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. 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 /* list of device pager objects */
80 static struct pagerlst dev_pager_object_list =
81 TAILQ_HEAD_INITIALIZER(dev_pager_object_list);
82 /* protect list manipulation */
83 static struct mtx dev_pager_mtx = MTX_INITIALIZER;
85 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
86 vm_ooffset_t foff, struct ucred *cred, u_short *pg_color);
87 static void old_dev_pager_dtor(void *handle);
88 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
89 int prot, vm_page_t *mres);
91 static struct cdev_pager_ops old_dev_pager_ops = {
92 .cdev_pg_ctor = old_dev_pager_ctor,
93 .cdev_pg_dtor = old_dev_pager_dtor,
94 .cdev_pg_fault = old_dev_pager_fault
98 cdev_pager_lookup(void *handle)
101 mtx_lock(&dev_pager_mtx);
102 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
103 mtx_unlock(&dev_pager_mtx);
108 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
109 vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
117 * Offset should be page aligned.
119 if (foff & PAGE_MASK)
122 size = round_page64(size);
124 if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
128 * Look up pager, creating as necessary.
130 mtx_lock(&dev_pager_mtx);
131 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
132 if (object == NULL) {
134 * Allocate object and associate it with the pager.
136 object = vm_object_allocate_hold(tp,
137 OFF_TO_IDX(foff + size));
138 object->handle = handle;
139 object->un_pager.devp.ops = ops;
140 object->un_pager.devp.dev = handle;
141 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
142 dev->si_object = object;
144 TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
147 vm_object_drop(object);
150 * Gain a reference to the object.
152 vm_object_hold(object);
153 vm_object_reference_locked(object);
154 if (OFF_TO_IDX(foff + size) > object->size)
155 object->size = OFF_TO_IDX(foff + size);
156 vm_object_drop(object);
158 mtx_unlock(&dev_pager_mtx);
167 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
169 return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
170 size, prot, foff, NULL));
175 cdev_pager_free_page(vm_object_t object, vm_page_t m)
177 if (object->type == OBJT_MGTDEVICE) {
179 KKASSERT((m->flags & PG_FICTITIOUS) != 0);
180 pmap_page_protect(m, VM_PROT_NONE);
183 } else if (object->type == OBJT_DEVICE) {
185 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
186 dev_pager_putfake(m);
194 dev_pager_dealloc(vm_object_t object)
198 mtx_lock(&dev_pager_mtx);
199 object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev);
201 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
203 if (object->type == OBJT_DEVICE) {
205 * Free up our fake pages.
207 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) !=
209 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist,
211 dev_pager_putfake(m);
214 mtx_unlock(&dev_pager_mtx);
221 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
227 mtx_lock(&dev_pager_mtx);
230 offset = page->pindex << PAGE_SHIFT;
232 error = object->un_pager.devp.ops->cdev_pg_fault(object,
233 offset, PROT_READ, mpp);
235 mtx_unlock(&dev_pager_mtx);
244 dev_pager_putpages(vm_object_t object, vm_page_t *m,
245 int count, boolean_t sync, int *rtvals)
247 panic("dev_pager_putpage called");
254 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex)
260 * The caller must hold dev_pager_mtx
263 dev_pager_getfake(vm_paddr_t paddr)
267 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK|M_ZERO);
269 m->flags = PG_BUSY | PG_FICTITIOUS;
270 m->valid = VM_PAGE_BITS_ALL;
278 m->phys_addr = paddr;
284 * Synthesized VM pages must be structurally stable for lockless lookups to
287 * The caller must hold dev_pager_mtx
290 dev_pager_putfake(vm_page_t m)
292 if (!(m->flags & PG_FICTITIOUS))
293 panic("dev_pager_putfake: bad page");
294 KKASSERT(m->object == NULL);
295 KKASSERT(m->hold_count == 0);
296 kfree(m, M_FICTITIOUS_PAGES);
300 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
301 vm_ooffset_t foff, struct ucred *cred, u_short *color)
310 * Check that the specified range of the device allows the desired
313 * XXX assumes VM_PROT_* == PROT_*
315 npages = OFF_TO_IDX(size);
316 for (off = foff; npages--; off += PAGE_SIZE) {
317 if (dev_dmmap(dev, off, (int)prot) == -1)
324 static void old_dev_pager_dtor(void *handle)
330 KKASSERT(dev->si_object);
331 dev->si_object = NULL;
335 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
336 int prot, vm_page_t *mres)
343 dev = object->handle;
344 offset = page->pindex;
346 paddr = pmap_phys_address(
347 dev_dmmap(dev, offset, prot));
348 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
349 KKASSERT(object->type == OBJT_DEVICE);
351 if (page->flags & PG_FICTITIOUS) {
353 * If the passed in reqpage page is already a fake page,
354 * update it with the new physical address.
356 page->phys_addr = paddr;
357 page->valid = VM_PAGE_BITS_ALL;
360 * Replace the passed in reqpage page with our own fake page
361 * and free up all the original pages.
363 page = dev_pager_getfake(paddr);
364 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
366 vm_object_hold(object);
368 if (vm_page_insert(page, object, offset) == FALSE) {
369 panic("dev_pager_getpage: page (%p,%016jx) exists",
370 object, (uintmax_t)offset);
372 vm_object_drop(object);
375 return (VM_PAGER_OK);