the cow argument so that we
 2606          * don't pass it around further.
 2607          * NOTE: We explicitly allow bi-directional stacks.
 2608          */
 2609         orient = cow & (MAP_STACK_GROWS_DOWN|MAP_STACK_GROWS_UP);
 2610         cow &= ~orient;
 2611         KASSERT(orient != 0, ("No stack grow direction"));
 2612 
 2613         if (addrbos < vm_map_min(map) || addrbos > map->max_offset)
 2614                 return (KERN_NO_SPACE);
 2615 
 2616         init_ssize = (max_ssize < sgrowsiz) ? max_ssize : sgrowsiz;
 2617 
 2618         PROC_LOCK(curthread->td_proc);
 2619         vmemlim = lim_cur(curthread->td_proc, RLIMIT_VMEM);
 2620         PROC_UNLOCK(curthread->td_proc);
 2621 
 2622         vm_map_lock(map);
 2623 
 2624         /* If addr is already mapped, no go */
 2625         if (vm_map_lookup_entry(map, addrbos, &prev_entry)) {
 2626                 vm_map_unlock(map);
 2627                 return (KERN_NO_SPACE);
 2628         }
 2629 
 2630         /* If we would blow our VMEM resource limit, no go */
 2631         if (map->size + init_ssize > vmemlim) {
 2632                 vm_map_unlock(map);
 2633                 return (KERN_NO_SPACE);
 2634         }
 2635 
 2636         /*
 2637          * If we can't accomodate max_ssize in the current mapping, no go.
 2638          * However, we need to be aware that subsequent user mappings might
 2639          * map into the space we have reserved for stack, and currently this
 2640          * space is not protected.
 2641          *
 2642          * Hopefully we will at least detect this condition when we try to
 2643          * grow the stack.
 2644          */
 2645         if ((prev_entry->next != &map->header) &&
 2646             (prev_entry->next->start < addrbos + max_ssize)) {
 2647                 vm_map_unlock(map);
 2648                 return (KERN_NO_SPACE);
 2649         }
 2650 
 2651         /*
 2652          * We initially map a stack of only init_ssize.  We will grow as
 2653          * needed later.  Depending on the orientation of the stack (i.e.
 2654          * the grow direction) we either map at the top of the range, the
 2655          * bottom of the range or in the middle.
 2656          *
 2657          * Note: we would normally expect prot and max to be VM_PROT_ALL,
 2658          * and cow to be 0.  Possibly we should eliminate these as input
 2659          * parameters, and just pass these values here in the insert call.
 2660          */
 2661         if (orient == MAP_STACK_GROWS_DOWN)
 2662                 bot = addrbos + max_ssize - init_ssize;
 2663         else if (orient == MAP_STACK_GROWS_UP)
 2664                 bot = addrbos;
 2665         else
 2666                 bot = round_page(addrbos + max_ssize/2 - init_ssize/2);
 2667         top = bot + init_ssize;
 2668         rv = vm_map_insert(map, NULL, 0, bot, top, prot, max, cow);
 2669 
 2670         /* Now set the avail_ssize amount. */
 2671         if (rv == KERN_SUCCESS) {
 2672                 if (prev_entry != &map->header)
 2673                         vm_map_clip_end(map, prev_entry, bot);
 2674                 new_entry = prev_entry->next;
 2675                 if (new_entry->end != top || new_entry->start != bot)
 2676                         panic("Bad entry start/end for new stack entry");
 2677 
 2678                 new_entry->avail_ssize = max_ssize - init_ssize;
 2679                 if (orient & MAP_STACK_GROWS_DOWN)
 2680                         new_entry->eflags |= MAP_ENTRY_GROWS_DOWN;
 2681                 if (orient & MAP_STACK_GROWS_UP)
 2682                         new_entry->eflags |= MAP_ENTRY_GROWS_UP;
 2683         }
 2684 
 2685         vm_map_unlock(map);
 2686         return (rv);
 2687 }
 2688 
 2689 /* Attempts to grow a vm stack entry.  Returns KERN_SUCCESS if the
 2690  * desired address is already mapped, or if we successfully grow
 2691  * the stack.  Also returns KERN_SUCCESS if addr is outside the
 2692  * stack range (this is strange, but preserves compatibility with
 2693  * the grow function in vm_machdep.c).
