4 * Copyright (c) 1990 University of Utah.
5 * Copyright (c) 1991, 1993
6 * The Regents of the University of California. All rights reserved.
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93
41 * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
49 #include <sys/device.h>
50 #include <sys/queue.h>
51 #include <sys/malloc.h>
52 #include <sys/thread2.h>
53 #include <sys/mutex2.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_page.h>
58 #include <vm/vm_pager.h>
59 #include <vm/vm_zone.h>
61 static void dev_pager_dealloc (vm_object_t
);
62 static int dev_pager_getpage (vm_object_t
, vm_page_t
*, int);
63 static void dev_pager_putpages (vm_object_t
, vm_page_t
*, int,
65 static boolean_t
dev_pager_haspage (vm_object_t
, vm_pindex_t
);
67 /* list of device pager objects */
68 static TAILQ_HEAD(, vm_page
) dev_freepages_list
=
69 TAILQ_HEAD_INITIALIZER(dev_freepages_list
);
70 static MALLOC_DEFINE(M_FICTITIOUS_PAGES
, "device-mapped pages",
71 "Device mapped pages");
73 static vm_page_t
dev_pager_getfake (vm_paddr_t
);
74 static void dev_pager_putfake (vm_page_t
);
76 struct pagerops devicepagerops
= {
83 static struct mtx dev_pager_mtx
= MTX_INITIALIZER
;
89 dev_pager_alloc(void *handle
, off_t size
, vm_prot_t prot
, off_t foff
)
97 * Make sure this device can be mapped.
102 * Offset should be page aligned.
104 if (foff
& PAGE_MASK
)
107 size
= round_page64(size
);
110 * Check that the specified range of the device allows the desired
113 * XXX assumes VM_PROT_* == PROT_*
115 npages
= OFF_TO_IDX(size
);
116 for (off
= foff
; npages
--; off
+= PAGE_SIZE
) {
117 if (dev_dmmap(dev
, off
, (int)prot
) == -1)
122 * Look up pager, creating as necessary.
124 mtx_lock(&dev_pager_mtx
);
125 object
= dev
->si_object
;
126 if (object
== NULL
) {
128 * Allocate object and associate it with the pager.
130 object
= vm_object_allocate_hold(OBJT_DEVICE
,
131 OFF_TO_IDX(foff
+ size
));
132 object
->handle
= handle
;
133 TAILQ_INIT(&object
->un_pager
.devp
.devp_pglist
);
134 dev
->si_object
= object
;
135 vm_object_drop(object
);
138 * Gain a reference to the object.
140 vm_object_hold(object
);
141 vm_object_reference_locked(object
);
142 if (OFF_TO_IDX(foff
+ size
) > object
->size
)
143 object
->size
= OFF_TO_IDX(foff
+ size
);
144 vm_object_drop(object
);
146 mtx_unlock(&dev_pager_mtx
);
155 dev_pager_dealloc(vm_object_t object
)
160 mtx_lock(&dev_pager_mtx
);
162 if ((dev
= object
->handle
) != NULL
) {
163 KKASSERT(dev
->si_object
);
164 dev
->si_object
= NULL
;
166 KKASSERT(object
->swblock_count
== 0);
169 * Free up our fake pages.
171 while ((m
= TAILQ_FIRST(&object
->un_pager
.devp
.devp_pglist
)) != 0) {
172 TAILQ_REMOVE(&object
->un_pager
.devp
.devp_pglist
, m
, pageq
);
173 dev_pager_putfake(m
);
175 mtx_unlock(&dev_pager_mtx
);
182 dev_pager_getpage(vm_object_t object
, vm_page_t
*mpp
, int seqaccess
)
190 mtx_lock(&dev_pager_mtx
);
193 dev
= object
->handle
;
194 offset
= page
->pindex
;
195 prot
= PROT_READ
; /* XXX should pass in? */
197 paddr
= pmap_phys_address(
198 dev_dmmap(dev
, (vm_offset_t
)offset
<< PAGE_SHIFT
, prot
));
199 KASSERT(paddr
!= -1,("dev_pager_getpage: map function returns error"));
201 if (page
->flags
& PG_FICTITIOUS
) {
203 * If the passed in reqpage page is a fake page, update it
204 * with the new physical address.
206 page
->phys_addr
= paddr
;
207 page
->valid
= VM_PAGE_BITS_ALL
;
210 * Replace the passed in reqpage page with our own fake page
211 * and free up all the original pages.
213 page
= dev_pager_getfake(paddr
);
214 TAILQ_INSERT_TAIL(&object
->un_pager
.devp
.devp_pglist
,
216 vm_object_hold(object
);
218 if (vm_page_insert(page
, object
, offset
) == FALSE
) {
219 panic("dev_pager_getpage: page (%p,%ld) exists",
222 vm_object_drop(object
);
224 mtx_unlock(&dev_pager_mtx
);
225 return (VM_PAGER_OK
);
232 dev_pager_putpages(vm_object_t object
, vm_page_t
*m
,
233 int count
, boolean_t sync
, int *rtvals
)
235 panic("dev_pager_putpage called");
242 dev_pager_haspage(vm_object_t object
, vm_pindex_t pindex
)
248 * The caller must hold dev_pager_mtx
251 dev_pager_getfake(vm_paddr_t paddr
)
255 if ((m
= TAILQ_FIRST(&dev_freepages_list
)) != NULL
) {
256 TAILQ_REMOVE(&dev_freepages_list
, m
, pageq
);
258 m
= kmalloc(sizeof(*m
), M_FICTITIOUS_PAGES
, M_WAITOK
);
260 bzero(m
, sizeof(*m
));
262 m
->flags
= PG_BUSY
| PG_FICTITIOUS
;
263 m
->valid
= VM_PAGE_BITS_ALL
;
271 m
->phys_addr
= paddr
;
277 * Synthesized VM pages must be structurally stable for lockless lookups to
280 * The caller must hold dev_pager_mtx
283 dev_pager_putfake(vm_page_t m
)
285 if (!(m
->flags
& PG_FICTITIOUS
))
286 panic("dev_pager_putfake: bad page");
287 KKASSERT(m
->object
== NULL
);
288 TAILQ_INSERT_HEAD(&dev_freepages_list
, m
, pageq
);