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