 2694  */
 2695 int
 2696 vm_map_growstack(struct proc *p, vm_offset_t addr)
 2697 {
 2698         vm_map_entry_t next_entry, prev_entry;
 2699         vm_map_entry_t new_entry, stack_entry;
 2700         struct vmspace *vm = p->p_vmspace;
 2701         vm_map_t map = &vm->vm_map;
 2702         vm_offset_t end;
 2703         size_t grow_amount, max_grow;
 2704         rlim_t stacklim, vmemlim;
 2705         int is_procstack, rv;
 2706 
 2707 Retry:
 2708         PROC_LOCK(p);
 2709         stacklim = lim_cur(p, RLIMIT_STACK);
 2710         vmemlim = lim_cur(p, RLIMIT_VMEM);
 2711         PROC_UNLOCK(p);
 2712 
 2713         vm_map_lock_read(map);
 2714 
 2715         /* If addr is already in the entry range, no need to grow.*/
 2716         if (vm_map_lookup_entry(map, addr, &prev_entry)) {
 2717                 vm_map_unlock_read(map);
 2718                 return (KERN_SUCCESS);
 2719         }
 2720 
 2721         next_entry = prev_entry->next;
 2722         if (!(prev_entry->eflags & MAP_ENTRY_GROWS_UP)) {
 2723                 /*
 2724                  * This entry does not grow upwards. Since the address lies
 2725                  * beyond this entry, the next entry (if one exists) has to
 2726                  * be a downward growable entry. The entry list header is
 2727                  * never a growable entry, so it suffices to check the flags.
 2728                  */
 2729                 if (!(next_entry->eflags & MAP_ENTRY_GROWS_DOWN)) {
 2730                         vm_map_unlock_read(map);
 2731                         return (KERN_SUCCESS);
 2732                 }
 2733                 stack_entry = next_entry;
 2734         } else {
 2735                 /*
 2736                  * This entry grows upward. If the next entry does not at
 2737                  * least grow downwards, this is the entry we need to grow.
 2738                  * otherwise we have two possible choices and we have to
 2739                  * select one.
 2740                  */
 2741                 if (next_entry->eflags & MAP_ENTRY_GROWS_DOWN) {
 2742                         /*
 2743                          * We have two choices; grow the entry closest to
 2744                          * the address to minimize the amount of growth.
 2745                          */
 2746                         if (addr - prev_entry->end <= next_entry->start - addr)
 2747                                 stack_entry = prev_entry;
 2748                         else
 2749                                 stack_entry = next_entry;
 2750                 } else
 2751                         stack_entry = prev_entry;
 2752         }
 2753 
 2754         if (stack_entry == next_entry) {
 2755                 KASSERT(stack_entry->eflags & MAP_ENTRY_GROWS_DOWN, ("foo"));
 2756                 KASSERT(addr < stack_entry->start, ("foo"));
 2757                 end = (prev_entry != &map->header) ? prev_entry->end :
 2758                     stack_entry->start - stack_entry->avail_ssize;
 2759                 grow_amount = roundup(stack_entry->start - addr, PAGE_SIZE);
 2760                 max_grow = stack_entry->start - end;
 2761         } else {
 2762                 KASSERT(stack_entry->eflags & MAP_ENTRY_GROWS_UP, ("foo"));
 2763                 KASSERT(addr >= stack_entry->end, ("foo"));
 2764                 end = (next_entry != &map->header) ? next_entry->start :
 2765                     stack_entry->end + stack_entry->avail_ssize;
 2766                 grow_amount = roundup(addr + 1 - stack_entry->end, PAGE_SIZE);
 2767                 max_grow = end - stack_entry->end;
 2768         }
 2769 
 2770         if (grow_amount > stack_entry->avail_ssize) {
 2771                 vm_map_unlock_read(map);
 2772                 return (KERN_NO_SPACE);
 2773         }
 2774 
 2775         /*
 2776          * If there is no longer enough space between the entries nogo, and
 2777          * adjust the available space.  Note: this  should only happen if the
 2778          * user has mapped into the stack area after the stack was created,
 2779          * and is probably an error.
 2780          *
 2781          * This also effectively destroys any guard page the user might have
 2782          * intended by limiting the stack size.
