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NetBSD/sys/vm/vm_map.c
cgd c26286a5c1 bring changes down from magnum
1993-12-20 12:39:55 +00:00

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/*
* Copyright (c) 1991 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 7.3 (Berkeley) 4/21/91
* vm_map.c,v 1.6 1993/07/15 14:25:28 cgd Exp
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* Virtual memory mapping module.
*/
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
/*
* Virtual memory maps provide for the mapping, protection,
* and sharing of virtual memory objects. In addition,
* this module provides for an efficient virtual copy of
* memory from one map to another.
*
* Synchronization is required prior to most operations.
*
* Maps consist of an ordered doubly-linked list of simple
* entries; a single hint is used to speed up lookups.
*
* In order to properly represent the sharing of virtual
* memory regions among maps, the map structure is bi-level.
* Top-level ("address") maps refer to regions of sharable
* virtual memory. These regions are implemented as
* ("sharing") maps, which then refer to the actual virtual
* memory objects. When two address maps "share" memory,
* their top-level maps both have references to the same
* sharing map. When memory is virtual-copied from one
* address map to another, the references in the sharing
* maps are actually copied -- no copying occurs at the
* virtual memory object level.
*
* Since portions of maps are specified by start/end addreses,
* which may not align with existing map entries, all
* routines merely "clip" entries to these start/end values.
* [That is, an entry is split into two, bordering at a
* start or end value.] Note that these clippings may not
* always be necessary (as the two resulting entries are then
* not changed); however, the clipping is done for convenience.
* No attempt is currently made to "glue back together" two
* abutting entries.
*
* As mentioned above, virtual copy operations are performed
* by copying VM object references from one sharing map to
* another, and then marking both regions as copy-on-write.
* It is important to note that only one writeable reference
* to a VM object region exists in any map -- this means that
* shadow object creation can be delayed until a write operation
* occurs.
*/
int vm_map_delete(vm_map_t, vm_offset_t, vm_offset_t);
/*
* vm_map_startup:
*
* Initialize the vm_map module. Must be called before
* any other vm_map routines.
*
* Map and entry structures are allocated from the general
* purpose memory pool with some exceptions:
*
* - The kernel map and kmem submap are allocated statically.
* - Kernel map entries are allocated out of a static pool.
*
* These restrictions are necessary since malloc() uses the
* maps and requires map entries.
*/
vm_offset_t kentry_data;
vm_size_t kentry_data_size;
vm_map_entry_t kentry_free;
vm_map_t kmap_free;
void
vm_map_startup()
{
register int i;
register vm_map_entry_t mep;
vm_map_t mp;
/*
* Static map structures for allocation before initialization of
* kernel map or kmem map. vm_map_create knows how to deal with them.
*/
kmap_free = mp = (vm_map_t) kentry_data;
i = MAX_KMAP;
while (--i > 0) {
mp->header.next = (vm_map_entry_t) (mp + 1);
mp++;
}
mp++->header.next = NULL;
/*
* Form a free list of statically allocated kernel map entries
* with the rest.
*/
kentry_free = mep = (vm_map_entry_t) mp;
i = (kentry_data_size - MAX_KMAP * sizeof *mp) / sizeof *mep;
while (--i > 0) {
mep->next = mep + 1;
mep++;
}
mep->next = NULL;
}
/*
* Allocate a vmspace structure, including a vm_map and pmap,
* and initialize those structures. The refcnt is set to 1.
* The remaining fields must be initialized by the caller.
*/
struct vmspace *
vmspace_alloc(min, max, pageable)
vm_offset_t min, max;
int pageable;
{
register struct vmspace *vm;
MALLOC(vm, struct vmspace *, sizeof(struct vmspace), M_VMMAP, M_WAITOK);
bzero(vm, (caddr_t) &vm->vm_startcopy - (caddr_t) vm);
vm_map_init(&vm->vm_map, min, max, pageable);
pmap_pinit(&vm->vm_pmap);
vm->vm_map.pmap = &vm->vm_pmap; /* XXX */
vm->vm_refcnt = 1;
return (vm);
}
void
vmspace_free(vm)
register struct vmspace *vm;
{
if (--vm->vm_refcnt == 0) {
/*
* Lock the map, to wait out all other references to it.
* Delete all of the mappings and pages they hold,
* then call the pmap module to reclaim anything left.
*/
vm_map_lock(&vm->vm_map);
(void) vm_map_delete(&vm->vm_map, vm->vm_map.min_offset,
vm->vm_map.max_offset);
pmap_release(&vm->vm_pmap);
FREE(vm, M_VMMAP);
}
}
/*
* vm_map_create:
*
* Creates and returns a new empty VM map with
* the given physical map structure, and having
* the given lower and upper address bounds.
*/
vm_map_t vm_map_create(pmap, min, max, pageable)
pmap_t pmap;
vm_offset_t min, max;
boolean_t pageable;
{
register vm_map_t result;
extern vm_map_t kmem_map;
if (kmem_map == NULL) {
result = kmap_free;
if (result == NULL)
panic("vm_map_create: out of maps");
kmap_free = (vm_map_t) result->header.next;
} else
MALLOC(result, vm_map_t, sizeof(struct vm_map),
M_VMMAP, M_WAITOK);
vm_map_init(result, min, max, pageable);
result->pmap = pmap;
return(result);
}
/*
* Initialize an existing vm_map structure
* such as that in the vmspace structure.
* The pmap is set elsewhere.
*/
void
vm_map_init(map, min, max, pageable)
register struct vm_map *map;
vm_offset_t min, max;
boolean_t pageable;
{
map->header.next = map->header.prev = &map->header;
map->nentries = 0;
map->size = 0;
map->ref_count = 1;
map->is_main_map = TRUE;
map->min_offset = min;
map->max_offset = max;
map->entries_pageable = pageable;
map->first_free = &map->header;
map->hint = &map->header;
map->timestamp = 0;
lock_init(&map->lock, TRUE);
simple_lock_init(&map->ref_lock);
simple_lock_init(&map->hint_lock);
}
/*
* vm_map_entry_create: [ internal use only ]
*
* Allocates a VM map entry for insertion.
* No entry fields are filled in. This routine is
*/
vm_map_entry_t vm_map_entry_create(map)
vm_map_t map;
{
vm_map_entry_t entry;
extern vm_map_t kernel_map, kmem_map, mb_map, pager_map;
if (map == kernel_map || map == kmem_map || map == mb_map
|| map == pager_map) {
if (entry = kentry_free)
kentry_free = kentry_free->next;
} else
MALLOC(entry, vm_map_entry_t, sizeof(struct vm_map_entry),
M_VMMAPENT, M_WAITOK);
if (entry == NULL)
panic("vm_map_entry_create: out of map entries");
return(entry);
}
/*
* vm_map_entry_dispose: [ internal use only ]
*
* Inverse of vm_map_entry_create.
*/
void
vm_map_entry_dispose(map, entry)
vm_map_t map;
vm_map_entry_t entry;
{
extern vm_map_t kernel_map, kmem_map, mb_map, pager_map;
if (map == kernel_map || map == kmem_map || map == mb_map
|| map == pager_map) {
entry->next = kentry_free;
kentry_free = entry;
} else
FREE(entry, M_VMMAPENT);
}
/*
* vm_map_entry_{un,}link:
*
* Insert/remove entries from maps.
