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freebsd/sys/vm/vm_map.c
John Dyson 5856e12e69 Fully implement vfork. Vfork is now much much faster than even our 
fork. (On my machine, fork is about 240usecs, vfork is 78usecs.)

Implement rfork(!RFPROC !RFMEM), which allows a thread to divorce its memory
	from the other threads of a group.

Implement rfork(!RFPROC RFCFDG), which closes all file descriptors, eliminating
	possible existing shares with other threads/processes.

Implement rfork(!RFPROC RFFDG), which divorces the file descriptors for a
	thread from the rest of the group.

Fix the case where a thread does an exec.  It is almost nonsense for a thread
	to modify the other threads address space by an exec, so we
	now automatically divorce the address space before modifying it.
1997-04-13 01:48:35 +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.
*
* $Id: vm_map.c,v 1.75 1997/04/07 07:16:05 peter Exp $
*/
/*
* Virtual memory mapping module.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/vmmeter.h>
#include <sys/mman.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <vm/vm_inherit.h>
#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#include <vm/vm_kern.h>
#include <vm/vm_pager.h>
#include <vm/vm_extern.h>
#include <vm/default_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.
*
* In order to properly represent the sharing of virtual
* memory regions among maps, the map structure is bi-level.
* Top-level ("address") maps refer to regions of sharable
* virtual memory. These regions are implemented as
* ("sharing") maps, which then refer to the actual virtual
* memory objects. When two address maps "share" memory,
* their top-level maps both have references to the same
* sharing map. When memory is virtual-copied from one
* address map to another, the references in the sharing
* maps are actually copied -- no copying occurs at the
* virtual memory object level.
*
* Since portions of maps are specified by start/end addreses,
* which may not align with existing map entries, all
* routines merely "clip" entries to these start/end values.
* [That is, an entry is split into two, bordering at a
* start or end value.] Note that these clippings may not
* always be necessary (as the two resulting entries are then
* not changed); however, the clipping is done for convenience.
* No attempt is currently made to "glue back together" two
* abutting entries.
*
* As mentioned above, virtual copy operations are performed
* by copying VM object references from one sharing map to
* another, and then marking both regions as copy-on-write.
* It is important to note that only one writeable reference
* to a VM object region exists in any map -- this means that
* shadow object creation can be delayed until a write operation
* occurs.
*/
/*
* vm_map_startup:
*
* Initialize the vm_map module. Must be called before
* any other vm_map routines.
*
* Map and entry structures are allocated from the general
* purpose memory pool with some exceptions:
*
* - The kernel map and kmem submap are allocated statically.
* - Kernel map entries are allocated out of a static pool.
*
* These restrictions are necessary since malloc() uses the
* maps and requires map entries.
*/
vm_offset_t kentry_data;
vm_size_t kentry_data_size;
static vm_map_entry_t kentry_free;
static vm_map_t kmap_free;
extern char kstack[];
extern int inmprotect;
static int kentry_count;
static vm_offset_t mapvm_start, mapvm, mapvmmax;
static int mapvmpgcnt;
static struct vm_map_entry *mappool;
static int mappoolcnt;
#define KENTRY_LOW_WATER 128
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));
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;
kentry_count = 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;
if (mapvmpgcnt == 0 && mapvm == 0) {
mapvmpgcnt = (cnt.v_page_count * sizeof(struct vm_map_entry) + PAGE_SIZE - 1) / PAGE_SIZE;
mapvm_start = mapvm = kmem_alloc_pageable(kernel_map,
mapvmpgcnt * PAGE_SIZE);
mapvmmax = mapvm_start + mapvmpgcnt * PAGE_SIZE;
if (!mapvm)
mapvmpgcnt = 0;
}
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)
panic("vmspace_free: attempt to free already freed vmspace");
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);
vm_map_unlock(&vm->vm_map);
while( vm->vm_map.ref_count != 1)
tsleep(&vm->vm_map.ref_count, PVM, "vmsfre", 0);
--vm->vm_map.ref_count;
pmap_release(&vm->vm_pmap);
FREE(vm, M_VMMAP);
} else {
wakeup(&vm->vm_map.ref_count);
}
}
/*
* 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;
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;
lockinit(&map->lock, PVM, "thrd_sleep", 0, 0);
simple_lock_init(&map->ref_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;
{
int s;
if (map == kernel_map || map == kmem_map ||
map == mb_map || map == pager_map) {
s = splvm();
entry->next = kentry_free;
kentry_free = entry;
++kentry_count;
splx(s);
} else {
entry->next = mappool;
mappool = entry;
++mappoolcnt;
}
}
/*
* vm_map_entry_create: [ internal use only ]
*
* Allocates a VM map entry for insertion.
