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freebsd/sys/vm/vm_map.c
Alan Cox 13458803f4 Give vm_fault()'s sequential access optimization a makeover. 
There are two aspects to the sequential access optimization: (1) read ahead
of pages that are expected to be accessed in the near future and (2) unmap
and cache behind of pages that are not expected to be accessed again.  This
revision changes both aspects.

The read ahead optimization is now more effective.  It starts with the same
initial read window as before, but arithmetically grows the window on
sequential page faults.  This can yield increased read bandwidth.  For
example, on one of my machines, a program using mmap() to read a file that
is several times larger than the machine's physical memory takes about 17%
less time to complete.

The unmap and cache behind optimization is now more selectively applied.
The read ahead window must grow to its maximum size before unmap and cache
behind is performed.  This significantly reduces the number of times that
pages are unmapped and cached only to be reactivated a short time later.

The unmap and cache behind optimization now clears each page's referenced
flag.  Previously, in the case of dirty pages, if the containing file was
still mapped at the time that the page daemon examined the dirty pages,
they would be reactivated.

From a stylistic standpoint, this revision also cleanly separates the
implementation of the read ahead and unmap/cache behind optimizations.

Glanced at:	kib
MFC after:	2 weeks
2012-05-10 15:16:42 +00:00

4075 lines
107 KiB
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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.
* 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.
*/
/*
* Virtual memory mapping module.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/ktr.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/racct.h>
#include <sys/resourcevar.h>
#include <sys/file.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/shm.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/vnode_pager.h>
#include <vm/swap_pager.h>
#include <vm/uma.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 self-adjusting binary search tree of these
* entries 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.
*/
static struct mtx map_sleep_mtx;
static uma_zone_t mapentzone;
static uma_zone_t kmapentzone;
static uma_zone_t mapzone;
static uma_zone_t vmspace_zone;
static struct vm_object kmapentobj;
static int vmspace_zinit(void *mem, int size, int flags);
static void vmspace_zfini(void *mem, int size);
static int vm_map_zinit(void *mem, int ize, int flags);
static void vm_map_zfini(void *mem, int size);
static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min,
vm_offset_t max);
static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map);
static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry);
#ifdef INVARIANTS
static void vm_map_zdtor(void *mem, int size, void *arg);
static void vmspace_zdtor(void *mem, int size, void *arg);
#endif
#define ENTRY_CHARGED(e) ((e)->cred != NULL || \
((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \
!((e)->eflags & MAP_ENTRY_NEEDS_COPY)))
/*
* PROC_VMSPACE_{UN,}LOCK() can be a noop as long as vmspaces are type
* stable.
*/
#define PROC_VMSPACE_LOCK(p) do { } while (0)
#define PROC_VMSPACE_UNLOCK(p) do { } while (0)
/*
* 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_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.
*/
void
vm_map_startup(void)
{
mtx_init(&map_sleep_mtx, "vm map sleep mutex", NULL, MTX_DEF);
mapzone = uma_zcreate("MAP", sizeof(struct vm_map), NULL,
#ifdef INVARIANTS
vm_map_zdtor,
#else
NULL,
#endif
vm_map_zinit, vm_map_zfini, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
uma_prealloc(mapzone, MAX_KMAP);
kmapentzone = uma_zcreate("KMAP ENTRY", sizeof(struct vm_map_entry),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
UMA_ZONE_MTXCLASS | UMA_ZONE_VM);
uma_prealloc(kmapentzone, MAX_KMAPENT);
mapentzone = uma_zcreate("MAP ENTRY", sizeof(struct vm_map_entry),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
}
static void
vmspace_zfini(void *mem, int size)
{
struct vmspace *vm;
vm = (struct vmspace *)mem;
vm_map_zfini(&vm->vm_map, sizeof(vm->vm_map));
}
static int
vmspace_zinit(void *mem, int size, int flags)
{
struct vmspace *vm;
vm = (struct vmspace *)mem;
vm->vm_map.pmap = NULL;
(void)vm_map_zinit(&vm->vm_map, sizeof(vm->vm_map), flags);
return (0);
}
static void
vm_map_zfini(void *mem, int size)
{
vm_map_t map;
map = (vm_map_t)mem;
mtx_destroy(&map->system_mtx);
sx_destroy(&map->lock);
}
static int
vm_map_zinit(void *mem, int size, int flags)
{
vm_map_t map;
map = (vm_map_t)mem;
map->nentries = 0;
map->size = 0;
mtx_init(&map->system_mtx, "system map", NULL, MTX_DEF | MTX_DUPOK);
sx_init(&map->lock, "user map");
return (0);
}
#ifdef INVARIANTS
static void
vmspace_zdtor(void *mem, int size, void *arg)
{
struct vmspace *vm;
vm = (struct vmspace *)mem;
vm_map_zdtor(&vm->vm_map, sizeof(vm->vm_map), arg);
}
static void
vm_map_zdtor(void *mem, int size, void *arg)
{
vm_map_t map;
map = (vm_map_t)mem;
KASSERT(map->nentries == 0,
("map %p nentries == %d on free.",
map, map->nentries));
KASSERT(map->size == 0,
("map %p size == %lu on free.",
map, (unsigned long)map->size));
}
#endif /* INVARIANTS */
/*
* Allocate a vmspace structure, including a vm_map and pmap,
* and initialize those structures. The refcnt is set to 1.
*/
struct vmspace *
vmspace_alloc(min, max)
vm_offset_t min, max;
{
struct vmspace *vm;
vm = uma_zalloc(vmspace_zone, M_WAITOK);
if (vm->vm_map.pmap == NULL && !pmap_pinit(vmspace_pmap(vm))) {
uma_zfree(vmspace_zone, vm);
return (NULL);
}
CTR1(KTR_VM, "vmspace_alloc: %p", vm);
_vm_map_init(&vm->vm_map, vmspace_pmap(vm), min, max);
vm->vm_refcnt = 1;
vm->vm_shm = NULL;
vm->vm_swrss = 0;
vm->vm_tsize = 0;
vm->vm_dsize = 0;
vm->vm_ssize = 0;
vm->vm_taddr = 0;
vm->vm_daddr = 0;
vm->vm_maxsaddr = 0;
return (vm);
}
void
vm_init2(void)
{
uma_zone_set_obj(kmapentzone, &kmapentobj, lmin(cnt.v_page_count,
(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / PAGE_SIZE) / 8 +
maxproc * 2 + maxfiles);
vmspace_zone = uma_zcreate("VMSPACE", sizeof(struct vmspace), NULL,
#ifdef INVARIANTS
vmspace_zdtor,
#else
NULL,
#endif
vmspace_zinit, vmspace_zfini, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
}
static void
vmspace_container_reset(struct proc *p)
{
#ifdef RACCT
PROC_LOCK(p);
racct_set(p, RACCT_DATA, 0);
racct_set(p, RACCT_STACK, 0);
racct_set(p, RACCT_RSS, 0);
racct_set(p, RACCT_MEMLOCK, 0);
racct_set(p, RACCT_VMEM, 0);
PROC_UNLOCK(p);
#endif
}
static inline void
vmspace_dofree(struct vmspace *vm)
{
CTR1(KTR_VM, "vmspace_free: %p", vm);
/*
* Make sure any SysV shm is freed, it might not have been in
* exit1().
*/
shmexit(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.
*/
(void)vm_map_remove(&vm->vm_map, vm->vm_map.min_offset,
vm->vm_map.max_offset);
pmap_release(vmspace_pmap(vm));
vm->vm_map.pmap = NULL;
uma_zfree(vmspace_zone, vm);
}
void
vmspace_free(struct vmspace *vm)
{
if (vm->vm_refcnt == 0)
panic("vmspace_free: attempt to free already freed vmspace");
if (atomic_fetchadd_int(&vm->vm_refcnt, -1) == 1)
vmspace_dofree(vm);
}
void
vmspace_exitfree(struct proc *p)
{
struct vmspace *vm;
PROC_VMSPACE_LOCK(p);
vm = p->p_vmspace;
p->p_vmspace = NULL;
PROC_VMSPACE_UNLOCK(p);
KASSERT(vm == &vmspace0, ("vmspace_exitfree: wrong vmspace"));
vmspace_free(vm);
}
void
vmspace_exit(struct thread *td)
{
int refcnt;
struct vmspace *vm;
struct proc *p;
/*
* Release user portion of address space.
* This releases references to vnodes,
* which could cause I/O if the file has been unlinked.
* Need to do this early enough that we can still sleep.
*
* The last exiting process to reach this point releases as
* much of the environment as it can. vmspace_dofree() is the
* slower fallback in case another process had a temporary
* reference to the vmspace.
*/
p = td->td_proc;
vm = p->p_vmspace;
atomic_add_int(&vmspace0.vm_refcnt, 1);
do {
refcnt = vm->vm_refcnt;
if (refcnt > 1 && p->p_vmspace != &vmspace0) {
/* Switch now since other proc might free vmspace */
PROC_VMSPACE_LOCK(p);
p->p_vmspace = &vmspace0;
PROC_VMSPACE_UNLOCK(p);
pmap_activate(td);
}
} while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1));
if (refcnt == 1) {
if (p->p_vmspace != vm) {
/* vmspace not yet freed, switch back */
PROC_VMSPACE_LOCK(p);
p->p_vmspace = vm;
PROC_VMSPACE_UNLOCK(p);
pmap_activate(td);
}
pmap_remove_pages(vmspace_pmap(vm));
/* Switch now since this proc will free vmspace */
PROC_VMSPACE_LOCK(p);
p->p_vmspace = &vmspace0;
PROC_VMSPACE_UNLOCK(p);
pmap_activate(td);
vmspace_dofree(vm);
}
vmspace_container_reset(p);
}
/* Acquire reference to vmspace owned by another process. */
struct vmspace *
vmspace_acquire_ref(struct proc *p)
{
struct vmspace *vm;
int refcnt;
PROC_VMSPACE_LOCK(p);
vm = p->p_vmspace;
if (vm == NULL) {
PROC_VMSPACE_UNLOCK(p);
return (NULL);
}
do {
refcnt = vm->vm_refcnt;
if (refcnt <= 0) { /* Avoid 0->1 transition */
PROC_VMSPACE_UNLOCK(p);
return (NULL);
}
} while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt + 1));
if (vm != p->p_vmspace) {
PROC_VMSPACE_UNLOCK(p);
vmspace_free(vm);
return (NULL);
}
PROC_VMSPACE_UNLOCK(p);
return (vm);
}
void
_vm_map_lock(vm_map_t map, const char *file, int line)
{
if (map->system_map)
mtx_lock_flags_(&map->system_mtx, 0, file, line);
else
sx_xlock_(&map->lock, file, line);
map->timestamp++;
}
static void
vm_map_process_deferred(void)
{
struct thread *td;
vm_map_entry_t entry;
vm_object_t object;
td = curthread;
while ((entry = td->td_map_def_user) != NULL) {
td->td_map_def_user = entry->next;
if ((entry->eflags & MAP_ENTRY_VN_WRITECNT) != 0) {
/*
* Decrement the object's writemappings and
* possibly the vnode's v_writecount.
