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 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93
37 * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
45 #include <sys/device.h>
46 #include <sys/queue.h>
47 #include <sys/malloc.h>
48 #include <sys/thread2.h>
49 #include <sys/mutex2.h>
52 #include <vm/vm_object.h>
53 #include <vm/vm_page.h>
54 #include <vm/vm_pager.h>
55 #include <vm/vm_zone.h>
57 static void dev_pager_dealloc (vm_object_t);
58 static int dev_pager_getpage (vm_object_t, vm_page_t *, int);
59 static void dev_pager_putpages (vm_object_t, vm_page_t *, int,
61 static boolean_t dev_pager_haspage (vm_object_t, vm_pindex_t);
63 /* list of device pager objects */
64 static TAILQ_HEAD(, vm_page) dev_freepages_list =
65 TAILQ_HEAD_INITIALIZER(dev_freepages_list);
66 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages",
67 "Device mapped pages");
69 static vm_page_t dev_pager_getfake (vm_paddr_t);
70 static void dev_pager_putfake (vm_page_t);
72 struct pagerops devicepagerops = {
79 static struct mtx dev_pager_mtx = MTX_INITIALIZER;
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_page64(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 * Look up pager, creating as necessary.
120 mtx_lock(&dev_pager_mtx);
121 object = dev->si_object;
122 if (object == NULL) {
124 * Allocate object and associate it with the pager.
126 object = vm_object_allocate_hold(OBJT_DEVICE,
127 OFF_TO_IDX(foff + size));
128 object->handle = handle;
129 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
130 dev->si_object = object;
131 vm_object_drop(object);
134 * Gain a reference to the object.
136 vm_object_hold(object);
137 vm_object_reference_locked(object);
138 if (OFF_TO_IDX(foff + size) > object->size)
139 object->size = OFF_TO_IDX(foff + size);
140 vm_object_drop(object);
142 mtx_unlock(&dev_pager_mtx);
151 dev_pager_dealloc(vm_object_t object)
156 mtx_lock(&dev_pager_mtx);
158 if ((dev = object->handle) != NULL) {
159 KKASSERT(dev->si_object);
160 dev->si_object = NULL;
162 KKASSERT(object->swblock_count == 0);
165 * Free up our fake pages.
167 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
168 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
169 dev_pager_putfake(m);
171 mtx_unlock(&dev_pager_mtx);
178 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
186 mtx_lock(&dev_pager_mtx);
189 dev = object->handle;
190 offset = page->pindex;
191 prot = PROT_READ; /* XXX should pass in? */
193 paddr = pmap_phys_address(
194 dev_dmmap(dev, offset << PAGE_SHIFT, prot));
195 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
197 if (page->flags & PG_FICTITIOUS) {
199 * If the passed in reqpage page is a fake page, update it
200 * with the new physical address.
202 page->phys_addr = paddr;
203 page->valid = VM_PAGE_BITS_ALL;
206 * Replace the passed in reqpage page with our own fake page
207 * and free up all the original pages.
209 page = dev_pager_getfake(paddr);
210 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
212 vm_object_hold(object);
214 if (vm_page_insert(page, object, offset) == FALSE) {
215 panic("dev_pager_getpage: page (%p,%ld) exists",
218 vm_object_drop(object);
220 mtx_unlock(&dev_pager_mtx);
221 return (VM_PAGER_OK);
228 dev_pager_putpages(vm_object_t object, vm_page_t *m,
229 int count, boolean_t sync, int *rtvals)
231 panic("dev_pager_putpage called");
238 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex)
244 * The caller must hold dev_pager_mtx
247 dev_pager_getfake(vm_paddr_t paddr)
251 if ((m = TAILQ_FIRST(&dev_freepages_list)) != NULL) {
252 TAILQ_REMOVE(&dev_freepages_list, m, pageq);
254 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK);
256 bzero(m, sizeof(*m));
258 m->flags = PG_BUSY | PG_FICTITIOUS;
259 m->valid = VM_PAGE_BITS_ALL;
267 m->phys_addr = paddr;
273 * Synthesized VM pages must be structurally stable for lockless lookups to
276 * The caller must hold dev_pager_mtx
279 dev_pager_putfake(vm_page_t m)
281 if (!(m->flags & PG_FICTITIOUS))
282 panic("dev_pager_putfake: bad page");
283 KKASSERT(m->object == NULL);
284 TAILQ_INSERT_HEAD(&dev_freepages_list, m, pageq);