* No entry fields are filled in. This routine is
*/
static vm_map_entry_t
vm_map_entry_create(map)
vm_map_t map;
{
vm_map_entry_t entry;
int i;
int s;
/*
* This is a *very* nasty (and sort of incomplete) hack!!!!
*/
if (kentry_count < KENTRY_LOW_WATER) {
s = splvm();
if (mapvmpgcnt && mapvm) {
vm_page_t m;
m = vm_page_alloc(kernel_object,
OFF_TO_IDX(mapvm - VM_MIN_KERNEL_ADDRESS),
(map == kmem_map || map == mb_map) ? VM_ALLOC_INTERRUPT : VM_ALLOC_NORMAL);
if (m) {
int newentries;
newentries = (PAGE_SIZE / sizeof(struct vm_map_entry));
vm_page_wire(m);
PAGE_WAKEUP(m);
m->valid = VM_PAGE_BITS_ALL;
pmap_kenter(mapvm, VM_PAGE_TO_PHYS(m));
m->flags |= PG_WRITEABLE;
entry = (vm_map_entry_t) mapvm;
mapvm += PAGE_SIZE;
--mapvmpgcnt;
for (i = 0; i < newentries; i++) {
vm_map_entry_dispose(kernel_map, entry);
entry++;
}
}
}
splx(s);
}
if (map == kernel_map || map == kmem_map ||
map == mb_map || map == pager_map) {
s = splvm();
entry = kentry_free;
if (entry) {
kentry_free = entry->next;
--kentry_count;
} else {
panic("vm_map_entry_create: out of map entries for kernel");
}
splx(s);
} else {
entry = mappool;
if (entry) {
mappool = entry->next;
--mappoolcnt;
} else {
MALLOC(entry, vm_map_entry_t, sizeof(struct vm_map_entry),
M_VMMAPENT, M_WAITOK);
}
}
return (entry);
}
/*
* vm_map_entry_{un,}link:
*
* Insert/remove entries from maps.
*/
#define vm_map_entry_link(map, after_where, entry) \
{ \
(map)->nentries++; \
(entry)->prev = (after_where); \
(entry)->next = (after_where)->next; \
(entry)->prev->next = (entry); \
(entry)->next->prev = (entry); \
}
#define vm_map_entry_unlink(map, entry) \
{ \
(map)->nentries--; \
(entry)->next->prev = (entry)->prev; \
(entry)->prev->next = (entry)->next; \
}
/*
* vm_map_reference:
*
* Creates another valid reference to the given map.
*
*/
void
vm_map_reference(map)
register vm_map_t map;
{
if (map == NULL)
return;
map->ref_count++;
}
/*
* 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;
c = map->ref_count;
if (c == 0)
panic("vm_map_deallocate: deallocating already freed map");
if (c != 1) {
--map->ref_count;
wakeup(&map->ref_count);
return;
}
/*
* Lock the map, to wait out all other references to it.
*/
vm_map_lock_drain_interlock(map);
(void) vm_map_delete(map, map->min_offset, map->max_offset);
--map->ref_count;
if( map->ref_count != 0) {
vm_map_unlock(map);
return;
}
pmap_destroy(map->pmap);
vm_map_unlock(map);
FREE(map, M_VMMAP);
}
/*
* 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.
*/
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.
*/
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.
*/
int
vm_map_insert(map, object, offset, start, end, prot, max, cow)
vm_map_t map;
vm_object_t object;
vm_ooffset_t offset;
vm_offset_t start;
vm_offset_t end;
vm_prot_t prot, max;
int cow;
{
register vm_map_entry_t new_entry;
register vm_map_entry_t prev_entry;
vm_map_entry_t temp_entry;
vm_object_t prev_object;
u_char protoeflags;
if ((object != NULL) && (cow & MAP_NOFAULT)) {
panic("vm_map_insert: paradoxical MAP_NOFAULT request");
}
/*
* 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_NEEDED)
protoeflags |= MAP_ENTRY_NEEDS_COPY;
if (cow & MAP_COPY_ON_WRITE)
protoeflags |= MAP_ENTRY_COW;
if (cow & MAP_NOFAULT)
protoeflags |= MAP_ENTRY_NOFAULT;
/*
* See if we can avoid creating a new entry by extending one of our
* neighbors. Or at least extend the object.
