sys/vm/device_pager.c

   1 /*-
   2  * Copyright (c) 1990 University of Utah.
   3  * Copyright (c) 1991, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * the Systems Programming Group of the University of Utah Computer
   8  * Science Department.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)device_pager.c      8.1 (Berkeley) 6/11/93
  35  */
  36
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD$");
  39
  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/vmmeter.h>
  50
  51 #include <vm/vm.h>
  52 #include <vm/vm_param.h>
  53 #include <vm/vm_object.h>
  54 #include <vm/vm_page.h>
  55 #include <vm/vm_pager.h>
  56 #include <vm/vm_phys.h>
  57 #include <vm/uma.h>
  58
  59 static void dev_pager_init(void);
  60 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
  61     vm_ooffset_t, struct ucred *);
  62 static void dev_pager_dealloc(vm_object_t);
  63 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *);
  64 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
  65 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
  66 static void dev_pager_free_page(vm_object_t object, vm_page_t m);
  67 static int dev_pager_populate(vm_object_t object, vm_pindex_t pidx,
  68     int fault_type, vm_prot_t, vm_pindex_t *first, vm_pindex_t *last);
  69
  70 /* list of device pager objects */
  71 static struct pagerlst dev_pager_object_list;
  72 /* protect list manipulation */
  73 static struct mtx dev_pager_mtx;
  74
  75 struct pagerops devicepagerops = {
  76         .pgo_init =     dev_pager_init,
  77         .pgo_alloc =    dev_pager_alloc,
  78         .pgo_dealloc =  dev_pager_dealloc,
  79         .pgo_getpages = dev_pager_getpages,
  80         .pgo_putpages = dev_pager_putpages,
  81         .pgo_haspage =  dev_pager_haspage,
  82 };
  83
  84 struct pagerops mgtdevicepagerops = {
  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 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, struct cdev_pager_ops *ops,
 126     vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
 127 {
 128         vm_object_t object, object1;
 129         vm_pindex_t pindex;
 130         u_short color;
 131
 132         if (tp != OBJT_DEVICE && tp != OBJT_MGTDEVICE)
 133                 return (NULL);
 134         KASSERT(tp == OBJT_MGTDEVICE || ops->cdev_pg_populate == NULL,
 135             ("populate on unmanaged device pager"));
 136
 137         /*
 138          * Offset should be page aligned.
 139          */
 140         if (foff & PAGE_MASK)
 141                 return (NULL);
 142
 143         /*
 144          * Treat the mmap(2) file offset as an unsigned value for a
 145          * device mapping.  This, in effect, allows a user to pass all
 146          * possible off_t values as the mapping cookie to the driver.  At
 147          * this point, we know that both foff and size are a multiple
 148          * of the page size.  Do a check to avoid wrap.
 149          */
 150         size = round_page(size);
 151         pindex = UOFF_TO_IDX(foff) + UOFF_TO_IDX(size);
 152         if (pindex > OBJ_MAX_SIZE || pindex < UOFF_TO_IDX(foff) ||
 153             pindex < UOFF_TO_IDX(size))
 154                 return (NULL);
 155
 156         if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
 157                 return (NULL);
 158         mtx_lock(&dev_pager_mtx);
 159
 160         /*
 161          * Look up pager, creating as necessary.
 162          */
 163         object1 = NULL;
 164         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 165         if (object == NULL) {
 166                 /*
 167                  * Allocate object and associate it with the pager.  Initialize
 168                  * the object's pg_color based upon the physical address of the
 169                  * device's memory.
 170                  */
 171                 mtx_unlock(&dev_pager_mtx);
 172                 object1 = vm_object_allocate(tp, pindex);
 173                 object1->flags |= OBJ_COLORED;
 174                 object1->pg_color = color;
 175                 object1->handle = handle;
 176                 object1->un_pager.devp.ops = ops;
 177                 object1->un_pager.devp.dev = handle;
 178                 TAILQ_INIT(&object1->un_pager.devp.devp_pglist);
 179                 mtx_lock(&dev_pager_mtx);
 180                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 181                 if (object != NULL) {
 182                         /*
 183                          * We raced with other thread while allocating object.