 2783          */
 2784         if (grow_amount > max_grow) {
 2785                 if (vm_map_lock_upgrade(map))
 2786                         goto Retry;
 2787 
 2788                 stack_entry->avail_ssize = max_grow;
 2789 
 2790                 vm_map_unlock(map);
 2791                 return (KERN_NO_SPACE);
 2792         }
 2793 
 2794         is_procstack = (addr >= (vm_offset_t)vm->vm_maxsaddr) ? 1 : 0;
 2795 
 2796         /*
 2797          * If this is the main process stack, see if we're over the stack
 2798          * limit.
 2799          */
 2800         if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) {
 2801                 vm_map_unlock_read(map);
 2802                 return (KERN_NO_SPACE);
 2803         }
 2804 
 2805         /* Round up the grow amount modulo SGROWSIZ */
 2806         grow_amount = roundup (grow_amount, sgrowsiz);
 2807         if (grow_amount > stack_entry->avail_ssize)
 2808                 grow_amount = stack_entry->avail_ssize;
 2809         if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) {
 2810                 grow_amount = stacklim - ctob(vm->vm_ssize);
 2811         }
 2812 
 2813         /* If we would blow our VMEM resource limit, no go */
 2814         if (map->size + grow_amount > vmemlim) {
 2815                 vm_map_unlock_read(map);
 2816                 return (KERN_NO_SPACE);
 2817         }
 2818 
 2819         if (vm_map_lock_upgrade(map))
 2820                 goto Retry;
 2821 
 2822         if (stack_entry == next_entry) {
 2823                 /*
 2824                  * Growing downward.
 2825                  */
 2826                 /* Get the preliminary new entry start value */
 2827                 addr = stack_entry->start - grow_amount;
 2828 
 2829                 /*
 2830                  * If this puts us into the previous entry, cut back our
 2831                  * growth to the available space. Also, see the note above.
 2832                  */
 2833                 if (addr < end) {
 2834                         stack_entry->avail_ssize = max_grow;
 2835                         addr = end;
 2836                 }
 2837 
 2838                 rv = vm_map_insert(map, NULL, 0, addr, stack_entry->start,
 2839                     p->p_sysent->sv_stackprot, VM_PROT_ALL, 0);
 2840 
 2841                 /* Adjust the available stack space by the amount we grew. */
 2842                 if (rv == KERN_SUCCESS) {
 2843                         if (prev_entry != &map->header)
 2844                                 vm_map_clip_end(map, prev_entry, addr);
 2845                         new_entry = prev_entry->next;
 2846                         KASSERT(new_entry == stack_entry->prev, ("foo"));
 2847                         KASSERT(new_entry->end == stack_entry->start, ("foo"));
 2848                         KASSERT(new_entry->start == addr, ("foo"));
 2849                         grow_amount = new_entry->end - new_entry->start;
 2850                         new_entry->avail_ssize = stack_entry->avail_ssize -
 2851                             grow_amount;
 2852                         stack_entry->eflags &= ~MAP_ENTRY_GROWS_DOWN;
 2853                         new_entry->eflags |= MAP_ENTRY_GROWS_DOWN;
 2854                 }
 2855         } else {
 2856                 /*
 2857                  * Growing upward.
 2858                  */
 2859                 addr = stack_entry->end + grow_amount;
 2860 
 2861                 /*
 2862                  * If this puts us into the next entry, cut back our growth
 2863                  * to the available space. Also, see the note above.
 2864                  */
 2865                 if (addr > end) {
 2866                         stack_entry->avail_ssize = end - stack_entry->end;
 2867                         addr = end;
 2868                 }
 2869 
 2870                 grow_amount = addr - stack_entry->end;
 2871 
 2872                 /* Grow the underlying object if applicable. */
 2873                 if (stack_entry->object.vm_object == NULL ||
 2874                     vm_object_coalesce(stack_entry->object.vm_object,
 2875                     stack_entry->offset,
 2876                     (vm_size_t)(stack_entry->end - stack_entry->start),
 2877                     (vm_size_t)grow_amount)) {
 2878                         map->size += (addr - stack_entry->end);
 2879                         /* Update the current entry. */
 2880                         stack_entry->end = addr;
 2881                         stack_entry->avail_ssize -= grow_amount;
 2882                         vm_map_entry_resize_free(map, stack_entry);
 2883                         rv = KERN_SUCCESS;
 2884 
 2885                         if (next_entry != &map->header)
 2886                                 vm_map_clip_start(map, next_entry, addr);
 2887                 } else
 2888                         rv = KERN_FAILURE;
 2889         }
 2890 
 2891         if (rv == KERN_SUCCESS && is_procstack)
 2892                 vm->vm_ssize += btoc(grow_amount);
 2893 
 2894         vm_map_unlock(map);
 2895 
 2896         /*
 2897          * Heed the MAP_WIREFUTURE flag if it was set for this process.