*/
KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
("Submap with writecount"));
object = entry->object.vm_object;
KASSERT(object != NULL, ("No object for writecount"));
vnode_pager_release_writecount(object, entry->start,
entry->end);
}
vm_map_entry_deallocate(entry, FALSE);
}
}
void
_vm_map_unlock(vm_map_t map, const char *file, int line)
{
if (map->system_map)
mtx_unlock_flags_(&map->system_mtx, 0, file, line);
else {
sx_xunlock_(&map->lock, file, line);
vm_map_process_deferred();
}
}
void
_vm_map_lock_read(vm_map_t map, const char *file, int line)
{
if (map->system_map)
mtx_lock_flags_(&map->system_mtx, 0, file, line);
else
sx_slock_(&map->lock, file, line);
}
void
_vm_map_unlock_read(vm_map_t map, const char *file, int line)
{
if (map->system_map)
mtx_unlock_flags_(&map->system_mtx, 0, file, line);
else {
sx_sunlock_(&map->lock, file, line);
vm_map_process_deferred();
}
}
int
_vm_map_trylock(vm_map_t map, const char *file, int line)
{
int error;
error = map->system_map ?
!mtx_trylock_flags_(&map->system_mtx, 0, file, line) :
!sx_try_xlock_(&map->lock, file, line);
if (error == 0)
map->timestamp++;
return (error == 0);
}
int
_vm_map_trylock_read(vm_map_t map, const char *file, int line)
{
int error;
error = map->system_map ?
!mtx_trylock_flags_(&map->system_mtx, 0, file, line) :
!sx_try_slock_(&map->lock, file, line);
return (error == 0);
}
/*
* _vm_map_lock_upgrade: [ internal use only ]
*
* Tries to upgrade a read (shared) lock on the specified map to a write
* (exclusive) lock. Returns the value "0" if the upgrade succeeds and a
* non-zero value if the upgrade fails. If the upgrade fails, the map is
* returned without a read or write lock held.
*
* Requires that the map be read locked.
*/
int
_vm_map_lock_upgrade(vm_map_t map, const char *file, int line)
{
unsigned int last_timestamp;
if (map->system_map) {
mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
} else {
if (!sx_try_upgrade_(&map->lock, file, line)) {
last_timestamp = map->timestamp;
sx_sunlock_(&map->lock, file, line);
vm_map_process_deferred();
/*
* If the map's timestamp does not change while the
* map is unlocked, then the upgrade succeeds.
*/
sx_xlock_(&map->lock, file, line);
if (last_timestamp != map->timestamp) {
sx_xunlock_(&map->lock, file, line);
return (1);
}
}
}
map->timestamp++;
return (0);
}
void
_vm_map_lock_downgrade(vm_map_t map, const char *file, int line)
{
if (map->system_map) {
mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
} else
sx_downgrade_(&map->lock, file, line);
}
/*
* vm_map_locked:
*
* Returns a non-zero value if the caller holds a write (exclusive) lock
* on the specified map and the value "0" otherwise.
*/
int
vm_map_locked(vm_map_t map)
{
if (map->system_map)
return (mtx_owned(&map->system_mtx));
else
return (sx_xlocked(&map->lock));
}
#ifdef INVARIANTS
static void
_vm_map_assert_locked(vm_map_t map, const char *file, int line)
{
if (map->system_map)
mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
else
sx_assert_(&map->lock, SA_XLOCKED, file, line);
}
#define VM_MAP_ASSERT_LOCKED(map) \
_vm_map_assert_locked(map, LOCK_FILE, LOCK_LINE)
#else
#define VM_MAP_ASSERT_LOCKED(map)
#endif
/*
* _vm_map_unlock_and_wait:
*
* Atomically releases the lock on the specified map and puts the calling
* thread to sleep. The calling thread will remain asleep until either
* vm_map_wakeup() is performed on the map or the specified timeout is
* exceeded.
*
* WARNING! This function does not perform deferred deallocations of
* objects and map entries. Therefore, the calling thread is expected to
* reacquire the map lock after reawakening and later perform an ordinary
* unlock operation, such as vm_map_unlock(), before completing its
* operation on the map.
*/
int
_vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line)
{
mtx_lock(&map_sleep_mtx);
if (map->system_map)
mtx_unlock_flags_(&map->system_mtx, 0, file, line);
else
sx_xunlock_(&map->lock, file, line);
return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps",
timo));
}
/*
* vm_map_wakeup:
*
* Awaken any threads that have slept on the map using
* vm_map_unlock_and_wait().
*/
void
vm_map_wakeup(vm_map_t map)
{
/*
* Acquire and release map_sleep_mtx to prevent a wakeup()
* from being performed (and lost) between the map unlock
* and the msleep() in _vm_map_unlock_and_wait().
*/
mtx_lock(&map_sleep_mtx);
mtx_unlock(&map_sleep_mtx);
wakeup(&map->root);
}
void
vm_map_busy(vm_map_t map)
{
VM_MAP_ASSERT_LOCKED(map);
map->busy++;
}
void
vm_map_unbusy(vm_map_t map)
{
VM_MAP_ASSERT_LOCKED(map);
KASSERT(map->busy, ("vm_map_unbusy: not busy"));
if (--map->busy == 0 && (map->flags & MAP_BUSY_WAKEUP)) {
vm_map_modflags(map, 0, MAP_BUSY_WAKEUP);
wakeup(&map->busy);
}
}
void
vm_map_wait_busy(vm_map_t map)
{
VM_MAP_ASSERT_LOCKED(map);
while (map->busy) {
vm_map_modflags(map, MAP_BUSY_WAKEUP, 0);
if (map->system_map)
msleep(&map->busy, &map->system_mtx, 0, "mbusy", 0);
else
sx_sleep(&map->busy, &map->lock, 0, "mbusy", 0);
}
map->timestamp++;
}
long
vmspace_resident_count(struct vmspace *vmspace)
{
return pmap_resident_count(vmspace_pmap(vmspace));
}
long
vmspace_wired_count(struct vmspace *vmspace)
{
return pmap_wired_count(vmspace_pmap(vmspace));
}
/*
* 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_t pmap, vm_offset_t min, vm_offset_t max)
{
vm_map_t result;
result = uma_zalloc(mapzone, M_WAITOK);
CTR1(KTR_VM, "vm_map_create: %p", result);
_vm_map_init(result, pmap, min, max);
return (result);
}
/*
* Initialize an existing vm_map structure
* such as that in the vmspace structure.
*/
static void
_vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max)
{
map->header.next = map->header.prev = &map->header;
map->needs_wakeup = FALSE;
map->system_map = 0;
map->pmap = pmap;
map->min_offset = min;
map->max_offset = max;
map->flags = 0;
map->root = NULL;
map->timestamp = 0;
map->busy = 0;
}
void
vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max)
{
_vm_map_init(map, pmap, min, max);
mtx_init(&map->system_mtx, "system map", NULL, MTX_DEF | MTX_DUPOK);
sx_init(&map->lock, "user map");
}
/*
* vm_map_entry_dispose: [ internal use only ]
*
* Inverse of vm_map_entry_create.
*/
static void
vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry)
{
uma_zfree(map->system_map ? 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(vm_map_t map)
{
vm_map_entry_t new_entry;
if (map->system_map)
new_entry = uma_zalloc(kmapentzone, M_NOWAIT);
else
new_entry = uma_zalloc(mapentzone, M_WAITOK);
if (new_entry == NULL)
panic("vm_map_entry_create: kernel resources exhausted");
return (new_entry);
}
/*
* vm_map_entry_set_behavior:
*
* Set the expected access behavior, either normal, random, or
* sequential.
*/
static inline void
vm_map_entry_set_behavior(vm_map_entry_t entry, u_char behavior)
{
entry->eflags = (entry->eflags & ~MAP_ENTRY_BEHAV_MASK) |
(behavior & MAP_ENTRY_BEHAV_MASK);
}
/*
* vm_map_entry_set_max_free:
*
* Set the max_free field in a vm_map_entry.
*/
static inline void
vm_map_entry_set_max_free(vm_map_entry_t entry)
{
entry->max_free = entry->adj_free;
if (entry->left != NULL && entry->left->max_free > entry->max_free)
entry->max_free = entry->left->max_free;
if (entry->right != NULL && entry->right->max_free > entry->max_free)
entry->max_free = entry->right->max_free;
}
/*
* vm_map_entry_splay:
*
* The Sleator and Tarjan top-down splay algorithm with the
* following variation. Max_free must be computed bottom-up, so
* on the downward pass, maintain the left and right spines in
* reverse order. Then, make a second pass up each side to fix
* the pointers and compute max_free. The time bound is O(log n)
* amortized.
*
* The new root is the vm_map_entry containing "addr", or else an
* adjacent entry (lower or higher) if addr is not in the tree.
*
* The map must be locked, and leaves it so.
*
* Returns: the new root.