 184                          */
 185                         if (pindex > object->size)
 186                                 object->size = pindex;
 187                         KASSERT(object->type == tp,
 188                             ("Inconsistent device pager type %p %d",
 189                             object, tp));
 190                         KASSERT(object->un_pager.devp.ops == ops,
 191                             ("Inconsistent devops %p %p", object, ops));
 192                 } else {
 193                         object = object1;
 194                         object1 = NULL;
 195                         object->handle = handle;
 196                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 197                             pager_object_list);
 198                         if (ops->cdev_pg_populate != NULL)
 199                                 vm_object_set_flag(object, OBJ_POPULATE);
 200                 }
 201         } else {
 202                 if (pindex > object->size)
 203                         object->size = pindex;
 204                 KASSERT(object->type == tp,
 205                     ("Inconsistent device pager type %p %d", object, tp));
 206         }
 207         mtx_unlock(&dev_pager_mtx);
 208         if (object1 != NULL) {
 209                 object1->handle = object1;
 210                 mtx_lock(&dev_pager_mtx);
 211                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object1,
 212                     pager_object_list);
 213                 mtx_unlock(&dev_pager_mtx);
 214                 vm_object_deallocate(object1);
 215         }
 216         return (object);
 217 }
 218
 219 static vm_object_t
 220 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 221     vm_ooffset_t foff, struct ucred *cred)
 222 {
 223
 224         return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
 225             size, prot, foff, cred));
 226 }
 227
 228 void
 229 cdev_pager_free_page(vm_object_t object, vm_page_t m)
 230 {
 231
 232         VM_OBJECT_ASSERT_WLOCKED(object);
 233         if (object->type == OBJT_MGTDEVICE) {
 234                 KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
 235                 pmap_remove_all(m);
 236                 vm_page_lock(m);
 237                 vm_page_remove(m);
 238                 vm_page_unlock(m);
 239         } else if (object->type == OBJT_DEVICE)
 240                 dev_pager_free_page(object, m);
 241 }
 242
 243 static void
 244 dev_pager_free_page(vm_object_t object, vm_page_t m)
 245 {
 246
 247         VM_OBJECT_ASSERT_WLOCKED(object);
 248         KASSERT((object->type == OBJT_DEVICE &&
 249             (m->oflags & VPO_UNMANAGED) != 0),
 250             ("Managed device or page obj %p m %p", object, m));
 251         TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, plinks.q);
 252         vm_page_putfake(m);
 253 }
 254
 255 static void
 256 dev_pager_dealloc(vm_object_t object)
 257 {
 258         vm_page_t m;
 259
 260         VM_OBJECT_WUNLOCK(object);
 261         object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev);
 262
 263         mtx_lock(&dev_pager_mtx);
 264         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 265         mtx_unlock(&dev_pager_mtx);
 266         VM_OBJECT_WLOCK(object);
 267
 268         if (object->type == OBJT_DEVICE) {
 269                 /*
 270                  * Free up our fake pages.
 271                  */
 272                 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist))
 273                     != NULL)
 274                         dev_pager_free_page(object, m);
 275         }
 276         object->handle = NULL;
 277         object->type = OBJT_DEAD;
 278 }
 279
 280 static int
 281 dev_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int *rbehind,
 282     int *rahead)
 283 {
 284         int error;
 285
 286         /* Since our haspage reports zero after/before, the count is 1. */
 287         KASSERT(count == 1, ("%s: count %d", __func__, count));
 288         VM_OBJECT_ASSERT_WLOCKED(object);
 289         if (object->un_pager.devp.ops->cdev_pg_fault == NULL)
 290                 return (VM_PAGER_FAIL);
 291         error = object->un_pager.devp.ops->cdev_pg_fault(object,
 292             IDX_TO_OFF(ma[0]->pindex), PROT_READ, &ma[0]);
 293
 294         VM_OBJECT_ASSERT_WLOCKED(object);
 295
 296         if (error == VM_PAGER_OK) {
 297                 KASSERT((object->type == OBJT_DEVICE &&
 298                      (ma[0]->oflags & VPO_UNMANAGED) != 0) ||
 299                     (object->type == OBJT_MGTDEVICE &&
 300                      (ma[0]->oflags & VPO_UNMANAGED) == 0),
 301                     ("Wrong page type %p %p", ma[0], object));
 302                 if (object->type == OBJT_DEVICE) {
 303                         TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
 304                             ma[0], plinks.q);
 305                 }
 306                 if (rbehind)
 307                         *rbehind = 0;
 308                 if (rahead)
 309                         *rahead = 0;
 310         }
 311
 312         return (error);
 313 }
 314
 315 static int
 316 dev_pager_populate(vm_object_t object, vm_pindex_t pidx, int fault_type,
 317     vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last)
