1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 */
38
39 #include <sys/cdefs.h>
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/conf.h>
43 #include <sys/lock.h>
44 #include <sys/proc.h>
45 #include <sys/mutex.h>
46 #include <sys/mman.h>
47 #include <sys/rwlock.h>
48 #include <sys/sx.h>
49 #include <sys/user.h>
50 #include <sys/vmmeter.h>
51
52 #include <vm/vm.h>
53 #include <vm/vm_param.h>
54 #include <vm/vm_object.h>
55 #include <vm/vm_page.h>
56 #include <vm/vm_pager.h>
57 #include <vm/vm_phys.h>
58 #include <vm/uma.h>
59
60 static void dev_pager_init(void);
61 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
62 vm_ooffset_t, struct ucred *);
63 static void dev_pager_dealloc(vm_object_t);
64 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *);
65 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
66 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
67 static void dev_pager_free_page(vm_object_t object, vm_page_t m);
68 static int dev_pager_populate(vm_object_t object, vm_pindex_t pidx,
69 int fault_type, vm_prot_t, vm_pindex_t *first, vm_pindex_t *last);
70
71 /* list of device pager objects */
72 static struct pagerlst dev_pager_object_list;
73 /* protect list manipulation */
74 static struct mtx dev_pager_mtx;
75
76 const struct pagerops devicepagerops = {
77 .pgo_kvme_type = KVME_TYPE_DEVICE,
78 .pgo_init = dev_pager_init,
79 .pgo_alloc = dev_pager_alloc,
80 .pgo_dealloc = dev_pager_dealloc,
81 .pgo_getpages = dev_pager_getpages,
82 .pgo_putpages = dev_pager_putpages,
83 .pgo_haspage = dev_pager_haspage,
84 };
85
86 const struct pagerops mgtdevicepagerops = {
87 .pgo_kvme_type = KVME_TYPE_MGTDEVICE,
88 .pgo_alloc = dev_pager_alloc,
89 .pgo_dealloc = dev_pager_dealloc,
90 .pgo_getpages = dev_pager_getpages,
91 .pgo_putpages = dev_pager_putpages,
92 .pgo_haspage = dev_pager_haspage,
93 .pgo_populate = dev_pager_populate,
94 };
95
96 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
97 vm_ooffset_t foff, struct ucred *cred, u_short *color);
98 static void old_dev_pager_dtor(void *handle);
99 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
100 int prot, vm_page_t *mres);
101
102 static const struct cdev_pager_ops old_dev_pager_ops = {
103 .cdev_pg_ctor = old_dev_pager_ctor,
104 .cdev_pg_dtor = old_dev_pager_dtor,
105 .cdev_pg_fault = old_dev_pager_fault
106 };
107
108 static void
dev_pager_init(void)109 dev_pager_init(void)
110 {
111
112 TAILQ_INIT(&dev_pager_object_list);
113 mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
114 }
115
116 vm_object_t
cdev_pager_lookup(void * handle)117 cdev_pager_lookup(void *handle)
118 {
119 vm_object_t object;
120
121 again:
122 mtx_lock(&dev_pager_mtx);
123 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
124 if (object != NULL && object->un_pager.devp.handle == NULL) {
125 msleep(&object->un_pager.devp.handle, &dev_pager_mtx,
126 PVM | PDROP, "cdplkp", 0);
127 vm_object_deallocate(object);
128 goto again;
129 }
130 mtx_unlock(&dev_pager_mtx);
131 return (object);
132 }
133
134 vm_object_t
cdev_pager_allocate(void * handle,enum obj_type tp,const struct cdev_pager_ops * ops,vm_ooffset_t size,vm_prot_t prot,vm_ooffset_t foff,struct ucred * cred)135 cdev_pager_allocate(void *handle, enum obj_type tp,
136 const struct cdev_pager_ops *ops, vm_ooffset_t size, vm_prot_t prot,
137 vm_ooffset_t foff, struct ucred *cred)
138 {
139 vm_object_t object;
140 vm_pindex_t pindex;
141
142 if (tp != OBJT_DEVICE && tp != OBJT_MGTDEVICE)
143 return (NULL);
144 KASSERT(tp == OBJT_MGTDEVICE || ops->cdev_pg_populate == NULL,
145 ("populate on unmanaged device pager"));
146
147 /*
148 * Offset should be page aligned.
