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freebsd-dev/sys/vm/vm_map.c
John Baldwin 21c641b2a9 - Add lots of vm_mtx assertions. 
- Add a few KTR tracepoints to track the addition and removal of
  vm_map_entry's and the creation adn free'ing of vmspace's.
- Adjust a few portions of code so that we update the process' vmspace
  pointer to its new vmspace before freeing the old vmspace.
2001-05-23 22:38:00 +00:00

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/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)vm_map.c 8.3 (Berkeley) 1/12/94
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $FreeBSD$
*/
/*
* Virtual memory mapping module.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/vmmeter.h>
#include <sys/mman.h>
#include <sys/vnode.h>
#include <sys/resourcevar.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vm_zone.h>
#include <vm/swap_pager.h>
/*
* Virtual memory maps provide for the mapping, protection,
* and sharing of virtual memory objects. In addition,
* this module provides for an efficient virtual copy of
* memory from one map to another.
*
* Synchronization is required prior to most operations.
*
* Maps consist of an ordered doubly-linked list of simple
* entries; a single hint is used to speed up lookups.
*
* Since portions of maps are specified by start/end addresses,
* which may not align with existing map entries, all
* routines merely "clip" entries to these start/end values.
* [That is, an entry is split into two, bordering at a
* start or end value.] Note that these clippings may not
* always be necessary (as the two resulting entries are then
* not changed); however, the clipping is done for convenience.
*
* As mentioned above, virtual copy operations are performed
* by copying VM object references from one map to
* another, and then marking both regions as copy-on-write.
*/
/*
* vm_map_startup:
*
* Initialize the vm_map module. Must be called before
* any other vm_map routines.
*
* Map and entry structures are allocated from the general
* purpose memory pool with some exceptions:
*
* - The kernel map and kmem submap are allocated statically.
* - Kernel map entries are allocated out of a static pool.
*
* These restrictions are necessary since malloc() uses the
* maps and requires map entries.
*/
static struct vm_zone kmapentzone_store, mapentzone_store, mapzone_store;
static vm_zone_t mapentzone, kmapentzone, mapzone, vmspace_zone;
static struct vm_object kmapentobj, mapentobj, mapobj;
static struct vm_map_entry map_entry_init[MAX_MAPENT];
static struct vm_map_entry kmap_entry_init[MAX_KMAPENT];
static struct vm_map map_init[MAX_KMAP];
static void _vm_map_clip_end __P((vm_map_t, vm_map_entry_t, vm_offset_t));
static void _vm_map_clip_start __P((vm_map_t, vm_map_entry_t, vm_offset_t));
static vm_map_entry_t vm_map_entry_create __P((vm_map_t));
static void vm_map_entry_delete __P((vm_map_t, vm_map_entry_t));
static void vm_map_entry_dispose __P((vm_map_t, vm_map_entry_t));
static void vm_map_entry_unwire __P((vm_map_t, vm_map_entry_t));
static void vm_map_copy_entry __P((vm_map_t, vm_map_t, vm_map_entry_t,
vm_map_entry_t));
static void vm_map_split __P((vm_map_entry_t));
void
vm_map_startup()
{
mapzone = &mapzone_store;
zbootinit(mapzone, "MAP", sizeof (struct vm_map),
map_init, MAX_KMAP);
kmapentzone = &kmapentzone_store;
zbootinit(kmapentzone, "KMAP ENTRY", sizeof (struct vm_map_entry),
kmap_entry_init, MAX_KMAPENT);
mapentzone = &mapentzone_store;
zbootinit(mapentzone, "MAP ENTRY", sizeof (struct vm_map_entry),
map_entry_init, MAX_MAPENT);
}
/*
* Allocate a vmspace structure, including a vm_map and pmap,
* and initialize those structures. The refcnt is set to 1.
* The remaining fields must be initialized by the caller.
*/
struct vmspace *
vmspace_alloc(min, max)
vm_offset_t min, max;
{
struct vmspace *vm;
mtx_assert(&vm_mtx, MA_OWNED);
vm = zalloc(vmspace_zone);
CTR1(KTR_VM, "vmspace_alloc: %p", vm);
vm_map_init(&vm->vm_map, min, max);
pmap_pinit(vmspace_pmap(vm));
vm->vm_map.pmap = vmspace_pmap(vm); /* XXX */
vm->vm_refcnt = 1;
vm->vm_shm = NULL;
return (vm);
}
void
vm_init2(void) {
zinitna(kmapentzone, &kmapentobj,
NULL, 0, cnt.v_page_count / 4, ZONE_INTERRUPT, 1);
zinitna(mapentzone, &mapentobj,
NULL, 0, 0, 0, 1);
zinitna(mapzone, &mapobj,
NULL, 0, 0, 0, 1);
vmspace_zone = zinit("VMSPACE", sizeof (struct vmspace), 0, 0, 3);
pmap_init2();
vm_object_init2();
}
void
vmspace_free(vm)
struct vmspace *vm;
{
mtx_assert(&vm_mtx, MA_OWNED);
if (vm->vm_refcnt == 0)
panic("vmspace_free: attempt to free already freed vmspace");
if (--vm->vm_refcnt == 0) {
CTR1(KTR_VM, "vmspace_free: %p", vm);
/*
* Lock the map, to wait out all other references to it.
* Delete all of the mappings and pages they hold, then call
* the pmap module to reclaim anything left.
*/
vm_map_lock(&vm->vm_map);
(void) vm_map_delete(&vm->vm_map, vm->vm_map.min_offset,
vm->vm_map.max_offset);
vm_map_unlock(&vm->vm_map);
pmap_release(vmspace_pmap(vm));
vm_map_destroy(&vm->vm_map);
zfree(vmspace_zone, vm);
}
}
/*
* vm_map_create:
*
* Creates and returns a new empty VM map with
* the given physical map structure, and having
* the given lower and upper address bounds.
*/
vm_map_t
vm_map_create(pmap, min, max)
pmap_t pmap;
vm_offset_t min, max;
{
vm_map_t result;
mtx_assert(&vm_mtx, MA_OWNED);
result = zalloc(mapzone);
CTR1(KTR_VM, "vm_map_create: %p", result);
vm_map_init(result, min, max);
result->pmap = pmap;
return (result);
}
/*
* Initialize an existing vm_map structure
* such as that in the vmspace structure.
* The pmap is set elsewhere.
*/
void
vm_map_init(map, min, max)
struct vm_map *map;
vm_offset_t min, max;
{
mtx_assert(&vm_mtx, MA_OWNED);
map->header.next = map->header.prev = &map->header;
map->nentries = 0;
map->size = 0;
map->system_map = 0;
map->infork = 0;
map->min_offset = min;
map->max_offset = max;
map->first_free = &map->header;
map->hint = &map->header;
map->timestamp = 0;
lockinit(&map->lock, PVM, "thrd_sleep", 0, LK_NOPAUSE);
}
void
vm_map_destroy(map)
struct vm_map *map;
{
mtx_assert(&vm_mtx, MA_OWNED);
lockdestroy(&map->lock);
}
/*
* vm_map_entry_dispose: [ internal use only ]
*
* Inverse of vm_map_entry_create.
*/
static void
vm_map_entry_dispose(map, entry)
vm_map_t map;
vm_map_entry_t entry;
{
zfree((map->system_map || !mapentzone) ? kmapentzone : mapentzone, entry);
}
/*
* vm_map_entry_create: [ internal use only ]
*
* Allocates a VM map entry for insertion.
* No entry fields are filled in.
*/
static vm_map_entry_t
vm_map_entry_create(map)
vm_map_t map;
{
vm_map_entry_t new_entry;
new_entry = zalloc((map->system_map || !mapentzone) ?
kmapentzone : mapentzone);
if (new_entry == NULL)
panic("vm_map_entry_create: kernel resources exhausted");
return(new_entry);
}
/*
* vm_map_entry_{un,}link:
*
* Insert/remove entries from maps.
*/
static __inline void
vm_map_entry_link(vm_map_t map,
vm_map_entry_t after_where,
vm_map_entry_t entry)
{
CTR4(KTR_VM,
"vm_map_entry_link: map %p, nentries %d, entry %p, after %p", map,
map->nentries, entry, after_where);
map->nentries++;
entry->prev = after_where;
entry->next = after_where->next;
entry->next->prev = entry;
after_where->next = entry;
}
static __inline void
vm_map_entry_unlink(vm_map_t map,
vm_map_entry_t entry)
{
vm_map_entry_t prev = entry->prev;
vm_map_entry_t next = entry->next;
next->prev = prev;
prev->next = next;
map->nentries--;
CTR3(KTR_VM, "vm_map_entry_unlink: map %p, nentries %d, entry %p", map,
map->nentries, entry);
}
/*
* SAVE_HINT:
*
* Saves the specified entry as the hint for
* future lookups.
*/
#define SAVE_HINT(map,value) \
(map)->hint = (value);
/*
* vm_map_lookup_entry: [ internal use only ]
*
* Finds the map entry containing (or
* immediately preceding) the specified address
* in the given map; the entry is returned
* in the "entry" parameter. The boolean
* result indicates whether the address is
* actually contained in the map.
*
* Doesn't block.
*/
boolean_t
vm_map_lookup_entry(map, address, entry)
vm_map_t map;
vm_offset_t address;
vm_map_entry_t *entry; /* OUT */
{
vm_map_entry_t cur;
vm_map_entry_t last;
mtx_assert(&vm_mtx, MA_OWNED);
/*
* Start looking either from the head of the list, or from the hint.
*/
cur = map->hint;
if (cur == &map->header)
cur = cur->next;
if (address >= cur->start) {
/*
* Go from hint to end of list.
*
* But first, make a quick check to see if we are already looking
* at the entry we want (which is usually the case). Note also
* that we don't need to save the hint here... it is the same
* hint (unless we are at the header, in which case the hint
* didn't buy us anything anyway).