*/
#define vm_map_entry_link(map, after_where, entry) \
{ \
(map)->nentries++; \
(entry)->prev = (after_where); \
(entry)->next = (after_where)->next; \
(entry)->prev->next = (entry); \
(entry)->next->prev = (entry); \
}
#define vm_map_entry_unlink(map, entry) \
{ \
(map)->nentries--; \
(entry)->next->prev = (entry)->prev; \
(entry)->prev->next = (entry)->next; \
}
/*
* vm_map_reference:
*
* Creates another valid reference to the given map.
*
*/
void
vm_map_reference(map)
register vm_map_t map;
{
if (map == NULL)
return;
simple_lock(&map->ref_lock);
map->ref_count++;
simple_unlock(&map->ref_lock);
}
/*
* vm_map_deallocate:
*
* Removes a reference from the specified map,
* destroying it if no references remain.
* The map should not be locked.
*/
void
vm_map_deallocate(map)
register vm_map_t map;
{
register int c;
if (map == NULL)
return;
simple_lock(&map->ref_lock);
c = --map->ref_count;
simple_unlock(&map->ref_lock);
if (c > 0) {
return;
}
/*
* Lock the map, to wait out all other references
* to it.
*/
vm_map_lock(map);
(void) vm_map_delete(map, map->min_offset, map->max_offset);
pmap_destroy(map->pmap);
FREE(map, M_VMMAP);
}
/*
* vm_map_insert: [ internal use only ]
*
* Inserts the given whole VM object into the target
* map at the specified address range. The object's
* size should match that of the address range.
*
* Requires that the map be locked, and leaves it so.
*/
int
vm_map_insert(map, object, offset, start, end)
vm_map_t map;
vm_object_t object;
vm_offset_t offset;
vm_offset_t start;
vm_offset_t end;
{
register vm_map_entry_t new_entry;
register vm_map_entry_t prev_entry;
vm_map_entry_t temp_entry;
/*
* Check that the start and end points are not bogus.
*/
if ((start < map->min_offset) || (end > map->max_offset) ||
(start >= end))
return(KERN_INVALID_ADDRESS);
/*
* Find the entry prior to the proposed
* starting address; if it's part of an
* existing entry, this range is bogus.
*/
if (vm_map_lookup_entry(map, start, &temp_entry))
return(KERN_NO_SPACE);
prev_entry = temp_entry;
/*
* Assert that the next entry doesn't overlap the
* end point.
*/
if ((prev_entry->next != &map->header) &&
(prev_entry->next->start < end))
return(KERN_NO_SPACE);
/*
* See if we can avoid creating a new entry by
* extending one of our neighbors.
*/
if (object == NULL) {
if ((prev_entry != &map->header) &&
(prev_entry->end == start) &&
(map->is_main_map) &&
(prev_entry->is_a_map == FALSE) &&
(prev_entry->is_sub_map == FALSE) &&
(prev_entry->inheritance == VM_INHERIT_DEFAULT) &&
(prev_entry->protection == VM_PROT_DEFAULT) &&
(prev_entry->max_protection == VM_PROT_DEFAULT) &&
(prev_entry->wired_count == 0)) {
if (vm_object_coalesce(prev_entry->object.vm_object,
NULL,
prev_entry->offset,
(vm_offset_t) 0,
(vm_size_t)(prev_entry->end
- prev_entry->start),
(vm_size_t)(end - prev_entry->end))) {
/*
* Coalesced the two objects - can extend
* the previous map entry to include the
* new range.
*/
map->size += (end - prev_entry->end);
prev_entry->end = end;
return(KERN_SUCCESS);
}
}
}
/*
* Create a new entry
*/
new_entry = vm_map_entry_create(map);
new_entry->start = start;
new_entry->end = end;
new_entry->is_a_map = FALSE;
new_entry->is_sub_map = FALSE;
new_entry->object.vm_object = object;
new_entry->offset = offset;
new_entry->copy_on_write = FALSE;
new_entry->needs_copy = FALSE;
if (map->is_main_map) {
new_entry->inheritance = VM_INHERIT_DEFAULT;
new_entry->protection = VM_PROT_DEFAULT;
new_entry->max_protection = VM_PROT_DEFAULT;
new_entry->wired_count = 0;
}
/*
* Insert the new entry into the list
*/
vm_map_entry_link(map, prev_entry, new_entry);
map->size += new_entry->end - new_entry->start;
/*
* Update the free space hint
*/
if ((map->first_free == prev_entry) && (prev_entry->end >= new_entry->start))
map->first_free = new_entry;
return(KERN_SUCCESS);
}
/*
* SAVE_HINT:
*
* Saves the specified entry as the hint for
* future lookups. Performs necessary interlocks.
*/
#define SAVE_HINT(map,value) \
simple_lock(&(map)->hint_lock); \
(map)->hint = (value); \
simple_unlock(&(map)->hint_lock);
/*
* vm_map_lookup_entry: [ internal use only ]
*
* Finds the map entry containing (or
* immediately preceding) the specified address
* in the given map; the entry is returned
* in the "entry" parameter. The boolean
* result indicates whether the address is
* actually contained in the map.
*/
boolean_t vm_map_lookup_entry(map, address, entry)
register vm_map_t map;
register vm_offset_t address;
vm_map_entry_t *entry; /* OUT */
{
register vm_map_entry_t cur;
register vm_map_entry_t last;
/*
* Start looking either from the head of the
* list, or from the hint.
*/
simple_lock(&map->hint_lock);
cur = map->hint;
simple_unlock(&map->hint_lock);
if (cur == &map->header)
cur = cur->next;
if (address >= cur->start) {
/*
* Go from hint to end of list.
*
* But first, make a quick check to see if
* we are already looking at the entry we
* want (which is usually the case).
* Note also that we don't need to save the hint
* here... it is the same hint (unless we are
* at the header, in which case the hint didn't
* buy us anything anyway).
*/
last = &map->header;
if ((cur != last) && (cur->end > address)) {
*entry = cur;
return(TRUE);
}
}
else {
/*
* Go from start to hint, *inclusively*
*/
last = cur->next;
cur = map->header.next;
}
/*
* Search linearly
*/
while (cur != last) {
if (cur->end > address) {
if (address >= cur->start) {
/*
* Save this lookup for future
* hints, and return
*/
*entry = cur;
SAVE_HINT(map, cur);
return(TRUE);
}
break;
}
cur = cur->next;
}
*entry = cur->prev;
SAVE_HINT(map, *entry);
return(FALSE);
}
/*
* vm_map_find finds an unallocated region in the target address
* map with the given length. The search is defined to be
* first-fit from the specified address; the region found is
* returned in the same parameter.
*
*/
int
vm_map_find(map, object, offset, addr, length, find_space)
vm_map_t map;
vm_object_t object;
vm_offset_t offset;
vm_offset_t *addr; /* IN/OUT */
vm_size_t length;
boolean_t find_space;
{
register vm_map_entry_t entry;
register vm_offset_t start;
register vm_offset_t end;
int result;
start = *addr;
vm_map_lock(map);
if (find_space) {
/*
* Calculate the first possible address.
