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  *      @(#)device_pager.c      8.1 (Berkeley) 6/11/93
  37  */
  38
  39 #include <sys/cdefs.h>
  40 __FBSDID("$FreeBSD$");
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/conf.h>
  45 #include <sys/lock.h>
  46 #include <sys/proc.h>
  47 #include <sys/mutex.h>
  48 #include <sys/mman.h>
  49 #include <sys/rwlock.h>
  50 #include <sys/sx.h>
  51 #include <sys/vmmeter.h>
  52
  53 #include <vm/vm.h>
  54 #include <vm/vm_param.h>
  55 #include <vm/vm_object.h>
  56 #include <vm/vm_page.h>
  57 #include <vm/vm_pager.h>
  58 #include <vm/vm_phys.h>
  59 #include <vm/uma.h>
  60
  61 static void dev_pager_init(void);
  62 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
  63     vm_ooffset_t, struct ucred *);
  64 static void dev_pager_dealloc(vm_object_t);
  65 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *);
  66 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
  67 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
  68 static void dev_pager_free_page(vm_object_t object, vm_page_t m);
  69 static int dev_pager_populate(vm_object_t object, vm_pindex_t pidx,
  70     int fault_type, vm_prot_t, vm_pindex_t *first, vm_pindex_t *last);
  71
  72 /* list of device pager objects */
  73 static struct pagerlst dev_pager_object_list;
  74 /* protect list manipulation */
  75 static struct mtx dev_pager_mtx;
  76
  77 struct pagerops devicepagerops = {
  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 struct pagerops mgtdevicepagerops = {
  87         .pgo_alloc =    dev_pager_alloc,
  88         .pgo_dealloc =  dev_pager_dealloc,
  89         .pgo_getpages = dev_pager_getpages,
  90         .pgo_putpages = dev_pager_putpages,
  91         .pgo_haspage =  dev_pager_haspage,
  92         .pgo_populate = dev_pager_populate,
  93 };
  94
  95 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
  96     vm_ooffset_t foff, struct ucred *cred, u_short *color);
  97 static void old_dev_pager_dtor(void *handle);
  98 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
  99     int prot, vm_page_t *mres);
 100
 101 static struct cdev_pager_ops old_dev_pager_ops = {
 102         .cdev_pg_ctor = old_dev_pager_ctor,
 103         .cdev_pg_dtor = old_dev_pager_dtor,
 104         .cdev_pg_fault = old_dev_pager_fault
 105 };
 106
 107 static void
 108 dev_pager_init(void)
 109 {
 110
 111         TAILQ_INIT(&dev_pager_object_list);
 112         mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
 113 }
 114
 115 vm_object_t
 116 cdev_pager_lookup(void *handle)
 117 {
 118         vm_object_t object;
 119
 120         mtx_lock(&dev_pager_mtx);
 121         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 122         mtx_unlock(&dev_pager_mtx);
 123         return (object);
 124 }
 125
 126 vm_object_t
 127 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
 128     vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
 129 {
 130         vm_object_t object, object1;
 131         vm_pindex_t pindex;
 132         u_short color;
 133
 134         if (tp != OBJT_DEVICE && tp != OBJT_MGTDEVICE)
 135                 return (NULL);
 136         KASSERT(tp == OBJT_MGTDEVICE || ops->cdev_pg_populate == NULL,
 137             ("populate on unmanaged device pager"));
 138
 139         /*
 140          * Offset should be page aligned.
 141          */
 142         if (foff & PAGE_MASK)
 143                 return (NULL);
 144
 145         /*
 146          * Treat the mmap(2) file offset as an unsigned value for a
 147          * device mapping.  This, in effect, allows a user to pass all
 148          * possible off_t values as the mapping cookie to the driver.  At
 149          * this point, we know that both foff and size are a multiple
 150          * of the page size.  Do a check to avoid wrap.
 151          */
 152         size = round_page(size);
 153         pindex = OFF_TO_IDX(foff) + OFF_TO_IDX(size);
 154         if (pindex > OBJ_MAX_SIZE || pindex < OFF_TO_IDX(foff) ||
 155             pindex < OFF_TO_IDX(size))
 156                 return (NULL);
 157
 158         if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
 159                 return (NULL);
 160         mtx_lock(&dev_pager_mtx);
 161
 162         /*
 163          * Look up pager, creating as necessary.
 164          */
 165         object1 = NULL;
 166         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 167         if (object == NULL) {
 168                 /*
 169                  * Allocate object and associate it with the pager.  Initialize
 170                  * the object's pg_color based upon the physical address of the
 171                  * device's memory.