*/
static vm_map_entry_t
vm_map_entry_splay(vm_offset_t addr, vm_map_entry_t root)
{
vm_map_entry_t llist, rlist;
vm_map_entry_t ltree, rtree;
vm_map_entry_t y;
/* Special case of empty tree. */
if (root == NULL)
return (root);
/*
* Pass One: Splay down the tree until we find addr or a NULL
* pointer where addr would go. llist and rlist are the two
* sides in reverse order (bottom-up), with llist linked by
* the right pointer and rlist linked by the left pointer in
* the vm_map_entry. Wait until Pass Two to set max_free on
* the two spines.
*/
llist = NULL;
rlist = NULL;
for (;;) {
/* root is never NULL in here. */
if (addr < root->start) {
y = root->left;
if (y == NULL)
break;
if (addr < y->start && y->left != NULL) {
/* Rotate right and put y on rlist. */
root->left = y->right;
y->right = root;
vm_map_entry_set_max_free(root);
root = y->left;
y->left = rlist;
rlist = y;
} else {
/* Put root on rlist. */
root->left = rlist;
rlist = root;
root = y;
}
} else if (addr >= root->end) {
y = root->right;
if (y == NULL)
break;
if (addr >= y->end && y->right != NULL) {
/* Rotate left and put y on llist. */
root->right = y->left;
y->left = root;
vm_map_entry_set_max_free(root);
root = y->right;
y->right = llist;
llist = y;
} else {
/* Put root on llist. */
root->right = llist;
llist = root;
root = y;
}
} else
break;
}
/*
* Pass Two: Walk back up the two spines, flip the pointers
* and set max_free. The subtrees of the root go at the
* bottom of llist and rlist.
*/
ltree = root->left;
while (llist != NULL) {
y = llist->right;
llist->right = ltree;
vm_map_entry_set_max_free(llist);
ltree = llist;
llist = y;
}
rtree = root->right;
while (rlist != NULL) {
y = rlist->left;
rlist->left = rtree;
vm_map_entry_set_max_free(rlist);
rtree = rlist;
rlist = y;
}
/*
* Final assembly: add ltree and rtree as subtrees of root.
*/
root->left = ltree;
root->right = rtree;
vm_map_entry_set_max_free(root);
return (root);
}
/*
* vm_map_entry_{un,}link:
*
* Insert/remove entries from maps.
*/
static 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);
VM_MAP_ASSERT_LOCKED(map);
map->nentries++;
entry->prev = after_where;
entry->next = after_where->next;
entry->next->prev = entry;
after_where->next = entry;
if (after_where != &map->header) {
if (after_where != map->root)
vm_map_entry_splay(after_where->start, map->root);
entry->right = after_where->right;
entry->left = after_where;
after_where->right = NULL;
after_where->adj_free = entry->start - after_where->end;
vm_map_entry_set_max_free(after_where);
} else {
entry->right = map->root;
entry->left = NULL;
}
entry->adj_free = (entry->next == &map->header ? map->max_offset :
entry->next->start) - entry->end;
vm_map_entry_set_max_free(entry);
map->root = entry;
}
static void
vm_map_entry_unlink(vm_map_t map,
vm_map_entry_t entry)
{
vm_map_entry_t next, prev, root;
VM_MAP_ASSERT_LOCKED(map);
if (entry != map->root)
vm_map_entry_splay(entry->start, map->root);
if (entry->left == NULL)
root = entry->right;
else {
root = vm_map_entry_splay(entry->start, entry->left);
root->right = entry->right;
root->adj_free = (entry->next == &map->header ? map->max_offset :
entry->next->start) - root->end;
vm_map_entry_set_max_free(root);
}
map->root = root;
prev = entry->prev;
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);
}
/*
* vm_map_entry_resize_free:
*
* Recompute the amount of free space following a vm_map_entry
* and propagate that value up the tree. Call this function after
* resizing a map entry in-place, that is, without a call to
* vm_map_entry_link() or _unlink().
*
* The map must be locked, and leaves it so.
*/
static void
vm_map_entry_resize_free(vm_map_t map, vm_map_entry_t entry)
{
/*
* Using splay trees without parent pointers, propagating
* max_free up the tree is done by moving the entry to the
* root and making the change there.
*/
if (entry != map->root)
map->root = vm_map_entry_splay(entry->start, map->root);
entry->adj_free = (entry->next == &map->header ? map->max_offset :
entry->next->start) - entry->end;
vm_map_entry_set_max_free(entry);
}
/*
* 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(
vm_map_t map,
vm_offset_t address,
vm_map_entry_t *entry) /* OUT */
{
vm_map_entry_t cur;
boolean_t locked;
/*
* If the map is empty, then the map entry immediately preceding
* "address" is the map's header.
*/
cur = map->root;
if (cur == NULL)
*entry = &map->header;
else if (address >= cur->start && cur->end > address) {
*entry = cur;
return (TRUE);
} else if ((locked = vm_map_locked(map)) ||
sx_try_upgrade(&map->lock)) {
/*
* Splay requires a write lock on the map. However, it only
* restructures the binary search tree; it does not otherwise
* change the map. Thus, the map's timestamp need not change
* on a temporary upgrade.
*/
map->root = cur = vm_map_entry_splay(address, cur);
if (!locked)
sx_downgrade(&map->lock);
/*
* If "address" is contained within a map entry, the new root
* is that map entry. Otherwise, the new root is a map entry
* immediately before or after "address".
*/
if (address >= cur->start) {
*entry = cur;
if (cur->end > address)
return (TRUE);
} else
*entry = cur->prev;
} else
/*
* Since the map is only locked for read access, perform a
* standard binary search tree lookup for "address".
*/
for (;;) {
if (address < cur->start) {
if (cur->left == NULL) {
*entry = cur->prev;
break;
}
cur = cur->left;
} else if (cur->end > address) {
*entry = cur;
return (TRUE);
} else {
if (cur->right == NULL) {
*entry = cur;
break;
}
cur = cur->right;
}
}
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;
struct ucred *cred;
vm_inherit_t inheritance;
boolean_t charge_prev_obj;
VM_MAP_ASSERT_LOCKED(map);
/*
* 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;
charge_prev_obj = FALSE;
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 (cow & MAP_VN_WRITECOUNT)
protoeflags |= MAP_ENTRY_VN_WRITECNT;
if (cow & MAP_INHERIT_SHARE)
inheritance = VM_INHERIT_SHARE;
else
inheritance = VM_INHERIT_DEFAULT;
cred = NULL;
KASSERT((object != kmem_object && object != kernel_object) ||
((object == kmem_object || object == kernel_object) &&
!(protoeflags & MAP_ENTRY_NEEDS_COPY)),
("kmem or kernel object and cow"));
if (cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT))
goto charged;
if ((cow & MAP_ACC_CHARGED) || ((prot & VM_PROT_WRITE) &&
((protoeflags & MAP_ENTRY_NEEDS_COPY) || object == NULL))) {
if (!(cow & MAP_ACC_CHARGED) && !swap_reserve(end - start))
return (KERN_RESOURCE_SHORTAGE);
KASSERT(object == NULL || (protoeflags & MAP_ENTRY_NEEDS_COPY) ||
object->cred == NULL,
("OVERCOMMIT: vm_map_insert o %p", object));
cred = curthread->td_ucred;
crhold(cred);
if (object == NULL && !(protoeflags & MAP_ENTRY_NEEDS_COPY))
charge_prev_obj = TRUE;
}
charged:
/* Expand the kernel pmap, if necessary. */
if (map == kernel_map && end > kernel_vm_end)
pmap_growkernel(end);
if (object != NULL) {
/*
* OBJ_ONEMAPPING must be cleared unless this mapping
* is trivially proven to be the only mapping for any
* of the object's pages. (Object granularity
* reference counting is insufficient to recognize
* aliases with precision.)
*/
VM_OBJECT_LOCK(object);
if (object->ref_count > 1 || object->shadow_count != 0)
vm_object_clear_flag(object, OBJ_ONEMAPPING);
VM_OBJECT_UNLOCK(object);
}
else if ((prev_entry != &map->header) &&
(prev_entry->eflags == protoeflags) &&
(prev_entry->end == start) &&
(prev_entry->wired_count == 0) &&
(prev_entry->cred == cred ||
(prev_entry->object.vm_object != NULL &&
(prev_entry->object.vm_object->cred == cred))) &&
vm_object_coalesce(prev_entry->object.vm_object,
prev_entry->offset,
(vm_size_t)(prev_entry->end - prev_entry->start),
(vm_size_t)(end - prev_entry->end), charge_prev_obj)) {
/*
* 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 == inheritance) &&
(prev_entry->protection == prot) &&
(prev_entry->max_protection == max)) {
map->size += (end - prev_entry->end);
prev_entry->end = end;
vm_map_entry_resize_free(map, prev_entry);
vm_map_simplify_entry(map, prev_entry);
if (cred != NULL)
crfree(cred);
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);
if (cred != NULL && object != NULL && object->cred != NULL &&
!(prev_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
/* Object already accounts for this uid. */
crfree(cred);
cred = NULL;
}
}
/*
* 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->cred = NULL;
new_entry->eflags = protoeflags;
new_entry->object.vm_object = object;
new_entry->offset = offset;
new_entry->avail_ssize = 0;
new_entry->inheritance = inheritance;
new_entry->protection = prot;
new_entry->max_protection = max;
new_entry->wired_count = 0;
new_entry->read_ahead = VM_FAULT_READ_AHEAD_INIT;
new_entry->next_read = OFF_TO_IDX(offset);
KASSERT(cred == NULL || !ENTRY_CHARGED(new_entry),
("OVERCOMMIT: vm_map_insert leaks vm_map %p", new_entry));
new_entry->cred = cred;
/*
* Insert the new entry into the list
*/
vm_map_entry_link(map, prev_entry, new_entry);
map->size += new_entry->end - new_entry->start;
/*
* It may be possible to merge the new entry with the next and/or
* previous entries. However, due to MAP_STACK_* being a hack, a
* panic can result from merging such entries.
