1 /*
2 * (MPSAFE)
3 *
4 * Copyright (c) 1990 University of Utah.
5 * Copyright (c) 1991, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
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.
23 *
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
34 * SUCH DAMAGE.
35 *
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 $
38 */
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/conf.h>
44 #include <sys/mman.h>
45 #include <sys/device.h>
46 #include <sys/queue.h>
47 #include <sys/malloc.h>
48 #include <sys/mutex2.h>
49
50 #include <vm/vm.h>
51 #include <vm/vm_object.h>
52 #include <vm/vm_page.h>
53 #include <vm/vm_pager.h>
54 #include <vm/vm_zone.h>
55 #include <vm/vm_page2.h>
56
57 static pgo_dealloc_t dev_pager_dealloc;
58 static pgo_getpage_t dev_pager_getpage;
59 static pgo_putpages_t dev_pager_putpages;
60 static pgo_haspage_t dev_pager_haspage;
61
62 struct pagerops devicepagerops = {
63 .pgo_dealloc = dev_pager_dealloc,
64 .pgo_getpage = dev_pager_getpage,
65 .pgo_putpages = dev_pager_putpages,
66 .pgo_haspage = dev_pager_haspage
67 };
68
69 /* list of device pager objects */
70 static TAILQ_HEAD(, vm_page) dev_freepages_list =
71 TAILQ_HEAD_INITIALIZER(dev_freepages_list);
72 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages",
73 "Device mapped pages");
74
75 static vm_page_t dev_pager_getfake (vm_paddr_t, int);
76 static void dev_pager_putfake (vm_page_t);
77
78 /* list of device pager objects */
79 static struct pagerlst dev_pager_object_list =
80 TAILQ_HEAD_INITIALIZER(dev_pager_object_list);
81 /* protect list manipulation */
82 static struct mtx dev_pager_mtx = MTX_INITIALIZER("devpgr");
83
84 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
85 vm_ooffset_t foff, struct ucred *cred, u_short *pg_color);
86 static void old_dev_pager_dtor(void *handle);
87 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
88 int prot, vm_page_t *mres);
89
90 static struct cdev_pager_ops old_dev_pager_ops = {
91 .cdev_pg_ctor = old_dev_pager_ctor,
92 .cdev_pg_dtor = old_dev_pager_dtor,
93 .cdev_pg_fault = old_dev_pager_fault
94 };
95
96 vm_object_t
cdev_pager_lookup(void * handle)97 cdev_pager_lookup(void *handle)
98 {
99 vm_object_t object;
100
101 mtx_lock(&dev_pager_mtx);
102 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
103 mtx_unlock(&dev_pager_mtx);
104
105 return (object);
106 }
107
108 vm_object_t
cdev_pager_allocate(void * handle,enum obj_type tp,struct cdev_pager_ops * ops,vm_ooffset_t size,vm_prot_t prot,vm_ooffset_t foff,struct ucred * cred)109 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
110 vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
111 {
112 cdev_t dev;
113 vm_object_t object;
114 u_short color;
115
116 /*
117 * Offset should be page aligned.
118 */
119 if (foff & PAGE_MASK)
120 return (NULL);
121
122 size = round_page64(size);
123
124 if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
125 return (NULL);
126
127 /*
128 * Look up pager, creating as necessary.
129 */
130 mtx_lock(&dev_pager_mtx);
131 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
132 if (object == NULL) {
133 /*
134 * Allocate object and associate it with the pager.
135 */
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
143 /*
144 * handle is only a device for old_dev_pager_ctor.
145 */
146 if (ops->cdev_pg_ctor == old_dev_pager_ctor) {
147 dev = handle;
148 dev->si_object = object;
149 }
150
151 TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
152 pager_object_entry);
153
154 vm_object_drop(object);
155 } else {
156 /*
157 * Gain a reference to the object.
158 */
159 vm_object_hold(object);
160 vm_object_reference_locked(object);
161 if (OFF_TO_IDX(foff + size) > object->size)
162 object->size = OFF_TO_IDX(foff + size);
163 vm_object_drop(object);
164 }
165 mtx_unlock(&dev_pager_mtx);
166
167 return (object);
168 }
169
170 /*
171 * No requirements.
172 */
173 vm_object_t
dev_pager_alloc(void * handle,off_t size,vm_prot_t prot,off_t foff)174 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
175 {
176 return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
177 size, prot, foff, NULL));
178 }
179
180 /*
181 * Caller must hold object lock.
182 */
183 void
cdev_pager_free_page(vm_object_t object,vm_page_t m)184 cdev_pager_free_page(vm_object_t object, vm_page_t m)
185 {
186 if (object->type == OBJT_MGTDEVICE) {
187 KKASSERT((m->flags & PG_FICTITIOUS) != 0);
188 pmap_page_protect(m, VM_PROT_NONE);
189 vm_page_remove(m);
190 vm_page_wakeup(m);
191 } else if (object->type == OBJT_DEVICE) {
192 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
193 dev_pager_putfake(m);
194 }
195 }
196
197 /*
198 * No requirements.
199 */
200 static void
dev_pager_dealloc(vm_object_t object)201 dev_pager_dealloc(vm_object_t object)
202 {
203 vm_page_t m;
204
205 /*
206 * NOTE: Callback may recurse into the device pager so do not
207 * obtain dev_pager_mtx until after it returns.
208 *
209 * The mutex should only be needed when manipulating the list.
210 */
211 object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev);
212
213 mtx_lock(&dev_pager_mtx);
214 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_entry);
215 mtx_unlock(&dev_pager_mtx);
216
217 if (object->type == OBJT_DEVICE) {
218 /*
219 * Free up our fake pages.