*/
last = &map->header;
if ((cur != last) && (cur->end > address)) {
*entry = cur;
return (TRUE);
}
} else {
/*
* Go from start to hint, *inclusively*
*/
last = cur->next;
cur = map->header.next;
}
/*
* Search linearly
*/
while (cur != last) {
if (cur->end > address) {
if (address >= cur->start) {
/*
* Save this lookup for future hints, and
* return
*/
*entry = cur;
SAVE_HINT(map, cur);
return (TRUE);
}
break;
}
cur = cur->next;
}
*entry = cur->prev;
SAVE_HINT(map, *entry);
return (FALSE);
}
/*
* vm_map_insert:
*
* Inserts the given whole VM object into the target
* map at the specified address range. The object's
* size should match that of the address range.
*
* Requires that the map be locked, and leaves it so.
*
* If object is non-NULL, ref count must be bumped by caller
* prior to making call to account for the new entry.
*/
int
vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max,
int cow)
{
vm_map_entry_t new_entry;
vm_map_entry_t prev_entry;
vm_map_entry_t temp_entry;
vm_eflags_t protoeflags;
mtx_assert(&vm_mtx, MA_OWNED);
/*
* Check that the start and end points are not bogus.
*/
if ((start < map->min_offset) || (end > map->max_offset) ||
(start >= end))
return (KERN_INVALID_ADDRESS);
/*
* Find the entry prior to the proposed starting address; if it's part
* of an existing entry, this range is bogus.
*/
if (vm_map_lookup_entry(map, start, &temp_entry))
return (KERN_NO_SPACE);
prev_entry = temp_entry;
/*
* Assert that the next entry doesn't overlap the end point.
*/
if ((prev_entry->next != &map->header) &&
(prev_entry->next->start < end))
return (KERN_NO_SPACE);
protoeflags = 0;
if (cow & MAP_COPY_ON_WRITE)
protoeflags |= MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY;
if (cow & MAP_NOFAULT) {
protoeflags |= MAP_ENTRY_NOFAULT;
KASSERT(object == NULL,
("vm_map_insert: paradoxical MAP_NOFAULT request"));
}
if (cow & MAP_DISABLE_SYNCER)
protoeflags |= MAP_ENTRY_NOSYNC;
if (cow & MAP_DISABLE_COREDUMP)
protoeflags |= MAP_ENTRY_NOCOREDUMP;
if (object) {
/*
* When object is non-NULL, it could be shared with another
* process. We have to set or clear OBJ_ONEMAPPING
* appropriately.
*/
if ((object->ref_count > 1) || (object->shadow_count != 0)) {
vm_object_clear_flag(object, OBJ_ONEMAPPING);
}
}
else if ((prev_entry != &map->header) &&
(prev_entry->eflags == protoeflags) &&
(prev_entry->end == start) &&
(prev_entry->wired_count == 0) &&
((prev_entry->object.vm_object == NULL) ||
vm_object_coalesce(prev_entry->object.vm_object,
OFF_TO_IDX(prev_entry->offset),
(vm_size_t)(prev_entry->end - prev_entry->start),
(vm_size_t)(end - prev_entry->end)))) {
/*
* We were able to extend the object. Determine if we
* can extend the previous map entry to include the
* new range as well.
*/
if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) &&
(prev_entry->protection == prot) &&
(prev_entry->max_protection == max)) {
map->size += (end - prev_entry->end);
prev_entry->end = end;
vm_map_simplify_entry(map, prev_entry);
return (KERN_SUCCESS);
}
/*
* If we can extend the object but cannot extend the
* map entry, we have to create a new map entry. We
* must bump the ref count on the extended object to
* account for it. object may be NULL.
*/
object = prev_entry->object.vm_object;
offset = prev_entry->offset +
(prev_entry->end - prev_entry->start);
vm_object_reference(object);
}
/*
* NOTE: if conditionals fail, object can be NULL here. This occurs
* in things like the buffer map where we manage kva but do not manage
* backing objects.
*/
/*
* Create a new entry
*/
new_entry = vm_map_entry_create(map);
new_entry->start = start;
new_entry->end = end;
new_entry->eflags = protoeflags;
new_entry->object.vm_object = object;
new_entry->offset = offset;
new_entry->avail_ssize = 0;
new_entry->inheritance = VM_INHERIT_DEFAULT;
new_entry->protection = prot;
new_entry->max_protection = max;
new_entry->wired_count = 0;
/*
* Insert the new entry into the list
*/
vm_map_entry_link(map, prev_entry, new_entry);
map->size += new_entry->end - new_entry->start;
/*
* Update the free space hint
*/
if ((map->first_free == prev_entry) &&
(prev_entry->end >= new_entry->start)) {
map->first_free = new_entry;
}
#if 0
/*
* Temporarily removed to avoid MAP_STACK panic, due to
* MAP_STACK being a huge hack. Will be added back in
* when MAP_STACK (and the user stack mapping) is fixed.
*/
/*
* It may be possible to simplify the entry
*/
vm_map_simplify_entry(map, new_entry);
#endif
if (cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) {
pmap_object_init_pt(map->pmap, start,
object, OFF_TO_IDX(offset), end - start,
cow & MAP_PREFAULT_PARTIAL);
}
return (KERN_SUCCESS);
}
/*
* Find sufficient space for `length' bytes in the given map, starting at
* `start'. The map must be locked. Returns 0 on success, 1 on no space.
*/
int
vm_map_findspace(map, start, length, addr)
vm_map_t map;
vm_offset_t start;
vm_size_t length;
vm_offset_t *addr;
{
vm_map_entry_t entry, next;
vm_offset_t end;
mtx_assert(&vm_mtx, MA_OWNED);
if (start < map->min_offset)
start = map->min_offset;
if (start > map->max_offset)
return (1);
/*
* Look for the first possible address; if there's already something
* at this address, we have to start after it.
*/
if (start == map->min_offset) {
if ((entry = map->first_free) != &map->header)
start = entry->end;
} else {
vm_map_entry_t tmp;
if (vm_map_lookup_entry(map, start, &tmp))
start = tmp->end;
entry = tmp;
}
/*
* Look through the rest of the map, trying to fit a new region in the
* gap between existing regions, or after the very last region.
*/
for (;; start = (entry = next)->end) {
/*
* Find the end of the proposed new region. Be sure we didn't
* go beyond the end of the map, or wrap around the address;
* if so, we lose. Otherwise, if this is the last entry, or
* if the proposed new region fits before the next entry, we
* win.
*/
end = start + length;
if (end > map->max_offset || end < start)
return (1);
next = entry->next;
if (next == &map->header || next->start >= end)
break;
}
SAVE_HINT(map, entry);
*addr = start;
if (map == kernel_map) {
vm_offset_t ksize;
if ((ksize = round_page(start + length)) > kernel_vm_end) {
pmap_growkernel(ksize);
}
}
return (0);
}
/*
* vm_map_find finds an unallocated region in the target address
* map with the given length. The search is defined to be
* first-fit from the specified address; the region found is
* returned in the same parameter.
*
* If object is non-NULL, ref count must be bumped by caller
* prior to making call to account for the new entry.
*/
int
vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t *addr, /* IN/OUT */
vm_size_t length, boolean_t find_space, vm_prot_t prot,
vm_prot_t max, int cow)
{
vm_offset_t start;
int result, s = 0;
mtx_assert(&vm_mtx, MA_OWNED);
start = *addr;
if (map == kmem_map || map == mb_map)
s = splvm();
vm_map_lock(map);
if (find_space) {
if (vm_map_findspace(map, start, length, addr)) {
vm_map_unlock(map);
if (map == kmem_map || map == mb_map)
splx(s);
return (KERN_NO_SPACE);
}
start = *addr;
}
result = vm_map_insert(map, object, offset,
start, start + length, prot, max, cow);
vm_map_unlock(map);
if (map == kmem_map || map == mb_map)
splx(s);
return (result);
}
/*
* vm_map_simplify_entry:
*
* Simplify the given map entry by merging with either neighbor. This
* routine also has the ability to merge with both neighbors.
*
* The map must be locked.
*
* This routine guarentees that the passed entry remains valid (though
* possibly extended). When merging, this routine may delete one or
* both neighbors.
*/
void
vm_map_simplify_entry(map, entry)
vm_map_t map;
vm_map_entry_t entry;
{
vm_map_entry_t next, prev;
vm_size_t prevsize, esize;
mtx_assert(&vm_mtx, MA_OWNED);
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
return;
prev = entry->prev;
if (prev != &map->header) {
prevsize = prev->end - prev->start;
if ( (prev->end == entry->start) &&
(prev->object.vm_object == entry->object.vm_object) &&
(!prev->object.vm_object ||
(prev->offset + prevsize == entry->offset)) &&
(prev->eflags == entry->eflags) &&
(prev->protection == entry->protection) &&
(prev->max_protection == entry->max_protection) &&
(prev->inheritance == entry->inheritance) &&
(prev->wired_count == entry->wired_count)) {
if (map->first_free == prev)
map->first_free = entry;
if (map->hint == prev)
map->hint = entry;
vm_map_entry_unlink(map, prev);
entry->start = prev->start;
entry->offset = prev->offset;
if (prev->object.vm_object)
vm_object_deallocate(prev->object.vm_object);
vm_map_entry_dispose(map, prev);
}
}
next = entry->next;
if (next != &map->header) {
esize = entry->end - entry->start;
if ((entry->end == next->start) &&
(next->object.vm_object == entry->object.vm_object) &&
(!entry->object.vm_object ||
(entry->offset + esize == next->offset)) &&
(next->eflags == entry->eflags) &&
(next->protection == entry->protection) &&
(next->max_protection == entry->max_protection) &&
(next->inheritance == entry->inheritance) &&
(next->wired_count == entry->wired_count)) {
if (map->first_free == next)
map->first_free = entry;
if (map->hint == next)
map->hint = entry;
vm_map_entry_unlink(map, next);
entry->end = next->end;
if (next->object.vm_object)
vm_object_deallocate(next->object.vm_object);
vm_map_entry_dispose(map, next);
}
}
}
/*
* vm_map_clip_start: [ internal use only ]
*
* Asserts that the given entry begins at or after
* the specified address; if necessary,
* it splits the entry into two.