*/
if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0)
vm_map_simplify_entry(map, new_entry);
if (cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) {
vm_map_pmap_enter(map, start, prot,
object, OFF_TO_IDX(offset), end - start,
cow & MAP_PREFAULT_PARTIAL);
}
return (KERN_SUCCESS);
}
/*
* vm_map_findspace:
*
* Find the first fit (lowest VM address) for "length" free bytes
* beginning at address >= start in the given map.
*
* In a vm_map_entry, "adj_free" is the amount of free space
* adjacent (higher address) to this entry, and "max_free" is the
* maximum amount of contiguous free space in its subtree. This
* allows finding a free region in one path down the tree, so
* O(log n) amortized with splay trees.
*
* The map must be locked, and leaves it so.
*
* Returns: 0 on success, and starting address in *addr,
* 1 if insufficient space.
*/
int
vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length,
vm_offset_t *addr) /* OUT */
{
vm_map_entry_t entry;
vm_offset_t st;
/*
* Request must fit within min/max VM address and must avoid
* address wrap.
*/
if (start < map->min_offset)
start = map->min_offset;
if (start + length > map->max_offset || start + length < start)
return (1);
/* Empty tree means wide open address space. */
if (map->root == NULL) {
*addr = start;
return (0);
}
/*
* After splay, if start comes before root node, then there
* must be a gap from start to the root.
*/
map->root = vm_map_entry_splay(start, map->root);
if (start + length <= map->root->start) {
*addr = start;
return (0);
}
/*
* Root is the last node that might begin its gap before
* start, and this is the last comparison where address
* wrap might be a problem.
*/
st = (start > map->root->end) ? start : map->root->end;
if (length <= map->root->end + map->root->adj_free - st) {
*addr = st;
return (0);
}
/* With max_free, can immediately tell if no solution. */
entry = map->root->right;
if (entry == NULL || length > entry->max_free)
return (1);
/*
* Search the right subtree in the order: left subtree, root,
* right subtree (first fit). The previous splay implies that
* all regions in the right subtree have addresses > start.
*/
while (entry != NULL) {
if (entry->left != NULL && entry->left->max_free >= length)
entry = entry->left;
else if (entry->adj_free >= length) {
*addr = entry->end;
return (0);
} else
entry = entry->right;
}
/* Can't get here, so panic if we do. */
panic("vm_map_findspace: max_free corrupt");
}
int
vm_map_fixed(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_size_t length, vm_prot_t prot,
vm_prot_t max, int cow)
{
vm_offset_t end;
int result;
end = start + length;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
(void) vm_map_delete(map, start, end);
result = vm_map_insert(map, object, offset, start, end, prot,
max, cow);
vm_map_unlock(map);
return (result);
}
/*
* 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, int find_space, vm_prot_t prot,
vm_prot_t max, int cow)
{
vm_offset_t start;
int result;
start = *addr;
vm_map_lock(map);
do {
if (find_space != VMFS_NO_SPACE) {
if (vm_map_findspace(map, start, length, addr)) {
vm_map_unlock(map);
return (KERN_NO_SPACE);
}
switch (find_space) {
case VMFS_ALIGNED_SPACE:
pmap_align_superpage(object, offset, addr,
length);
break;
#ifdef VMFS_TLB_ALIGNED_SPACE
case VMFS_TLB_ALIGNED_SPACE:
pmap_align_tlb(addr);
break;
#endif
default:
break;
}
start = *addr;
}
result = vm_map_insert(map, object, offset, start, start +
length, prot, max, cow);
} while (result == KERN_NO_SPACE && (find_space == VMFS_ALIGNED_SPACE
#ifdef VMFS_TLB_ALIGNED_SPACE
|| find_space == VMFS_TLB_ALIGNED_SPACE
#endif
));
vm_map_unlock(map);
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(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_IN_TRANSITION | 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) &&
(prev->cred == entry->cred)) {
vm_map_entry_unlink(map, prev);
entry->start = prev->start;
entry->offset = prev->offset;
if (entry->prev != &map->header)
vm_map_entry_resize_free(map, entry->prev);
/*
* If the backing object is a vnode object,
* vm_object_deallocate() calls vrele().
* However, vrele() does not lock the vnode
* because the vnode has additional
* references. Thus, the map lock can be kept
* without causing a lock-order reversal with
* the vnode lock.
*
* Since we count the number of virtual page
* mappings in object->un_pager.vnp.writemappings,
* the writemappings value should not be adjusted
* when the entry is disposed of.
*/
if (prev->object.vm_object)
vm_object_deallocate(prev->object.vm_object);
if (prev->cred != NULL)
crfree(prev->cred);
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) &&
(next->cred == entry->cred)) {
vm_map_entry_unlink(map, next);
entry->end = next->end;
vm_map_entry_resize_free(map, entry);
/*
* See comment above.
*/
if (next->object.vm_object)
vm_object_deallocate(next->object.vm_object);
if (next->cred != NULL)
crfree(next->cred);
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(vm_map_t map, vm_map_entry_t entry, vm_offset_t start)
{
vm_map_entry_t new_entry;
VM_MAP_ASSERT_LOCKED(map);
/*
* 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;
if (entry->cred != NULL) {
object->cred = entry->cred;
object->charge = entry->end - entry->start;
entry->cred = NULL;
}
} else if (entry->object.vm_object != NULL &&
((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) &&
entry->cred != NULL) {
VM_OBJECT_LOCK(entry->object.vm_object);
KASSERT(entry->object.vm_object->cred == NULL,
("OVERCOMMIT: vm_entry_clip_start: both cred e %p", entry));
entry->object.vm_object->cred = entry->cred;
entry->object.vm_object->charge = entry->end - entry->start;
VM_OBJECT_UNLOCK(entry->object.vm_object);
entry->cred = NULL;
}
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
new_entry->end = start;
entry->offset += (start - entry->start);
entry->start = start;
if (new_entry->cred != NULL)
crhold(entry->cred);
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);
/*
* The object->un_pager.vnp.writemappings for the
* object of MAP_ENTRY_VN_WRITECNT type entry shall be
* kept as is here. The virtual pages are
* re-distributed among the clipped entries, so the sum is
* left the same.
*/
}
}
/*
* 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(vm_map_t map, vm_map_entry_t entry, vm_offset_t end)
{
vm_map_entry_t new_entry;
VM_MAP_ASSERT_LOCKED(map);
/*
* 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;
if (entry->cred != NULL) {
object->cred = entry->cred;
object->charge = entry->end - entry->start;
entry->cred = NULL;
}
} else if (entry->object.vm_object != NULL &&
((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) &&
entry->cred != NULL) {
VM_OBJECT_LOCK(entry->object.vm_object);
KASSERT(entry->object.vm_object->cred == NULL,
("OVERCOMMIT: vm_entry_clip_end: both cred e %p", entry));
entry->object.vm_object->cred = entry->cred;
entry->object.vm_object->charge = entry->end - entry->start;
VM_OBJECT_UNLOCK(entry->object.vm_object);
entry->cred = NULL;
}
/*
* 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);
if (new_entry->cred != NULL)
crhold(entry->cred);
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_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(
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;
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);
}
/*
* The maximum number of pages to map
*/
#define MAX_INIT_PT 96
/*
* vm_map_pmap_enter:
*
* Preload read-only mappings for the given object's resident pages into
* the given map. This eliminates the soft faults on process startup and
* immediately after an mmap(2). Because these are speculative mappings,
* cached pages are not reactivated and mapped.
*/
void
vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot,
vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags)
{
vm_offset_t start;
vm_page_t p, p_start;
vm_pindex_t psize, tmpidx;
if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL)
return;
VM_OBJECT_LOCK(object);
if (object->type == OBJT_DEVICE || object->type == OBJT_SG) {
pmap_object_init_pt(map->pmap, addr, object, pindex, size);
goto unlock_return;
}
psize = atop(size);
if ((flags & MAP_PREFAULT_PARTIAL) && psize > MAX_INIT_PT &&
object->resident_page_count > MAX_INIT_PT)
goto unlock_return;
if (psize + pindex > object->size) {
if (object->size < pindex)
goto unlock_return;
psize = object->size - pindex;
}
start = 0;
p_start = NULL;
p = vm_page_find_least(object, pindex);
/*
* Assert: the variable p is either (1) the page with the
* least pindex greater than or equal to the parameter pindex
* or (2) NULL.
*/
for (;
p != NULL && (tmpidx = p->pindex - pindex) < psize;
p = TAILQ_NEXT(p, listq)) {
/*
* don't allow an madvise to blow away our really
* free pages allocating pv entries.
*/
if ((flags & MAP_PREFAULT_MADVISE) &&
cnt.v_free_count < cnt.v_free_reserved) {
psize = tmpidx;
break;
}
if (p->valid == VM_PAGE_BITS_ALL) {
if (p_start == NULL) {
start = addr + ptoa(tmpidx);
p_start = p;
}
} else if (p_start != NULL) {
pmap_enter_object(map->pmap, start, addr +
ptoa(tmpidx), p_start, prot);
p_start = NULL;
}
}
if (p_start != NULL)
pmap_enter_object(map->pmap, start, addr + ptoa(psize),
p_start, prot);
unlock_return:
VM_OBJECT_UNLOCK(object);
}
/*
* 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, entry;
vm_object_t obj;
struct ucred *cred;
vm_prot_t old_prot;
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;
}
/*
* Do an accounting pass for private read-only mappings that
* now will do cow due to allowed write (e.g. debugger sets
* breakpoint on text segment)
*/
for (current = entry; (current != &map->header) &&
(current->start < end); current = current->next) {
vm_map_clip_end(map, current, end);
if (set_max ||
((new_prot & ~(current->protection)) & VM_PROT_WRITE) == 0 ||
ENTRY_CHARGED(current)) {
continue;
}
cred = curthread->td_ucred;
obj = current->object.vm_object;
if (obj == NULL || (current->eflags & MAP_ENTRY_NEEDS_COPY)) {
if (!swap_reserve(current->end - current->start)) {
vm_map_unlock(map);
return (KERN_RESOURCE_SHORTAGE);
}
crhold(cred);
current->cred = cred;
continue;
}
VM_OBJECT_LOCK(obj);
if (obj->type != OBJT_DEFAULT && obj->type != OBJT_SWAP) {
VM_OBJECT_UNLOCK(obj);
continue;
}
/*
* Charge for the whole object allocation now, since
* we cannot distinguish between non-charged and
* charged clipped mapping of the same object later.