*/
if (start < map->min_offset)
start = map->min_offset;
if (start > map->max_offset) {
vm_map_unlock(map);
return (KERN_NO_SPACE);
}
/*
* 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_entry;
if (vm_map_lookup_entry(map, start, &tmp_entry))
start = tmp_entry->end;
entry = tmp_entry;
}
/*
* In any case, the "entry" always precedes
* the proposed new region throughout the
* loop:
*/
while (TRUE) {
register vm_map_entry_t next;
/*
* Find the end of the proposed new region.
* Be sure we didn't go beyond the end, or
* wrap around the address.
*/
end = start + length;
if ((end > map->max_offset) || (end < start)) {
vm_map_unlock(map);
return (KERN_NO_SPACE);
}
/*
* If there are no more entries, we must win.
*/
next = entry->next;
if (next == &map->header)
break;
/*
* If there is another entry, it must be
* after the end of the potential new region.
*/
if (next->start >= end)
break;
/*
* Didn't fit -- move to the next entry.
*/
entry = next;
start = entry->end;
}
*addr = start;
SAVE_HINT(map, entry);
}
result = vm_map_insert(map, object, offset, start, start + length);
vm_map_unlock(map);
return(result);
}
/*
* vm_map_simplify_entry: [ internal use only ]
*
* Simplify the given map entry by:
* removing extra sharing maps
* [XXX maybe later] merging with a neighbor
*/
void
vm_map_simplify_entry(map, entry)
vm_map_t map;
vm_map_entry_t entry;
{
#ifdef lint
map++;
#endif lint
/*
* If this entry corresponds to a sharing map, then
* see if we can remove the level of indirection.
* If it's not a sharing map, then it points to
* a VM object, so see if we can merge with either
* of our neighbors.
*/
if (entry->is_sub_map)
return;
if (entry->is_a_map) {
#if 0
vm_map_t my_share_map;
int count;
my_share_map = entry->object.share_map;
simple_lock(&my_share_map->ref_lock);
count = my_share_map->ref_count;
simple_unlock(&my_share_map->ref_lock);
if (count == 1) {
/* Can move the region from
* entry->start to entry->end (+ entry->offset)
* in my_share_map into place of entry.
* Later.
*/
}
#endif 0
}
else {
/*
* Try to merge with our neighbors.
*
* Conditions for merge are:
*
* 1. entries are adjacent.
* 2. both entries point to objects
* with null pagers.
*
* If a merge is possible, we replace the two
* entries with a single entry, then merge
* the two objects into a single object.
*
* Now, all that is left to do is write the
* code!
*/
}
}
/*
* vm_map_clip_start: [ internal use only ]
*
* Asserts that the given entry begins at or after
* the specified address; if necessary,
* it splits the entry into two.
*/
#define vm_map_clip_start(map, entry, startaddr) \
{ \
if (startaddr > entry->start) \
_vm_map_clip_start(map, entry, startaddr); \
}
/*
* This routine is called only when it is known that
* the entry must be split.
*/
void
_vm_map_clip_start(map, entry, start)
register vm_map_t map;
register vm_map_entry_t entry;
register vm_offset_t start;
{
register vm_map_entry_t new_entry;
/*
* See if we can simplify this entry first
*/
vm_map_simplify_entry(map, entry);
/*
* Split off the front portion --
* note that we must insert the new
* entry BEFORE this one, so that
* this entry has the specified starting
* address.
*/
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
new_entry->end = start;
entry->offset += (start - entry->start);
entry->start = start;
vm_map_entry_link(map, entry->prev, new_entry);
if (entry->is_a_map || entry->is_sub_map)
vm_map_reference(new_entry->object.share_map);
else
vm_object_reference(new_entry->object.vm_object);
}
/*
* vm_map_clip_end: [ internal use only ]
*
* Asserts that the given entry ends at or before
* the specified address; if necessary,
* it splits the entry into two.
*/
void _vm_map_clip_end();
#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.
*/
void
_vm_map_clip_end(map, entry, end)
register vm_map_t map;
register vm_map_entry_t entry;
register vm_offset_t end;
{
register vm_map_entry_t new_entry;
/*
* Create a new entry and insert it
* AFTER the specified entry
*/
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
new_entry->start = entry->end = end;
new_entry->offset += (end - entry->start);
vm_map_entry_link(map, entry, new_entry);
if (entry->is_a_map || entry->is_sub_map)
vm_map_reference(new_entry->object.share_map);
else
vm_object_reference(new_entry->object.vm_object);
}
/*
* VM_MAP_RANGE_CHECK: [ internal use only ]
*
* Asserts that the starting and ending region
* addresses fall within the valid range of the map.
*/
#define VM_MAP_RANGE_CHECK(map, start, end) \
{ \
if (start < vm_map_min(map)) \
start = vm_map_min(map); \
if (end > vm_map_max(map)) \
end = vm_map_max(map); \
if (start > end) \
start = end; \
}
/*
* vm_map_submap: [ kernel use only ]
*
* Mark the given range as handled by a subordinate map.
*
* This range must have been created with vm_map_find,
* and no other operations may have been performed on this
* range prior to calling vm_map_submap.
*
* Only a limited number of operations can be performed
* within this rage after calling vm_map_submap:
* vm_fault
* [Don't try vm_map_copy!]
*
* To remove a submapping, one must first remove the
* range from the superior map, and then destroy the
* submap (if desired). [Better yet, don't try it.]
*/
int
vm_map_submap(map, start, end, submap)
register vm_map_t map;
register vm_offset_t start;
register vm_offset_t end;
vm_map_t submap;
{
vm_map_entry_t entry;
register int result = KERN_INVALID_ARGUMENT;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry)) {
vm_map_clip_start(map, entry, start);
}
else
entry = entry->next;
vm_map_clip_end(map, entry, end);
if ((entry->start == start) && (entry->end == end) &&
(!entry->is_a_map) &&
(entry->object.vm_object == NULL) &&
(!entry->copy_on_write)) {
entry->is_a_map = FALSE;
entry->is_sub_map = TRUE;
vm_map_reference(entry->object.sub_map = submap);
result = KERN_SUCCESS;
}
vm_map_unlock(map);
return(result);
}
/*
* vm_map_protect:
*
* Sets the protection of the specified address
* region in the target map. If "set_max" is
* specified, the maximum protection is to be set;
* otherwise, only the current protection is affected.
*/
int
vm_map_protect(map, start, end, new_prot, set_max)
register vm_map_t map;
register vm_offset_t start;
register vm_offset_t end;
register vm_prot_t new_prot;
register boolean_t set_max;
{
register vm_map_entry_t current;
vm_map_entry_t entry;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry)) {
vm_map_clip_start(map, entry, start);
}
else
entry = entry->next;
/*
* Make a first pass to check for protection
* violations.