*/
#define vm_map_clip_start(map, entry, startaddr) \
{ \
if (startaddr > entry->start) \
_vm_map_clip_start(map, entry, startaddr); \
}
/*
* This routine is called only when it is known that
* the entry must be split.
*/
static void
_vm_map_clip_start(map, entry, start)
vm_map_t map;
vm_map_entry_t entry;
vm_offset_t start;
{
vm_map_entry_t new_entry;
/*
* Split off the front portion -- note that we must insert the new
* entry BEFORE this one, so that this entry has the specified
* starting address.
*/
vm_map_simplify_entry(map, entry);
/*
* If there is no object backing this entry, we might as well create
* one now. If we defer it, an object can get created after the map
* is clipped, and individual objects will be created for the split-up
* map. This is a bit of a hack, but is also about the best place to
* put this improvement.
*/
if (entry->object.vm_object == NULL && !map->system_map) {
vm_object_t object;
object = vm_object_allocate(OBJT_DEFAULT,
atop(entry->end - entry->start));
entry->object.vm_object = object;
entry->offset = 0;
}
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
new_entry->end = start;
entry->offset += (start - entry->start);
entry->start = start;
vm_map_entry_link(map, entry->prev, new_entry);
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
vm_object_reference(new_entry->object.vm_object);
}
}
/*
* vm_map_clip_end: [ internal use only ]
*
* Asserts that the given entry ends at or before
* the specified address; if necessary,
* it splits the entry into two.
*/
#define vm_map_clip_end(map, entry, endaddr) \
{ \
if (endaddr < entry->end) \
_vm_map_clip_end(map, entry, endaddr); \
}
/*
* This routine is called only when it is known that
* the entry must be split.
*/
static void
_vm_map_clip_end(map, entry, end)
vm_map_t map;
vm_map_entry_t entry;
vm_offset_t end;
{
vm_map_entry_t new_entry;
/*
* If there is no object backing this entry, we might as well create
* one now. If we defer it, an object can get created after the map
* is clipped, and individual objects will be created for the split-up
* map. This is a bit of a hack, but is also about the best place to
* put this improvement.
*/
if (entry->object.vm_object == NULL && !map->system_map) {
vm_object_t object;
object = vm_object_allocate(OBJT_DEFAULT,
atop(entry->end - entry->start));
entry->object.vm_object = object;
entry->offset = 0;
}
/*
* Create a new entry and insert it AFTER the specified entry
*/
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
new_entry->start = entry->end = end;
new_entry->offset += (end - entry->start);
vm_map_entry_link(map, entry, new_entry);
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
vm_object_reference(new_entry->object.vm_object);
}
}
/*
* VM_MAP_RANGE_CHECK: [ internal use only ]
*
* Asserts that the starting and ending region
* addresses fall within the valid range of the map.
*/
#define VM_MAP_RANGE_CHECK(map, start, end) \
{ \
if (start < vm_map_min(map)) \
start = vm_map_min(map); \
if (end > vm_map_max(map)) \
end = vm_map_max(map); \
if (start > end) \
start = end; \
}
/*
* vm_map_submap: [ kernel use only ]
*
* Mark the given range as handled by a subordinate map.
*
* This range must have been created with vm_map_find,
* and no other operations may have been performed on this
* range prior to calling vm_map_submap.
*
* Only a limited number of operations can be performed
* within this rage after calling vm_map_submap:
* vm_fault
* [Don't try vm_map_copy!]
*
* To remove a submapping, one must first remove the
* range from the superior map, and then destroy the
* submap (if desired). [Better yet, don't try it.]
*/
int
vm_map_submap(map, start, end, submap)
vm_map_t map;
vm_offset_t start;
vm_offset_t end;
vm_map_t submap;
{
vm_map_entry_t entry;
int result = KERN_INVALID_ARGUMENT;
mtx_assert(&vm_mtx, MA_OWNED);
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry)) {
vm_map_clip_start(map, entry, start);
} else
entry = entry->next;
vm_map_clip_end(map, entry, end);
if ((entry->start == start) && (entry->end == end) &&
((entry->eflags & MAP_ENTRY_COW) == 0) &&
(entry->object.vm_object == NULL)) {
entry->object.sub_map = submap;
entry->eflags |= MAP_ENTRY_IS_SUB_MAP;
result = KERN_SUCCESS;
}
vm_map_unlock(map);
return (result);
}
/*
* vm_map_protect:
*
* Sets the protection of the specified address
* region in the target map. If "set_max" is
* specified, the maximum protection is to be set;
* otherwise, only the current protection is affected.
*/
int
vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_prot_t new_prot, boolean_t set_max)
{
vm_map_entry_t current;
vm_map_entry_t entry;
mtx_assert(&vm_mtx, MA_OWNED);
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry)) {
vm_map_clip_start(map, entry, start);
} else {
entry = entry->next;
}
/*
* Make a first pass to check for protection violations.
*/
current = entry;
while ((current != &map->header) && (current->start < end)) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP) {
vm_map_unlock(map);
return (KERN_INVALID_ARGUMENT);
}
if ((new_prot & current->max_protection) != new_prot) {
vm_map_unlock(map);
return (KERN_PROTECTION_FAILURE);
}
current = current->next;
}
/*
* Go back and fix up protections. [Note that clipping is not
* necessary the second time.]
*/
current = entry;
while ((current != &map->header) && (current->start < end)) {
vm_prot_t old_prot;
vm_map_clip_end(map, current, end);
old_prot = current->protection;
if (set_max)
current->protection =
(current->max_protection = new_prot) &
old_prot;
else
current->protection = new_prot;
/*
* Update physical map if necessary. Worry about copy-on-write
* here -- CHECK THIS XXX
*/
if (current->protection != old_prot) {
#define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \
VM_PROT_ALL)
pmap_protect(map->pmap, current->start,
current->end,
current->protection & MASK(current));
#undef MASK
}
vm_map_simplify_entry(map, current);
current = current->next;
}
vm_map_unlock(map);
return (KERN_SUCCESS);
}
/*
* vm_map_madvise:
*
* This routine traverses a processes map handling the madvise
* system call. Advisories are classified as either those effecting
* the vm_map_entry structure, or those effecting the underlying
* objects.
*/
int
vm_map_madvise(map, start, end, behav)
vm_map_t map;
vm_offset_t start, end;
int behav;
{
vm_map_entry_t current, entry;
int modify_map = 0;
mtx_assert(&vm_mtx, MA_OWNED);
/*
* Some madvise calls directly modify the vm_map_entry, in which case
* we need to use an exclusive lock on the map and we need to perform
* various clipping operations. Otherwise we only need a read-lock
* on the map.
*/
switch(behav) {
case MADV_NORMAL:
case MADV_SEQUENTIAL:
case MADV_RANDOM:
case MADV_NOSYNC:
case MADV_AUTOSYNC:
case MADV_NOCORE:
case MADV_CORE:
modify_map = 1;
vm_map_lock(map);
break;
case MADV_WILLNEED:
case MADV_DONTNEED:
case MADV_FREE:
vm_map_lock_read(map);
break;
default:
return (KERN_INVALID_ARGUMENT);
}
/*
* Locate starting entry and clip if necessary.
*/
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry)) {
if (modify_map)
vm_map_clip_start(map, entry, start);
} else {
entry = entry->next;
}
if (modify_map) {
/*
* madvise behaviors that are implemented in the vm_map_entry.
*
* We clip the vm_map_entry so that behavioral changes are
* limited to the specified address range.
*/
for (current = entry;
(current != &map->header) && (current->start < end);
current = current->next
) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
vm_map_clip_end(map, current, end);
switch (behav) {
case MADV_NORMAL:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL);
break;
case MADV_SEQUENTIAL:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL);
break;
case MADV_RANDOM:
vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM);
break;
case MADV_NOSYNC:
current->eflags |= MAP_ENTRY_NOSYNC;
break;
case MADV_AUTOSYNC:
current->eflags &= ~MAP_ENTRY_NOSYNC;
break;
case MADV_NOCORE:
current->eflags |= MAP_ENTRY_NOCOREDUMP;
break;
case MADV_CORE:
current->eflags &= ~MAP_ENTRY_NOCOREDUMP;
break;
default:
break;
}
vm_map_simplify_entry(map, current);
}
vm_map_unlock(map);
} else {
vm_pindex_t pindex;
int count;
/*
* madvise behaviors that are implemented in the underlying
* vm_object.
*
* Since we don't clip the vm_map_entry, we have to clip
* the vm_object pindex and count.
*/
for (current = entry;
(current != &map->header) && (current->start < end);
current = current->next
) {
vm_offset_t useStart;
if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
pindex = OFF_TO_IDX(current->offset);
count = atop(current->end - current->start);
useStart = current->start;
if (current->start < start) {
pindex += atop(start - current->start);
count -= atop(start - current->start);
useStart = start;
}
if (current->end > end)
count -= atop(current->end - end);
if (count <= 0)
continue;
vm_object_madvise(current->object.vm_object,
pindex, count, behav);
if (behav == MADV_WILLNEED) {
pmap_object_init_pt(
map->pmap,
useStart,
current->object.vm_object,
pindex,
(count << PAGE_SHIFT),
0
);
}
}
vm_map_unlock_read(map);
}
return(0);
}
/*
* vm_map_inherit:
*
* Sets the inheritance of the specified address
* range in the target map. Inheritance
* affects how the map will be shared with
* child maps at the time of vm_map_fork.
