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uvm_map.c
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uvm_map.c
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/* $NetBSD: uvm_map.c,v 1.297.2.1 2011/06/23 14:20:35 cherry Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* Copyright (c) 1991, 1993, The Regents of the University of California.
*
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. 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.
*
* @(#)vm_map.c 8.3 (Berkeley) 1/12/94
* from: Id: uvm_map.c,v 1.1.2.27 1998/02/07 01:16:54 chs Exp
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* 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.
*/
/*
* uvm_map.c: uvm map operations
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.297.2.1 2011/06/23 14:20:35 cherry Exp $");
#include "opt_ddb.h"
#include "opt_uvmhist.h"
#include "opt_uvm.h"
#include "opt_sysv.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mman.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/kernel.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/lockdebug.h>
#include <sys/atomic.h>
#ifndef __USER_VA0_IS_SAFE
#include <sys/sysctl.h>
#include <sys/kauth.h>
#include "opt_user_va0_disable_default.h"
#endif
#ifdef SYSVSHM
#include <sys/shm.h>
#endif
#include <uvm/uvm.h>
#include <uvm/uvm_readahead.h>
#if defined(DDB) || defined(DEBUGPRINT)
#include <uvm/uvm_ddb.h>
#endif
#if !defined(UVMMAP_COUNTERS)
#define UVMMAP_EVCNT_DEFINE(name) /* nothing */
#define UVMMAP_EVCNT_INCR(ev) /* nothing */
#define UVMMAP_EVCNT_DECR(ev) /* nothing */
#else /* defined(UVMMAP_NOCOUNTERS) */
#include <sys/evcnt.h>
#define UVMMAP_EVCNT_DEFINE(name) \
struct evcnt uvmmap_evcnt_##name = EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, \
"uvmmap", #name); \
EVCNT_ATTACH_STATIC(uvmmap_evcnt_##name);
#define UVMMAP_EVCNT_INCR(ev) uvmmap_evcnt_##ev.ev_count++
#define UVMMAP_EVCNT_DECR(ev) uvmmap_evcnt_##ev.ev_count--
#endif /* defined(UVMMAP_NOCOUNTERS) */
UVMMAP_EVCNT_DEFINE(ubackmerge)
UVMMAP_EVCNT_DEFINE(uforwmerge)
UVMMAP_EVCNT_DEFINE(ubimerge)
UVMMAP_EVCNT_DEFINE(unomerge)
UVMMAP_EVCNT_DEFINE(kbackmerge)
UVMMAP_EVCNT_DEFINE(kforwmerge)
UVMMAP_EVCNT_DEFINE(kbimerge)
UVMMAP_EVCNT_DEFINE(knomerge)
UVMMAP_EVCNT_DEFINE(map_call)
UVMMAP_EVCNT_DEFINE(mlk_call)
UVMMAP_EVCNT_DEFINE(mlk_hint)
UVMMAP_EVCNT_DEFINE(mlk_list)
UVMMAP_EVCNT_DEFINE(mlk_tree)
UVMMAP_EVCNT_DEFINE(mlk_treeloop)
UVMMAP_EVCNT_DEFINE(mlk_listloop)
UVMMAP_EVCNT_DEFINE(uke_alloc)
UVMMAP_EVCNT_DEFINE(uke_free)
UVMMAP_EVCNT_DEFINE(ukh_alloc)
UVMMAP_EVCNT_DEFINE(ukh_free)
const char vmmapbsy[] = "vmmapbsy";
/*
* cache for vmspace structures.
*/
static struct pool_cache uvm_vmspace_cache;
/*
* cache for dynamically-allocated map entries.
*/
static struct pool_cache uvm_map_entry_cache;
MALLOC_DEFINE(M_VMMAP, "VM map", "VM map structures");
MALLOC_DEFINE(M_VMPMAP, "VM pmap", "VM pmap");
#ifdef PMAP_GROWKERNEL
/*
* This global represents the end of the kernel virtual address
* space. If we want to exceed this, we must grow the kernel
* virtual address space dynamically.
*
* Note, this variable is locked by kernel_map's lock.