*/
KASSERT(obj->charge == 0,
("vm_map_protect: object %p overcharged\n", obj));
if (!swap_reserve(ptoa(obj->size))) {
VM_OBJECT_UNLOCK(obj);
vm_map_unlock(map);
return (KERN_RESOURCE_SHORTAGE);
}
crhold(cred);
obj->cred = cred;
obj->charge = ptoa(obj->size);
VM_OBJECT_UNLOCK(obj);
}
/*
* Go back and fix up protections. [Note that clipping is not
* necessary the second time.]
*/
current = entry;
while ((current != &map->header) && (current->start < end)) {
old_prot = current->protection;
if (set_max)
current->protection =
(current->max_protection = new_prot) &
old_prot;
else
current->protection = new_prot;
if ((current->eflags & (MAP_ENTRY_COW | MAP_ENTRY_USER_WIRED))
== (MAP_ENTRY_COW | MAP_ENTRY_USER_WIRED) &&
(current->protection & VM_PROT_WRITE) != 0 &&
(old_prot & VM_PROT_WRITE) == 0) {
vm_fault_copy_entry(map, map, current, current, NULL);
}
/*
* When restricting access, update the physical map. Worry
* about copy-on-write here.
*/
if ((old_prot & ~current->protection) != 0) {
#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(
vm_map_t map,
vm_offset_t start,
vm_offset_t end,
int behav)
{
vm_map_entry_t current, entry;
int modify_map = 0;
/*
* 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 pstart, pend;
/*
* 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;
pstart = OFF_TO_IDX(current->offset);
pend = pstart + atop(current->end - current->start);
useStart = current->start;
if (current->start < start) {
pstart += atop(start - current->start);
useStart = start;
}
if (current->end > end)
pend -= atop(current->end - end);
if (pstart >= pend)
continue;
vm_object_madvise(current->object.vm_object, pstart,
pend, behav);
if (behav == MADV_WILLNEED) {
vm_map_pmap_enter(map,
useStart,
current->protection,
current->object.vm_object,
pstart,
ptoa(pend - pstart),
MAP_PREFAULT_MADVISE
);
}
}
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 vmspace_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;
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);
}
/*
* vm_map_unwire:
*
* Implements both kernel and user unwiring.
*/
int
vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
int flags)
{
vm_map_entry_t entry, first_entry, tmp_entry;
vm_offset_t saved_start;
unsigned int last_timestamp;
int rv;
boolean_t need_wakeup, result, user_unwire;
user_unwire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &first_entry)) {
if (flags & VM_MAP_WIRE_HOLESOK)
first_entry = first_entry->next;
else {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
}
last_timestamp = map->timestamp;
entry = first_entry;
while (entry != &map->header && entry->start < end) {
if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
/*
* We have not yet clipped the entry.
*/
saved_start = (start >= entry->start) ? start :
entry->start;
entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
if (vm_map_unlock_and_wait(map, 0)) {
/*
* Allow interruption of user unwiring?
*/
}
vm_map_lock(map);
if (last_timestamp+1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked.
* Specifically, the entry may have been
* clipped, merged, or deleted.
*/
if (!vm_map_lookup_entry(map, saved_start,
&tmp_entry)) {
if (flags & VM_MAP_WIRE_HOLESOK)
tmp_entry = tmp_entry->next;
else {
if (saved_start == start) {
/*
* First_entry has been deleted.
*/
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
end = saved_start;
rv = KERN_INVALID_ADDRESS;
goto done;
}
}
if (entry == first_entry)
first_entry = tmp_entry;
else
first_entry = NULL;
entry = tmp_entry;
}
last_timestamp = map->timestamp;
continue;
}
vm_map_clip_start(map, entry, start);
vm_map_clip_end(map, entry, end);
/*
* Mark the entry in case the map lock is released. (See
* above.)
*/
entry->eflags |= MAP_ENTRY_IN_TRANSITION;
/*
* Check the map for holes in the specified region.
* If VM_MAP_WIRE_HOLESOK was specified, skip this check.
*/
if (((flags & VM_MAP_WIRE_HOLESOK) == 0) &&
(entry->end < end && (entry->next == &map->header ||
entry->next->start > entry->end))) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
goto done;
}
/*
* If system unwiring, require that the entry is system wired.
*/
if (!user_unwire &&
vm_map_entry_system_wired_count(entry) == 0) {
end = entry->end;
rv = KERN_INVALID_ARGUMENT;
goto done;
}
entry = entry->next;
}
rv = KERN_SUCCESS;
done:
need_wakeup = FALSE;
if (first_entry == NULL) {
result = vm_map_lookup_entry(map, start, &first_entry);
if (!result && (flags & VM_MAP_WIRE_HOLESOK))
first_entry = first_entry->next;
else
KASSERT(result, ("vm_map_unwire: lookup failed"));
}
entry = first_entry;
while (entry != &map->header && entry->start < end) {
if (rv == KERN_SUCCESS && (!user_unwire ||
(entry->eflags & MAP_ENTRY_USER_WIRED))) {
if (user_unwire)
entry->eflags &= ~MAP_ENTRY_USER_WIRED;
entry->wired_count--;
if (entry->wired_count == 0) {
/*
* Retain the map lock.
*/
vm_fault_unwire(map, entry->start, entry->end,
entry->object.vm_object != NULL &&
(entry->object.vm_object->type == OBJT_DEVICE ||
entry->object.vm_object->type == OBJT_SG));
}
}
KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION,
("vm_map_unwire: in-transition flag missing"));
entry->eflags &= ~MAP_ENTRY_IN_TRANSITION;
if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
need_wakeup = TRUE;
}
vm_map_simplify_entry(map, entry);
entry = entry->next;
}
vm_map_unlock(map);
if (need_wakeup)
vm_map_wakeup(map);
return (rv);
}
/*
* vm_map_wire:
*
* Implements both kernel and user wiring.
*/
int
vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end,
int flags)
{
vm_map_entry_t entry, first_entry, tmp_entry;
vm_offset_t saved_end, saved_start;
unsigned int last_timestamp;
int rv;
boolean_t fictitious, need_wakeup, result, user_wire;
vm_prot_t prot;
prot = 0;
if (flags & VM_MAP_WIRE_WRITE)
prot |= VM_PROT_WRITE;
user_wire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &first_entry)) {
if (flags & VM_MAP_WIRE_HOLESOK)
first_entry = first_entry->next;
else {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
}
last_timestamp = map->timestamp;
entry = first_entry;
while (entry != &map->header && entry->start < end) {
if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
/*
* We have not yet clipped the entry.
*/
saved_start = (start >= entry->start) ? start :
entry->start;
entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
if (vm_map_unlock_and_wait(map, 0)) {
/*
* Allow interruption of user wiring?
*/
}
vm_map_lock(map);
if (last_timestamp + 1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked.
* Specifically, the entry may have been
* clipped, merged, or deleted.
*/
if (!vm_map_lookup_entry(map, saved_start,
&tmp_entry)) {
if (flags & VM_MAP_WIRE_HOLESOK)
tmp_entry = tmp_entry->next;
else {
if (saved_start == start) {
/*
* first_entry has been deleted.
*/
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
end = saved_start;
rv = KERN_INVALID_ADDRESS;
goto done;
}
}
if (entry == first_entry)
first_entry = tmp_entry;
else
first_entry = NULL;
entry = tmp_entry;
}
last_timestamp = map->timestamp;
continue;
}
vm_map_clip_start(map, entry, start);
vm_map_clip_end(map, entry, end);
/*
* Mark the entry in case the map lock is released. (See
* above.)
*/
entry->eflags |= MAP_ENTRY_IN_TRANSITION;
if ((entry->protection & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0
|| (entry->protection & prot) != prot) {
entry->eflags |= MAP_ENTRY_WIRE_SKIPPED;
if ((flags & VM_MAP_WIRE_HOLESOK) == 0) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
goto done;
}
goto next_entry;
}
if (entry->wired_count == 0) {
entry->wired_count++;
saved_start = entry->start;
saved_end = entry->end;
fictitious = entry->object.vm_object != NULL &&
(entry->object.vm_object->type == OBJT_DEVICE ||
entry->object.vm_object->type == OBJT_SG);
/*
* Release the map lock, relying on the in-transition
* mark. Mark the map busy for fork.
*/
vm_map_busy(map);
vm_map_unlock(map);
rv = vm_fault_wire(map, saved_start, saved_end,
fictitious);
vm_map_lock(map);
vm_map_unbusy(map);
if (last_timestamp + 1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked. The entry
* may have been clipped, but NOT merged or
* deleted.
*/
result = vm_map_lookup_entry(map, saved_start,
&tmp_entry);
KASSERT(result, ("vm_map_wire: lookup failed"));
if (entry == first_entry)
first_entry = tmp_entry;
else
first_entry = NULL;
entry = tmp_entry;
while (entry->end < saved_end) {
if (rv != KERN_SUCCESS) {
KASSERT(entry->wired_count == 1,
("vm_map_wire: bad count"));
entry->wired_count = -1;
}
entry = entry->next;
}
}
last_timestamp = map->timestamp;
if (rv != KERN_SUCCESS) {
KASSERT(entry->wired_count == 1,
("vm_map_wire: bad count"));
/*
* Assign an out-of-range value to represent
* the failure to wire this entry.
*/
entry->wired_count = -1;
end = entry->end;
goto done;
}
} else if (!user_wire ||
(entry->eflags & MAP_ENTRY_USER_WIRED) == 0) {
entry->wired_count++;
}
/*
* Check the map for holes in the specified region.
* If VM_MAP_WIRE_HOLESOK was specified, skip this check.
