sys/vm/device_pager.c

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