149 */
150 if (foff & PAGE_MASK)
151 return (NULL);
152
153 /*
154 * Treat the mmap(2) file offset as an unsigned value for a
155 * device mapping. This, in effect, allows a user to pass all
156 * possible off_t values as the mapping cookie to the driver. At
157 * this point, we know that both foff and size are a multiple
158 * of the page size. Do a check to avoid wrap.
159 */
160 size = round_page(size);
161 pindex = OFF_TO_IDX(foff) + OFF_TO_IDX(size);
162 if (pindex > OBJ_MAX_SIZE || pindex < OFF_TO_IDX(foff) ||
163 pindex < OFF_TO_IDX(size))
164 return (NULL);
165
166 again:
167 mtx_lock(&dev_pager_mtx);
168
169 /*
170 * Look up pager, creating as necessary.
171 */
172 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
173 if (object == NULL) {
174 vm_object_t object1;
175
176 /*
177 * Allocate object and associate it with the pager. Initialize
178 * the object's pg_color based upon the physical address of the
179 * device's memory.
180 */
181 mtx_unlock(&dev_pager_mtx);
182 object1 = vm_object_allocate(tp, pindex);
183 mtx_lock(&dev_pager_mtx);
184 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
185 if (object != NULL) {
186 object1->type = OBJT_DEAD;
187 vm_object_deallocate(object1);
188 object1 = NULL;
189 if (object->un_pager.devp.handle == NULL) {
190 msleep(&object->un_pager.devp.handle,
191 &dev_pager_mtx, PVM | PDROP, "cdplkp", 0);
192 vm_object_deallocate(object);
193 goto again;
194 }
195
196 /*
197 * We raced with other thread while allocating object.
198 */
199 if (pindex > object->size)
200 object->size = pindex;
201 KASSERT(object->type == tp,
202 ("Inconsistent device pager type %p %d",
203 object, tp));
204 KASSERT(object->un_pager.devp.ops == ops,
205 ("Inconsistent devops %p %p", object, ops));
206 } else {
207 u_short color;
208
209 object = object1;
210 object1 = NULL;
211 object->handle = handle;
212 object->un_pager.devp.ops = ops;
213 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
214 TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
215 pager_object_list);
216 mtx_unlock(&dev_pager_mtx);
217 if (ops->cdev_pg_populate != NULL)
218 vm_object_set_flag(object, OBJ_POPULATE);
219 if (ops->cdev_pg_ctor(handle, size, prot, foff,
220 cred, &color) != 0) {
221 mtx_lock(&dev_pager_mtx);
222 TAILQ_REMOVE(&dev_pager_object_list, object,
223 pager_object_list);
224 wakeup(&object->un_pager.devp.handle);
225 mtx_unlock(&dev_pager_mtx);
226 object->type = OBJT_DEAD;
227 vm_object_deallocate(object);
228 object = NULL;
229 mtx_lock(&dev_pager_mtx);
230 } else {
231 mtx_lock(&dev_pager_mtx);
232 object->flags |= OBJ_COLORED;
233 object->pg_color = color;
234 object->un_pager.devp.handle = handle;
235 wakeup(&object->un_pager.devp.handle);
236 }
237 }
238 MPASS(object1 == NULL);
239 } else {
240 if (object->un_pager.devp.handle == NULL) {
241 msleep(&object->un_pager.devp.handle,
242 &dev_pager_mtx, PVM | PDROP, "cdplkp", 0);
243 vm_object_deallocate(object);
244 goto again;
245 }
246 if (pindex > object->size)
247 object->size = pindex;
248 KASSERT(object->type == tp,
249 ("Inconsistent device pager type %p %d", object, tp));
250 }
251 mtx_unlock(&dev_pager_mtx);
252 return (object);
253 }
254
255 static vm_object_t
dev_pager_alloc(void * handle,vm_ooffset_t size,vm_prot_t prot,vm_ooffset_t foff,struct ucred * cred)256 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
257 vm_ooffset_t foff, struct ucred *cred)
258 {
259
260 return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
261 size, prot, foff, cred));
262 }
263
264 void