*/
next_entry:
if (((flags & VM_MAP_WIRE_HOLESOK) == 0) &&
(entry->end < end && (entry->next == &map->header ||
entry->next->start > entry->end))) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
goto done;
}
entry = entry->next;
}
rv = KERN_SUCCESS;
done:
need_wakeup = FALSE;
if (first_entry == NULL) {
result = vm_map_lookup_entry(map, start, &first_entry);
if (!result && (flags & VM_MAP_WIRE_HOLESOK))
first_entry = first_entry->next;
else
KASSERT(result, ("vm_map_wire: lookup failed"));
}
entry = first_entry;
while (entry != &map->header && entry->start < end) {
if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0)
goto next_entry_done;
if (rv == KERN_SUCCESS) {
if (user_wire)
entry->eflags |= MAP_ENTRY_USER_WIRED;
} else if (entry->wired_count == -1) {
/*
* Wiring failed on this entry. Thus, unwiring is
* unnecessary.
*/
entry->wired_count = 0;
} else {
if (!user_wire ||
(entry->eflags & MAP_ENTRY_USER_WIRED) == 0)
entry->wired_count--;
if (entry->wired_count == 0) {
/*
* Retain the map lock.
*/
vm_fault_unwire(map, entry->start, entry->end,
entry->object.vm_object != NULL &&
(entry->object.vm_object->type == OBJT_DEVICE ||
entry->object.vm_object->type == OBJT_SG));
}
}
next_entry_done:
KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION,
("vm_map_wire: in-transition flag missing"));
entry->eflags &= ~(MAP_ENTRY_IN_TRANSITION|MAP_ENTRY_WIRE_SKIPPED);
if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
need_wakeup = TRUE;
}
vm_map_simplify_entry(map, entry);
entry = entry->next;
}
vm_map_unlock(map);
if (need_wakeup)
vm_map_wakeup(map);
return (rv);
}
/*
* vm_map_sync
*
* 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.
*
* If the size of the region from start to end is zero, we are
* supposed to flush all modified pages within the region containing
* start. Unfortunately, a region can be split or coalesced with
* neighboring regions, making it difficult to determine what the
* original region was. Therefore, we approximate this requirement by
* flushing the current region containing start.
*
* Returns an error if any part of the specified range is not mapped.
*/
int
vm_map_sync(
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;
unsigned int last_timestamp;
boolean_t failed;
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);
} else if (start == end) {
start = entry->start;
end = entry->end;
}
/*
* Make a first pass to check for user-wired memory and holes.
*/
for (current = entry; current != &map->header && current->start < end;
current = current->next) {
if (invalidate && (current->eflags & MAP_ENTRY_USER_WIRED)) {
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(map->pmap, start, end);
failed = FALSE;
/*
* Make a second pass, cleaning/uncaching pages from the indicated
* objects as we go.
*/
for (current = entry; current != &map->header && current->start < end;) {
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;
}
vm_object_reference(object);
last_timestamp = map->timestamp;
vm_map_unlock_read(map);
if (!vm_object_sync(object, offset, size, syncio, invalidate))
failed = TRUE;
start += size;
vm_object_deallocate(object);
vm_map_lock_read(map);
if (last_timestamp == map->timestamp ||
!vm_map_lookup_entry(map, start, &current))
current = current->next;
}
vm_map_unlock_read(map);
return (failed ? KERN_FAILURE : 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(vm_map_t map, vm_map_entry_t entry)
{
vm_fault_unwire(map, entry->start, entry->end,
entry->object.vm_object != NULL &&
(entry->object.vm_object->type == OBJT_DEVICE ||
entry->object.vm_object->type == OBJT_SG));
entry->wired_count = 0;
}
static void
vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map)
{
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
vm_object_deallocate(entry->object.vm_object);
uma_zfree(system_map ? kmapentzone : mapentzone, entry);
}
/*
* vm_map_entry_delete: [ internal use only ]
*
* Deallocate the given entry from the target map.
*/
static void
vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry)
{
vm_object_t object;
vm_pindex_t offidxstart, offidxend, count, size1;
vm_ooffset_t size;
vm_map_entry_unlink(map, entry);
object = entry->object.vm_object;
size = entry->end - entry->start;
map->size -= size;
if (entry->cred != NULL) {
swap_release_by_cred(size, entry->cred);
crfree(entry->cred);
}
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0 &&
(object != NULL)) {
KASSERT(entry->cred == NULL || object->cred == NULL ||
(entry->eflags & MAP_ENTRY_NEEDS_COPY),
("OVERCOMMIT vm_map_entry_delete: both cred %p", entry));
count = OFF_TO_IDX(size);
offidxstart = OFF_TO_IDX(entry->offset);
offidxend = offidxstart + count;
VM_OBJECT_LOCK(object);
if (object->ref_count != 1 &&
((object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING ||
object == kernel_object || object == kmem_object)) {
vm_object_collapse(object);
/*
* The option OBJPR_NOTMAPPED can be passed here
* because vm_map_delete() already performed
* pmap_remove() on the only mapping to this range
* of pages.
*/
vm_object_page_remove(object, offidxstart, offidxend,
OBJPR_NOTMAPPED);
if (object->type == OBJT_SWAP)
swap_pager_freespace(object, offidxstart, count);
if (offidxend >= object->size &&
offidxstart < object->size) {
size1 = object->size;
object->size = offidxstart;
if (object->cred != NULL) {
size1 -= object->size;
KASSERT(object->charge >= ptoa(size1),
("vm_map_entry_delete: object->charge < 0"));
swap_release_by_cred(ptoa(size1), object->cred);
object->charge -= ptoa(size1);
}
}
}
VM_OBJECT_UNLOCK(object);
} else
entry->object.vm_object = NULL;
if (map->system_map)
vm_map_entry_deallocate(entry, TRUE);
else {
entry->next = curthread->td_map_def_user;
curthread->td_map_def_user = entry;
}
}
/*
* vm_map_delete: [ internal use only ]
*
* Deallocates the given address range from the target
* map.
*/
int
vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end)
{
vm_map_entry_t entry;
vm_map_entry_t first_entry;
VM_MAP_ASSERT_LOCKED(map);
/*
* 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);
}
/*
* Step through all entries in this region
*/
while ((entry != &map->header) && (entry->start < end)) {
vm_map_entry_t next;
/*
* Wait for wiring or unwiring of an entry to complete.
* Also wait for any system wirings to disappear on
* user maps.
*/
if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 ||
(vm_map_pmap(map) != kernel_pmap &&
vm_map_entry_system_wired_count(entry) != 0)) {
unsigned int last_timestamp;
vm_offset_t saved_start;
vm_map_entry_t tmp_entry;
saved_start = entry->start;
entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
last_timestamp = map->timestamp;
(void) vm_map_unlock_and_wait(map, 0);
vm_map_lock(map);
if (last_timestamp + 1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked.
* Specifically, the entry may have been
* clipped, merged, or deleted.
*/
if (!vm_map_lookup_entry(map, saved_start,
&tmp_entry))
entry = tmp_entry->next;
else {
entry = tmp_entry;
vm_map_clip_start(map, entry,
saved_start);
}
}
continue;
}
vm_map_clip_end(map, entry, end);
next = entry->next;
/*
* 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);
}
pmap_remove(map->pmap, entry->start, entry->end);
/*
* Delete the entry 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(vm_map_t map, vm_offset_t start, vm_offset_t end)
{
int result;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
result = vm_map_delete(map, start, end);
vm_map_unlock(map);
return (result);
}
/*
* vm_map_check_protection:
*
* Assert that the target map allows the specified privilege on the
* entire address region given. The entire region must be allocated.
*
* WARNING! This code does not and should not check whether the
* contents of the region is accessible. For example a smaller file
* might be mapped into a larger address space.
*
* NOTE! This code is also called by munmap().
*
* The map must be locked. A read lock is sufficient.
*/
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;
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(
vm_map_t src_map,
vm_map_t dst_map,
vm_map_entry_t src_entry,
vm_map_entry_t dst_entry,
vm_ooffset_t *fork_charge)
{
vm_object_t src_object;
vm_map_entry_t fake_entry;
vm_offset_t size;
struct ucred *cred;
int charged;
VM_MAP_ASSERT_LOCKED(dst_map);
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.
*/
size = src_entry->end - src_entry->start;
if ((src_object = src_entry->object.vm_object) != NULL) {
VM_OBJECT_LOCK(src_object);
charged = ENTRY_CHARGED(src_entry);
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_object_split(src_entry);
src_object = src_entry->object.vm_object;
}
}
vm_object_reference_locked(src_object);
vm_object_clear_flag(src_object, OBJ_ONEMAPPING);
if (src_entry->cred != NULL &&
!(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
KASSERT(src_object->cred == NULL,
("OVERCOMMIT: vm_map_copy_entry: cred %p",
src_object));
src_object->cred = src_entry->cred;
src_object->charge = size;
}
VM_OBJECT_UNLOCK(src_object);
dst_entry->object.vm_object = src_object;
if (charged) {
cred = curthread->td_ucred;
crhold(cred);
dst_entry->cred = cred;
*fork_charge += size;
if (!(src_entry->eflags &
MAP_ENTRY_NEEDS_COPY)) {
crhold(cred);
src_entry->cred = cred;
*fork_charge += size;
}
}
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;
if (src_entry->eflags & MAP_ENTRY_VN_WRITECNT) {
/*
* MAP_ENTRY_VN_WRITECNT cannot
* indicate write reference from
* src_entry, since the entry is
* marked as needs copy. Allocate a
* fake entry that is used to
* decrement object->un_pager.vnp.writecount
* at the appropriate time. Attach
* fake_entry to the deferred list.
*/
fake_entry = vm_map_entry_create(dst_map);
fake_entry->eflags = MAP_ENTRY_VN_WRITECNT;
src_entry->eflags &= ~MAP_ENTRY_VN_WRITECNT;
vm_object_reference(src_object);
fake_entry->object.vm_object = src_object;
fake_entry->start = src_entry->start;
fake_entry->end = src_entry->end;
fake_entry->next = curthread->td_map_def_user;
curthread->td_map_def_user = fake_entry;
}
} else {
dst_entry->object.vm_object = NULL;
dst_entry->offset = 0;
if (src_entry->cred != NULL) {
dst_entry->cred = curthread->td_ucred;
crhold(dst_entry->cred);
*fork_charge += size;
}
}
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,
fork_charge);
}
}
/*
* vmspace_map_entry_forked:
* Update the newly-forked vmspace each time a map entry is inherited
* or copied. The values for vm_dsize and vm_tsize are approximate
* (and mostly-obsolete ideas in the face of mmap(2) et al.)