*/
vaddr_t uvm_maxkaddr;
#endif
#ifndef __USER_VA0_IS_SAFE
#ifndef __USER_VA0_DISABLE_DEFAULT
#define __USER_VA0_DISABLE_DEFAULT 1
#endif
#ifdef USER_VA0_DISABLE_DEFAULT /* kernel config option overrides */
#undef __USER_VA0_DISABLE_DEFAULT
#define __USER_VA0_DISABLE_DEFAULT USER_VA0_DISABLE_DEFAULT
#endif
static int user_va0_disable = __USER_VA0_DISABLE_DEFAULT;
#endif
/*
* macros
*/
/*
* VM_MAP_USE_KMAPENT: determine if uvm_kmapent_alloc/free is used
* for the vm_map.
*/
extern struct vm_map *pager_map; /* XXX */
#define VM_MAP_USE_KMAPENT_FLAGS(flags) \
(((flags) & VM_MAP_INTRSAFE) != 0)
#define VM_MAP_USE_KMAPENT(map) \
(VM_MAP_USE_KMAPENT_FLAGS((map)->flags) || (map) == kernel_map)
/*
* UVM_ET_ISCOMPATIBLE: check some requirements for map entry merging
*/
#define UVM_ET_ISCOMPATIBLE(ent, type, uobj, meflags, \
prot, maxprot, inh, adv, wire) \
((ent)->etype == (type) && \
(((ent)->flags ^ (meflags)) & (UVM_MAP_NOMERGE | UVM_MAP_QUANTUM)) \
== 0 && \
(ent)->object.uvm_obj == (uobj) && \
(ent)->protection == (prot) && \
(ent)->max_protection == (maxprot) && \
(ent)->inheritance == (inh) && \
(ent)->advice == (adv) && \
(ent)->wired_count == (wire))
/*
* uvm_map_entry_link: insert entry into a map
*
* => map must be locked
*/
#define uvm_map_entry_link(map, after_where, entry) do { \
uvm_mapent_check(entry); \
(map)->nentries++; \
(entry)->prev = (after_where); \
(entry)->next = (after_where)->next; \
(entry)->prev->next = (entry); \
(entry)->next->prev = (entry); \
uvm_rb_insert((map), (entry)); \
} while (/*CONSTCOND*/ 0)
/*
* uvm_map_entry_unlink: remove entry from a map
*
* => map must be locked
*/
#define uvm_map_entry_unlink(map, entry) do { \
KASSERT((entry) != (map)->first_free); \
KASSERT((entry) != (map)->hint); \
uvm_mapent_check(entry); \
(map)->nentries--; \
(entry)->next->prev = (entry)->prev; \
(entry)->prev->next = (entry)->next; \
uvm_rb_remove((map), (entry)); \
} while (/*CONSTCOND*/ 0)
/*
* SAVE_HINT: saves the specified entry as the hint for future lookups.
*
* => map need not be locked.
*/
#define SAVE_HINT(map, check, value) do { \
if ((map)->hint == (check)) \
(map)->hint = (value); \
} while (/*CONSTCOND*/ 0)
/*
* clear_hints: ensure that hints don't point to the entry.
*
* => map must be write-locked.