 318 {
 319
 320         VM_OBJECT_ASSERT_WLOCKED(object);
 321         if (object->un_pager.devp.ops->cdev_pg_populate == NULL)
 322                 return (VM_PAGER_FAIL);
 323         return (object->un_pager.devp.ops->cdev_pg_populate(object, pidx,
 324             fault_type, max_prot, first, last));
 325 }
 326
 327 static int
 328 old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
 329     vm_page_t *mres)
 330 {
 331         vm_paddr_t paddr;
 332         vm_page_t m_paddr, page;
 333         struct cdev *dev;
 334         struct cdevsw *csw;
 335         struct file *fpop;
 336         struct thread *td;
 337         vm_memattr_t memattr, memattr1;
 338         int ref, ret;
 339
 340         memattr = object->memattr;
 341
 342         VM_OBJECT_WUNLOCK(object);
 343
 344         dev = object->handle;
 345         csw = dev_refthread(dev, &ref);
 346         if (csw == NULL) {
 347                 VM_OBJECT_WLOCK(object);
 348                 return (VM_PAGER_FAIL);
 349         }
 350         td = curthread;
 351         fpop = td->td_fpop;
 352         td->td_fpop = NULL;
 353         ret = csw->d_mmap(dev, offset, &paddr, prot, &memattr);
 354         td->td_fpop = fpop;
 355         dev_relthread(dev, ref);
 356         if (ret != 0) {
 357                 printf(
 358             "WARNING: dev_pager_getpage: map function returns error %d", ret);
 359                 VM_OBJECT_WLOCK(object);
 360                 return (VM_PAGER_FAIL);
 361         }
 362
 363         /* If "paddr" is a real page, perform a sanity check on "memattr". */
 364         if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
 365             (memattr1 = pmap_page_get_memattr(m_paddr)) != memattr) {
 366                 /*
 367                  * For the /dev/mem d_mmap routine to return the
 368                  * correct memattr, pmap_page_get_memattr() needs to
 369                  * be called, which we do there.
 370                  */
 371                 if ((csw->d_flags & D_MEM) == 0) {
 372                         printf("WARNING: Device driver %s has set "
 373                             "\"memattr\" inconsistently (drv %u pmap %u).\n",
 374                             csw->d_name, memattr, memattr1);
 375                 }
 376                 memattr = memattr1;
 377         }
 378         if (((*mres)->flags & PG_FICTITIOUS) != 0) {
 379                 /*
 380                  * If the passed in result page is a fake page, update it with
 381                  * the new physical address.
 382                  */
 383                 page = *mres;
 384                 VM_OBJECT_WLOCK(object);
 385                 vm_page_updatefake(page, paddr, memattr);
 386         } else {
 387                 /*
 388                  * Replace the passed in reqpage page with our own fake page and
 389                  * free up the all of the original pages.
 390                  */
 391                 page = vm_page_getfake(paddr, memattr);
 392                 VM_OBJECT_WLOCK(object);
 393                 vm_page_replace_checked(page, object, (*mres)->pindex, *mres);
 394                 vm_page_lock(*mres);
 395                 vm_page_free(*mres);
 396                 vm_page_unlock(*mres);
 397                 *mres = page;
 398         }
 399         page->valid = VM_PAGE_BITS_ALL;
 400         return (VM_PAGER_OK);
 401 }
 402
 403 static void
 404 dev_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
 405     int *rtvals)
 406 {
 407
 408         panic("dev_pager_putpage called");
 409 }
 410
 411 static boolean_t
 412 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
 413     int *after)
 414 {
 415
 416         if (before != NULL)
 417                 *before = 0;
 418         if (after != NULL)
 419                 *after = 0;
 420         return (TRUE);
 421 }
 422
 423 static int
 424 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
 425     vm_ooffset_t foff, struct ucred *cred, u_short *color)
 426 {
 427         struct cdev *dev;
 428         struct cdevsw *csw;
 429         vm_memattr_t dummy;
 430         vm_ooffset_t off;
 431         vm_paddr_t paddr;
 432         unsigned int npages;
 433         int ref;
 434
 435         /*
 436          * Make sure this device can be mapped.
 437          */
 438         dev = handle;
 439         csw = dev_refthread(dev, &ref);
 440         if (csw == NULL)
 441                 return (ENXIO);
 442
 443         /*
 444          * Check that the specified range of the device allows the desired
 445          * protection.
 446          *
 447          * XXX assumes VM_PROT_* == PROT_*
 448          */
 449         npages = OFF_TO_IDX(size);
 450         paddr = 0; /* Make paddr initialized for the case of size == 0. */
 451         for (off = foff; npages--; off += PAGE_SIZE) {
 452                 if (csw->d_mmap(dev, off, &paddr, (int)prot, &dummy) != 0) {
 453                         dev_relthread(dev, ref);
 454                         return (EINVAL);
 455                 }
 456         }
 457
 458         dev_ref(dev);
 459         dev_relthread(dev, ref);
 460         *color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
 461         return (0);
 462 }
 463
 464 static void
 465 old_dev_pager_dtor(void *handle)
 466 {
 467
 468         dev_rel(handle);
 469 }