*/
if ((object == NULL) &&
(prev_entry != &map->header) &&
(( prev_entry->eflags & (MAP_ENTRY_IS_A_MAP | MAP_ENTRY_IS_SUB_MAP)) == 0) &&
(prev_entry->end == start) &&
(prev_entry->wired_count == 0)) {
if ((protoeflags == prev_entry->eflags) &&
((cow & MAP_NOFAULT) ||
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)))) {
/*
* Coalesced the two objects. Can we extend the
* previous map entry to include the new range?
*/
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;
if ((cow & MAP_NOFAULT) == 0) {
prev_object = prev_entry->object.vm_object;
default_pager_convert_to_swapq(prev_object);
}
return (KERN_SUCCESS);
}
else {
object = prev_entry->object.vm_object;
offset = prev_entry->offset + (prev_entry->end -
prev_entry->start);
vm_object_reference(object);
}
}
}
/*
* 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;
if (map->is_main_map) {
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;
default_pager_convert_to_swapq(object);
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)
register vm_map_t map;
register vm_offset_t start;
vm_size_t length;
vm_offset_t *addr;
{
register vm_map_entry_t entry, next;
register vm_offset_t end;
if (start < map->min_offset)
start = map->min_offset;
if (start > map->max_offset)
return (1);
/*
* Look for the first possible address; if there's already something
* at this address, we have to start after it.
*/
if (start == map->min_offset) {
if ((entry = map->first_free) != &map->header)
start = entry->end;
} else {
vm_map_entry_t tmp;
if (vm_map_lookup_entry(map, start, &tmp))
start = tmp->end;
entry = tmp;
}
/*
* Look through the rest of the map, trying to fit a new region in the
* gap between existing regions, or after the very last region.
*/
for (;; start = (entry = next)->end) {
/*
* Find the end of the proposed new region. Be sure we didn't
* go beyond the end of the map, or wrap around the address;
* if so, we lose. Otherwise, if this is the last entry, or
* if the proposed new region fits before the next entry, we
* win.
*/
end = start + length;
if (end > map->max_offset || end < start)
return (1);
next = entry->next;
if (next == &map->header || next->start >= end)
break;
}
SAVE_HINT(map, entry);
*addr = start;
if (map == kernel_map && round_page(start + length) > kernel_vm_end)
pmap_growkernel(round_page(start + length));
return (0);
}
/*
* vm_map_find finds an unallocated region in the target address
* map with the given length. The search is defined to be
* first-fit from the specified address; the region found is
* returned in the same parameter.
*
*/
int
vm_map_find(map, object, offset, addr, length, find_space, prot, max, cow)
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, max;
int cow;
{
register vm_offset_t start;
int result, s = 0;
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.
*/
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;
if (entry->eflags & (MAP_ENTRY_IS_SUB_MAP|MAP_ENTRY_IS_A_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->object.vm_object->behavior == entry->object.vm_object->behavior)) &&
(!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) &&
(!next->object.vm_object || (next->object.vm_object->behavior == entry->object.vm_object->behavior)) &&
(!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)
register vm_map_t map;
register vm_map_entry_t entry;
register vm_offset_t start;
{
register 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);
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_A_MAP|MAP_ENTRY_IS_SUB_MAP))
vm_map_reference(new_entry->object.share_map);
else
vm_object_reference(new_entry->object.vm_object);
}
/*
* vm_map_clip_end: [ internal use only ]
*
* Asserts that the given entry ends at or before
* the specified address; if necessary,
* it splits the entry into two.
*/
#define vm_map_clip_end(map, entry, endaddr) \
{ \
if (endaddr < entry->end) \
_vm_map_clip_end(map, entry, endaddr); \
}
/*
* This routine is called only when it is known that
* the entry must be split.
