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