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
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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(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;
137 * Gain a reference to the object.
139 vm_object_reference(object);
140 if (OFF_TO_IDX(foff + size) > object->size)
141 object->size = OFF_TO_IDX(foff + size);
143 mtx_unlock(&dev_pager_mtx);
152 dev_pager_dealloc(vm_object_t object)
157 mtx_lock(&dev_pager_mtx);
159 if ((dev = object->handle) != NULL) {
160 KKASSERT(dev->si_object);
161 dev->si_object = NULL;
163 KKASSERT(object->swblock_count == 0);
166 * Free up our fake pages.
168 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
169 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
170 dev_pager_putfake(m);
172 mtx_unlock(&dev_pager_mtx);
179 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
187 mtx_lock(&dev_pager_mtx);
190 dev = object->handle;
191 offset = page->pindex;
192 prot = PROT_READ; /* XXX should pass in? */
194 paddr = pmap_phys_address(
195 dev_dmmap(dev, (vm_offset_t)offset << PAGE_SHIFT, prot));
196 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
198 if (page->flags & PG_FICTITIOUS) {
200 * If the passed in reqpage page is a fake page, update it
201 * with the new physical address.
203 page->phys_addr = paddr;
204 page->valid = VM_PAGE_BITS_ALL;
207 * Replace the passed in reqpage page with our own fake page
208 * and free up all the original pages.
210 page = dev_pager_getfake(paddr);
211 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
213 lwkt_gettoken(&vm_token);
214 vm_object_hold(object);
217 vm_page_insert(page, object, offset);
219 vm_object_drop(object);
220 lwkt_reltoken(&vm_token);
222 mtx_unlock(&dev_pager_mtx);
223 return (VM_PAGER_OK);
230 dev_pager_putpages(vm_object_t object, vm_page_t *m,
231 int count, boolean_t sync, int *rtvals)
233 panic("dev_pager_putpage called");
240 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex)
246 * The caller must hold dev_pager_mtx
249 dev_pager_getfake(vm_paddr_t paddr)
253 if ((m = TAILQ_FIRST(&dev_freepages_list)) != NULL) {
254 TAILQ_REMOVE(&dev_freepages_list, m, pageq);
256 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK);
258 bzero(m, sizeof(*m));
260 m->flags = PG_BUSY | PG_FICTITIOUS;
261 m->valid = VM_PAGE_BITS_ALL;
269 m->phys_addr = paddr;
275 * Synthesized VM pages must be structurally stable for lockless lookups to
278 * The caller must hold dev_pager_mtx
281 dev_pager_putfake(vm_page_t m)
283 if (!(m->flags & PG_FICTITIOUS))
284 panic("dev_pager_putfake: bad page");
285 KKASSERT(m->object == NULL);
286 TAILQ_INSERT_HEAD(&dev_freepages_list, m, pageq);