*/
static void
_vm_map_clip_end(map, entry, end)
register vm_map_t map;
register vm_map_entry_t entry;
register vm_offset_t end;
{
register vm_map_entry_t new_entry;
/*
* Create a new entry and insert it AFTER the specified entry
*/
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
new_entry->start = entry->end = end;
new_entry->offset += (end - entry->start);
vm_map_entry_link(map, entry, new_entry);
if (entry->eflags & (MAP_ENTRY_IS_A_MAP|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->eflags & (MAP_ENTRY_IS_A_MAP|MAP_ENTRY_COW)) == 0) &&
(entry->object.vm_object == NULL)) {
entry->eflags |= MAP_ENTRY_IS_SUB_MAP;
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->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)
#define max(a,b) ((a) > (b) ? (a) : (b))
if (current->eflags & MAP_ENTRY_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
}
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.
*/
void
vm_map_madvise(map, pmap, start, end, advise)
vm_map_t map;
pmap_t pmap;
vm_offset_t start, end;
int advise;
{
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;
for(current = entry;
(current != &map->header) && (current->start < end);
current = current->next) {
vm_size_t size = current->end - current->start;
if (current->eflags & (MAP_ENTRY_IS_A_MAP|MAP_ENTRY_IS_SUB_MAP)) {
continue;
}
/*
* Create an object if needed
*/
if (current->object.vm_object == NULL) {
vm_object_t object;
object = vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(size));
current->object.vm_object = object;
current->offset = 0;
}
vm_map_clip_end(map, current, end);
switch (advise) {
case MADV_NORMAL:
current->object.vm_object->behavior = OBJ_NORMAL;
break;
case MADV_SEQUENTIAL:
current->object.vm_object->behavior = OBJ_SEQUENTIAL;
break;
case MADV_RANDOM:
current->object.vm_object->behavior = OBJ_RANDOM;
break;
/*
* Right now, we could handle DONTNEED and WILLNEED with common code.
* They are mostly the same, except for the potential async reads (NYI).
*/
case MADV_FREE:
case MADV_DONTNEED:
{
vm_pindex_t pindex;
int count;
size = current->end - current->start;
pindex = OFF_TO_IDX(entry->offset);
count = OFF_TO_IDX(size);
/*
* MADV_DONTNEED removes the page from all
* pmaps, so pmap_remove is not necessary.
*/
vm_object_madvise(current->object.vm_object,
pindex, count, advise);
}
break;
case MADV_WILLNEED:
{
vm_pindex_t pindex;
int count;
size = current->end - current->start;
pindex = OFF_TO_IDX(current->offset);
count = OFF_TO_IDX(size);
vm_object_madvise(current->object.vm_object,
pindex, count, advise);
pmap_object_init_pt(pmap, current->start,
current->object.vm_object, pindex,
(count << PAGE_SHIFT), 0);
}
break;
default:
break;
}
}
vm_map_simplify_entry(map, entry);
vm_map_unlock(map);
return;
}
/*
* 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_simplify_entry(map, temp_entry);
vm_map_unlock(map);
return (KERN_SUCCESS);
}
/*
* Implement the semantics of mlock
*/
int
vm_map_user_pageable(map, start, end, new_pageable)
register vm_map_t map;
register vm_offset_t start;
register vm_offset_t end;
register boolean_t new_pageable;
{
register vm_map_entry_t entry;
vm_map_entry_t start_entry;
register vm_offset_t failed = 0;
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.
*/
vm_map_set_recursive(map);
entry = start_entry;
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);
}
entry = entry->next;
}
vm_map_simplify_entry(map, start_entry);
vm_map_clear_recursive(map);
} else {
/*
* Because of the possiblity of blocking, etc. We restart
* through the process's map entries from beginning so that
* we don't end up depending on a map entry that could have
* changed.
*/
rescan:
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_A_MAP|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,
OFF_TO_IDX(entry->end
- entry->start));
entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
} else if (entry->object.vm_object == NULL) {
entry->object.vm_object =
vm_object_allocate(OBJT_DEFAULT,
OFF_TO_IDX(entry->end - entry->start));
entry->offset = (vm_offset_t) 0;
}
default_pager_convert_to_swapq(entry->object.vm_object);
}
vm_map_clip_start(map, entry, start);
vm_map_clip_end(map, entry, end);
entry->wired_count++;
entry->eflags |= MAP_ENTRY_USER_WIRED;
/* First we need to allow map modifications */
vm_map_set_recursive(map);
if (lockmgr(&map->lock, LK_EXCLUPGRADE,
(void *)0, curproc)) {
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;
}
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);
lockmgr(&map->lock, LK_DOWNGRADE, (void *)0, curproc);
goto rescan;
}
}
vm_map_unlock(map);
return KERN_SUCCESS;
}
/*
* vm_map_pageable:
*
* Sets the pageability of the specified address
* range in the target map. Regions specified
* as not pageable require locked-down physical
* memory and physical page maps.