*/
static void
vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2,
vm_map_entry_t entry)
{
vm_size_t entrysize;
vm_offset_t newend;
entrysize = entry->end - entry->start;
vm2->vm_map.size += entrysize;
if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) {
vm2->vm_ssize += btoc(entrysize);
} else if (entry->start >= (vm_offset_t)vm1->vm_daddr &&
entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) {
newend = MIN(entry->end,
(vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize));
vm2->vm_dsize += btoc(newend - entry->start);
} else if (entry->start >= (vm_offset_t)vm1->vm_taddr &&
entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) {
newend = MIN(entry->end,
(vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize));
vm2->vm_tsize += btoc(newend - entry->start);
}
}
/*
* 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.
*
* XXX It might be worth coalescing the entries added to the new vmspace.
*
* The source map must not be locked.
*/
struct vmspace *
vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
{
struct vmspace *vm2;
vm_map_t new_map, old_map;
vm_map_entry_t new_entry, old_entry;
vm_object_t object;
int locked;
old_map = &vm1->vm_map;
/* Copy immutable fields of vm1 to vm2. */
vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset);
if (vm2 == NULL)
return (NULL);
vm2->vm_taddr = vm1->vm_taddr;
vm2->vm_daddr = vm1->vm_daddr;
vm2->vm_maxsaddr = vm1->vm_maxsaddr;
vm_map_lock(old_map);
if (old_map->busy)
vm_map_wait_busy(old_map);
new_map = &vm2->vm_map;
locked = vm_map_trylock(new_map); /* trylock to silence WITNESS */
KASSERT(locked, ("vmspace_fork: lock failed"));
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 = 0;
if (old_entry->cred != NULL) {
object->cred = old_entry->cred;
object->charge = old_entry->end -
old_entry->start;
old_entry->cred = NULL;
}
}
/*
* 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,
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);
/*
* As in vm_map_simplify_entry(), the
* vnode lock will not be acquired in
* this call to vm_object_deallocate().
*/
vm_object_deallocate(object);
object = old_entry->object.vm_object;
}
VM_OBJECT_LOCK(object);
vm_object_clear_flag(object, OBJ_ONEMAPPING);
if (old_entry->cred != NULL) {
KASSERT(object->cred == NULL, ("vmspace_fork both cred"));
object->cred = old_entry->cred;
object->charge = old_entry->end - old_entry->start;
old_entry->cred = NULL;
}
VM_OBJECT_UNLOCK(object);
/*
* 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 |
MAP_ENTRY_IN_TRANSITION);
new_entry->wired_count = 0;
if (new_entry->eflags & MAP_ENTRY_VN_WRITECNT) {
object = new_entry->object.vm_object;
KASSERT(((struct vnode *)object->handle)->
v_writecount > 0,
("vmspace_fork: v_writecount"));
KASSERT(object->un_pager.vnp.writemappings > 0,
("vmspace_fork: vnp.writecount"));
vnode_pager_update_writecount(object,
new_entry->start, new_entry->end);
}
/*
* 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);
vmspace_map_entry_forked(vm1, vm2, 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;
/*
* Copied entry is COW over the old object.
*/
new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED |
MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_VN_WRITECNT);
new_entry->wired_count = 0;
new_entry->object.vm_object = NULL;
new_entry->cred = NULL;
vm_map_entry_link(new_map, new_map->header.prev,
new_entry);
vmspace_map_entry_forked(vm1, vm2, new_entry);
vm_map_copy_entry(old_map, new_map, old_entry,
new_entry, fork_charge);
break;
}
old_entry = old_entry->next;
}
/*
* Use inlined vm_map_unlock() to postpone handling the deferred
* map entries, which cannot be done until both old_map and
* new_map locks are released.
*/
sx_xunlock(&old_map->lock);
sx_xunlock(&new_map->lock);
vm_map_process_deferred();
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 new_entry, prev_entry;
vm_offset_t bot, top;
vm_size_t init_ssize;
int orient, rv;
rlim_t vmemlim;
/*
* The stack orientation is piggybacked with the cow argument.
* Extract it into orient and mask the cow argument so that we
* don't pass it around further.
* NOTE: We explicitly allow bi-directional stacks.
*/
orient = cow & (MAP_STACK_GROWS_DOWN|MAP_STACK_GROWS_UP);
cow &= ~orient;
KASSERT(orient != 0, ("No stack grow direction"));
if (addrbos < vm_map_min(map) ||
addrbos > vm_map_max(map) ||
addrbos + max_ssize < addrbos)
return (KERN_NO_SPACE);
init_ssize = (max_ssize < sgrowsiz) ? max_ssize : sgrowsiz;
PROC_LOCK(curthread->td_proc);
vmemlim = lim_cur(curthread->td_proc, RLIMIT_VMEM);
PROC_UNLOCK(curthread->td_proc);
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 would blow our VMEM resource limit, no go */
if (map->size + init_ssize > vmemlim) {
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. Depending on the orientation of the stack (i.e.
* the grow direction) we either map at the top of the range, the
* bottom of the range or in the middle.
*
* 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.
*/
if (orient == MAP_STACK_GROWS_DOWN)
bot = addrbos + max_ssize - init_ssize;
else if (orient == MAP_STACK_GROWS_UP)
bot = addrbos;
else
bot = round_page(addrbos + max_ssize/2 - init_ssize/2);
top = bot + init_ssize;
rv = vm_map_insert(map, NULL, 0, bot, top, 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, bot);
new_entry = prev_entry->next;
if (new_entry->end != top || new_entry->start != bot)
panic("Bad entry start/end for new stack entry");
new_entry->avail_ssize = max_ssize - init_ssize;
if (orient & MAP_STACK_GROWS_DOWN)
new_entry->eflags |= MAP_ENTRY_GROWS_DOWN;
if (orient & MAP_STACK_GROWS_UP)
new_entry->eflags |= MAP_ENTRY_GROWS_UP;
}
vm_map_unlock(map);
return (rv);
}
static int stack_guard_page = 0;
TUNABLE_INT("security.bsd.stack_guard_page", &stack_guard_page);
SYSCTL_INT(_security_bsd, OID_AUTO, stack_guard_page, CTLFLAG_RW,
&stack_guard_page, 0,
"Insert stack guard page ahead of the growable segments.");
/* 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).
*/
int
vm_map_growstack(struct proc *p, vm_offset_t addr)
{
vm_map_entry_t next_entry, prev_entry;
vm_map_entry_t new_entry, stack_entry;
struct vmspace *vm = p->p_vmspace;
vm_map_t map = &vm->vm_map;
vm_offset_t end;
size_t grow_amount, max_grow;
rlim_t stacklim, vmemlim;
int is_procstack, rv;
struct ucred *cred;
#ifdef notyet
uint64_t limit;
#endif
#ifdef RACCT
int error;
#endif
Retry:
PROC_LOCK(p);
stacklim = lim_cur(p, RLIMIT_STACK);
vmemlim = lim_cur(p, RLIMIT_VMEM);
PROC_UNLOCK(p);
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);
return (KERN_SUCCESS);
}
next_entry = prev_entry->next;
if (!(prev_entry->eflags & MAP_ENTRY_GROWS_UP)) {
/*
* This entry does not grow upwards. Since the address lies
* beyond this entry, the next entry (if one exists) has to
* be a downward growable entry. The entry list header is
* never a growable entry, so it suffices to check the flags.
*/
if (!(next_entry->eflags & MAP_ENTRY_GROWS_DOWN)) {
vm_map_unlock_read(map);
return (KERN_SUCCESS);
}
stack_entry = next_entry;
} else {
/*
* This entry grows upward. If the next entry does not at
* least grow downwards, this is the entry we need to grow.
* otherwise we have two possible choices and we have to
* select one.
*/
if (next_entry->eflags & MAP_ENTRY_GROWS_DOWN) {
/*
* We have two choices; grow the entry closest to
* the address to minimize the amount of growth.
*/
if (addr - prev_entry->end <= next_entry->start - addr)
stack_entry = prev_entry;
else
stack_entry = next_entry;
} else
stack_entry = prev_entry;
}
if (stack_entry == next_entry) {
KASSERT(stack_entry->eflags & MAP_ENTRY_GROWS_DOWN, ("foo"));
KASSERT(addr < stack_entry->start, ("foo"));
end = (prev_entry != &map->header) ? prev_entry->end :
stack_entry->start - stack_entry->avail_ssize;
grow_amount = roundup(stack_entry->start - addr, PAGE_SIZE);
max_grow = stack_entry->start - end;
} else {
KASSERT(stack_entry->eflags & MAP_ENTRY_GROWS_UP, ("foo"));
KASSERT(addr >= stack_entry->end, ("foo"));
end = (next_entry != &map->header) ? next_entry->start :
stack_entry->end + stack_entry->avail_ssize;
grow_amount = roundup(addr + 1 - stack_entry->end, PAGE_SIZE);
max_grow = end - stack_entry->end;
}
if (grow_amount > stack_entry->avail_ssize) {
vm_map_unlock_read(map);
return (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_guard_page ? PAGE_SIZE : 0) > max_grow) {
if (vm_map_lock_upgrade(map))
goto Retry;
stack_entry->avail_ssize = max_grow;
vm_map_unlock(map);
return (KERN_NO_SPACE);
}
is_procstack = (addr >= (vm_offset_t)vm->vm_maxsaddr) ? 1 : 0;
/*
* If this is the main process stack, see if we're over the stack
* limit.