*/
static void
clear_hints(struct vm_map *map, struct vm_map_entry *ent)
{
SAVE_HINT(map, ent, ent->prev);
if (map->first_free == ent) {
map->first_free = ent->prev;
}
}
/*
* VM_MAP_RANGE_CHECK: check and correct range
*
* => map must at least be read locked
*/
#define VM_MAP_RANGE_CHECK(map, start, end) do { \
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; \
} while (/*CONSTCOND*/ 0)
/*
* local prototypes
*/
static struct vm_map_entry *
uvm_mapent_alloc(struct vm_map *, int);
static struct vm_map_entry *
uvm_mapent_alloc_split(struct vm_map *,
const struct vm_map_entry *, int,
struct uvm_mapent_reservation *);
static void uvm_mapent_copy(struct vm_map_entry *, struct vm_map_entry *);
static void uvm_mapent_free(struct vm_map_entry *);
#if defined(DEBUG)
static void _uvm_mapent_check(const struct vm_map_entry *, const char *,
int);
#define uvm_mapent_check(map) _uvm_mapent_check(map, __FILE__, __LINE__)
#else /* defined(DEBUG) */
#define uvm_mapent_check(e) /* nothing */
#endif /* defined(DEBUG) */
static struct vm_map_entry *
uvm_kmapent_alloc(struct vm_map *, int);
static void uvm_kmapent_free(struct vm_map_entry *);
static vsize_t uvm_kmapent_overhead(vsize_t);
static void uvm_map_entry_unwire(struct vm_map *, struct vm_map_entry *);
static void uvm_map_reference_amap(struct vm_map_entry *, int);
static int uvm_map_space_avail(vaddr_t *, vsize_t, voff_t, vsize_t, int,
struct vm_map_entry *);
static void uvm_map_unreference_amap(struct vm_map_entry *, int);
int _uvm_map_sanity(struct vm_map *);
int _uvm_tree_sanity(struct vm_map *);
static vsize_t uvm_rb_maxgap(const struct vm_map_entry *);
#define ROOT_ENTRY(map) ((struct vm_map_entry *)(map)->rb_tree.rbt_root)
#define LEFT_ENTRY(entry) ((struct vm_map_entry *)(entry)->rb_node.rb_left)
#define RIGHT_ENTRY(entry) ((struct vm_map_entry *)(entry)->rb_node.rb_right)
#define PARENT_ENTRY(map, entry) \
(ROOT_ENTRY(map) == (entry) \
? NULL : (struct vm_map_entry *)RB_FATHER(&(entry)->rb_node))
static int
uvm_map_compare_nodes(void *ctx, const void *nparent, const void *nkey)
{
const struct vm_map_entry *eparent = nparent;
const struct vm_map_entry *ekey = nkey;
KASSERT(eparent->start < ekey->start || eparent->start >= ekey->end);
KASSERT(ekey->start < eparent->start || ekey->start >= eparent->end);
if (eparent->start < ekey->start)
return -1;
if (eparent->end >= ekey->start)
return 1;
return 0;
}
static int
uvm_map_compare_key(void *ctx, const void *nparent, const void *vkey)
{
const struct vm_map_entry *eparent = nparent;
const vaddr_t va = *(const vaddr_t *) vkey;
if (eparent->start < va)
return -1;
if (eparent->end >= va)
return 1;
return 0;
}
static const rb_tree_ops_t uvm_map_tree_ops = {
.rbto_compare_nodes = uvm_map_compare_nodes,
.rbto_compare_key = uvm_map_compare_key,
.rbto_node_offset = offsetof(struct vm_map_entry, rb_node),
.rbto_context = NULL
};
/*
* uvm_rb_gap: return the gap size between our entry and next entry.
*/
static inline vsize_t
uvm_rb_gap(const struct vm_map_entry *entry)
{
KASSERT(entry->next != NULL);
return entry->next->start - entry->end;
}
static vsize_t
uvm_rb_maxgap(const struct vm_map_entry *entry)
{
struct vm_map_entry *child;
vsize_t maxgap = entry->gap;
/*
* We need maxgap to be the largest gap of us or any of our
* descendents. Since each of our children's maxgap is the
* cached value of their largest gap of themselves or their
* descendents, we can just use that value and avoid recursing
* down the tree to calculate it.
*/
if ((child = LEFT_ENTRY(entry)) != NULL && maxgap < child->maxgap)
maxgap = child->maxgap;
if ((child = RIGHT_ENTRY(entry)) != NULL && maxgap < child->maxgap)
maxgap = child->maxgap;
return maxgap;
}
static void
uvm_rb_fixup(struct vm_map *map, struct vm_map_entry *entry)
{
struct vm_map_entry *parent;
KASSERT(entry->gap == uvm_rb_gap(entry));
entry->maxgap = uvm_rb_maxgap(entry);
while ((parent = PARENT_ENTRY(map, entry)) != NULL) {
struct vm_map_entry *brother;
vsize_t maxgap = parent->gap;
unsigned int which;
KDASSERT(parent->gap == uvm_rb_gap(parent));
if (maxgap < entry->maxgap)
maxgap = entry->maxgap;
/*
* Since we work towards the root, we know entry's maxgap
* value is OK, but its brothers may now be out-of-date due
* to rebalancing. So refresh it.