cdev_pager_free_page(vm_object_t object,vm_page_t m)265 cdev_pager_free_page(vm_object_t object, vm_page_t m)
266 {
267
268 VM_OBJECT_ASSERT_WLOCKED(object);
269 if (object->type == OBJT_MGTDEVICE) {
270 KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
271 pmap_remove_all(m);
272 (void)vm_page_remove(m);
273 } else if (object->type == OBJT_DEVICE)
274 dev_pager_free_page(object, m);
275 }
276
277 static void
dev_pager_free_page(vm_object_t object,vm_page_t m)278 dev_pager_free_page(vm_object_t object, vm_page_t m)
279 {
280
281 VM_OBJECT_ASSERT_WLOCKED(object);
282 KASSERT((object->type == OBJT_DEVICE &&
283 (m->oflags & VPO_UNMANAGED) != 0),
284 ("Managed device or page obj %p m %p", object, m));
285 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, plinks.q);
286 vm_page_putfake(m);
287 }
288
289 static void
dev_pager_dealloc(vm_object_t object)290 dev_pager_dealloc(vm_object_t object)
291 {
292 vm_page_t m;
293
294 VM_OBJECT_WUNLOCK(object);
295 object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.handle);
296
297 mtx_lock(&dev_pager_mtx);
298 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
299 mtx_unlock(&dev_pager_mtx);
300 VM_OBJECT_WLOCK(object);
301
302 if (object->type == OBJT_DEVICE) {
303 /*
304 * Free up our fake pages.
305 */
306 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist))
307 != NULL) {
308 if (vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL) == 0)
309 continue;
310
311 dev_pager_free_page(object, m);
312 }
313 }
314 object->handle = NULL;
315 object->type = OBJT_DEAD;
316 }
317
318 static int
dev_pager_getpages(vm_object_t object,vm_page_t * ma,int count,int * rbehind,int * rahead)319 dev_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int *rbehind,
320 int *rahead)
321 {
322 int error;
323
324 /* Since our haspage reports zero after/before, the count is 1. */
325 KASSERT(count == 1, ("%s: count %d", __func__, count));
326 if (object->un_pager.devp.ops->cdev_pg_fault == NULL)
327 return (VM_PAGER_FAIL);
328 VM_OBJECT_WLOCK(object);
329 error = object->un_pager.devp.ops->cdev_pg_fault(object,
330 IDX_TO_OFF(ma[0]->pindex), PROT_READ, &ma[0]);
331
332 VM_OBJECT_ASSERT_WLOCKED(object);
333
334 if (error == VM_PAGER_OK) {
335 KASSERT((object->type == OBJT_DEVICE &&
336 (ma[0]->oflags & VPO_UNMANAGED) != 0) ||
337 (object->type == OBJT_MGTDEVICE &&
338 (ma[0]->oflags & VPO_UNMANAGED) == 0),
339 ("Wrong page type %p %p", ma[0], object));
340 if (object->type == OBJT_DEVICE) {
341 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
342 ma[0], plinks.q);
343 }
344 if (rbehind)
345 *rbehind = 0;
346 if (rahead)
347 *rahead = 0;
348 }
349 VM_OBJECT_WUNLOCK(object);
350
351 return (error);
352 }
353
354 static int
dev_pager_populate(vm_object_t object,vm_pindex_t pidx,int fault_type,vm_prot_t max_prot,vm_pindex_t * first,vm_pindex_t * last)355 dev_pager_populate(vm_object_t object, vm_pindex_t pidx, int fault_type,
356 vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last)
357 {
358
359 VM_OBJECT_ASSERT_WLOCKED(object);
360 if (object->un_pager.devp.ops->cdev_pg_populate == NULL)
361 return (VM_PAGER_FAIL);
362 return (object->un_pager.devp.ops->cdev_pg_populate(object, pidx,
363 fault_type, max_prot, first, last));
364 }
365
366 static int
old_dev_pager_fault(vm_object_t object,vm_ooffset_t offset,int prot,vm_page_t * mres)367 old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
368 vm_page_t *mres)
369 {
370 vm_paddr_t paddr;
371 vm_page_t m_paddr, page;
372 struct cdev *dev;
373 struct cdevsw *csw;
374 struct file *fpop;