 2898          */
 2899         if (rv == KERN_SUCCESS && (map->flags & MAP_WIREFUTURE)) {
 2900                 vm_map_wire(map,
 2901                     (stack_entry == next_entry) ? addr : addr - grow_amount,
 2902                     (stack_entry == next_entry) ? stack_entry->start : addr,
 2903                     (p->p_flag & P_SYSTEM)
 2904                     ? VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES
 2905                     : VM_MAP_WIRE_USER|VM_MAP_WIRE_NOHOLES);
 2906         }
 2907 
 2908         return (rv);
 2909 }
 2910 
 2911 /*
 2912  * Unshare the specified VM space for exec.  If other processes are
 2913  * mapped to it, then create a new one.  The new vmspace is null.
 2914  */
 2915 void
 2916 vmspace_exec(struct proc *p, vm_offset_t minuser, vm_offset_t maxuser)
 2917 {
 2918         struct vmspace *oldvmspace = p->p_vmspace;
 2919         struct vmspace *newvmspace;
 2920 
 2921         newvmspace = vmspace_alloc(minuser, maxuser);
 2922         newvmspace->vm_swrss = oldvmspace->vm_swrss;
 2923         /*
 2924          * This code is written like this for prototype purposes.  The
 2925          * goal is to avoid running down the vmspace here, but let the
 2926          * other process's that are still using the vmspace to finally
 2927          * run it down.  Even though there is little or no chance of blocking
 2928          * here, it is a good idea to keep this form for future mods.
 2929          */
 2930         p->p_vmspace = newvmspace;
 2931         if (p == curthread->td_proc)            /* XXXKSE ? */
 2932                 pmap_activate(curthread);
 2933         vmspace_free(oldvmspace);
 2934 }
 2935 
 2936 /*
 2937  * Unshare the specified VM space for forcing COW.  This
 2938  * is called by rfork, for the (RFMEM|RFPROC) == 0 case.
 2939  */
 2940 void
 2941 vmspace_unshare(struct proc *p)
 2942 {
 2943         struct vmspace *oldvmspace = p->p_vmspace;
 2944         struct vmspace *newvmspace;
 2945 
 2946         if (oldvmspace->vm_refcnt == 1)
 2947                 return;
 2948         newvmspace = vmspace_fork(oldvmspace);
 2949         p->p_vmspace = newvmspace;
 2950         if (p == curthread->td_proc)            /* XXXKSE ? */
 2951                 pmap_activate(curthread);
 2952         vmspace_free(oldvmspace);
 2953 }
 2954 
 2955 /*
 2956  *      vm_map_lookup:
 2957  *
 2958  *      Finds the VM object, offset, and
 2959  *      protection for a given virtual address in the
 2960  *      specified map, assuming a page fault of the
 2961  *      type specified.
 2962  *
 2963  *      Leaves the map in question locked for read; return
 2964  *      values are guaranteed until a vm_map_lookup_done
 2965  *      call is performed.  Note that the map argument
 2966  *      is in/out; the returned map must be used in
 2967  *      the call to vm_map_lookup_done.
 2968  *
 2969  *      A handle (out_entry) is returned for use in
 2970  *      vm_map_lookup_done, to make that fast.
 2971  *
 2972  *      If a lookup is requested with "write protection"
 2973  *      specified, the map may be changed to perform virtual
 2974  *      copying operations, although the data referenced will
 2975  *      remain the same.
 2976  */
 2977 int
 2978 vm_map_lookup(vm_map_t *var_map,                /* IN/OUT */
 2979               vm_offset_t vaddr,
 2980               vm_prot_t fault_typea,
 2981               vm_map_entry_t *out_entry,        /* OUT */
 2982               vm_object_t *object,              /* OUT */
 2983               vm_pindex_t *pindex,              /* OUT */
 2984               vm_prot_t *out_prot,              /* OUT */
 2985               boolean_t *wired)                 /* OUT */
 2986 {
 2987         vm_map_entry_t entry;
 2988         vm_map_t map = *var_map;
 2989         vm_prot_t prot;
 2990         vm_prot_t fault_type = fault_typea;
 2991 
 2992 RetryLookup:;
 2993         /*
 2994          * Lookup the faulting address.