 172                  */
 173                 mtx_unlock(&dev_pager_mtx);
 174                 object1 = vm_object_allocate(tp, pindex);
 175                 object1->flags |= OBJ_COLORED;
 176                 object1->pg_color = color;
 177                 object1->handle = handle;
 178                 object1->un_pager.devp.ops = ops;
 179                 object1->un_pager.devp.dev = handle;
 180                 TAILQ_INIT(&object1->un_pager.devp.devp_pglist);
 181                 mtx_lock(&dev_pager_mtx);
 182                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 183                 if (object != NULL) {
 184                         /*
 185                          * We raced with other thread while allocating object.
 186                          */
 187                         if (pindex > object->size)
 188                                 object->size = pindex;
 189                         KASSERT(object->type == tp,
 190                             ("Inconsistent device pager type %p %d",
 191                             object, tp));
 192                         KASSERT(object->un_pager.devp.ops == ops,
 193                             ("Inconsistent devops %p %p", object, ops));
 194                 } else {
 195                         object = object1;
 196                         object1 = NULL;
 197                         object->handle = handle;
 198                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 199                             pager_object_list);
 200                         if (ops->cdev_pg_populate != NULL)
 201                                 vm_object_set_flag(object, OBJ_POPULATE);
 202                 }
 203         } else {
 204                 if (pindex > object->size)
 205                         object->size = pindex;
 206                 KASSERT(object->type == tp,
 207                     ("Inconsistent device pager type %p %d", object, tp));
 208         }
 209         mtx_unlock(&dev_pager_mtx);
 210         if (object1 != NULL) {
 211                 object1->handle = object1;
 212                 mtx_lock(&dev_pager_mtx);
 213                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object1,
 214                     pager_object_list);
 215                 mtx_unlock(&dev_pager_mtx);
 216                 vm_object_deallocate(object1);
 217         }
 218         return (object);
 219 }
 220
 221 static vm_object_t
 222 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 223     vm_ooffset_t foff, struct ucred *cred)
 224 {
 225
 226         return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
 227             size, prot, foff, cred));
 228 }
 229
 230 void
 231 cdev_pager_free_page(vm_object_t object, vm_page_t m)
 232 {
 233
 234         VM_OBJECT_ASSERT_WLOCKED(object);
 235         if (object->type == OBJT_MGTDEVICE) {
 236                 KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
 237                 pmap_remove_all(m);
 238                 (void)vm_page_remove(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                         if (vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL) == 0)
 275                                 continue;
 276
 277                         dev_pager_free_page(object, m);
 278                 }
 279         }
 280         object->handle = NULL;
 281         object->type = OBJT_DEAD;
 282 }
 283
 284 static int
 285 dev_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int *rbehind,
 286     int *rahead)
 287 {
 288         int error;
 289
 290         /* Since our haspage reports zero after/before, the count is 1. */
 291         KASSERT(count == 1, ("%s: count %d", __func__, count));
 292         if (object->un_pager.devp.ops->cdev_pg_fault == NULL)
 293                 return (VM_PAGER_FAIL);
 294         VM_OBJECT_WLOCK(object);
 295         error = object->un_pager.devp.ops->cdev_pg_fault(object,
 296             IDX_TO_OFF(ma[0]->pindex), PROT_READ, &ma[0]);
 297
 298         VM_OBJECT_ASSERT_WLOCKED(object);
 299
 300         if (error == VM_PAGER_OK) {
 301                 KASSERT((object->type == OBJT_DEVICE &&
 302                      (ma[0]->oflags & VPO_UNMANAGED) != 0) ||
 303                     (object->type == OBJT_MGTDEVICE &&
 304                      (ma[0]->oflags & VPO_UNMANAGED) == 0),
 305                     ("Wrong page type %p %p", ma[0], object));
 306                 if (object->type == OBJT_DEVICE) {
 307                         TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
 308                             ma[0], plinks.q);
 309                 }
 310                 if (rbehind)
 311                         *rbehind = 0;
 312                 if (rahead)
 313                         *rahead = 0;
 314         }
 315         VM_OBJECT_WUNLOCK(object);
 316
 317         return (error);
 318 }
 319
 320 static int
 321 dev_pager_populate(vm_object_t object, vm_pindex_t pidx, int fault_type,
 322     vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last)
 323 {
 324
 325         VM_OBJECT_ASSERT_WLOCKED(object);