*/
which = RB_POSITION(&entry->rb_node) ^ RB_DIR_OTHER;
brother = (struct vm_map_entry *)parent->rb_node.rb_nodes[which];
if (brother != NULL) {
KDASSERT(brother->gap == uvm_rb_gap(brother));
brother->maxgap = uvm_rb_maxgap(brother);
if (maxgap < brother->maxgap)
maxgap = brother->maxgap;
}
parent->maxgap = maxgap;
entry = parent;
}
}
static void
uvm_rb_insert(struct vm_map *map, struct vm_map_entry *entry)
{
struct vm_map_entry *ret;
entry->gap = entry->maxgap = uvm_rb_gap(entry);
if (entry->prev != &map->header)
entry->prev->gap = uvm_rb_gap(entry->prev);
ret = rb_tree_insert_node(&map->rb_tree, entry);
KASSERTMSG(ret == entry,
("uvm_rb_insert: map %p: duplicate entry %p", map, ret)
);
/*
* If the previous entry is not our immediate left child, then it's an
* ancestor and will be fixed up on the way to the root. We don't
* have to check entry->prev against &map->header since &map->header
* will never be in the tree.
*/
uvm_rb_fixup(map,
LEFT_ENTRY(entry) == entry->prev ? entry->prev : entry);
}
static void
uvm_rb_remove(struct vm_map *map, struct vm_map_entry *entry)
{
struct vm_map_entry *prev_parent = NULL, *next_parent = NULL;
/*
* If we are removing an interior node, then an adjacent node will
* be used to replace its position in the tree. Therefore we will
* need to fixup the tree starting at the parent of the replacement
* node. So record their parents for later use.
*/
if (entry->prev != &map->header)
prev_parent = PARENT_ENTRY(map, entry->prev);
if (entry->next != &map->header)
next_parent = PARENT_ENTRY(map, entry->next);
rb_tree_remove_node(&map->rb_tree, entry);
/*
* If the previous node has a new parent, fixup the tree starting
* at the previous node's old parent.
*/
if (entry->prev != &map->header) {
/*
* Update the previous entry's gap due to our absence.
*/
entry->prev->gap = uvm_rb_gap(entry->prev);
uvm_rb_fixup(map, entry->prev);
if (prev_parent != NULL
&& prev_parent != entry
&& prev_parent != PARENT_ENTRY(map, entry->prev))
uvm_rb_fixup(map, prev_parent);
}
/*
* If the next node has a new parent, fixup the tree starting
* at the next node's old parent.
*/
if (entry->next != &map->header) {
uvm_rb_fixup(map, entry->next);
if (next_parent != NULL
&& next_parent != entry
&& next_parent != PARENT_ENTRY(map, entry->next))
uvm_rb_fixup(map, next_parent);
}
}
#if defined(DEBUG)
int uvm_debug_check_map = 0;
int uvm_debug_check_rbtree = 0;
#define uvm_map_check(map, name) \
_uvm_map_check((map), (name), __FILE__, __LINE__)
static void
_uvm_map_check(struct vm_map *map, const char *name,
const char *file, int line)
{
if ((uvm_debug_check_map && _uvm_map_sanity(map)) ||
(uvm_debug_check_rbtree && _uvm_tree_sanity(map))) {
panic("uvm_map_check failed: \"%s\" map=%p (%s:%d)",
name, map, file, line);
}
}
#else /* defined(DEBUG) */
#define uvm_map_check(map, name) /* nothing */
#endif /* defined(DEBUG) */
#if defined(DEBUG) || defined(DDB)
int
_uvm_map_sanity(struct vm_map *map)
{
bool first_free_found = false;
bool hint_found = false;
const struct vm_map_entry *e;
struct vm_map_entry *hint = map->hint;
e = &map->header;
for (;;) {
if (map->first_free == e) {
first_free_found = true;
} else if (!first_free_found && e->next->start > e->end) {
printf("first_free %p should be %p\n",
map->first_free, e);
return -1;
}
if (hint == e) {
hint_found = true;
}
e = e->next;
if (e == &map->header) {
break;
}
}
if (!first_free_found) {
printf("stale first_free\n");
return -1;
}
if (!hint_found) {
printf("stale hint\n");
return -1;
}
return 0;
}
int
_uvm_tree_sanity(struct vm_map *map)
{
struct vm_map_entry *tmp, *trtmp;
int n = 0, i = 1;
for (tmp = map->header.next; tmp != &map->header; tmp = tmp->next) {
if (tmp->gap != uvm_rb_gap(tmp)) {
printf("%d/%d gap %lx != %lx %s\n",
n + 1, map->nentries,
(ulong)tmp->gap, (ulong)uvm_rb_gap(tmp),
tmp->next == &map->header ? "(last)" : "");
goto error;
}
/*
* If any entries are out of order, tmp->gap will be unsigned
* and will likely exceed the size of the map.