*
* The map must not be locked, but a reference
* must remain to the map throughout the call.
*/
int
vm_map_pageable(map, start, end, new_pageable)
register vm_map_t map;
register vm_offset_t start;
register vm_offset_t end;
register boolean_t new_pageable;
{
register vm_map_entry_t entry;
vm_map_entry_t start_entry;
register vm_offset_t failed = 0;
int rv;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
/*
* Only one pageability change may take place at one time, since
* vm_fault assumes it will be called only once for each
* wiring/unwiring. Therefore, we have to make sure we're actually
* changing the pageability for the entire region. We do so before
* making any changes.
*/
if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
entry = start_entry;
/*
* Actions are rather different for wiring and unwiring, so we have
* two separate cases.
*/
if (new_pageable) {
vm_map_clip_start(map, entry, start);
/*
* Unwiring. First ensure that the range to be unwired is
* really wired down and that there are no holes.
*/
while ((entry != &map->header) && (entry->start < end)) {
if (entry->wired_count == 0 ||
(entry->end < end &&
(entry->next == &map->header ||
entry->next->start > entry->end))) {
vm_map_unlock(map);
return (KERN_INVALID_ARGUMENT);
}
entry = entry->next;
}
/*
* Now decrement the wiring count for each region. If a region
* becomes completely unwired, unwire its physical pages and
* mappings.
*/
vm_map_set_recursive(map);
entry = start_entry;
while ((entry != &map->header) && (entry->start < end)) {
vm_map_clip_end(map, entry, end);
entry->wired_count--;
if (entry->wired_count == 0)
vm_fault_unwire(map, entry->start, entry->end);
entry = entry->next;
}
vm_map_simplify_entry(map, start_entry);
vm_map_clear_recursive(map);
} 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 sharing maps, because we won't
* hold the lock on the sharing map.
*/
if ((entry->eflags & (MAP_ENTRY_IS_A_MAP|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,
OFF_TO_IDX(entry->end
- entry->start));
entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
} else if (entry->object.vm_object == NULL) {
entry->object.vm_object =
vm_object_allocate(OBJT_DEFAULT,
OFF_TO_IDX(entry->end - entry->start));
entry->offset = (vm_offset_t) 0;
}
default_pager_convert_to_swapq(entry->object.vm_object);
}
}
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_set_recursive(map);
lockmgr(&map->lock, LK_DOWNGRADE, (void*)0, curproc);
}
rv = 0;
entry = start_entry;
while (entry != &map->header && entry->start < end) {
/*
* If vm_fault_wire fails for any page we need to undo
* what has been done. We decrement the wiring count
* for those pages which have not yet been wired (now)
* and unwire those that have (later).
*
* XXX this violates the locking protocol on the map,
* needs to be fixed.
*/
if (rv)
entry->wired_count--;
else if (entry->wired_count == 1) {
rv = vm_fault_wire(map, entry->start, entry->end);
if (rv) {
failed = entry->start;
entry->wired_count--;
}
}
entry = entry->next;
}
if (vm_map_pmap(map) == kernel_pmap) {
vm_map_lock(map);
} else {
vm_map_clear_recursive(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;
{
register vm_map_entry_t current;
vm_map_entry_t entry;
vm_size_t size;
vm_object_t object;
vm_ooffset_t offset;
vm_map_lock_read(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &entry)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
}
/*
* Make a first pass to check for holes.
*/
for (current = entry; current->start < end; current = current->next) {
if (current->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);
}
}
/*
* 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_A_MAP|MAP_ENTRY_IS_SUB_MAP)) {
register vm_map_t smap;
vm_map_entry_t tentry;
vm_size_t tsize;
smap = current->object.share_map;
vm_map_lock_read(smap);
(void) vm_map_lookup_entry(smap, offset, &tentry);
tsize = tentry->end - offset;
if (tsize < size)
size = tsize;
object = tentry->object.vm_object;
offset = tentry->offset + (offset - tentry->start);
vm_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 (invalidate)
pmap_remove(vm_map_pmap(map), current->start,
current->start + size);
if (object && (object->type == OBJT_VNODE)) {
/*
* Flush pages if writing is allowed. XXX should we continue
* on an error?