 326         if (object->un_pager.devp.ops->cdev_pg_populate == NULL)
 327                 return (VM_PAGER_FAIL);
 328         return (object->un_pager.devp.ops->cdev_pg_populate(object, pidx,
 329             fault_type, max_prot, first, last));
 330 }
 331
 332 static int
 333 old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
 334     vm_page_t *mres)
 335 {
 336         vm_paddr_t paddr;
 337         vm_page_t m_paddr, page;
 338         struct cdev *dev;
 339         struct cdevsw *csw;
 340         struct file *fpop;
 341         struct thread *td;
 342         vm_memattr_t memattr, memattr1;
 343         int ref, ret;
 344
 345         memattr = object->memattr;
 346
 347         VM_OBJECT_WUNLOCK(object);
 348
 349         dev = object->handle;
 350         csw = dev_refthread(dev, &ref);
 351         if (csw == NULL) {
 352                 VM_OBJECT_WLOCK(object);
 353                 return (VM_PAGER_FAIL);
 354         }
 355         td = curthread;
 356         fpop = td->td_fpop;
 357         td->td_fpop = NULL;
 358         ret = csw->d_mmap(dev, offset, &paddr, prot, &memattr);
 359         td->td_fpop = fpop;
 360         dev_relthread(dev, ref);
 361         if (ret != 0) {
 362                 printf(
 363             "WARNING: dev_pager_getpage: map function returns error %d", ret);
 364                 VM_OBJECT_WLOCK(object);
 365                 return (VM_PAGER_FAIL);
 366         }
 367
 368         /* If "paddr" is a real page, perform a sanity check on "memattr". */
 369         if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
 370             (memattr1 = pmap_page_get_memattr(m_paddr)) != memattr) {
 371                 /*
 372                  * For the /dev/mem d_mmap routine to return the
 373                  * correct memattr, pmap_page_get_memattr() needs to
 374                  * be called, which we do there.
 375                  */
 376                 if ((csw->d_flags & D_MEM) == 0) {
 377                         printf("WARNING: Device driver %s has set "
 378                             "\"memattr\" inconsistently (drv %u pmap %u).\n",
 379                             csw->d_name, memattr, memattr1);
 380                 }
 381                 memattr = memattr1;
 382         }
 383         if (((*mres)->flags & PG_FICTITIOUS) != 0) {
 384                 /*
 385                  * If the passed in result page is a fake page, update it with
 386                  * the new physical address.
 387                  */
 388                 page = *mres;
 389                 VM_OBJECT_WLOCK(object);
 390                 vm_page_updatefake(page, paddr, memattr);
 391         } else {
 392                 /*
 393                  * Replace the passed in reqpage page with our own fake page and
 394                  * free up the all of the original pages.
 395                  */
 396                 page = vm_page_getfake(paddr, memattr);
 397                 VM_OBJECT_WLOCK(object);
 398                 vm_page_replace(page, object, (*mres)->pindex, *mres);
 399                 *mres = page;
 400         }
 401         vm_page_valid(page);
 402         return (VM_PAGER_OK);
 403 }
 404
 405 static void
 406 dev_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
 407     int *rtvals)
 408 {
 409
 410         panic("dev_pager_putpage called");
 411 }
 412
 413 static boolean_t
 414 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
 415     int *after)
 416 {
 417
 418         if (before != NULL)
 419                 *before = 0;
 420         if (after != NULL)
 421                 *after = 0;
 422         return (TRUE);
 423 }
 424
 425 static int
 426 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
 427     vm_ooffset_t foff, struct ucred *cred, u_short *color)
 428 {
 429         struct cdev *dev;
 430         struct cdevsw *csw;
 431         vm_memattr_t dummy;
 432         vm_ooffset_t off;
 433         vm_paddr_t paddr;
 434         unsigned int npages;
 435         int ref;
 436
 437         /*
 438          * Make sure this device can be mapped.
 439          */
 440         dev = handle;
 441         csw = dev_refthread(dev, &ref);
 442         if (csw == NULL)
 443                 return (ENXIO);
 444
 445         /*
 446          * Check that the specified range of the device allows the desired
 447          * protection.
 448          *
 449          * XXX assumes VM_PROT_* == PROT_*
 450          */
 451         npages = OFF_TO_IDX(size);
 452         paddr = 0; /* Make paddr initialized for the case of size == 0. */
 453         for (off = foff; npages--; off += PAGE_SIZE) {
 454                 if (csw->d_mmap(dev, off, &paddr, (int)prot, &dummy) != 0) {
 455                         dev_relthread(dev, ref);
 456                         return (EINVAL);
 457                 }
 458         }
 459
 460         dev_ref(dev);
 461         dev_relthread(dev, ref);
 462         *color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
 463         return (0);
 464 }
 465
 466 static void
 467 old_dev_pager_dtor(void *handle)
 468 {
 469
 470         dev_rel(handle);
 471 }