*/
int
vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_inherit_t new_inheritance)
{
vm_map_entry_t entry;
vm_map_entry_t temp_entry;
mtx_assert(&vm_mtx, MA_OWNED);
switch (new_inheritance) {
case VM_INHERIT_NONE:
case VM_INHERIT_COPY:
case VM_INHERIT_SHARE:
break;
default:
return (KERN_INVALID_ARGUMENT);
}
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &temp_entry)) {
entry = temp_entry;
vm_map_clip_start(map, entry, start);
} else
entry = temp_entry->next;
while ((entry != &map->header) && (entry->start < end)) {
vm_map_clip_end(map, entry, end);
entry->inheritance = new_inheritance;
vm_map_simplify_entry(map, entry);
entry = entry->next;
}
vm_map_unlock(map);
return (KERN_SUCCESS);
}
/*
* Implement the semantics of mlock
*/
int
vm_map_user_pageable(map, start, end, new_pageable)
vm_map_t map;
vm_offset_t start;
vm_offset_t end;
boolean_t new_pageable;
{
vm_map_entry_t entry;
vm_map_entry_t start_entry;
vm_offset_t estart;
int rv;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
if (new_pageable) {
entry = start_entry;
vm_map_clip_start(map, entry, start);
/*
* Now decrement the wiring count for each region. If a region
* becomes completely unwired, unwire its physical pages and
* mappings.
*/
while ((entry != &map->header) && (entry->start < end)) {
if (entry->eflags & MAP_ENTRY_USER_WIRED) {
vm_map_clip_end(map, entry, end);
entry->eflags &= ~MAP_ENTRY_USER_WIRED;
entry->wired_count--;
if (entry->wired_count == 0)
vm_fault_unwire(map, entry->start, entry->end);
}
vm_map_simplify_entry(map,entry);
entry = entry->next;
}
} else {
entry = start_entry;
while ((entry != &map->header) && (entry->start < end)) {
if (entry->eflags & MAP_ENTRY_USER_WIRED) {
entry = entry->next;
continue;
}
if (entry->wired_count != 0) {
entry->wired_count++;
entry->eflags |= MAP_ENTRY_USER_WIRED;
entry = entry->next;
continue;
}
/* Here on entry being newly wired */
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
int copyflag = entry->eflags & MAP_ENTRY_NEEDS_COPY;
if (copyflag && ((entry->protection & VM_PROT_WRITE) != 0)) {
vm_object_shadow(&entry->object.vm_object,
&entry->offset,
atop(entry->end - entry->start));
entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
} else if (entry->object.vm_object == NULL &&
!map->system_map) {
entry->object.vm_object =
vm_object_allocate(OBJT_DEFAULT,
atop(entry->end - entry->start));
entry->offset = (vm_offset_t) 0;
}
}
vm_map_clip_start(map, entry, start);
vm_map_clip_end(map, entry, end);
entry->wired_count++;
entry->eflags |= MAP_ENTRY_USER_WIRED;
estart = entry->start;
/* First we need to allow map modifications */
vm_map_set_recursive(map);
vm_map_lock_downgrade(map);
map->timestamp++;
rv = vm_fault_user_wire(map, entry->start, entry->end);
if (rv) {
entry->wired_count--;
entry->eflags &= ~MAP_ENTRY_USER_WIRED;
vm_map_clear_recursive(map);
vm_map_unlock(map);
(void) vm_map_user_pageable(map, start, entry->start, TRUE);
return rv;
}
vm_map_clear_recursive(map);
if (vm_map_lock_upgrade(map)) {
vm_map_lock(map);
if (vm_map_lookup_entry(map, estart, &entry)
== FALSE) {
vm_map_unlock(map);
(void) vm_map_user_pageable(map,
start,
estart,
TRUE);
return (KERN_INVALID_ADDRESS);
}
}
vm_map_simplify_entry(map,entry);
}
}
map->timestamp++;
vm_map_unlock(map);
return KERN_SUCCESS;
}
/*
* vm_map_pageable:
*
* Sets the pageability of the specified address
* range in the target map. Regions specified
* as not pageable require locked-down physical
* memory and physical page maps.
*
* The map must not be locked, but a reference
* must remain to the map throughout the call.
*/
int
vm_map_pageable(map, start, end, new_pageable)
vm_map_t map;
vm_offset_t start;
vm_offset_t end;
boolean_t new_pageable;
{
vm_map_entry_t entry;
vm_map_entry_t start_entry;
vm_offset_t failed = 0;
int rv;
mtx_assert(&vm_mtx, MA_OWNED);
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
/*
* Only one pageability change may take place at one time, since
* vm_fault assumes it will be called only once for each
* wiring/unwiring. Therefore, we have to make sure we're actually
* changing the pageability for the entire region. We do so before
* making any changes.
*/
if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
entry = start_entry;
/*
* Actions are rather different for wiring and unwiring, so we have
* two separate cases.
*/
if (new_pageable) {
vm_map_clip_start(map, entry, start);
/*
* Unwiring. First ensure that the range to be unwired is
* really wired down and that there are no holes.
*/
while ((entry != &map->header) && (entry->start < end)) {
if (entry->wired_count == 0 ||
(entry->end < end &&
(entry->next == &map->header ||
entry->next->start > entry->end))) {
vm_map_unlock(map);
return (KERN_INVALID_ARGUMENT);
}
entry = entry->next;
}
/*
* Now decrement the wiring count for each region. If a region
* becomes completely unwired, unwire its physical pages and
* mappings.
*/
entry = start_entry;
while ((entry != &map->header) && (entry->start < end)) {
vm_map_clip_end(map, entry, end);
entry->wired_count--;
if (entry->wired_count == 0)
vm_fault_unwire(map, entry->start, entry->end);
vm_map_simplify_entry(map, entry);
entry = entry->next;
}
} else {
/*
* Wiring. We must do this in two passes:
*
* 1. Holding the write lock, we create any shadow or zero-fill
* objects that need to be created. Then we clip each map
* entry to the region to be wired and increment its wiring
* count. We create objects before clipping the map entries
* to avoid object proliferation.
*
* 2. We downgrade to a read lock, and call vm_fault_wire to
* fault in the pages for any newly wired area (wired_count is
* 1).
*
* Downgrading to a read lock for vm_fault_wire avoids a possible
* deadlock with another process that may have faulted on one
* of the pages to be wired (it would mark the page busy,
* blocking us, then in turn block on the map lock that we
* hold). Because of problems in the recursive lock package,
* we cannot upgrade to a write lock in vm_map_lookup. Thus,
* any actions that require the write lock must be done
* beforehand. Because we keep the read lock on the map, the
* copy-on-write status of the entries we modify here cannot
* change.
*/
/*
* Pass 1.
*/
while ((entry != &map->header) && (entry->start < end)) {
if (entry->wired_count == 0) {
/*
* Perform actions of vm_map_lookup that need
* the write lock on the map: create a shadow
* object for a copy-on-write region, or an
* object for a zero-fill region.
*
* We don't have to do this for entries that
* point to sub maps, because we won't
* hold the lock on the sub map.
*/
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
int copyflag = entry->eflags & MAP_ENTRY_NEEDS_COPY;
if (copyflag &&
((entry->protection & VM_PROT_WRITE) != 0)) {
vm_object_shadow(&entry->object.vm_object,
&entry->offset,
atop(entry->end - entry->start));
entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
} else if (entry->object.vm_object == NULL &&
!map->system_map) {
entry->object.vm_object =
vm_object_allocate(OBJT_DEFAULT,
atop(entry->end - entry->start));
entry->offset = (vm_offset_t) 0;
}
}
}
vm_map_clip_start(map, entry, start);
vm_map_clip_end(map, entry, end);
entry->wired_count++;
/*
* Check for holes
*/
if (entry->end < end &&
(entry->next == &map->header ||
entry->next->start > entry->end)) {
/*
* Found one. Object creation actions do not
* need to be undone, but the wired counts
* need to be restored.
*/
while (entry != &map->header && entry->end > start) {
entry->wired_count--;
entry = entry->prev;
}
vm_map_unlock(map);
return (KERN_INVALID_ARGUMENT);
}
entry = entry->next;
}
/*
* Pass 2.
*/
/*
* HACK HACK HACK HACK
*
* If we are wiring in the kernel map or a submap of it,
* unlock the map to avoid deadlocks. We trust that the
* kernel is well-behaved, and therefore will not do
* anything destructive to this region of the map while
* we have it unlocked. We cannot trust user processes
* to do the same.
*
* HACK HACK HACK HACK
*/
if (vm_map_pmap(map) == kernel_pmap) {
vm_map_unlock(map); /* trust me ... */
} else {
vm_map_lock_downgrade(map);
}
rv = 0;
entry = start_entry;
while (entry != &map->header && entry->start < end) {
/*
* If vm_fault_wire fails for any page we need to undo
* what has been done. We decrement the wiring count
* for those pages which have not yet been wired (now)
* and unwire those that have (later).
*
* XXX this violates the locking protocol on the map,
* needs to be fixed.
*/
if (rv)
entry->wired_count--;
else if (entry->wired_count == 1) {
rv = vm_fault_wire(map, entry->start, entry->end);
if (rv) {
failed = entry->start;
entry->wired_count--;
}
}
entry = entry->next;
}
if (vm_map_pmap(map) == kernel_pmap) {
vm_map_lock(map);
}
if (rv) {
vm_map_unlock(map);
(void) vm_map_pageable(map, start, failed, TRUE);
return (rv);
}
vm_map_simplify_entry(map, start_entry);
}
vm_map_unlock(map);
return (KERN_SUCCESS);
}
/*
* vm_map_clean
*
* Push any dirty cached pages in the address range to their pager.
* If syncio is TRUE, dirty pages are written synchronously.
* If invalidate is TRUE, any cached pages are freed as well.
*
* Returns an error if any part of the specified range is not mapped.
*/
int
vm_map_clean(map, start, end, syncio, invalidate)
vm_map_t map;
vm_offset_t start;
vm_offset_t end;
boolean_t syncio;
boolean_t invalidate;
{
vm_map_entry_t current;
vm_map_entry_t entry;
vm_size_t size;
vm_object_t object;
vm_ooffset_t offset;
mtx_assert(&Giant, MA_OWNED);
mtx_assert(&vm_mtx, MA_OWNED);
vm_map_lock_read(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &entry)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
}
/*
* Make a first pass to check for holes.