*
* XXX Doing async I/O and then removing all the pages from
* the object before it completes is probably a very bad
* idea.
*/
if (current->protection & VM_PROT_WRITE) {
vm_object_page_clean(object,
OFF_TO_IDX(offset),
OFF_TO_IDX(offset + size),
(syncio||invalidate)?1:0, TRUE);
if (invalidate)
vm_object_page_remove(object,
OFF_TO_IDX(offset),
OFF_TO_IDX(offset + size),
FALSE);
}
}
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;
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.
*/
static void
vm_map_entry_delete(map, entry)
register vm_map_t map;
register vm_map_entry_t entry;
{
vm_map_entry_unlink(map, entry);
map->size -= entry->end - entry->start;
if (entry->eflags & (MAP_ENTRY_IS_A_MAP|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 (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_object_t object;
vm_ooffset_t offset;
vm_map_clip_end(map, entry, end);
next = entry->next;
s = entry->start;
e = entry->end;
offset = entry->offset;
/*
* 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, OFF_TO_IDX(offset),
OFF_TO_IDX(offset + (e - s)), FALSE);
} else if (!map->is_main_map) {
vm_object_pmap_remove(object,
OFF_TO_IDX(offset),
OFF_TO_IDX(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, s = 0;
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(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.
*/
static 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;
{
if ((dst_entry->eflags|src_entry->eflags) &
(MAP_ENTRY_IS_A_MAP|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) {
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)) {
su = (src_map->ref_count == 1);
}
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,
OFF_TO_IDX(src_entry->offset),
OFF_TO_IDX(src_entry->offset + (src_entry->end
- src_entry->start)));
}
}
/*
* Make a copy of the object.
*/
if (src_entry->object.vm_object) {
if ((src_entry->object.vm_object->handle == NULL) &&
(src_entry->object.vm_object->type == OBJT_DEFAULT ||
src_entry->object.vm_object->type == OBJT_SWAP))
vm_object_collapse(src_entry->object.vm_object);
++src_entry->object.vm_object->ref_count;
src_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY);
dst_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY);
dst_entry->object.vm_object =
src_entry->object.vm_object;
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)
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_object_t object;
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->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,
OFF_TO_IDX(old_entry->end -
old_entry->start));
old_entry->object.vm_object = object;
old_entry->offset = (vm_offset_t) 0;
} else if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) {
vm_object_shadow(&old_entry->object.vm_object,
&old_entry->offset,
OFF_TO_IDX(old_entry->end -
old_entry->start));
old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
object = old_entry->object.vm_object;
}
/*
* Clone the entry, referencing the sharing map.
*/
new_entry = vm_map_entry_create(new_map);
*new_entry = *old_entry;
new_entry->wired_count = 0;
++object->ref_count;
/*
* 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->eflags &= ~MAP_ENTRY_IS_A_MAP;
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;
vm_map_unlock(old_map);
return (vm2);
}
/*
* 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;
newvmspace = vmspace_alloc(map->min_offset, map->max_offset,
map->entries_pageable);
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.
*/
vm_map_reference(&oldvmspace->vm_map);
vmspace_free(oldvmspace);
p->p_vmspace = newvmspace;
if (p == curproc)
pmap_activate(p);
vm_map_deallocate(&oldvmspace->vm_map);
}
/*
* 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;
if (oldvmspace->vm_refcnt == 1)
return;
newvmspace = vmspace_fork(oldvmspace);
vm_map_reference(&oldvmspace->vm_map);
vmspace_free(oldvmspace);
p->p_vmspace = newvmspace;
if (p == curproc)
pmap_activate(p);
vm_map_deallocate(&oldvmspace->vm_map);
}
/*
* vm_map_lookup:
*
* Finds the VM object, offset, and
* protection for a given virtual address in the
* specified map, assuming a page fault of the
* type specified.
*
* Leaves the map in question locked for read; return
* values are guaranteed until a vm_map_lookup_done
* call is performed. Note that the map argument
* is in/out; the returned map must be used in
* the call to vm_map_lookup_done.
*
* A handle (out_entry) is returned for use in
* vm_map_lookup_done, to make that fast.
*
* If a lookup is requested with "write protection"
* specified, the map may be changed to perform virtual
* copying operations, although the data referenced will
* remain the same.