*/
current = entry;
while ((current != &map->header) && (current->start < end)) {
if (current->is_sub_map)
return(KERN_INVALID_ARGUMENT);
if ((new_prot & current->max_protection) != new_prot) {
vm_map_unlock(map);
return(KERN_PROTECTION_FAILURE);
}
current = current->next;
}
/*
* Go back and fix up protections.
* [Note that clipping is not necessary the second time.]
*/
current = entry;
while ((current != &map->header) && (current->start < end)) {
vm_prot_t old_prot;
vm_map_clip_end(map, current, end);
old_prot = current->protection;
if (set_max)
current->protection =
(current->max_protection = new_prot) &
old_prot;
else
current->protection = new_prot;
/*
* Update physical map if necessary.
* Worry about copy-on-write here -- CHECK THIS XXX
*/
if (current->protection != old_prot) {
#define MASK(entry) ((entry)->copy_on_write ? ~VM_PROT_WRITE : \
VM_PROT_ALL)
#define max(a,b) ((a) > (b) ? (a) : (b))
if (current->is_a_map) {
vm_map_entry_t share_entry;
vm_offset_t share_end;
vm_map_lock(current->object.share_map);
(void) vm_map_lookup_entry(
current->object.share_map,
current->offset,
&share_entry);
share_end = current->offset +
(current->end - current->start);
while ((share_entry !=
&current->object.share_map->header) &&
(share_entry->start < share_end)) {
pmap_protect(map->pmap,
(max(share_entry->start,
current->offset) -
current->offset +
current->start),
min(share_entry->end,
share_end) -
current->offset +
current->start,
current->protection &
MASK(share_entry));
share_entry = share_entry->next;
}
vm_map_unlock(current->object.share_map);
}
else
pmap_protect(map->pmap, current->start,
current->end,
current->protection & MASK(entry));
#undef max
#undef MASK
}
current = current->next;
}
vm_map_unlock(map);
return(KERN_SUCCESS);
}
/*
* vm_map_inherit:
*
* Sets the inheritance of the specified address
* range in the target map. Inheritance
* affects how the map will be shared with
* child maps at the time of vm_map_fork.
*/
int
vm_map_inherit(map, start, end, new_inheritance)
register vm_map_t map;
register vm_offset_t start;
register vm_offset_t end;
register vm_inherit_t new_inheritance;
{
register vm_map_entry_t entry;
vm_map_entry_t temp_entry;
switch (new_inheritance) {
case VM_INHERIT_NONE:
case VM_INHERIT_COPY:
case VM_INHERIT_SHARE:
break;
default:
return(KERN_INVALID_ARGUMENT);
}
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &temp_entry)) {
entry = temp_entry;
vm_map_clip_start(map, entry, start);
}
else
entry = temp_entry->next;
while ((entry != &map->header) && (entry->start < end)) {
vm_map_clip_end(map, entry, end);
entry->inheritance = new_inheritance;
entry = entry->next;
}
vm_map_unlock(map);
return(KERN_SUCCESS);
}
/*
* vm_map_pageable:
*
* Sets the pageability of the specified address
* range in the target map. Regions specified
* as not pageable require locked-down physical
* memory and physical page maps.
*
* The map must not be locked, but a reference
* must remain to the map throughout the call.
*/
int
vm_map_pageable(map, start, end, new_pageable)
register vm_map_t map;
register vm_offset_t start;
register vm_offset_t end;
register boolean_t new_pageable;
{
register vm_map_entry_t entry;
vm_map_entry_t temp_entry;
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, &temp_entry)) {
entry = temp_entry;
vm_map_clip_start(map, entry, start);
}
else
entry = temp_entry->next;
temp_entry = entry;
/*
* Actions are rather different for wiring and unwiring,
* so we have two separate cases.
*/
if (new_pageable) {
/*
* Unwiring. First ensure that the range to be
* unwired is really wired down.
*/
while ((entry != &map->header) && (entry->start < end)) {
if (entry->wired_count == 0) {
vm_map_unlock(map);
return(KERN_INVALID_ARGUMENT);
}
entry = entry->next;
}
/*
* Now decrement the wiring count for each region.
* If a region becomes completely unwired,
* unwire its physical pages and mappings.
*/
lock_set_recursive(&map->lock);
entry = temp_entry;
while ((entry != &map->header) && (entry->start < end)) {
vm_map_clip_end(map, entry, end);
entry->wired_count--;
if (entry->wired_count == 0)
vm_fault_unwire(map, entry->start, entry->end);
entry = entry->next;
}
lock_clear_recursive(&map->lock);
}
else {
/*
* Wiring. We must do this in two passes:
*
* 1. Holding the write lock, we increment the
* wiring count. For any area that is not already
* wired, we create any shadow objects that need
* to be created.
*
* 2. We downgrade to a read lock, and call
* vm_fault_wire to fault in the pages for any
* newly wired area (wired_count is 1).
*
* Downgrading to a read lock for vm_fault_wire avoids
* a possible deadlock with another thread that may have
* faulted on one of the pages to be wired (it would mark
* the page busy, blocking us, then in turn block on the
* map lock that we hold). Because of problems in the
* recursive lock package, we cannot upgrade to a write
* lock in vm_map_lookup. Thus, any actions that require
* the write lock must be done beforehand. Because we
* keep the read lock on the map, the copy-on-write status
* of the entries we modify here cannot change.
*/
/*
* Pass 1.
*/
entry = temp_entry;
while ((entry != &map->header) && (entry->start < end)) {
vm_map_clip_end(map, entry, end);
entry->wired_count++;
if (entry->wired_count == 1) {
/*
* Perform actions of vm_map_lookup that need
* the write lock on the map: create a shadow
* object for a copy-on-write region, or an
* object for a zero-fill region.
*
* We don't have to do this for entries that
* point to sharing maps, because we won't hold
* the lock on the sharing map.
*/
if (!entry->is_a_map) {
if (entry->needs_copy &&
((entry->protection & VM_PROT_WRITE) != 0)) {
vm_object_shadow(&entry->object.vm_object,
&entry->offset,
(vm_size_t)(entry->end
- entry->start));
entry->needs_copy = FALSE;
}
else if (entry->object.vm_object == NULL) {
entry->object.vm_object =
vm_object_allocate((vm_size_t)(entry->end
- entry->start));
entry->offset = (vm_offset_t)0;
}
}
}
entry = entry->next;
}
/*
* Pass 2.
*/
/*
* HACK HACK HACK HACK
*
* If we are wiring in the kernel map or a submap of it,
* unlock the map to avoid deadlocks. We trust that the
* kernel threads are well-behaved, and therefore will
* not do anything destructive to this region of the map
* while we have it unlocked. We cannot trust user threads
* to do the same.
*
* HACK HACK HACK HACK
*/
if (vm_map_pmap(map) == kernel_pmap) {
vm_map_unlock(map); /* trust me ... */
}
else {
lock_set_recursive(&map->lock);
lock_write_to_read(&map->lock);
}
entry = temp_entry;
while (entry != &map->header && entry->start < end) {
if (entry->wired_count == 1) {
vm_fault_wire(map, entry->start, entry->end);
}
entry = entry->next;
}
if (vm_map_pmap(map) == kernel_pmap) {
vm_map_lock(map);
}
else {
lock_clear_recursive(&map->lock);
}
}
vm_map_unlock(map);
return(KERN_SUCCESS);
}
/*
* vm_map_entry_unwire: [ internal use only ]
*
* Make the region specified by this entry pageable.