*/
for (current = entry; current->start < end; current = current->next) {
if (current->eflags & MAP_ENTRY_IS_SUB_MAP) {
vm_map_unlock_read(map);
return (KERN_INVALID_ARGUMENT);
}
if (end > current->end &&
(current->next == &map->header ||
current->end != current->next->start)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
}
}
if (invalidate)
pmap_remove(vm_map_pmap(map), start, end);
/*
* Make a second pass, cleaning/uncaching pages from the indicated
* objects as we go.
*/
for (current = entry; current->start < end; current = current->next) {
offset = current->offset + (start - current->start);
size = (end <= current->end ? end : current->end) - start;
if (current->eflags & MAP_ENTRY_IS_SUB_MAP) {
vm_map_t smap;
vm_map_entry_t tentry;
vm_size_t tsize;
smap = current->object.sub_map;
vm_map_lock_read(smap);
(void) vm_map_lookup_entry(smap, offset, &tentry);
tsize = tentry->end - offset;
if (tsize < size)
size = tsize;
object = tentry->object.vm_object;
offset = tentry->offset + (offset - tentry->start);
vm_map_unlock_read(smap);
} else {
object = current->object.vm_object;
}
/*
* Note that there is absolutely no sense in writing out
* anonymous objects, so we track down the vnode object
* to write out.
* We invalidate (remove) all pages from the address space
* anyway, for semantic correctness.
*/
while (object->backing_object) {
object = object->backing_object;
offset += object->backing_object_offset;
if (object->size < OFF_TO_IDX( offset + size))
size = IDX_TO_OFF(object->size) - offset;
}
if (object && (object->type == OBJT_VNODE) &&
(current->protection & VM_PROT_WRITE)) {
/*
* Flush pages if writing is allowed, invalidate them
* if invalidation requested. Pages undergoing I/O
* will be ignored by vm_object_page_remove().
*
* We cannot lock the vnode and then wait for paging
* to complete without deadlocking against vm_fault.
* Instead we simply call vm_object_page_remove() and
* allow it to block internally on a page-by-page
* basis when it encounters pages undergoing async
* I/O.
*/
int flags;
vm_object_reference(object);
mtx_unlock(&vm_mtx);
vn_lock(object->handle, LK_EXCLUSIVE | LK_RETRY, curproc);
mtx_lock(&vm_mtx);
flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
flags |= invalidate ? OBJPC_INVAL : 0;
vm_object_page_clean(object,
OFF_TO_IDX(offset),
OFF_TO_IDX(offset + size + PAGE_MASK),
flags);
if (invalidate) {
/*vm_object_pip_wait(object, "objmcl");*/
vm_object_page_remove(object,
OFF_TO_IDX(offset),
OFF_TO_IDX(offset + size + PAGE_MASK),
FALSE);
}
VOP_UNLOCK(object->handle, 0, curproc);
vm_object_deallocate(object);
}
start += size;
}
vm_map_unlock_read(map);
return (KERN_SUCCESS);
}
/*
* vm_map_entry_unwire: [ internal use only ]
*
* Make the region specified by this entry pageable.
*
* The map in question should be locked.
* [This is the reason for this routine's existence.]
*/
static void
vm_map_entry_unwire(map, entry)
vm_map_t map;
vm_map_entry_t entry;
{
vm_fault_unwire(map, entry->start, entry->end);
entry->wired_count = 0;
}
/*
* vm_map_entry_delete: [ internal use only ]
*
* Deallocate the given entry from the target map.
*/
static void
vm_map_entry_delete(map, entry)
vm_map_t map;
vm_map_entry_t entry;
{
vm_map_entry_unlink(map, entry);
map->size -= entry->end - entry->start;
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
vm_object_deallocate(entry->object.vm_object);
}
vm_map_entry_dispose(map, entry);
}
/*
* vm_map_delete: [ internal use only ]
*
* Deallocates the given address range from the target
* map.
*/
int
vm_map_delete(map, start, end)
vm_map_t map;
vm_offset_t start;
vm_offset_t end;
{
vm_object_t object;
vm_map_entry_t entry;
vm_map_entry_t first_entry;
mtx_assert(&vm_mtx, MA_OWNED);
/*
* Find the start of the region, and clip it
*/
if (!vm_map_lookup_entry(map, start, &first_entry))
entry = first_entry->next;
else {
entry = first_entry;
vm_map_clip_start(map, entry, start);
/*
* Fix the lookup hint now, rather than each time though the
* loop.
*/
SAVE_HINT(map, entry->prev);
}
/*
* Save the free space hint
*/
if (entry == &map->header) {
map->first_free = &map->header;
} else if (map->first_free->start >= start) {
map->first_free = entry->prev;
}
/*
* Step through all entries in this region
*/
while ((entry != &map->header) && (entry->start < end)) {
vm_map_entry_t next;
vm_offset_t s, e;
vm_pindex_t offidxstart, offidxend, count;
vm_map_clip_end(map, entry, end);
s = entry->start;
e = entry->end;
next = entry->next;
offidxstart = OFF_TO_IDX(entry->offset);
count = OFF_TO_IDX(e - s);
object = entry->object.vm_object;
/*
* Unwire before removing addresses from the pmap; otherwise,
* unwiring will put the entries back in the pmap.
*/
if (entry->wired_count != 0) {
vm_map_entry_unwire(map, entry);
}
offidxend = offidxstart + count;
if ((object == kernel_object) || (object == kmem_object)) {
vm_object_page_remove(object, offidxstart, offidxend, FALSE);
} else {
pmap_remove(map->pmap, s, e);
if (object != NULL &&
object->ref_count != 1 &&
(object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING &&
(object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
vm_object_collapse(object);
vm_object_page_remove(object, offidxstart, offidxend, FALSE);
if (object->type == OBJT_SWAP) {
swap_pager_freespace(object, offidxstart, count);
}
if (offidxend >= object->size &&
offidxstart < object->size) {
object->size = offidxstart;
}
}
}
/*
* Delete the entry (which may delete the object) only after
* removing all pmap entries pointing to its pages.
* (Otherwise, its page frames may be reallocated, and any
* modify bits will be set in the wrong object!)
*/
vm_map_entry_delete(map, entry);
entry = next;
}
return (KERN_SUCCESS);
}
/*
* vm_map_remove:
*
* Remove the given address range from the target map.
* This is the exported form of vm_map_delete.
*/
int
vm_map_remove(map, start, end)
vm_map_t map;
vm_offset_t start;
vm_offset_t end;
{
int result, s = 0;
mtx_assert(&vm_mtx, MA_OWNED);
if (map == kmem_map || map == mb_map)
s = splvm();
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
result = vm_map_delete(map, start, end);
vm_map_unlock(map);
if (map == kmem_map || map == mb_map)
splx(s);
return (result);
}
/*
* vm_map_check_protection:
*
* Assert that the target map allows the specified
* privilege on the entire address region given.
* The entire region must be allocated.
*/
boolean_t
vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_prot_t protection)
{
vm_map_entry_t entry;
vm_map_entry_t tmp_entry;
mtx_assert(&vm_mtx, MA_OWNED);
if (!vm_map_lookup_entry(map, start, &tmp_entry)) {
return (FALSE);
}
entry = tmp_entry;
while (start < end) {
if (entry == &map->header) {
return (FALSE);
}
/*
* No holes allowed!
*/
if (start < entry->start) {
return (FALSE);
}
/*
* Check protection associated with entry.
*/
if ((entry->protection & protection) != protection) {
return (FALSE);
}
/* go to next entry */
start = entry->end;
entry = entry->next;
}
return (TRUE);
}
/*
* Split the pages in a map entry into a new object. This affords
* easier removal of unused pages, and keeps object inheritance from
* being a negative impact on memory usage.
*/
static void
vm_map_split(entry)
vm_map_entry_t entry;
{
vm_page_t m;
vm_object_t orig_object, new_object, source;
vm_offset_t s, e;
vm_pindex_t offidxstart, offidxend, idx;
vm_size_t size;
vm_ooffset_t offset;
mtx_assert(&vm_mtx, MA_OWNED);
orig_object = entry->object.vm_object;
if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
return;
if (orig_object->ref_count <= 1)
return;
offset = entry->offset;
s = entry->start;
e = entry->end;
offidxstart = OFF_TO_IDX(offset);
offidxend = offidxstart + OFF_TO_IDX(e - s);
size = offidxend - offidxstart;
new_object = vm_pager_allocate(orig_object->type,
NULL, IDX_TO_OFF(size), VM_PROT_ALL, 0LL);
if (new_object == NULL)
return;
source = orig_object->backing_object;
if (source != NULL) {
vm_object_reference(source); /* Referenced by new_object */
TAILQ_INSERT_TAIL(&source->shadow_head,
new_object, shadow_list);
vm_object_clear_flag(source, OBJ_ONEMAPPING);
new_object->backing_object_offset =
orig_object->backing_object_offset + IDX_TO_OFF(offidxstart);
new_object->backing_object = source;
source->shadow_count++;
source->generation++;
}
for (idx = 0; idx < size; idx++) {
vm_page_t m;
retry:
m = vm_page_lookup(orig_object, offidxstart + idx);
if (m == NULL)
continue;
/*
* We must wait for pending I/O to complete before we can
* rename the page.
*
* We do not have to VM_PROT_NONE the page as mappings should
* not be changed by this operation.
*/
if (vm_page_sleep_busy(m, TRUE, "spltwt"))
goto retry;
vm_page_busy(m);
vm_page_rename(m, new_object, idx);
/* page automatically made dirty by rename and cache handled */
vm_page_busy(m);
}
if (orig_object->type == OBJT_SWAP) {
vm_object_pip_add(orig_object, 1);
/*
* copy orig_object pages into new_object
* and destroy unneeded pages in
* shadow object.
