2 * Copyright (c) 1990 University of Utah.
3 * Copyright (c) 1991, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * the Systems Programming Group of the University of Utah Computer
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93
39 * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $
40 * $DragonFly: src/sys/vm/device_pager.c,v 1.13 2008/01/21 10:25:18 corecode Exp $
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
48 #include <sys/device.h>
49 #include <sys/queue.h>
50 #include <sys/malloc.h>
51 #include <sys/thread2.h>
54 #include <vm/vm_object.h>
55 #include <vm/vm_page.h>
56 #include <vm/vm_pager.h>
57 #include <vm/vm_zone.h>
59 static vm_object_t
dev_pager_alloc (void *, off_t
, vm_prot_t
, off_t
);
60 static void dev_pager_dealloc (vm_object_t
);
61 static int dev_pager_getpage (vm_object_t
, vm_page_t
*, int);
62 static void dev_pager_putpages (vm_object_t
, vm_page_t
*, int,
64 static boolean_t
dev_pager_haspage (vm_object_t
, vm_pindex_t
);
66 /* list of device pager objects */
67 static TAILQ_HEAD(, vm_page
) dev_freepages_list
=
68 TAILQ_HEAD_INITIALIZER(dev_freepages_list
);
69 static MALLOC_DEFINE(M_FICTITIOUS_PAGES
, "device-mapped pages", "Device mapped pages");
71 static vm_page_t
dev_pager_getfake (vm_paddr_t
);
72 static void dev_pager_putfake (vm_page_t
);
74 static int dev_pager_alloc_lock
, dev_pager_alloc_lock_want
;
76 struct pagerops devicepagerops
= {
85 dev_pager_alloc(void *handle
, off_t size
, vm_prot_t prot
, off_t foff
)
93 * Make sure this device can be mapped.
98 * Offset should be page aligned.
100 if (foff
& PAGE_MASK
)
103 size
= round_page(size
);
106 * Check that the specified range of the device allows the desired
109 * XXX assumes VM_PROT_* == PROT_*
111 npages
= OFF_TO_IDX(size
);
112 for (off
= foff
; npages
--; off
+= PAGE_SIZE
) {
113 if (dev_dmmap(dev
, off
, (int)prot
) == -1)
118 * Lock to prevent object creation race condition.
120 while (dev_pager_alloc_lock
) {
121 dev_pager_alloc_lock_want
++;
122 tsleep(&dev_pager_alloc_lock
, 0, "dvpall", 0);
123 dev_pager_alloc_lock_want
--;
125 dev_pager_alloc_lock
= 1;
128 * Look up pager, creating as necessary.
130 object
= dev
->si_object
;
131 if (object
== NULL
) {
133 * Allocate object and associate it with the pager.
135 object
= vm_object_allocate(OBJT_DEVICE
,
136 OFF_TO_IDX(foff
+ size
));
137 object
->handle
= handle
;
138 TAILQ_INIT(&object
->un_pager
.devp
.devp_pglist
);
139 dev
->si_object
= object
;
142 * Gain a reference to the object.
144 vm_object_reference(object
);
145 if (OFF_TO_IDX(foff
+ size
) > object
->size
)
146 object
->size
= OFF_TO_IDX(foff
+ size
);
149 dev_pager_alloc_lock
= 0;
150 if (dev_pager_alloc_lock_want
)
151 wakeup(&dev_pager_alloc_lock
);
157 dev_pager_dealloc(vm_object_t object
)
162 if ((dev
= object
->handle
) != NULL
) {
163 KKASSERT(dev
->si_object
);
164 dev
->si_object
= NULL
;
168 * Free up our fake pages.
170 while ((m
= TAILQ_FIRST(&object
->un_pager
.devp
.devp_pglist
)) != 0) {
171 TAILQ_REMOVE(&object
->un_pager
.devp
.devp_pglist
, m
, pageq
);
172 dev_pager_putfake(m
);
177 dev_pager_getpage(vm_object_t object
, vm_page_t
*mpp
, int seqaccess
)
186 dev
= object
->handle
;
187 offset
= page
->pindex
;
188 prot
= PROT_READ
; /* XXX should pass in? */
190 paddr
= pmap_phys_address(
191 dev_dmmap(dev
, (vm_offset_t
)offset
<< PAGE_SHIFT
, prot
));
192 KASSERT(paddr
!= -1,("dev_pager_getpage: map function returns error"));
194 if (page
->flags
& PG_FICTITIOUS
) {
196 * If the passed in reqpage page is a fake page, update it
197 * with the new physical address.
199 page
->phys_addr
= paddr
;
200 page
->valid
= VM_PAGE_BITS_ALL
;
203 * Replace the passed in reqpage page with our own fake page
204 * and free up all the original pages.
206 page
= dev_pager_getfake(paddr
);
207 TAILQ_INSERT_TAIL(&object
->un_pager
.devp
.devp_pglist
, page
, pageq
);
210 vm_page_insert(page
, object
, offset
);
213 return (VM_PAGER_OK
);
217 dev_pager_putpages(vm_object_t object
, vm_page_t
*m
,
218 int count
, boolean_t sync
, int *rtvals
)
220 panic("dev_pager_putpage called");
224 dev_pager_haspage(vm_object_t object
, vm_pindex_t pindex
)
230 dev_pager_getfake(vm_paddr_t paddr
)
234 if ((m
= TAILQ_FIRST(&dev_freepages_list
)) != NULL
) {
235 TAILQ_REMOVE(&dev_freepages_list
, m
, pageq
);
237 m
= kmalloc(sizeof(*m
), M_FICTITIOUS_PAGES
, M_WAITOK
);
239 bzero(m
, sizeof(*m
));
241 m
->flags
= PG_BUSY
| PG_FICTITIOUS
;
242 m
->valid
= VM_PAGE_BITS_ALL
;
250 m
->phys_addr
= paddr
;
256 * Synthesized VM pages must be structurally stable for lockless lookups to
260 dev_pager_putfake(vm_page_t m
)
262 if (!(m
->flags
& PG_FICTITIOUS
))
263 panic("dev_pager_putfake: bad page");
264 KKASSERT(m
->object
== NULL
);
265 TAILQ_INSERT_HEAD(&dev_freepages_list
, m
, pageq
);