*/
if (tmp->gap >= vm_map_max(map) - vm_map_min(map)) {
printf("too large gap %zu\n", (size_t)tmp->gap);
goto error;
}
n++;
}
if (n != map->nentries) {
printf("nentries: %d vs %d\n", n, map->nentries);
goto error;
}
trtmp = NULL;
for (tmp = map->header.next; tmp != &map->header; tmp = tmp->next) {
if (tmp->maxgap != uvm_rb_maxgap(tmp)) {
printf("maxgap %lx != %lx\n",
(ulong)tmp->maxgap,
(ulong)uvm_rb_maxgap(tmp));
goto error;
}
if (trtmp != NULL && trtmp->start >= tmp->start) {
printf("corrupt: 0x%"PRIxVADDR"x >= 0x%"PRIxVADDR"x\n",
trtmp->start, tmp->start);
goto error;
}
trtmp = tmp;
}
for (tmp = map->header.next; tmp != &map->header;
tmp = tmp->next, i++) {
trtmp = rb_tree_iterate(&map->rb_tree, tmp, RB_DIR_LEFT);
if (trtmp == NULL)
trtmp = &map->header;
if (tmp->prev != trtmp) {
printf("lookup: %d: %p->prev=%p: %p\n",
i, tmp, tmp->prev, trtmp);
goto error;
}
trtmp = rb_tree_iterate(&map->rb_tree, tmp, RB_DIR_RIGHT);
if (trtmp == NULL)
trtmp = &map->header;
if (tmp->next != trtmp) {
printf("lookup: %d: %p->next=%p: %p\n",
i, tmp, tmp->next, trtmp);
goto error;
}
trtmp = rb_tree_find_node(&map->rb_tree, &tmp->start);
if (trtmp != tmp) {
printf("lookup: %d: %p - %p: %p\n", i, tmp, trtmp,
PARENT_ENTRY(map, tmp));
goto error;
}
}
return (0);
error:
return (-1);
}
#endif /* defined(DEBUG) || defined(DDB) */
#ifdef DIAGNOSTIC
static struct vm_map *uvm_kmapent_map(struct vm_map_entry *);
#endif
/*
* vm_map_lock: acquire an exclusive (write) lock on a map.
*
* => Note that "intrsafe" maps use only exclusive, spin locks.
*
* => The locking protocol provides for guaranteed upgrade from shared ->
* exclusive by whichever thread currently has the map marked busy.
* See "LOCKING PROTOCOL NOTES" in uvm_map.h. This is horrible; among
* other problems, it defeats any fairness guarantees provided by RW
* locks.
*/
void
vm_map_lock(struct vm_map *map)
{
if ((map->flags & VM_MAP_INTRSAFE) != 0) {
mutex_spin_enter(&map->mutex);
return;
}
for (;;) {
rw_enter(&map->lock, RW_WRITER);
if (map->busy == NULL)
break;
if (map->busy == curlwp)
break;
mutex_enter(&map->misc_lock);
rw_exit(&map->lock);
if (map->busy != NULL)
cv_wait(&map->cv, &map->misc_lock);
mutex_exit(&map->misc_lock);
}
map->timestamp++;
}
/*
* vm_map_lock_try: try to lock a map, failing if it is already locked.