*/
if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) {
vm_map_unlock_read(map);
return (KERN_NO_SPACE);
}
#ifdef RACCT
PROC_LOCK(p);
if (is_procstack &&
racct_set(p, RACCT_STACK, ctob(vm->vm_ssize) + grow_amount)) {
PROC_UNLOCK(p);
vm_map_unlock_read(map);
return (KERN_NO_SPACE);
}
PROC_UNLOCK(p);
#endif
/* 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 > stacklim)) {
grow_amount = trunc_page((vm_size_t)stacklim) -
ctob(vm->vm_ssize);
}
#ifdef notyet
PROC_LOCK(p);
limit = racct_get_available(p, RACCT_STACK);
PROC_UNLOCK(p);
if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > limit))
grow_amount = limit - ctob(vm->vm_ssize);
#endif
/* If we would blow our VMEM resource limit, no go */
if (map->size + grow_amount > vmemlim) {
vm_map_unlock_read(map);
rv = KERN_NO_SPACE;
goto out;
}
#ifdef RACCT
PROC_LOCK(p);
if (racct_set(p, RACCT_VMEM, map->size + grow_amount)) {
PROC_UNLOCK(p);
vm_map_unlock_read(map);
rv = KERN_NO_SPACE;
goto out;
}
PROC_UNLOCK(p);
#endif
if (vm_map_lock_upgrade(map))
goto Retry;
if (stack_entry == next_entry) {
/*
* Growing downward.
*/
/* 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 = max_grow;
addr = end;
if (stack_guard_page)
addr += PAGE_SIZE;
}
rv = vm_map_insert(map, NULL, 0, addr, stack_entry->start,
p->p_sysent->sv_stackprot, 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_entry = prev_entry->next;
KASSERT(new_entry == stack_entry->prev, ("foo"));
KASSERT(new_entry->end == stack_entry->start, ("foo"));
KASSERT(new_entry->start == addr, ("foo"));
grow_amount = new_entry->end - new_entry->start;
new_entry->avail_ssize = stack_entry->avail_ssize -
grow_amount;
stack_entry->eflags &= ~MAP_ENTRY_GROWS_DOWN;
new_entry->eflags |= MAP_ENTRY_GROWS_DOWN;
}
} else {
/*
* Growing upward.
*/
addr = stack_entry->end + grow_amount;
/*
* If this puts us into the next entry, cut back our growth
* to the available space. Also, see the note above.
*/
if (addr > end) {
stack_entry->avail_ssize = end - stack_entry->end;
addr = end;
if (stack_guard_page)
addr -= PAGE_SIZE;
}
grow_amount = addr - stack_entry->end;
cred = stack_entry->cred;
if (cred == NULL && stack_entry->object.vm_object != NULL)
cred = stack_entry->object.vm_object->cred;
if (cred != NULL && !swap_reserve_by_cred(grow_amount, cred))
rv = KERN_NO_SPACE;
/* Grow the underlying object if applicable. */
else if (stack_entry->object.vm_object == NULL ||
vm_object_coalesce(stack_entry->object.vm_object,
stack_entry->offset,
(vm_size_t)(stack_entry->end - stack_entry->start),
(vm_size_t)grow_amount, cred != NULL)) {
map->size += (addr - stack_entry->end);
/* Update the current entry. */
stack_entry->end = addr;
stack_entry->avail_ssize -= grow_amount;
vm_map_entry_resize_free(map, stack_entry);
rv = KERN_SUCCESS;
if (next_entry != &map->header)
vm_map_clip_start(map, next_entry, addr);
} else
rv = KERN_FAILURE;
}
if (rv == KERN_SUCCESS && is_procstack)
vm->vm_ssize += btoc(grow_amount);
vm_map_unlock(map);
/*
* Heed the MAP_WIREFUTURE flag if it was set for this process.
*/
if (rv == KERN_SUCCESS && (map->flags & MAP_WIREFUTURE)) {
vm_map_wire(map,
(stack_entry == next_entry) ? addr : addr - grow_amount,
(stack_entry == next_entry) ? stack_entry->start : addr,
(p->p_flag & P_SYSTEM)
? VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES
: VM_MAP_WIRE_USER|VM_MAP_WIRE_NOHOLES);
}
out:
#ifdef RACCT
if (rv != KERN_SUCCESS) {
PROC_LOCK(p);
error = racct_set(p, RACCT_VMEM, map->size);
KASSERT(error == 0, ("decreasing RACCT_VMEM failed"));
error = racct_set(p, RACCT_STACK, ctob(vm->vm_ssize));
KASSERT(error == 0, ("decreasing RACCT_STACK failed"));
PROC_UNLOCK(p);
}
#endif
return (rv);
}
/*
* Unshare the specified VM space for exec. If other processes are
* mapped to it, then create a new one. The new vmspace is null.
*/
int
vmspace_exec(struct proc *p, vm_offset_t minuser, vm_offset_t maxuser)
{
struct vmspace *oldvmspace = p->p_vmspace;
struct vmspace *newvmspace;
newvmspace = vmspace_alloc(minuser, maxuser);
if (newvmspace == NULL)
return (ENOMEM);
newvmspace->vm_swrss = oldvmspace->vm_swrss;
/*
* 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.
*/
PROC_VMSPACE_LOCK(p);
p->p_vmspace = newvmspace;
PROC_VMSPACE_UNLOCK(p);
if (p == curthread->td_proc)
pmap_activate(curthread);
vmspace_free(oldvmspace);
return (0);
}
/*
* Unshare the specified VM space for forcing COW. This
* is called by rfork, for the (RFMEM|RFPROC) == 0 case.
*/
int
vmspace_unshare(struct proc *p)
{
struct vmspace *oldvmspace = p->p_vmspace;
struct vmspace *newvmspace;
vm_ooffset_t fork_charge;
if (oldvmspace->vm_refcnt == 1)
return (0);
fork_charge = 0;
newvmspace = vmspace_fork(oldvmspace, &fork_charge);
if (newvmspace == NULL)
return (ENOMEM);
if (!swap_reserve_by_cred(fork_charge, p->p_ucred)) {
vmspace_free(newvmspace);
return (ENOMEM);
}
PROC_VMSPACE_LOCK(p);
p->p_vmspace = newvmspace;
PROC_VMSPACE_UNLOCK(p);
if (p == curthread->td_proc)
pmap_activate(curthread);
vmspace_free(oldvmspace);
return (0);
}
/*
* 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(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;
vm_object_t eobject;
vm_size_t size;
struct ucred *cred;
RetryLookup:;
vm_map_lock_read(map);
/*
* Lookup the faulting address.
*/
if (!vm_map_lookup_entry(map, vaddr, out_entry)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
}
entry = *out_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.
*/
prot = entry->protection;
fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
if ((fault_type & prot) != fault_type || prot == VM_PROT_NONE) {
vm_map_unlock_read(map);
return (KERN_PROTECTION_FAILURE);
}
if ((entry->eflags & MAP_ENTRY_USER_WIRED) &&
(entry->eflags & MAP_ENTRY_COW) &&
(fault_type & VM_PROT_WRITE)) {
vm_map_unlock_read(map);
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)
fault_type = entry->protection;
size = entry->end - entry->start;
/*
* 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) != 0 ||
(fault_typea & VM_PROT_COPY) != 0) {
/*
* 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;
if (entry->cred == NULL) {
/*
* The debugger owner is charged for
* the memory.
*/
cred = curthread->td_ucred;
crhold(cred);
if (!swap_reserve_by_cred(size, cred)) {
crfree(cred);
vm_map_unlock(map);
return (KERN_RESOURCE_SHORTAGE);
}
entry->cred = cred;
}
vm_object_shadow(&entry->object.vm_object,
&entry->offset, size);
entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
eobject = entry->object.vm_object;
if (eobject->cred != NULL) {
/*
* The object was not shadowed.
*/
swap_release_by_cred(size, entry->cred);
crfree(entry->cred);
entry->cred = NULL;
} else if (entry->cred != NULL) {
VM_OBJECT_LOCK(eobject);
eobject->cred = entry->cred;
eobject->charge = size;
VM_OBJECT_UNLOCK(eobject);
entry->cred = NULL;
}
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(size));
entry->offset = 0;
if (entry->cred != NULL) {
VM_OBJECT_LOCK(entry->object.vm_object);
entry->object.vm_object->cred = entry->cred;
entry->object.vm_object->charge = size;
VM_OBJECT_UNLOCK(entry->object.vm_object);
entry->cred = NULL;
}
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;
*out_prot = prot;
return (KERN_SUCCESS);
}
/*
* vm_map_lookup_locked:
*
* Lookup the faulting address. A version of vm_map_lookup that returns
* KERN_FAILURE instead of blocking on map lock or memory allocation.
*/
int
vm_map_lookup_locked(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;
/*
* Lookup the faulting address.
*/
if (!vm_map_lookup_entry(map, vaddr, out_entry))
return (KERN_INVALID_ADDRESS);
entry = *out_entry;
/*
* Fail if the entry refers to a submap.
*/
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
return (KERN_FAILURE);
/*
* Check whether this task is allowed to have this page.
*/
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))
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)
fault_type = entry->protection;
if (entry->eflags & MAP_ENTRY_NEEDS_COPY) {
/*
* Fail if the entry was copy-on-write for a write fault.
*/
if (fault_type & VM_PROT_WRITE)
return (KERN_FAILURE);
/*
* We're attempting to read a copy-on-write page --
* don't allow writes.
*/
prot &= ~VM_PROT_WRITE;
}
/*
* Fail if an object should be created.
*/
if (entry->object.vm_object == NULL && !map->system_map)
return (KERN_FAILURE);
/*
* 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;
*out_prot = prot;
return (KERN_SUCCESS);
}
/*
* 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(vm_map_t map, vm_map_entry_t entry)
{
/*
* 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)
{
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) {
db_printf(", share=%p, offset=0x%jx\n",
(void *)entry->object.sub_map,
(uintmax_t)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 {
if (entry->cred != NULL)
db_printf(", ruid %d", entry->cred->cr_ruid);
db_printf(", object=%p, offset=0x%jx",
(void *)entry->object.vm_object,
(uintmax_t)entry->offset);
if (entry->object.vm_object && entry->object.vm_object->cred)
db_printf(", obj ruid %d charge %jx",
entry->object.vm_object->cred->cr_ruid,
(uintmax_t)entry->object.vm_object->charge);
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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