*/
swap_pager_copy(orig_object, new_object, offidxstart, 0);
vm_object_pip_wakeup(orig_object);
}
for (idx = 0; idx < size; idx++) {
m = vm_page_lookup(new_object, idx);
if (m) {
vm_page_wakeup(m);
}
}
entry->object.vm_object = new_object;
entry->offset = 0LL;
vm_object_deallocate(orig_object);
}
/*
* vm_map_copy_entry:
*
* Copies the contents of the source entry to the destination
* entry. The entries *must* be aligned properly.
*/
static void
vm_map_copy_entry(src_map, dst_map, src_entry, dst_entry)
vm_map_t src_map, dst_map;
vm_map_entry_t src_entry, dst_entry;
{
vm_object_t src_object;
if ((dst_entry->eflags|src_entry->eflags) & MAP_ENTRY_IS_SUB_MAP)
return;
if (src_entry->wired_count == 0) {
/*
* If the source entry is marked needs_copy, it is already
* write-protected.
*/
if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) {
pmap_protect(src_map->pmap,
src_entry->start,
src_entry->end,
src_entry->protection & ~VM_PROT_WRITE);
}
/*
* Make a copy of the object.
*/
if ((src_object = src_entry->object.vm_object) != NULL) {
if ((src_object->handle == NULL) &&
(src_object->type == OBJT_DEFAULT ||
src_object->type == OBJT_SWAP)) {
vm_object_collapse(src_object);
if ((src_object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) {
vm_map_split(src_entry);
src_object = src_entry->object.vm_object;
}
}
vm_object_reference(src_object);
vm_object_clear_flag(src_object, OBJ_ONEMAPPING);
dst_entry->object.vm_object = src_object;
src_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY);
dst_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY);
dst_entry->offset = src_entry->offset;
} else {
dst_entry->object.vm_object = NULL;
dst_entry->offset = 0;
}
pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start,
dst_entry->end - dst_entry->start, src_entry->start);
} else {
/*
* Of course, wired down pages can't be set copy-on-write.
* Cause wired pages to be copied into the new map by
* simulating faults (the new pages are pageable)
*/
vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry);
}
}
/*
* vmspace_fork:
* Create a new process vmspace structure and vm_map
* based on those of an existing process. The new map
* is based on the old map, according to the inheritance
* values on the regions in that map.
*
* The source map must not be locked.
*/
struct vmspace *
vmspace_fork(vm1)
struct vmspace *vm1;
{
struct vmspace *vm2;
vm_map_t old_map = &vm1->vm_map;
vm_map_t new_map;
vm_map_entry_t old_entry;
vm_map_entry_t new_entry;
vm_object_t object;
mtx_assert(&vm_mtx, MA_OWNED);
vm_map_lock(old_map);
old_map->infork = 1;
vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset);
bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy,
(caddr_t) (vm1 + 1) - (caddr_t) &vm1->vm_startcopy);
new_map = &vm2->vm_map; /* XXX */
new_map->timestamp = 1;
old_entry = old_map->header.next;
while (old_entry != &old_map->header) {
if (old_entry->eflags & MAP_ENTRY_IS_SUB_MAP)
panic("vm_map_fork: encountered a submap");
switch (old_entry->inheritance) {
case VM_INHERIT_NONE:
break;
case VM_INHERIT_SHARE:
/*
* Clone the entry, creating the shared object if necessary.
*/
object = old_entry->object.vm_object;
if (object == NULL) {
object = vm_object_allocate(OBJT_DEFAULT,
atop(old_entry->end - old_entry->start));
old_entry->object.vm_object = object;
old_entry->offset = (vm_offset_t) 0;
}
/*
* Add the reference before calling vm_object_shadow
* to insure that a shadow object is created.
*/
vm_object_reference(object);
if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) {
vm_object_shadow(&old_entry->object.vm_object,
&old_entry->offset,
atop(old_entry->end - old_entry->start));
old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
/* Transfer the second reference too. */
vm_object_reference(
old_entry->object.vm_object);
vm_object_deallocate(object);
object = old_entry->object.vm_object;
}
vm_object_clear_flag(object, OBJ_ONEMAPPING);
/*
* Clone the entry, referencing the shared object.
*/
new_entry = vm_map_entry_create(new_map);
*new_entry = *old_entry;
new_entry->eflags &= ~MAP_ENTRY_USER_WIRED;
new_entry->wired_count = 0;
/*
* Insert the entry into the new map -- we know we're
* inserting at the end of the new map.
*/
vm_map_entry_link(new_map, new_map->header.prev,
new_entry);
/*
* Update the physical map
*/
pmap_copy(new_map->pmap, old_map->pmap,
new_entry->start,
(old_entry->end - old_entry->start),
old_entry->start);
break;
case VM_INHERIT_COPY:
/*
* Clone the entry and link into the map.
*/
new_entry = vm_map_entry_create(new_map);
*new_entry = *old_entry;
new_entry->eflags &= ~MAP_ENTRY_USER_WIRED;
new_entry->wired_count = 0;
new_entry->object.vm_object = NULL;
vm_map_entry_link(new_map, new_map->header.prev,
new_entry);
vm_map_copy_entry(old_map, new_map, old_entry,
new_entry);
break;
}
old_entry = old_entry->next;
}
new_map->size = old_map->size;
old_map->infork = 0;
vm_map_unlock(old_map);
return (vm2);
}
int
vm_map_stack (vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
vm_prot_t prot, vm_prot_t max, int cow)
{
vm_map_entry_t prev_entry;
vm_map_entry_t new_stack_entry;
vm_size_t init_ssize;
int rv;
mtx_assert(&vm_mtx, MA_OWNED);
if (VM_MIN_ADDRESS > 0 && addrbos < VM_MIN_ADDRESS)
return (KERN_NO_SPACE);
if (max_ssize < SGROWSIZ)
init_ssize = max_ssize;
else
init_ssize = SGROWSIZ;
vm_map_lock(map);
/* If addr is already mapped, no go */
if (vm_map_lookup_entry(map, addrbos, &prev_entry)) {
vm_map_unlock(map);
return (KERN_NO_SPACE);
}
/* If we can't accomodate max_ssize in the current mapping,
* no go. However, we need to be aware that subsequent user
* mappings might map into the space we have reserved for
* stack, and currently this space is not protected.
*
* Hopefully we will at least detect this condition
* when we try to grow the stack.
*/
if ((prev_entry->next != &map->header) &&
(prev_entry->next->start < addrbos + max_ssize)) {
vm_map_unlock(map);
return (KERN_NO_SPACE);
}
/* We initially map a stack of only init_ssize. We will
* grow as needed later. Since this is to be a grow
* down stack, we map at the top of the range.
*
* Note: we would normally expect prot and max to be
* VM_PROT_ALL, and cow to be 0. Possibly we should
* eliminate these as input parameters, and just
* pass these values here in the insert call.
*/
rv = vm_map_insert(map, NULL, 0, addrbos + max_ssize - init_ssize,
addrbos + max_ssize, prot, max, cow);
/* Now set the avail_ssize amount */
if (rv == KERN_SUCCESS){
if (prev_entry != &map->header)
vm_map_clip_end(map, prev_entry, addrbos + max_ssize - init_ssize);
new_stack_entry = prev_entry->next;
if (new_stack_entry->end != addrbos + max_ssize ||
new_stack_entry->start != addrbos + max_ssize - init_ssize)
panic ("Bad entry start/end for new stack entry");
else
new_stack_entry->avail_ssize = max_ssize - init_ssize;
}
vm_map_unlock(map);
return (rv);
}
/* Attempts to grow a vm stack entry. Returns KERN_SUCCESS if the
* desired address is already mapped, or if we successfully grow
* the stack. Also returns KERN_SUCCESS if addr is outside the
* stack range (this is strange, but preserves compatibility with
* the grow function in vm_machdep.c).
*
* Will grab vm_mtx if needed
*/
int
vm_map_growstack (struct proc *p, vm_offset_t addr)
{
vm_map_entry_t prev_entry;
vm_map_entry_t stack_entry;
vm_map_entry_t new_stack_entry;
struct vmspace *vm = p->p_vmspace;
vm_map_t map = &vm->vm_map;
vm_offset_t end;
int grow_amount;
int rv;
int is_procstack;
int hadvmlock;
hadvmlock = mtx_owned(&vm_mtx);
if (!hadvmlock)
mtx_lock(&vm_mtx);
#define myreturn(rval) do { \
if (!hadvmlock) \
mtx_unlock(&vm_mtx); \
return (rval); \
} while (0)
Retry:
vm_map_lock_read(map);
/* If addr is already in the entry range, no need to grow.*/
if (vm_map_lookup_entry(map, addr, &prev_entry)) {
vm_map_unlock_read(map);
myreturn (KERN_SUCCESS);
}
if ((stack_entry = prev_entry->next) == &map->header) {
vm_map_unlock_read(map);
myreturn (KERN_SUCCESS);
}
if (prev_entry == &map->header)
end = stack_entry->start - stack_entry->avail_ssize;
else
end = prev_entry->end;
/* This next test mimics the old grow function in vm_machdep.c.
* It really doesn't quite make sense, but we do it anyway
* for compatibility.
*
* If not growable stack, return success. This signals the
* caller to proceed as he would normally with normal vm.
*/
if (stack_entry->avail_ssize < 1 ||
addr >= stack_entry->start ||
addr < stack_entry->start - stack_entry->avail_ssize) {
vm_map_unlock_read(map);
myreturn (KERN_SUCCESS);
}
/* Find the minimum grow amount */
grow_amount = roundup (stack_entry->start - addr, PAGE_SIZE);
if (grow_amount > stack_entry->avail_ssize) {
vm_map_unlock_read(map);
myreturn (KERN_NO_SPACE);
}
/* If there is no longer enough space between the entries
* nogo, and adjust the available space. Note: this
* should only happen if the user has mapped into the
* stack area after the stack was created, and is
* probably an error.