*/
bool
vm_map_lock_try(struct vm_map *map)
{
if ((map->flags & VM_MAP_INTRSAFE) != 0)
return mutex_tryenter(&map->mutex);
if (!rw_tryenter(&map->lock, RW_WRITER))
return false;
if (map->busy != NULL) {
rw_exit(&map->lock);
return false;
}
map->timestamp++;
return true;
}
/*
* vm_map_unlock: release an exclusive lock on a map.
*/
void
vm_map_unlock(struct vm_map *map)
{
if ((map->flags & VM_MAP_INTRSAFE) != 0)
mutex_spin_exit(&map->mutex);
else {
KASSERT(rw_write_held(&map->lock));
KASSERT(map->busy == NULL || map->busy == curlwp);
rw_exit(&map->lock);
}
}
/*
* vm_map_unbusy: mark the map as unbusy, and wake any waiters that
* want an exclusive lock.
*/
void
vm_map_unbusy(struct vm_map *map)
{
KASSERT(map->busy == curlwp);
/*
* Safe to clear 'busy' and 'waiters' with only a read lock held:
*
* o they can only be set with a write lock held
* o writers are blocked out with a read or write hold
* o at any time, only one thread owns the set of values
*/
mutex_enter(&map->misc_lock);
map->busy = NULL;
cv_broadcast(&map->cv);
mutex_exit(&map->misc_lock);
}
/*
* vm_map_lock_read: acquire a shared (read) lock on a map.
*/
void
vm_map_lock_read(struct vm_map *map)
{
KASSERT((map->flags & VM_MAP_INTRSAFE) == 0);
rw_enter(&map->lock, RW_READER);
}
/*
* vm_map_unlock_read: release a shared lock on a map.
*/
void
vm_map_unlock_read(struct vm_map *map)
{
KASSERT((map->flags & VM_MAP_INTRSAFE) == 0);
rw_exit(&map->lock);
}
/*
* vm_map_busy: mark a map as busy.
*
* => the caller must hold the map write locked
*/
void
vm_map_busy(struct vm_map *map)
{
KASSERT(rw_write_held(&map->lock));
KASSERT(map->busy == NULL);
map->busy = curlwp;
}
/*
* vm_map_locked_p: return true if the map is write locked.
*
* => only for debug purposes like KASSERTs.
* => should not be used to verify that a map is not locked.
*/
bool
vm_map_locked_p(struct vm_map *map)
{
if ((map->flags & VM_MAP_INTRSAFE) != 0) {
return mutex_owned(&map->mutex);
} else {
return rw_write_held(&map->lock);
}
}
/*
* uvm_mapent_alloc: allocate a map entry
*/
static struct vm_map_entry *
uvm_mapent_alloc(struct vm_map *map, int flags)
{
struct vm_map_entry *me;
int pflags = (flags & UVM_FLAG_NOWAIT) ? PR_NOWAIT : PR_WAITOK;
UVMHIST_FUNC("uvm_mapent_alloc"); UVMHIST_CALLED(maphist);
if (VM_MAP_USE_KMAPENT(map)) {
me = uvm_kmapent_alloc(map, flags);
} else {
me = pool_cache_get(&uvm_map_entry_cache, pflags);
if (__predict_false(me == NULL))
return NULL;
me->flags = 0;
}
UVMHIST_LOG(maphist, "<- new entry=0x%x [kentry=%d]", me,
((map->flags & VM_MAP_INTRSAFE) != 0 || map == kernel_map), 0, 0);
return (me);
}
/*
* uvm_mapent_alloc_split: allocate a map entry for clipping.
*
* => map must be locked by caller if UVM_MAP_QUANTUM is set.
