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freebsd-src/sys/vm/vm_map.c
Bosko Milekic 08442f8a82 Introduce numerous SMP friendly changes to the mbuf allocator. Namely, 
introduce a modified allocation mechanism for mbufs and mbuf clusters; one
which can scale under SMP and which offers the possibility of resource
reclamation to be implemented in the future. Notable advantages:

 o Reduce contention for SMP by offering per-CPU pools and locks.
 o Better use of data cache due to per-CPU pools.
 o Much less code cache pollution due to excessively large allocation macros.
 o Framework for `grouping' objects from same page together so as to be able
   to possibly free wired-down pages back to the system if they are no longer
   needed by the network stacks.

 Additional things changed with this addition:

  - Moved some mbuf specific declarations and initializations from
    sys/conf/param.c into mbuf-specific code where they belong.
  - m_getclr() has been renamed to m_get_clrd() because the old name is really
    confusing. m_getclr() HAS been preserved though and is defined to the new
    name. No tree sweep has been done "to change the interface," as the old
    name will continue to be supported and is not depracated. The change was
    merely done because m_getclr() sounds too much like "m_get a cluster."
  - TEMPORARILY disabled mbtypes statistics displaying in netstat(1) and
    systat(1) (see TODO below).
  - Fixed systat(1) to display number of "free mbufs" based on new per-CPU
    stat structures.
  - Fixed netstat(1) to display new per-CPU stats based on sysctl-exported
    per-CPU stat structures. All infos are fetched via sysctl.

 TODO (in order of priority):

  - Re-enable mbtypes statistics in both netstat(1) and systat(1) after
    introducing an SMP friendly way to collect the mbtypes stats under the
    already introduced per-CPU locks (i.e. hopefully don't use atomic() - it
    seems too costly for a mere stat update, especially when other locks are
    already present).
  - Optionally have systat(1) display not only "total free mbufs" but also
    "total free mbufs per CPU pool."
  - Fix minor length-fetching issues in netstat(1) related to recently
    re-enabled option to read mbuf stats from a core file.
  - Move reference counters at least for mbuf clusters into an unused portion
    of the cluster itself, to save space and need to allocate a counter.
  - Look into introducing resource freeing possibly from a kproc.

Reviewed by (in parts): jlemon, jake, silby, terry
Tested by: jlemon (Intel & Alpha), mjacob (Intel & Alpha)
Preliminary performance measurements: jlemon (and me, obviously)
URL: http://people.freebsd.org/~bmilekic/mb_alloc/
2001-06-22 06:35:32 +00:00

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