*/
int
vm_map_lookup(var_map, vaddr, fault_type, out_entry,
object, pindex, 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_pindex_t *pindex; /* 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.
*/
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.
*/
prot = entry->protection;
if ((fault_type & VM_PROT_OVERRIDE_WRITE) == 0 ||
(entry->eflags & MAP_ENTRY_COW) == 0 ||
(entry->wired_count != 0)) {
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.
*/
*wired = (entry->wired_count != 0);
if (*wired)
prot = fault_type = entry->protection;
/*
* If we don't already have a VM object, track it down.
*/
su = (entry->eflags & MAP_ENTRY_IS_A_MAP) == 0;
if (su) {
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->eflags & MAP_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 (lockmgr(&share_map->lock, LK_EXCLUPGRADE,
(void *)0, curproc)) {
if (share_map != map)
vm_map_unlock_read(map);
goto RetryLookup;
}
vm_object_shadow(
&entry->object.vm_object,
&entry->offset,
OFF_TO_IDX(entry->end - entry->start));
entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
lockmgr(&share_map->lock, LK_DOWNGRADE,
(void *)0, curproc);
} 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 (lockmgr(&share_map->lock, LK_EXCLUPGRADE,
(void *)0, curproc)) {
if (share_map != map)
vm_map_unlock_read(map);
goto RetryLookup;
}
entry->object.vm_object = vm_object_allocate(OBJT_DEFAULT,
OFF_TO_IDX(entry->end - entry->start));
entry->offset = 0;
lockmgr(&share_map->lock, LK_DOWNGRADE, (void *)0, curproc);
}
if (entry->object.vm_object != NULL)
default_pager_convert_to_swapq(entry->object.vm_object);
/*
* 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((share_offset - entry->start) + entry->offset);
*object = entry->object.vm_object;
/*
* Return whether this is the only map sharing this data.
*/
if (!su) {
su = (share_map->ref_count == 1);
}
*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->eflags & MAP_ENTRY_IS_A_MAP)
vm_map_unlock_read(entry->object.share_map);
/*
* Unlock the main-level map
*/
vm_map_unlock_read(map);
}
#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)
{
/* XXX convert args. */
register vm_map_t map = (vm_map_t)addr;
boolean_t full = have_addr;
register vm_map_entry_t entry;
db_iprintf("%s map 0x%x: pmap=0x%x,ref=%d,nentries=%d,version=%d\n",
(map->is_main_map ? "Task" : "Share"),
(int) map, (int) (map->pmap), map->ref_count, map->nentries,
map->timestamp);
if (!full && db_indent)
return;
db_indent += 2;
for (entry = map->header.next; entry != &map->header;
entry = entry->next) {
db_iprintf("map entry 0x%x: start=0x%x, end=0x%x, ",
(int) entry, (int) entry->start, (int) entry->end);
if (map->is_main_map) {
static char *inheritance_name[4] =
{"share", "copy", "none", "donate_copy"};
db_printf("prot=%x/%x/%s, ",
entry->protection,
entry->max_protection,
inheritance_name[entry->inheritance]);
if (entry->wired_count != 0)
db_printf("wired, ");
}
if (entry->eflags & (MAP_ENTRY_IS_A_MAP|MAP_ENTRY_IS_SUB_MAP)) {
db_printf("share=0x%x, offset=0x%x\n",
(int) entry->object.share_map,
(int) entry->offset);
if ((entry->prev == &map->header) ||
((entry->prev->eflags & MAP_ENTRY_IS_A_MAP) == 0) ||
(entry->prev->object.share_map !=
entry->object.share_map)) {
db_indent += 2;
vm_map_print((int)entry->object.share_map,
full, 0, (char *)0);
db_indent -= 2;
}
} else {
db_printf("object=0x%x, offset=0x%x",
(int) entry->object.vm_object,
(int) entry->offset);
if (entry->eflags & MAP_ENTRY_COW)
db_printf(", copy (%s)",
(entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done");
db_printf("\n");
if ((entry->prev == &map->header) ||
(entry->prev->eflags & MAP_ENTRY_IS_A_MAP) ||
(entry->prev->object.vm_object !=
entry->object.vm_object)) {
db_indent += 2;
vm_object_print((int)entry->object.vm_object,
full, 0, (char *)0);
db_indent -= 2;
}
}
}
db_indent -= 2;
}
#endif /* DDB */
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