*
* The map in question should be locked.
* [This is the reason for this routine's existence.]
*/
void
vm_map_entry_unwire(map, entry)
vm_map_t map;
register vm_map_entry_t entry;
{
vm_fault_unwire(map, entry->start, entry->end);
entry->wired_count = 0;
}
/*
* vm_map_entry_delete: [ internal use only ]
*
* Deallocate the given entry from the target map.
*/
void
vm_map_entry_delete(map, entry)
register vm_map_t map;
register vm_map_entry_t entry;
{
if (entry->wired_count != 0)
vm_map_entry_unwire(map, entry);
vm_map_entry_unlink(map, entry);
map->size -= entry->end - entry->start;
if (entry->is_a_map || entry->is_sub_map)
vm_map_deallocate(entry->object.share_map);
else
vm_object_deallocate(entry->object.vm_object);
vm_map_entry_dispose(map, entry);
}
/*
* vm_map_delete: [ internal use only ]
*
* Deallocates the given address range from the target
* map.
*
* When called with a sharing map, removes pages from
* that region from all physical maps.
*/
int
vm_map_delete(map, start, end)
register vm_map_t map;
vm_offset_t start;
register vm_offset_t end;
{
register vm_map_entry_t entry;
vm_map_entry_t first_entry;
/*
* Find the start of the region, and clip it
*/
if (!vm_map_lookup_entry(map, start, &first_entry))
entry = first_entry->next;
else {
entry = first_entry;
vm_map_clip_start(map, entry, start);
/*
* Fix the lookup hint now, rather than each
* time though the loop.
*/
SAVE_HINT(map, entry->prev);
}
/*
* Save the free space hint
*/
if (map->first_free->start >= start)
map->first_free = entry->prev;
/*
* Step through all entries in this region
*/
while ((entry != &map->header) && (entry->start < end)) {
vm_map_entry_t next;
register vm_offset_t s, e;
register vm_object_t object;
vm_map_clip_end(map, entry, end);
next = entry->next;
s = entry->start;
e = entry->end;
/*
* Unwire before removing addresses from the pmap;
* otherwise, unwiring will put the entries back in
* the pmap.
*/
object = entry->object.vm_object;
if (entry->wired_count != 0)
vm_map_entry_unwire(map, entry);
/*
* If this is a sharing map, we must remove
* *all* references to this data, since we can't
* find all of the physical maps which are sharing
* it.
*/
if (object == kernel_object || object == kmem_object)
vm_object_page_remove(object, entry->offset,
entry->offset + (e - s));
else if (!map->is_main_map)
vm_object_pmap_remove(object,
entry->offset,
entry->offset + (e - s));
else
pmap_remove(map->pmap, s, e);
/*
* Delete the entry (which may delete the object)
* only after removing all pmap entries pointing
* to its pages. (Otherwise, its page frames may
* be reallocated, and any modify bits will be
* set in the wrong object!)
*/
vm_map_entry_delete(map, entry);
entry = next;
}
return(KERN_SUCCESS);
}
/*
* vm_map_remove:
*
* Remove the given address range from the target map.
* This is the exported form of vm_map_delete.
*/
int
vm_map_remove(map, start, end)
register vm_map_t map;
register vm_offset_t start;
register vm_offset_t end;
{
register int result;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
result = vm_map_delete(map, start, end);
vm_map_unlock(map);
return(result);
}
/*
* vm_map_check_protection:
*
* Assert that the target map allows the specified
* privilege on the entire address region given.
* The entire region must be allocated.
*/
boolean_t vm_map_check_protection(map, start, end, protection)
register vm_map_t map;
register vm_offset_t start;
register vm_offset_t end;
register vm_prot_t protection;
{
register vm_map_entry_t entry;
vm_map_entry_t tmp_entry;
if (!vm_map_lookup_entry(map, start, &tmp_entry)) {
return(FALSE);
}
entry = tmp_entry;
while (start < end) {
if (entry == &map->header) {
return(FALSE);
}
/*
* No holes allowed!
*/
if (start < entry->start) {
return(FALSE);
}
/*
* Check protection associated with entry.
*/
if ((entry->protection & protection) != protection) {
return(FALSE);
}
/* go to next entry */
start = entry->end;
entry = entry->next;
}
return(TRUE);
}
/*
* vm_map_copy_entry:
*
* Copies the contents of the source entry to the destination
* entry. The entries *must* be aligned properly.
*/
void
vm_map_copy_entry(src_map, dst_map, src_entry, dst_entry)
vm_map_t src_map, dst_map;
register vm_map_entry_t src_entry, dst_entry;
{
vm_object_t temp_object;
if (src_entry->is_sub_map || dst_entry->is_sub_map)
return;
if (dst_entry->object.vm_object != NULL &&
!(dst_entry->object.vm_object->flags & OBJ_INTERNAL))
printf("vm_map_copy_entry: copying over permanent data!\n");
/*
* If our destination map was wired down,
* unwire it now.
*/
if (dst_entry->wired_count != 0)
vm_map_entry_unwire(dst_map, dst_entry);
/*
* If we're dealing with a sharing map, we
* must remove the destination pages from
* all maps (since we cannot know which maps
* this sharing map belongs in).
*/
if (dst_map->is_main_map)
pmap_remove(dst_map->pmap, dst_entry->start, dst_entry->end);
else
vm_object_pmap_remove(dst_entry->object.vm_object,
dst_entry->offset,
dst_entry->offset +
(dst_entry->end - dst_entry->start));
if (src_entry->wired_count == 0) {
boolean_t src_needs_copy;
/*
* If the source entry is marked needs_copy,
* it is already write-protected.
*/
if (!src_entry->needs_copy) {
boolean_t su;
/*
* If the source entry has only one mapping,
* we can just protect the virtual address
* range.
*/
if (!(su = src_map->is_main_map)) {
simple_lock(&src_map->ref_lock);
su = (src_map->ref_count == 1);
simple_unlock(&src_map->ref_lock);
}
if (su) {
pmap_protect(src_map->pmap,
src_entry->start,
src_entry->end,
src_entry->protection & ~VM_PROT_WRITE);
}
else {
vm_object_pmap_copy(src_entry->object.vm_object,
src_entry->offset,
src_entry->offset + (src_entry->end
-src_entry->start));
}
}
/*
* Make a copy of the object.
*/
temp_object = dst_entry->object.vm_object;
vm_object_copy(src_entry->object.vm_object,
src_entry->offset,
(vm_size_t)(src_entry->end -
src_entry->start),
&dst_entry->object.vm_object,
&dst_entry->offset,
&src_needs_copy);
/*
* If we didn't get a copy-object now, mark the
* source map entry so that a shadow will be created
* to hold its changed pages.
*/
if (src_needs_copy)
src_entry->needs_copy = TRUE;
/*
* The destination always needs to have a shadow
* created.