*
* This also effectively destroys any guard page the user
* might have intended by limiting the stack size.
*/
if (grow_amount > stack_entry->start - end) {
if (vm_map_lock_upgrade(map))
goto Retry;
stack_entry->avail_ssize = stack_entry->start - end;
vm_map_unlock(map);
myreturn (KERN_NO_SPACE);
}
is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr;
/* If this is the main process stack, see if we're over the
* stack limit.
*/
if (is_procstack && (ctob(vm->vm_ssize) + grow_amount >
p->p_rlimit[RLIMIT_STACK].rlim_cur)) {
vm_map_unlock_read(map);
myreturn (KERN_NO_SPACE);
}
/* Round up the grow amount modulo SGROWSIZ */
grow_amount = roundup (grow_amount, SGROWSIZ);
if (grow_amount > stack_entry->avail_ssize) {
grow_amount = stack_entry->avail_ssize;
}
if (is_procstack && (ctob(vm->vm_ssize) + grow_amount >
p->p_rlimit[RLIMIT_STACK].rlim_cur)) {
grow_amount = p->p_rlimit[RLIMIT_STACK].rlim_cur -
ctob(vm->vm_ssize);
}
if (vm_map_lock_upgrade(map))
goto Retry;
/* Get the preliminary new entry start value */
addr = stack_entry->start - grow_amount;
/* If this puts us into the previous entry, cut back our growth
* to the available space. Also, see the note above.
*/
if (addr < end) {
stack_entry->avail_ssize = stack_entry->start - end;
addr = end;
}
rv = vm_map_insert(map, NULL, 0, addr, stack_entry->start,
VM_PROT_ALL,
VM_PROT_ALL,
0);
/* Adjust the available stack space by the amount we grew. */
if (rv == KERN_SUCCESS) {
if (prev_entry != &map->header)
vm_map_clip_end(map, prev_entry, addr);
new_stack_entry = prev_entry->next;
if (new_stack_entry->end != stack_entry->start ||
new_stack_entry->start != addr)
panic ("Bad stack grow start/end in new stack entry");
else {
new_stack_entry->avail_ssize = stack_entry->avail_ssize -
(new_stack_entry->end -
new_stack_entry->start);
if (is_procstack)
vm->vm_ssize += btoc(new_stack_entry->end -
new_stack_entry->start);
}
}
vm_map_unlock(map);
myreturn (rv);
#undef myreturn
}
/*
* Unshare the specified VM space for exec. If other processes are
* mapped to it, then create a new one. The new vmspace is null.
*/
void
vmspace_exec(struct proc *p) {
struct vmspace *oldvmspace = p->p_vmspace;
struct vmspace *newvmspace;
vm_map_t map = &p->p_vmspace->vm_map;
mtx_assert(&vm_mtx, MA_OWNED);
newvmspace = vmspace_alloc(map->min_offset, map->max_offset);
bcopy(&oldvmspace->vm_startcopy, &newvmspace->vm_startcopy,
(caddr_t) (newvmspace + 1) - (caddr_t) &newvmspace->vm_startcopy);
/*
* This code is written like this for prototype purposes. The
* goal is to avoid running down the vmspace here, but let the
* other process's that are still using the vmspace to finally
* run it down. Even though there is little or no chance of blocking
* here, it is a good idea to keep this form for future mods.
*/
p->p_vmspace = newvmspace;
pmap_pinit2(vmspace_pmap(newvmspace));
vmspace_free(oldvmspace);
if (p == curproc)
pmap_activate(p);
}
/*
* Unshare the specified VM space for forcing COW. This
* is called by rfork, for the (RFMEM|RFPROC) == 0 case.
*/
void
vmspace_unshare(struct proc *p) {
struct vmspace *oldvmspace = p->p_vmspace;
struct vmspace *newvmspace;
mtx_assert(&vm_mtx, MA_OWNED);
if (oldvmspace->vm_refcnt == 1)
return;
newvmspace = vmspace_fork(oldvmspace);
p->p_vmspace = newvmspace;
pmap_pinit2(vmspace_pmap(newvmspace));
vmspace_free(oldvmspace);
if (p == curproc)
pmap_activate(p);
}
/*
* vm_map_lookup:
*
* Finds the VM object, offset, and
* protection for a given virtual address in the
* specified map, assuming a page fault of the
* type specified.
*
* Leaves the map in question locked for read; return
* values are guaranteed until a vm_map_lookup_done
* call is performed. Note that the map argument
* is in/out; the returned map must be used in
* the call to vm_map_lookup_done.
*
* A handle (out_entry) is returned for use in
* vm_map_lookup_done, to make that fast.
*
* If a lookup is requested with "write protection"
* specified, the map may be changed to perform virtual
* copying operations, although the data referenced will
* remain the same.
*
* Can block locking maps and while calling vm_object_shadow().
* Will drop/reaquire the vm_mtx.
*/
int
vm_map_lookup(vm_map_t *var_map, /* IN/OUT */
vm_offset_t vaddr,
vm_prot_t fault_typea,
vm_map_entry_t *out_entry, /* OUT */
vm_object_t *object, /* OUT */
vm_pindex_t *pindex, /* OUT */
vm_prot_t *out_prot, /* OUT */
boolean_t *wired) /* OUT */
{
vm_map_entry_t entry;
vm_map_t map = *var_map;
vm_prot_t prot;
vm_prot_t fault_type = fault_typea;
mtx_assert(&vm_mtx, MA_OWNED);
RetryLookup:;
/*
* Lookup the faulting address.
*/
vm_map_lock_read(map);
#define RETURN(why) \
{ \
vm_map_unlock_read(map); \
return(why); \
}
/*
* If the map has an interesting hint, try it before calling full
* blown lookup routine.
*/
entry = map->hint;
*out_entry = entry;
if ((entry == &map->header) ||
(vaddr < entry->start) || (vaddr >= entry->end)) {
vm_map_entry_t tmp_entry;
/*
* Entry was either not a valid hint, or the vaddr was not
* contained in the entry, so do a full lookup.
*/
if (!vm_map_lookup_entry(map, vaddr, &tmp_entry))
RETURN(KERN_INVALID_ADDRESS);
entry = tmp_entry;
*out_entry = entry;
}
/*
* Handle submaps.
*/
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
vm_map_t old_map = map;
*var_map = map = entry->object.sub_map;
vm_map_unlock_read(old_map);
goto RetryLookup;
}
/*
* Check whether this task is allowed to have this page.
* Note the special case for MAP_ENTRY_COW
* pages with an override. This is to implement a forced
* COW for debuggers.
*/
if (fault_type & VM_PROT_OVERRIDE_WRITE)
prot = entry->max_protection;
else
prot = entry->protection;
fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
if ((fault_type & prot) != fault_type) {
RETURN(KERN_PROTECTION_FAILURE);
}
if ((entry->eflags & MAP_ENTRY_USER_WIRED) &&
(entry->eflags & MAP_ENTRY_COW) &&
(fault_type & VM_PROT_WRITE) &&
(fault_typea & VM_PROT_OVERRIDE_WRITE) == 0) {
RETURN(KERN_PROTECTION_FAILURE);
}
/*
* If this page is not pageable, we have to get it for all possible
* accesses.
*/
*wired = (entry->wired_count != 0);
if (*wired)
prot = fault_type = entry->protection;
/*
* If the entry was copy-on-write, we either ...
*/
if (entry->eflags & MAP_ENTRY_NEEDS_COPY) {
/*
* If we want to write the page, we may as well handle that
* now since we've got the map locked.
*
* If we don't need to write the page, we just demote the
* permissions allowed.
*/
if (fault_type & VM_PROT_WRITE) {
/*
* Make a new object, and place it in the object
* chain. Note that no new references have appeared
* -- one just moved from the map to the new
* object.
*/
if (vm_map_lock_upgrade(map))
goto RetryLookup;
vm_object_shadow(
&entry->object.vm_object,
&entry->offset,
atop(entry->end - entry->start));
entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
vm_map_lock_downgrade(map);
} else {
/*
* We're attempting to read a copy-on-write page --
* don't allow writes.
*/
prot &= ~VM_PROT_WRITE;
}
}
/*
* Create an object if necessary.
*/
if (entry->object.vm_object == NULL &&
!map->system_map) {
if (vm_map_lock_upgrade(map))
goto RetryLookup;
entry->object.vm_object = vm_object_allocate(OBJT_DEFAULT,
atop(entry->end - entry->start));
entry->offset = 0;
vm_map_lock_downgrade(map);
}
/*
* Return the object/offset from this entry. If the entry was
* copy-on-write or empty, it has been fixed up.
*/
*pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
*object = entry->object.vm_object;
/*
* Return whether this is the only map sharing this data.
*/
*out_prot = prot;
return (KERN_SUCCESS);
#undef RETURN
}
/*
* vm_map_lookup_done:
*
* Releases locks acquired by a vm_map_lookup
* (according to the handle returned by that lookup).
*/
void
vm_map_lookup_done(map, entry)
vm_map_t map;
vm_map_entry_t entry;
{
/*
* Unlock the main-level map
*/
mtx_assert(&vm_mtx, MA_OWNED);
vm_map_unlock_read(map);
}
/*
* Implement uiomove with VM operations. This handles (and collateral changes)
* support every combination of source object modification, and COW type
* operations.