 2995          */
 2996 
 2997         vm_map_lock_read(map);
 2998 #define RETURN(why) \
 2999                 { \
 3000                 vm_map_unlock_read(map); \
 3001                 return (why); \
 3002                 }
 3003 
 3004         /*
 3005          * If the map has an interesting hint, try it before calling full
 3006          * blown lookup routine.
 3007          */
 3008         entry = map->root;
 3009         *out_entry = entry;
 3010         if (entry == NULL ||
 3011             (vaddr < entry->start) || (vaddr >= entry->end)) {
 3012                 /*
 3013                  * Entry was either not a valid hint, or the vaddr was not
 3014                  * contained in the entry, so do a full lookup.
 3015                  */
 3016                 if (!vm_map_lookup_entry(map, vaddr, out_entry))
 3017                         RETURN(KERN_INVALID_ADDRESS);
 3018 
 3019                 entry = *out_entry;
 3020         }
 3021 
 3022         /*
 3023          * Handle submaps.
 3024          */
 3025         if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
 3026                 vm_map_t old_map = map;
 3027 
 3028                 *var_map = map = entry->object.sub_map;
 3029                 vm_map_unlock_read(old_map);
 3030                 goto RetryLookup;
 3031         }
 3032 
 3033         /*
 3034          * Check whether this task is allowed to have this page.
 3035          * Note the special case for MAP_ENTRY_COW
 3036          * pages with an override.  This is to implement a forced
 3037          * COW for debuggers.
 3038          */
 3039         if (fault_type & VM_PROT_OVERRIDE_WRITE)
 3040                 prot = entry->max_protection;
 3041         else
 3042                 prot = entry->protection;
 3043         fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
 3044         if ((fault_type & prot) != fault_type) {
 3045                         RETURN(KERN_PROTECTION_FAILURE);
 3046         }
 3047         if ((entry->eflags & MAP_ENTRY_USER_WIRED) &&
 3048             (entry->eflags & MAP_ENTRY_COW) &&
 3049             (fault_type & VM_PROT_WRITE) &&
 3050             (fault_typea & VM_PROT_OVERRIDE_WRITE) == 0) {
 3051                 RETURN(KERN_PROTECTION_FAILURE);
 3052         }
 3053 
 3054         /*
 3055          * If this page is not pageable, we have to get it for all possible
 3056          * accesses.
 3057          */
 3058         *wired = (entry->wired_count != 0);
 3059         if (*wired)
 3060                 prot = fault_type = entry->protection;
 3061 
 3062         /*
 3063          * If the entry was copy-on-write, we either ...
 3064          */
 3065         if (entry->eflags & MAP_ENTRY_NEEDS_COPY) {
 3066                 /*
 3067                  * If we want to write the page, we may as well handle that
 3068                  * now since we've got the map locked.
 3069                  *
 3070                  * If we don't need to write the page, we just demote the
 3071                  * permissions allowed.
 3072                  */
 3073                 if (fault_type & VM_PROT_WRITE) {
 3074                         /*
 3075                          * Make a new object, and place it in the object
 3076                          * chain.  Note that no new references have appeared
 3077                          * -- one just moved from the map to the new
 3078                          * object.
 3079                          */
 3080                         if (vm_map_lock_upgrade(map))
 3081                                 goto RetryLookup;
 3082 
 3083                         vm_object_shadow(
 3084                             &entry->object.vm_object,
 3085                             &entry->offset,
 3086                             atop(entry->end - entry->start));
 3087                         entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
 3088 
 3089                         vm_map_lock_downgrade(map);
 3090                 } else {
 3091                         /*
 3092                          * We're attempting to read a copy-on-write page --
 3093                          * don't allow writes.
 3094                          */
 3095                         prot &= ~VM_PROT_WRITE;
 3096                 }
 3097         }
 3098 
 3099         /*
 3100          * Create an object if necessary.
 3101          */
 3102         if (entry->object.vm_object == NULL &&
 3103             !map->system_map) {
 3104                 if (vm_map_lock_upgrade(map))
 3105                         goto RetryLookup;
 3106                 entry->object.vm_object = vm_object_allocate(OBJT_DEFAULT,
 3107                     atop(entry->end - entry->start));
 3108                 entry->offset = 0;
 3109                 vm_map_lock_downgrade(map);
 3110         }
 3111 
 3112         /*
 3113          * Return the object/offset from this entry.  If the entry was
 3114          * copy-on-write or empty, it has been fixed up.