*/
dst_entry->needs_copy = TRUE;
/*
* Mark the entries copy-on-write, so that write-enabling
* the entry won't make copy-on-write pages writable.
*/
src_entry->copy_on_write = TRUE;
dst_entry->copy_on_write = TRUE;
/*
* Get rid of the old object.
*/
vm_object_deallocate(temp_object);
pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start,
dst_entry->end - dst_entry->start, src_entry->start);
}
else {
/*
* Of course, wired down pages can't be set copy-on-write.
* Cause wired pages to be copied into the new
* map by simulating faults (the new pages are
* pageable)
*/
vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry);
}
}
/*
* vm_map_copy:
*
* Perform a virtual memory copy from the source
* address map/range to the destination map/range.
*
* If src_destroy or dst_alloc is requested,
* the source and destination regions should be
* disjoint, not only in the top-level map, but
* in the sharing maps as well. [The best way
* to guarantee this is to use a new intermediate
* map to make copies. This also reduces map
* fragmentation.]
*/
int
vm_map_copy(dst_map, src_map,
dst_addr, len, src_addr,
dst_alloc, src_destroy)
vm_map_t dst_map;
vm_map_t src_map;
vm_offset_t dst_addr;
vm_size_t len;
vm_offset_t src_addr;
boolean_t dst_alloc;
boolean_t src_destroy;
{
register
vm_map_entry_t src_entry;
register
vm_map_entry_t dst_entry;
vm_map_entry_t tmp_entry;
vm_offset_t src_start;
vm_offset_t src_end;
vm_offset_t dst_start;
vm_offset_t dst_end;
vm_offset_t src_clip;
vm_offset_t dst_clip;
int result;
boolean_t old_src_destroy;
/*
* XXX While we figure out why src_destroy screws up,
* we'll do it by explicitly vm_map_delete'ing at the end.
*/
old_src_destroy = src_destroy;
src_destroy = FALSE;
/*
* Compute start and end of region in both maps
*/
src_start = src_addr;
src_end = src_start + len;
dst_start = dst_addr;
dst_end = dst_start + len;
/*
* Check that the region can exist in both source
* and destination.
*/
if ((dst_end < dst_start) || (src_end < src_start))
return(KERN_NO_SPACE);
/*
* Lock the maps in question -- we avoid deadlock
* by ordering lock acquisition by map value
*/
if (src_map == dst_map) {
vm_map_lock(src_map);
}
else if ((int) src_map < (int) dst_map) {
vm_map_lock(src_map);
vm_map_lock(dst_map);
} else {
vm_map_lock(dst_map);
vm_map_lock(src_map);
}
result = KERN_SUCCESS;
/*
* Check protections... source must be completely readable and
* destination must be completely writable. [Note that if we're
* allocating the destination region, we don't have to worry
* about protection, but instead about whether the region
* exists.]
*/
if (src_map->is_main_map && dst_map->is_main_map) {
if (!vm_map_check_protection(src_map, src_start, src_end,
VM_PROT_READ)) {
result = KERN_PROTECTION_FAILURE;
goto Return;
}
if (dst_alloc) {
/* XXX Consider making this a vm_map_find instead */
if ((result = vm_map_insert(dst_map, NULL,
(vm_offset_t) 0, dst_start, dst_end)) != KERN_SUCCESS)
goto Return;
}
else if (!vm_map_check_protection(dst_map, dst_start, dst_end,
VM_PROT_WRITE)) {
result = KERN_PROTECTION_FAILURE;
goto Return;
}
}
/*
* Find the start entries and clip.
*
* Note that checking protection asserts that the
* lookup cannot fail.
*
* Also note that we wait to do the second lookup
* until we have done the first clip, as the clip
* may affect which entry we get!
*/
(void) vm_map_lookup_entry(src_map, src_addr, &tmp_entry);
src_entry = tmp_entry;
vm_map_clip_start(src_map, src_entry, src_start);
(void) vm_map_lookup_entry(dst_map, dst_addr, &tmp_entry);
dst_entry = tmp_entry;
vm_map_clip_start(dst_map, dst_entry, dst_start);
/*
* If both source and destination entries are the same,
* retry the first lookup, as it may have changed.
*/
if (src_entry == dst_entry) {
(void) vm_map_lookup_entry(src_map, src_addr, &tmp_entry);
src_entry = tmp_entry;
}
/*
* If source and destination entries are still the same,
* a null copy is being performed.
*/
if (src_entry == dst_entry)
goto Return;
/*
* Go through entries until we get to the end of the
* region.
*/
while (src_start < src_end) {
/*
* Clip the entries to the endpoint of the entire region.
*/
vm_map_clip_end(src_map, src_entry, src_end);
vm_map_clip_end(dst_map, dst_entry, dst_end);
/*
* Clip each entry to the endpoint of the other entry.
*/
src_clip = src_entry->start + (dst_entry->end - dst_entry->start);
vm_map_clip_end(src_map, src_entry, src_clip);
dst_clip = dst_entry->start + (src_entry->end - src_entry->start);
vm_map_clip_end(dst_map, dst_entry, dst_clip);
/*
* Both entries now match in size and relative endpoints.
*
* If both entries refer to a VM object, we can
* deal with them now.
*/
if (!src_entry->is_a_map && !dst_entry->is_a_map) {
vm_map_copy_entry(src_map, dst_map, src_entry,
dst_entry);
}
else {
register vm_map_t new_dst_map;
vm_offset_t new_dst_start;
vm_size_t new_size;
vm_map_t new_src_map;
vm_offset_t new_src_start;
/*
* We have to follow at least one sharing map.
*/
new_size = (dst_entry->end - dst_entry->start);
if (src_entry->is_a_map) {
new_src_map = src_entry->object.share_map;
new_src_start = src_entry->offset;
}
else {
new_src_map = src_map;
new_src_start = src_entry->start;
lock_set_recursive(&src_map->lock);
}
if (dst_entry->is_a_map) {
vm_offset_t new_dst_end;
new_dst_map = dst_entry->object.share_map;
new_dst_start = dst_entry->offset;
/*
* Since the destination sharing entries
* will be merely deallocated, we can
* do that now, and replace the region
* with a null object. [This prevents
* splitting the source map to match
* the form of the destination map.]
* Note that we can only do so if the
* source and destination do not overlap.
*/
new_dst_end = new_dst_start + new_size;
if (new_dst_map != new_src_map) {
vm_map_lock(new_dst_map);
(void) vm_map_delete(new_dst_map,
new_dst_start,
new_dst_end);
(void) vm_map_insert(new_dst_map,
NULL,
(vm_offset_t) 0,
new_dst_start,
new_dst_end);
vm_map_unlock(new_dst_map);
}
}
else {
new_dst_map = dst_map;
new_dst_start = dst_entry->start;
lock_set_recursive(&dst_map->lock);
}
/*
* Recursively copy the sharing map.
*/
(void) vm_map_copy(new_dst_map, new_src_map,
new_dst_start, new_size, new_src_start,
FALSE, FALSE);
if (dst_map == new_dst_map)
lock_clear_recursive(&dst_map->lock);
if (src_map == new_src_map)
lock_clear_recursive(&src_map->lock);
}
/*
* Update variables for next pass through the loop.