*/
static struct vm_map_entry *
uvm_mapent_alloc_split(struct vm_map *map,
const struct vm_map_entry *old_entry, int flags,
struct uvm_mapent_reservation *umr)
{
struct vm_map_entry *me;
KASSERT(!VM_MAP_USE_KMAPENT(map) ||
(old_entry->flags & UVM_MAP_QUANTUM) || !UMR_EMPTY(umr));
if (old_entry->flags & UVM_MAP_QUANTUM) {
struct vm_map_kernel *vmk = vm_map_to_kernel(map);
KASSERT(vm_map_locked_p(map));
me = vmk->vmk_merged_entries;
KASSERT(me);
vmk->vmk_merged_entries = me->next;
KASSERT(me->flags & UVM_MAP_QUANTUM);
} else {
me = uvm_mapent_alloc(map, flags);
}
return me;
}
/*
* uvm_mapent_free: free map entry
*/
static void
uvm_mapent_free(struct vm_map_entry *me)
{
UVMHIST_FUNC("uvm_mapent_free"); UVMHIST_CALLED(maphist);
UVMHIST_LOG(maphist,"<- freeing map entry=0x%x [flags=%d]",
me, me->flags, 0, 0);
if (me->flags & UVM_MAP_KERNEL) {
uvm_kmapent_free(me);
} else {
pool_cache_put(&uvm_map_entry_cache, me);
}
}
/*
* uvm_mapent_free_merged: free merged map entry
*
* => keep the entry if needed.
* => caller shouldn't hold map locked if VM_MAP_USE_KMAPENT(map) is true.
* => map should be locked if UVM_MAP_QUANTUM is set.
*/
static void
uvm_mapent_free_merged(struct vm_map *map, struct vm_map_entry *me)
{
KASSERT(!(me->flags & UVM_MAP_KERNEL) || uvm_kmapent_map(me) == map);
if (me->flags & UVM_MAP_QUANTUM) {
/*
* keep this entry for later splitting.
*/
struct vm_map_kernel *vmk;
KASSERT(vm_map_locked_p(map));
KASSERT(VM_MAP_IS_KERNEL(map));
KASSERT(!VM_MAP_USE_KMAPENT(map) ||
(me->flags & UVM_MAP_KERNEL));
vmk = vm_map_to_kernel(map);
me->next = vmk->vmk_merged_entries;
vmk->vmk_merged_entries = me;
} else {
uvm_mapent_free(me);
}
}
/*
* uvm_mapent_copy: copy a map entry, preserving flags
*/
static inline void
uvm_mapent_copy(struct vm_map_entry *src, struct vm_map_entry *dst)
{
memcpy(dst, src, ((char *)&src->uvm_map_entry_stop_copy) -
((char *)src));
}
/*
* uvm_mapent_overhead: calculate maximum kva overhead necessary for
* map entries.
*
* => size and flags are the same as uvm_km_suballoc's ones.
*/
vsize_t
uvm_mapent_overhead(vsize_t size, int flags)
{
if (VM_MAP_USE_KMAPENT_FLAGS(flags)) {
return uvm_kmapent_overhead(size);
}
return 0;
}
#if defined(DEBUG)
static void
_uvm_mapent_check(const struct vm_map_entry *entry, const char *file, int line)
{
if (entry->start >= entry->end) {
goto bad;
}
if (UVM_ET_ISOBJ(entry)) {
if (entry->object.uvm_obj == NULL) {
goto bad;
}
} else if (UVM_ET_ISSUBMAP(entry)) {
if (entry->object.sub_map == NULL) {
goto bad;
}
} else {
if (entry->object.uvm_obj != NULL ||
entry->object.sub_map != NULL) {
goto bad;
}
}
if (!UVM_ET_ISOBJ(entry)) {
if (entry->offset != 0) {
goto bad;
}
}
return;
bad:
panic("%s: bad entry %p (%s:%d)", __func__, entry, file, line);
}
#endif /* defined(DEBUG) */
/*
* uvm_map_entry_unwire: unwire a map entry
*
* => map should be locked by caller
*/
static inline void
uvm_map_entry_unwire(struct vm_map *map, struct vm_map_entry *entry)
{
entry->wired_count = 0;
uvm_fault_unwire_locked(map, entry->start, entry->end);
}
/*
* wrapper for calling amap_ref()
*/
static inline void
uvm_map_reference_amap(struct vm_map_entry *entry, int flags)
{
amap_ref(entry->aref.ar_amap, entry->aref.ar_pageoff,
(entry->end - entry->start) >> PAGE_SHIFT, flags);
}
/*
* wrapper for calling amap_unref()
*/
static inline void
uvm_map_unreference_amap(struct vm_map_entry *entry, int flags)