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