 3115          */
 3116         *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
 3117         *object = entry->object.vm_object;
 3118 
 3119         *out_prot = prot;
 3120         return (KERN_SUCCESS);
 3121 
 3122 #undef  RETURN
 3123 }
 3124 
 3125 /*
 3126  *      vm_map_lookup_locked:
 3127  *
 3128  *      Lookup the faulting address.  A version of vm_map_lookup that returns 
 3129  *      KERN_FAILURE instead of blocking on map lock or memory allocation.
 3130  */
 3131 int
 3132 vm_map_lookup_locked(vm_map_t *var_map,         /* IN/OUT */
 3133                      vm_offset_t vaddr,
 3134                      vm_prot_t fault_typea,
 3135                      vm_map_entry_t *out_entry, /* OUT */
 3136                      vm_object_t *object,       /* OUT */
 3137                      vm_pindex_t *pindex,       /* OUT */
 3138                      vm_prot_t *out_prot,       /* OUT */
 3139                      boolean_t *wired)          /* OUT */
 3140 {
 3141         vm_map_entry_t entry;
 3142         vm_map_t map = *var_map;
 3143         vm_prot_t prot;
 3144         vm_prot_t fault_type = fault_typea;
 3145 
 3146         /*
 3147          * If the map has an interesting hint, try it before calling full
 3148          * blown lookup routine.
 3149          */
 3150         entry = map->root;
 3151         *out_entry = entry;
 3152         if (entry == NULL ||
 3153             (vaddr < entry->start) || (vaddr >= entry->end)) {
 3154                 /*
 3155                  * Entry was either not a valid hint, or the vaddr was not
 3156                  * contained in the entry, so do a full lookup.
 3157                  */
 3158                 if (!vm_map_lookup_entry(map, vaddr, out_entry))
 3159                         return (KERN_INVALID_ADDRESS);
 3160 
 3161                 entry = *out_entry;
 3162         }
 3163 
 3164         /*
 3165          * Fail if the entry refers to a submap.
 3166          */
 3167         if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
 3168                 return (KERN_FAILURE);
 3169 
 3170         /*
 3171          * Check whether this task is allowed to have this page.
 3172          * Note the special case for MAP_ENTRY_COW
 3173          * pages with an override.  This is to implement a forced
 3174          * COW for debuggers.
 3175          */
 3176         if (fault_type & VM_PROT_OVERRIDE_WRITE)
 3177                 prot = entry->max_protection;
 3178         else
 3179                 prot = entry->protection;
 3180         fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
 3181         if ((fault_type & prot) != fault_type)
 3182                 return (KERN_PROTECTION_FAILURE);
 3183         if ((entry->eflags & MAP_ENTRY_USER_WIRED) &&
 3184             (entry->eflags & MAP_ENTRY_COW) &&
 3185             (fault_type & VM_PROT_WRITE) &&
 3186             (fault_typea & VM_PROT_OVERRIDE_WRITE) == 0)
 3187                 return (KERN_PROTECTION_FAILURE);
 3188 
 3189         /*
 3190          * If this page is not pageable, we have to get it for all possible
 3191          * accesses.
 3192          */
 3193         *wired = (entry->wired_count != 0);
 3194         if (*wired)
 3195                 prot = fault_type = entry->protection;
 3196 
 3197         if (entry->eflags & MAP_ENTRY_NEEDS_COPY) {
 3198                 /*
 3199                  * Fail if the entry was copy-on-write for a write fault.
 3200                  */
 3201                 if (fault_type & VM_PROT_WRITE)
 3202                         return (KERN_FAILURE);
 3203                 /*
 3204                  * We're attempting to read a copy-on-write page --
 3205                  * don't allow writes.
 3206                  */
 3207                 prot &= ~VM_PROT_WRITE;
 3208         }
 3209 
 3210         /*
 3211          * Fail if an object should be created.
 3212          */
 3213         if (entry->object.vm_object == NULL && !map->system_map)
 3214                 return (KERN_FAILURE);
 3215 
 3216         /*
 3217          * Return the object/offset from this entry.  If the entry was
 3218          * copy-on-write or empty, it has been fixed up.