*/
src_start = src_entry->end;
src_entry = src_entry->next;
dst_start = dst_entry->end;
dst_entry = dst_entry->next;
/*
* If the source is to be destroyed, here is the
* place to do it.
*/
if (src_destroy && src_map->is_main_map &&
dst_map->is_main_map)
vm_map_entry_delete(src_map, src_entry->prev);
}
/*
* Update the physical maps as appropriate
*/
if (src_map->is_main_map && dst_map->is_main_map) {
if (src_destroy)
pmap_remove(src_map->pmap, src_addr, src_addr + len);
}
/*
* Unlock the maps
*/
Return: ;
if (old_src_destroy)
vm_map_delete(src_map, src_addr, src_addr + len);
vm_map_unlock(src_map);
if (src_map != dst_map)
vm_map_unlock(dst_map);
return(result);
}
/*
* vmspace_fork:
* Create a new process vmspace structure and vm_map
* based on those of an existing process. The new map
* is based on the old map, according to the inheritance
* values on the regions in that map.
*
* The source map must not be locked.
*/
struct vmspace *
vmspace_fork(vm1)
register struct vmspace *vm1;
{
register struct vmspace *vm2;
vm_map_t old_map = &vm1->vm_map;
vm_map_t new_map;
vm_map_entry_t old_entry;
vm_map_entry_t new_entry;
pmap_t new_pmap;
vm_map_lock(old_map);
vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset,
old_map->entries_pageable);
bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy,
(caddr_t) (vm1 + 1) - (caddr_t) &vm1->vm_startcopy);
new_pmap = &vm2->vm_pmap; /* XXX */
new_map = &vm2->vm_map; /* XXX */
old_entry = old_map->header.next;
while (old_entry != &old_map->header) {
if (old_entry->is_sub_map)
panic("vm_map_fork: encountered a submap");
switch (old_entry->inheritance) {
case VM_INHERIT_NONE:
break;
case VM_INHERIT_SHARE:
/*
* If we don't already have a sharing map:
*/
if (!old_entry->is_a_map) {
vm_map_t new_share_map;
vm_map_entry_t new_share_entry;
/*
* Create a new sharing map
*/
new_share_map = vm_map_create(NULL,
old_entry->start,
old_entry->end,
TRUE);
new_share_map->is_main_map = FALSE;
/*
* Create the only sharing entry from the
* old task map entry.
*/
new_share_entry =
vm_map_entry_create(new_share_map);
*new_share_entry = *old_entry;
/*
* Insert the entry into the new sharing
* map
*/
vm_map_entry_link(new_share_map,
new_share_map->header.prev,
new_share_entry);
/*
* Fix up the task map entry to refer
* to the sharing map now.
*/
old_entry->is_a_map = TRUE;
old_entry->object.share_map = new_share_map;
old_entry->offset = old_entry->start;
}
/*
* Clone the entry, referencing the sharing map.
*/
new_entry = vm_map_entry_create(new_map);
*new_entry = *old_entry;
vm_map_reference(new_entry->object.share_map);
/*
* Insert the entry into the new map -- we
* know we're inserting at the end of the new
* map.
*/
vm_map_entry_link(new_map, new_map->header.prev,
new_entry);
/*
* Update the physical map
*/
pmap_copy(new_map->pmap, old_map->pmap,
new_entry->start,
(old_entry->end - old_entry->start),
old_entry->start);
break;
case VM_INHERIT_COPY:
/*
* Clone the entry and link into the map.
*/
new_entry = vm_map_entry_create(new_map);
*new_entry = *old_entry;
new_entry->wired_count = 0;
new_entry->object.vm_object = NULL;
new_entry->is_a_map = FALSE;
vm_map_entry_link(new_map, new_map->header.prev,
new_entry);
if (old_entry->is_a_map) {
int check;
check = vm_map_copy(new_map,
old_entry->object.share_map,
new_entry->start,
(vm_size_t)(new_entry->end -
new_entry->start),
old_entry->offset,
FALSE, FALSE);
if (check != KERN_SUCCESS)
printf("vm_map_fork: copy in share_map region failed\n");
}
else {
vm_map_copy_entry(old_map, new_map, old_entry,
new_entry);
}
break;
}
old_entry = old_entry->next;
}
new_map->size = old_map->size;
vm_map_unlock(old_map);
return(vm2);
}
/*
* vm_map_lookup:
*
* Finds the VM object, offset, and
* protection for a given virtual address in the
* specified map, assuming a page fault of the
* type specified.
*
* Leaves the map in question locked for read; return
* values are guaranteed until a vm_map_lookup_done
* call is performed. Note that the map argument
* is in/out; the returned map must be used in
* the call to vm_map_lookup_done.
*
* A handle (out_entry) is returned for use in
* vm_map_lookup_done, to make that fast.
*
* If a lookup is requested with "write protection"
* specified, the map may be changed to perform virtual
* copying operations, although the data referenced will
* remain the same.
*/
vm_map_lookup(var_map, vaddr, fault_type, out_entry,
object, offset, out_prot, wired, single_use)
vm_map_t *var_map; /* IN/OUT */
register vm_offset_t vaddr;
register vm_prot_t fault_type;
vm_map_entry_t *out_entry; /* OUT */
vm_object_t *object; /* OUT */
vm_offset_t *offset; /* OUT */
vm_prot_t *out_prot; /* OUT */
boolean_t *wired; /* OUT */
boolean_t *single_use; /* OUT */
{
vm_map_t share_map;
vm_offset_t share_offset;
register vm_map_entry_t entry;
register vm_map_t map = *var_map;
register vm_prot_t prot;
register boolean_t su;
RetryLookup: ;
/*
* Lookup the faulting address.
*/
vm_map_lock_read(map);
#define RETURN(why) \
{ \
vm_map_unlock_read(map); \
return(why); \
}
/*
* If the map has an interesting hint, try it before calling
* full blown lookup routine.
*/
simple_lock(&map->hint_lock);
entry = map->hint;
simple_unlock(&map->hint_lock);
*out_entry = entry;
if ((entry == &map->header) ||
(vaddr < entry->start) || (vaddr >= entry->end)) {
vm_map_entry_t tmp_entry;
/*
* Entry was either not a valid hint, or the vaddr
* was not contained in the entry, so do a full lookup.
*/
if (!vm_map_lookup_entry(map, vaddr, &tmp_entry))
RETURN(KERN_INVALID_ADDRESS);
entry = tmp_entry;
*out_entry = entry;
}
/*
* Handle submaps.
*/
if (entry->is_sub_map) {
vm_map_t old_map = map;
*var_map = map = entry->object.sub_map;
vm_map_unlock_read(old_map);
goto RetryLookup;
}
/*
* Check whether this task is allowed to have
* this page.
*/
prot = entry->protection;
if ((fault_type & (prot)) != fault_type)
RETURN(KERN_PROTECTION_FAILURE);
/*
* If this page is not pageable, we have to get
* it for all possible accesses.
*/
if (*wired = (entry->wired_count != 0))
prot = fault_type = entry->protection;
/*
* If we don't already have a VM object, track
* it down.