375 struct thread *td;
376 vm_memattr_t memattr, memattr1;
377 int ref, ret;
378
379 memattr = object->memattr;
380
381 VM_OBJECT_WUNLOCK(object);
382
383 dev = object->handle;
384 csw = dev_refthread(dev, &ref);
385 if (csw == NULL) {
386 VM_OBJECT_WLOCK(object);
387 return (VM_PAGER_FAIL);
388 }
389 td = curthread;
390 fpop = td->td_fpop;
391 td->td_fpop = NULL;
392 ret = csw->d_mmap(dev, offset, &paddr, prot, &memattr);
393 td->td_fpop = fpop;
394 dev_relthread(dev, ref);
395 if (ret != 0) {
396 printf(
397 "WARNING: dev_pager_getpage: map function returns error %d", ret);
398 VM_OBJECT_WLOCK(object);
399 return (VM_PAGER_FAIL);
400 }
401
402 /* If "paddr" is a real page, perform a sanity check on "memattr". */
403 if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
404 (memattr1 = pmap_page_get_memattr(m_paddr)) != memattr) {
405 /*
406 * For the /dev/mem d_mmap routine to return the
407 * correct memattr, pmap_page_get_memattr() needs to
408 * be called, which we do there.
409 */
410 if ((csw->d_flags & D_MEM) == 0) {
411 printf("WARNING: Device driver %s has set "
412 "\"memattr\" inconsistently (drv %u pmap %u).\n",
413 csw->d_name, memattr, memattr1);
414 }
415 memattr = memattr1;
416 }
417 if (((*mres)->flags & PG_FICTITIOUS) != 0) {
418 /*
419 * If the passed in result page is a fake page, update it with
420 * the new physical address.
421 */
422 page = *mres;
423 VM_OBJECT_WLOCK(object);
424 vm_page_updatefake(page, paddr, memattr);
425 } else {
426 /*
427 * Replace the passed in reqpage page with our own fake page and
428 * free up the all of the original pages.
429 */
430 page = vm_page_getfake(paddr, memattr);
431 VM_OBJECT_WLOCK(object);
432 vm_page_replace(page, object, (*mres)->pindex, *mres);
433 *mres = page;
434 }
435 vm_page_valid(page);
436 return (VM_PAGER_OK);
437 }
438
439 static void
dev_pager_putpages(vm_object_t object,vm_page_t * m,int count,int flags,int * rtvals)440 dev_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
441 int *rtvals)
442 {
443
444 panic("dev_pager_putpage called");
445 }
446
447 static boolean_t
dev_pager_haspage(vm_object_t object,vm_pindex_t pindex,int * before,int * after)448 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
449 int *after)
450 {
451
452 if (before != NULL)
453 *before = 0;
454 if (after != NULL)
455 *after = 0;
456 return (TRUE);
457 }
458
459 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)460 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
461 vm_ooffset_t foff, struct ucred *cred, u_short *color)
462 {
463 struct cdev *dev;
464 struct cdevsw *csw;
465 vm_memattr_t dummy;
466 vm_ooffset_t off;
467 vm_paddr_t paddr;
468 unsigned int npages;
469 int ref;
470
471 /*
472 * Make sure this device can be mapped.
473 */
474 dev = handle;
475 csw = dev_refthread(dev, &ref);
476 if (csw == NULL)
477 return (ENXIO);
478
479 /*
480 * Check that the specified range of the device allows the desired
481 * protection.
482 *
483 * XXX assumes VM_PROT_* == PROT_*
484 */
485 npages = OFF_TO_IDX(size);
486 paddr = 0; /* Make paddr initialized for the case of size == 0. */
487 for (off = foff; npages--; off += PAGE_SIZE) {
488 if (csw->d_mmap(dev, off, &paddr, (int)prot, &dummy) != 0) {
489 dev_relthread(dev, ref);
490 return (EINVAL);
491 }
492 }
493
494 dev_ref(dev);
495 dev_relthread(dev, ref);
496 *color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
497 return (0);
498 }
499
500 static void
old_dev_pager_dtor(void * handle)501 old_dev_pager_dtor(void *handle)
502 {
503
504 dev_rel(handle);
505 }
506