220 */
221 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) !=
222 NULL) {
223 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist,
224 m, pageq);
225 dev_pager_putfake(m);
226 }
227 }
228 }
229
230 /*
231 * No requirements.
232 *
233 * WARNING! Do not obtain dev_pager_mtx here, doing so will cause a
234 * deadlock in DRMs VM paging code.
235 */
236 static int
dev_pager_getpage(vm_object_t object,vm_pindex_t pindex,vm_page_t * mpp,int seqaccess)237 dev_pager_getpage(vm_object_t object, vm_pindex_t pindex,
238 vm_page_t *mpp, int seqaccess)
239 {
240 int error;
241
242 error = object->un_pager.devp.ops->cdev_pg_fault(
243 object, IDX_TO_OFF(pindex),
244 PROT_READ, mpp);
245
246 return (error);
247 }
248
249 /*
250 * No requirements.
251 */
252 static void
dev_pager_putpages(vm_object_t object,vm_page_t * m,int count,int flags,int * rtvals)253 dev_pager_putpages(vm_object_t object, vm_page_t *m,
254 int count, int flags, int *rtvals)
255 {
256 panic("dev_pager_putpage called");
257 }
258
259 /*
260 * No requirements.
261 */
262 static boolean_t
dev_pager_haspage(vm_object_t object,vm_pindex_t pindex)263 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex)
264 {
265 return (TRUE);
266 }
267
268 /*
269 * The caller does not need to hold dev_pager_mtx() but caller must ensure
270 * no page-use collision.
271 */
272 static vm_page_t
dev_pager_getfake(vm_paddr_t paddr,int pat_mode)273 dev_pager_getfake(vm_paddr_t paddr, int pat_mode)
274 {
275 vm_page_t m;
276
277 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK|M_ZERO);
278
279 pmap_page_init(m);
280
281 m->flags = PG_FICTITIOUS | PG_UNQUEUED;
282 m->valid = VM_PAGE_BITS_ALL;
283 m->dirty = 0;
284 m->queue = PQ_NONE;
285 m->object = NULL;
286
287 m->busy_count = PBUSY_LOCKED;
288 m->wire_count = 1;
289 m->hold_count = 0;
290 m->phys_addr = paddr;
291 m->pat_mode = pat_mode;
292
293 spin_init(&m->spin, "dev_page");
294
295 return (m);
296 }
297
298 /*
299 * The caller does not need to hold dev_pager_mtx() but caller must ensure
300 * no page-use collision within the object.
301 */
302 static void
dev_pager_putfake(vm_page_t m)303 dev_pager_putfake(vm_page_t m)
304 {
305 if (!(m->flags & PG_FICTITIOUS))
306 panic("dev_pager_putfake: bad page");
307 KKASSERT(m->object == NULL);
308 KKASSERT(m->hold_count == 0);
309 kfree(m, M_FICTITIOUS_PAGES);
310 }
311
312 static int
old_dev_pager_ctor(void * handle,vm_ooffset_t size,vm_prot_t prot,vm_ooffset_t foff,struct ucred * cred,u_short * color)313 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
314 vm_ooffset_t foff, struct ucred *cred, u_short *color)
315 {
316 unsigned int npages;
317 vm_offset_t off;
318 cdev_t dev;
319
320 dev = handle;
321
322 /*
323 * Check that the specified range of the device allows the desired
324 * protection.
325 *
326 * XXX assumes VM_PROT_* == PROT_*
327 */
328 npages = OFF_TO_IDX(size);
329 for (off = foff; npages--; off += PAGE_SIZE) {
330 if (dev_dmmap(dev, off, (int)prot, NULL) == -1)
331 return (EINVAL);
332 }
333
334 return (0);
335 }
336
old_dev_pager_dtor(void * handle)337 static void old_dev_pager_dtor(void *handle)
338 {
339 cdev_t dev;
340
341 dev = handle;
342 if (dev != NULL) {
343 KKASSERT(dev->si_object);
344 dev->si_object = NULL;
345 }
346 }
347
348 static int
old_dev_pager_fault(vm_object_t object,vm_ooffset_t offset,int prot,vm_page_t * mres)349 old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
350 int prot, vm_page_t *mres)
351 {
352 vm_paddr_t paddr;
353 vm_page_t page;
354 vm_offset_t pidx = OFF_TO_IDX(offset);
355 cdev_t dev;
356
357 page = *mres;
358 dev = object->handle;
359
360 paddr = pmap_phys_address(dev_dmmap(dev, offset, prot, NULL));
361 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
362 KKASSERT(object->type == OBJT_DEVICE);
363
364 if (page->flags & PG_FICTITIOUS) {
365 /*
366 * If the passed in reqpage page is already a fake page,
367 * update it with the new physical address.
368 */
369 page->phys_addr = paddr;
370 page->valid = VM_PAGE_BITS_ALL;
371 } else {
372 /*
373 * Replace the passed in reqpage page with our own fake page
374 * and free up all the original pages. Object lock must be
375 * held when manipulating devp_pglist and inserting the
376 * page.
377 */
378 page = dev_pager_getfake(paddr, object->memattr);
379 vm_object_hold(object);
380 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
381 page, pageq);
382 vm_page_free(*mres);
383 if (vm_page_insert(page, object, pidx) == FALSE) {
384 panic("dev_pager_getpage: page (%p,%016jx) exists",
385 object, (uintmax_t)pidx);
386 }
387 vm_object_drop(object);
388 }
389 return (VM_PAGER_OK);
390 }
391
392