*/
int
vm_uiomove(mapa, srcobject, cp, cnta, uaddra, npages)
vm_map_t mapa;
vm_object_t srcobject;
off_t cp;
int cnta;
vm_offset_t uaddra;
int *npages;
{
vm_map_t map;
vm_object_t first_object, oldobject, object;
vm_map_entry_t entry;
vm_prot_t prot;
boolean_t wired;
int tcnt, rv;
vm_offset_t uaddr, start, end, tend;
vm_pindex_t first_pindex, osize, oindex;
off_t ooffset;
int cnt;
mtx_assert(&vm_mtx, MA_OWNED);
if (npages)
*npages = 0;
cnt = cnta;
uaddr = uaddra;
while (cnt > 0) {
map = mapa;
if ((vm_map_lookup(&map, uaddr,
VM_PROT_READ, &entry, &first_object,
&first_pindex, &prot, &wired)) != KERN_SUCCESS) {
return EFAULT;
}
vm_map_clip_start(map, entry, uaddr);
tcnt = cnt;
tend = uaddr + tcnt;
if (tend > entry->end) {
tcnt = entry->end - uaddr;
tend = entry->end;
}
vm_map_clip_end(map, entry, tend);
start = entry->start;
end = entry->end;
osize = atop(tcnt);
oindex = OFF_TO_IDX(cp);
if (npages) {
vm_pindex_t idx;
for (idx = 0; idx < osize; idx++) {
vm_page_t m;
if ((m = vm_page_lookup(srcobject, oindex + idx)) == NULL) {
vm_map_lookup_done(map, entry);
return 0;
}
/*
* disallow busy or invalid pages, but allow
* m->busy pages if they are entirely valid.
*/
if ((m->flags & PG_BUSY) ||
((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL)) {
vm_map_lookup_done(map, entry);
return 0;
}
}
}
/*
* If we are changing an existing map entry, just redirect
* the object, and change mappings.
*/
if ((first_object->type == OBJT_VNODE) &&
((oldobject = entry->object.vm_object) == first_object)) {
if ((entry->offset != cp) || (oldobject != srcobject)) {
/*
* Remove old window into the file
*/
pmap_remove (map->pmap, uaddr, tend);
/*
* Force copy on write for mmaped regions
*/
vm_object_pmap_copy_1 (srcobject, oindex, oindex + osize);
/*
* Point the object appropriately
*/
if (oldobject != srcobject) {
/*
* Set the object optimization hint flag
*/
vm_object_set_flag(srcobject, OBJ_OPT);
vm_object_reference(srcobject);
entry->object.vm_object = srcobject;
if (oldobject) {
vm_object_deallocate(oldobject);
}
}
entry->offset = cp;
map->timestamp++;
} else {
pmap_remove (map->pmap, uaddr, tend);
}
} else if ((first_object->ref_count == 1) &&
(first_object->size == osize) &&
((first_object->type == OBJT_DEFAULT) ||
(first_object->type == OBJT_SWAP)) ) {
oldobject = first_object->backing_object;
if ((first_object->backing_object_offset != cp) ||
(oldobject != srcobject)) {
/*
* Remove old window into the file
*/
pmap_remove (map->pmap, uaddr, tend);
/*
* Remove unneeded old pages
*/
vm_object_page_remove(first_object, 0, 0, 0);
/*
* Invalidate swap space
*/
if (first_object->type == OBJT_SWAP) {
swap_pager_freespace(first_object,
0,
first_object->size);
}
/*
* Force copy on write for mmaped regions
*/
vm_object_pmap_copy_1 (srcobject, oindex, oindex + osize);
/*
* Point the object appropriately
*/
if (oldobject != srcobject) {
/*
* Set the object optimization hint flag
*/
vm_object_set_flag(srcobject, OBJ_OPT);
vm_object_reference(srcobject);
if (oldobject) {
TAILQ_REMOVE(&oldobject->shadow_head,
first_object, shadow_list);
oldobject->shadow_count--;
/* XXX bump generation? */
vm_object_deallocate(oldobject);
}
TAILQ_INSERT_TAIL(&srcobject->shadow_head,
first_object, shadow_list);
srcobject->shadow_count++;
/* XXX bump generation? */
first_object->backing_object = srcobject;
}
first_object->backing_object_offset = cp;
map->timestamp++;
} else {
pmap_remove (map->pmap, uaddr, tend);
}
/*
* Otherwise, we have to do a logical mmap.
*/
} else {
vm_object_set_flag(srcobject, OBJ_OPT);
vm_object_reference(srcobject);
pmap_remove (map->pmap, uaddr, tend);
vm_object_pmap_copy_1 (srcobject, oindex, oindex + osize);
vm_map_lock_upgrade(map);
if (entry == &map->header) {
map->first_free = &map->header;
} else if (map->first_free->start >= start) {
map->first_free = entry->prev;
}
SAVE_HINT(map, entry->prev);
vm_map_entry_delete(map, entry);
object = srcobject;
ooffset = cp;
rv = vm_map_insert(map, object, ooffset, start, tend,
VM_PROT_ALL, VM_PROT_ALL, MAP_COPY_ON_WRITE);
if (rv != KERN_SUCCESS)
panic("vm_uiomove: could not insert new entry: %d", rv);
}
/*
* Map the window directly, if it is already in memory
*/
pmap_object_init_pt(map->pmap, uaddr,
srcobject, oindex, tcnt, 0);
map->timestamp++;
vm_map_unlock(map);
cnt -= tcnt;
uaddr += tcnt;
cp += tcnt;
if (npages)
*npages += osize;
}
return 0;
}
/*
* Performs the copy_on_write operations necessary to allow the virtual copies
* into user space to work. This has to be called for write(2) system calls
* from other processes, file unlinking, and file size shrinkage.
*
* Requires that the vm_mtx is held
*/
void
vm_freeze_copyopts(object, froma, toa)
vm_object_t object;
vm_pindex_t froma, toa;
{
int rv;
vm_object_t robject;
vm_pindex_t idx;
mtx_assert(&vm_mtx, MA_OWNED);
if ((object == NULL) ||
((object->flags & OBJ_OPT) == 0))
return;
if (object->shadow_count > object->ref_count)
panic("vm_freeze_copyopts: sc > rc");
while((robject = TAILQ_FIRST(&object->shadow_head)) != NULL) {
vm_pindex_t bo_pindex;
vm_page_t m_in, m_out;
bo_pindex = OFF_TO_IDX(robject->backing_object_offset);
vm_object_reference(robject);
vm_object_pip_wait(robject, "objfrz");
if (robject->ref_count == 1) {
vm_object_deallocate(robject);
continue;
}
vm_object_pip_add(robject, 1);
for (idx = 0; idx < robject->size; idx++) {
m_out = vm_page_grab(robject, idx,
VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
if (m_out->valid == 0) {
m_in = vm_page_grab(object, bo_pindex + idx,
VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
if (m_in->valid == 0) {
rv = vm_pager_get_pages(object, &m_in, 1, 0);
if (rv != VM_PAGER_OK) {
printf("vm_freeze_copyopts: cannot read page from file: %lx\n", (long)m_in->pindex);
continue;
}
vm_page_deactivate(m_in);
}
vm_page_protect(m_in, VM_PROT_NONE);
pmap_copy_page(VM_PAGE_TO_PHYS(m_in), VM_PAGE_TO_PHYS(m_out));
m_out->valid = m_in->valid;
vm_page_dirty(m_out);
vm_page_activate(m_out);
vm_page_wakeup(m_in);
}
vm_page_wakeup(m_out);
}
object->shadow_count--;
object->ref_count--;
TAILQ_REMOVE(&object->shadow_head, robject, shadow_list);
robject->backing_object = NULL;
robject->backing_object_offset = 0;
vm_object_pip_wakeup(robject);
vm_object_deallocate(robject);
}
vm_object_clear_flag(object, OBJ_OPT);
}
#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>
#include <ddb/ddb.h>
/*
* vm_map_print: [ debug ]
*/
DB_SHOW_COMMAND(map, vm_map_print)
{
static int nlines;
/* XXX convert args. */
vm_map_t map = (vm_map_t)addr;
boolean_t full = have_addr;
vm_map_entry_t entry;
db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n",
(void *)map,
(void *)map->pmap, map->nentries, map->timestamp);
nlines++;
if (!full && db_indent)
return;
db_indent += 2;
for (entry = map->header.next; entry != &map->header;
entry = entry->next) {
db_iprintf("map entry %p: start=%p, end=%p\n",
(void *)entry, (void *)entry->start, (void *)entry->end);
nlines++;
{
static char *inheritance_name[4] =
{"share", "copy", "none", "donate_copy"};
db_iprintf(" prot=%x/%x/%s",
entry->protection,
entry->max_protection,
inheritance_name[(int)(unsigned char)entry->inheritance]);
if (entry->wired_count != 0)
db_printf(", wired");
}
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
/* XXX no %qd in kernel. Truncate entry->offset. */
db_printf(", share=%p, offset=0x%lx\n",
(void *)entry->object.sub_map,
(long)entry->offset);
nlines++;
if ((entry->prev == &map->header) ||
(entry->prev->object.sub_map !=
entry->object.sub_map)) {
db_indent += 2;
vm_map_print((db_expr_t)(intptr_t)
entry->object.sub_map,
full, 0, (char *)0);
db_indent -= 2;
}
} else {
/* XXX no %qd in kernel. Truncate entry->offset. */
db_printf(", object=%p, offset=0x%lx",
(void *)entry->object.vm_object,
(long)entry->offset);
if (entry->eflags & MAP_ENTRY_COW)
db_printf(", copy (%s)",
(entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done");
db_printf("\n");
nlines++;
if ((entry->prev == &map->header) ||
(entry->prev->object.vm_object !=
entry->object.vm_object)) {
db_indent += 2;
vm_object_print((db_expr_t)(intptr_t)
entry->object.vm_object,
full, 0, (char *)0);
nlines += 4;
db_indent -= 2;
}
}
}
db_indent -= 2;
if (db_indent == 0)
nlines = 0;
}
DB_SHOW_COMMAND(procvm, procvm)
{
struct proc *p;
if (have_addr) {
p = (struct proc *) addr;
} else {
p = curproc;
}
db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n",
(void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map,
(void *)vmspace_pmap(p->p_vmspace));
vm_map_print((db_expr_t)(intptr_t)&p->p_vmspace->vm_map, 1, 0, NULL);
}
#endif /* DDB */
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