*/
if (su = !entry->is_a_map) {
share_map = map;
share_offset = vaddr;
}
else {
vm_map_entry_t share_entry;
/*
* Compute the sharing map, and offset into it.
*/
share_map = entry->object.share_map;
share_offset = (vaddr - entry->start) + entry->offset;
/*
* Look for the backing store object and offset
*/
vm_map_lock_read(share_map);
if (!vm_map_lookup_entry(share_map, share_offset,
&share_entry)) {
vm_map_unlock_read(share_map);
RETURN(KERN_INVALID_ADDRESS);
}
entry = share_entry;
}
/*
* If the entry was copy-on-write, we either ...
*/
if (entry->needs_copy) {
/*
* If we want to write the page, we may as well
* handle that now since we've got the sharing
* map locked.
*
* If we don't need to write the page, we just
* demote the permissions allowed.
*/
if (fault_type & VM_PROT_WRITE) {
/*
* Make a new object, and place it in the
* object chain. Note that no new references
* have appeared -- one just moved from the
* share map to the new object.
*/
if (lock_read_to_write(&share_map->lock)) {
if (share_map != map)
vm_map_unlock_read(map);
goto RetryLookup;
}
vm_object_shadow(
&entry->object.vm_object,
&entry->offset,
(vm_size_t) (entry->end - entry->start));
entry->needs_copy = FALSE;
lock_write_to_read(&share_map->lock);
}
else {
/*
* We're attempting to read a copy-on-write
* page -- don't allow writes.
*/
prot &= (~VM_PROT_WRITE);
}
}
/*
* Create an object if necessary.
*/
if (entry->object.vm_object == NULL) {
if (lock_read_to_write(&share_map->lock)) {
if (share_map != map)
vm_map_unlock_read(map);
goto RetryLookup;
}
entry->object.vm_object = vm_object_allocate(
(vm_size_t)(entry->end - entry->start));
entry->offset = 0;
lock_write_to_read(&share_map->lock);
}
/*
* Return the object/offset from this entry. If the entry
* was copy-on-write or empty, it has been fixed up.
*/
*offset = (share_offset - entry->start) + entry->offset;
*object = entry->object.vm_object;
/*
* Return whether this is the only map sharing this data.
*/
if (!su) {
simple_lock(&share_map->ref_lock);
su = (share_map->ref_count == 1);
simple_unlock(&share_map->ref_lock);
}
*out_prot = prot;
*single_use = su;
return(KERN_SUCCESS);
#undef RETURN
}
/*
* vm_map_lookup_done:
*
* Releases locks acquired by a vm_map_lookup
* (according to the handle returned by that lookup).
*/
void
vm_map_lookup_done(map, entry)
register vm_map_t map;
vm_map_entry_t entry;
{
/*
* If this entry references a map, unlock it first.
*/
if (entry->is_a_map)
vm_map_unlock_read(entry->object.share_map);
/*
* Unlock the main-level map
*/
vm_map_unlock_read(map);
}
/*
* Routine: vm_map_simplify
* Purpose:
* Attempt to simplify the map representation in
* the vicinity of the given starting address.
* Note:
* This routine is intended primarily to keep the
* kernel maps more compact -- they generally don't
* benefit from the "expand a map entry" technology
* at allocation time because the adjacent entry
* is often wired down.
*/
void
vm_map_simplify(map, start)
vm_map_t map;
vm_offset_t start;
{
vm_map_entry_t this_entry;
vm_map_entry_t prev_entry;
vm_map_lock(map);
if (
(vm_map_lookup_entry(map, start, &this_entry)) &&
((prev_entry = this_entry->prev) != &map->header) &&
(prev_entry->end == start) &&
(map->is_main_map) &&
(prev_entry->is_a_map == FALSE) &&
(prev_entry->is_sub_map == FALSE) &&
(this_entry->is_a_map == FALSE) &&
(this_entry->is_sub_map == FALSE) &&
(prev_entry->inheritance == this_entry->inheritance) &&
(prev_entry->protection == this_entry->protection) &&
(prev_entry->max_protection == this_entry->max_protection) &&
(prev_entry->wired_count == this_entry->wired_count) &&
(prev_entry->copy_on_write == this_entry->copy_on_write) &&
(prev_entry->needs_copy == this_entry->needs_copy) &&
(prev_entry->object.vm_object == this_entry->object.vm_object) &&
((prev_entry->offset + (prev_entry->end - prev_entry->start))
== this_entry->offset)
) {
if (map->first_free == this_entry)
map->first_free = prev_entry;
SAVE_HINT(map, prev_entry);
vm_map_entry_unlink(map, this_entry);
prev_entry->end = this_entry->end;
vm_object_deallocate(this_entry->object.vm_object);
vm_map_entry_dispose(map, this_entry);
}
vm_map_unlock(map);
}
#if defined(DDB) || defined(DIAGNOSTIC)
/*
* vm_map_print: [ debug ]
*/
void
vm_map_print(map, full)
register vm_map_t map;
boolean_t full;
{
extern void _vm_map_print();
_vm_map_print(map, full, printf);
}
void
_vm_map_print(map, full, pr)
register vm_map_t map;
boolean_t full;
int (*pr)();
{
register vm_map_entry_t entry;
extern int indent;
iprintf(pr, "%s map 0x%x: pmap=0x%x,ref=%d,nentries=%d,version=%d\n",
(map->is_main_map ? "Task" : "Share"),
(int) map, (int) (map->pmap), map->ref_count, map->nentries,
map->timestamp);
if (!full && indent)
return;
indent += 2;
for (entry = map->header.next; entry != &map->header;
entry = entry->next) {
iprintf(pr, "map entry 0x%x: start=0x%x, end=0x%x, ",
(int) entry, (int) entry->start, (int) entry->end);
if (map->is_main_map) {
static char *inheritance_name[4] =
{ "share", "copy", "none", "donate_copy"};
(*pr)("prot=%x/%x/%s, ",
entry->protection,
entry->max_protection,
inheritance_name[entry->inheritance]);
if (entry->wired_count != 0)
(*pr)("wired, ");
}
if (entry->is_a_map || entry->is_sub_map) {
(*pr)("share=0x%x, offset=0x%x\n",
(int) entry->object.share_map,
(int) entry->offset);
if ((entry->prev == &map->header) ||
(!entry->prev->is_a_map) ||
(entry->prev->object.share_map !=
entry->object.share_map)) {
indent += 2;
vm_map_print(entry->object.share_map, full);
indent -= 2;
}
}
else {
(*pr)("object=0x%x, offset=0x%x",
(int) entry->object.vm_object,
(int) entry->offset);
if (entry->copy_on_write)
(*pr)(", copy (%s)",
entry->needs_copy ? "needed" : "done");
(*pr)("\n");
if ((entry->prev == &map->header) ||
(entry->prev->is_a_map) ||
(entry->prev->object.vm_object !=
entry->object.vm_object)) {
indent += 2;
_vm_object_print(entry->object.vm_object, full, pr);
indent -= 2;
}
}
}
indent -= 2;
}
#endif
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