 3219          */
 3220         *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
 3221         *object = entry->object.vm_object;
 3222 
 3223         *out_prot = prot;
 3224         return (KERN_SUCCESS);
 3225 }
 3226 
 3227 /*
 3228  *      vm_map_lookup_done:
 3229  *
 3230  *      Releases locks acquired by a vm_map_lookup
 3231  *      (according to the handle returned by that lookup).
 3232  */
 3233 void
 3234 vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry)
 3235 {
 3236         /*
 3237          * Unlock the main-level map
 3238          */
 3239         vm_map_unlock_read(map);
 3240 }
 3241 
 3242 #include "opt_ddb.h"
 3243 #ifdef DDB
 3244 #include <sys/kernel.h>
 3245 
 3246 #include <ddb/ddb.h>
 3247 
 3248 /*
 3249  *      vm_map_print:   [ debug ]
 3250  */
 3251 DB_SHOW_COMMAND(map, vm_map_print)
 3252 {
 3253         static int nlines;
 3254         /* XXX convert args. */
 3255         vm_map_t map = (vm_map_t)addr;
 3256         boolean_t full = have_addr;
 3257 
 3258         vm_map_entry_t entry;
 3259 
 3260         db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n",
 3261             (void *)map,
 3262             (void *)map->pmap, map->nentries, map->timestamp);
 3263         nlines++;
 3264 
 3265         if (!full && db_indent)
 3266                 return;
 3267 
 3268         db_indent += 2;
 3269         for (entry = map->header.next; entry != &map->header;
 3270             entry = entry->next) {
 3271                 db_iprintf("map entry %p: start=%p, end=%p\n",
 3272                     (void *)entry, (void *)entry->start, (void *)entry->end);
 3273                 nlines++;
 3274                 {
 3275                         static char *inheritance_name[4] =
 3276                         {"share", "copy", "none", "donate_copy"};
 3277 
 3278                         db_iprintf(" prot=%x/%x/%s",
 3279                             entry->protection,
 3280                             entry->max_protection,
 3281                             inheritance_name[(int)(unsigned char)entry->inheritance]);
 3282                         if (entry->wired_count != 0)
 3283                                 db_printf(", wired");
 3284                 }
 3285                 if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
 3286                         db_printf(", share=%p, offset=0x%jx\n",
 3287                             (void *)entry->object.sub_map,
 3288                             (uintmax_t)entry->offset);
 3289                         nlines++;
 3290                         if ((entry->prev == &map->header) ||
 3291                             (entry->prev->object.sub_map !=
 3292                                 entry->object.sub_map)) {
 3293                                 db_indent += 2;
 3294                                 vm_map_print((db_expr_t)(intptr_t)
 3295                                              entry->object.sub_map,
 3296                                              full, 0, (char *)0);
 3297                                 db_indent -= 2;
 3298                         }
 3299                 } else {
 3300                         db_printf(", object=%p, offset=0x%jx",
 3301                             (void *)entry->object.vm_object,
 3302                             (uintmax_t)entry->offset);
 3303                         if (entry->eflags & MAP_ENTRY_COW)
 3304                                 db_printf(", copy (%s)",
 3305                                     (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done");
 3306                         db_printf("\n");
 3307                         nlines++;
 3308 
 3309                         if ((entry->prev == &map->header) ||
 3310                             (entry->prev->object.vm_object !=
 3311                                 entry->object.vm_object)) {
 3312                                 db_indent += 2;
 3313                                 vm_object_print((db_expr_t)(intptr_t)
 3314                                                 entry->object.vm_object,
 3315                                                 full, 0, (char *)0);
 3316                                 nlines += 4;
 3317                                 db_indent -= 2;
 3318                         }
 3319                 }
 3320         }
 3321         db_indent -= 2;
 3322         if (db_indent == 0)
 3323                 nlines = 0;
 3324 }
 3325 
 3326 
 3327 DB_SHOW_COMMAND(procvm, procvm)
 3328 {
 3329         struct proc *p;
 3330 
 3331         if (have_addr) {
 3332                 p = (struct proc *) addr;
 3333         } else {
 3334                 p = curproc;
 3335         }
 3336 
 3337         db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n",
 3338             (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map,
 3339             (void *)vmspace_pmap(p->p_vmspace));
 3340 
 3341         vm_map_print((db_expr_t)(intptr_t)&p->p_vmspace->vm_map, 1, 0, NULL);
 3342 }
 3343 
 3344 #endif /* DDB */

Cache object: e167ce1111a5e3e8c18a79b382cebcf2


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.