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/sx.h>
  48
  49 #include <vm/vm.h>
  50 #include <vm/vm_object.h>
  51 #include <vm/vm_page.h>
  52 #include <vm/vm_pager.h>
  53 #include <vm/uma.h>
  54
  55 static void dev_pager_init(void);
  56 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
  57     vm_ooffset_t, struct ucred *);
  58 static void dev_pager_dealloc(vm_object_t);
  59 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int);
  60 static void dev_pager_putpages(vm_object_t, vm_page_t *, int,
  61                 boolean_t, int *);
  62 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *,
  63                 int *);
  64 static void dev_pager_free_page(vm_object_t object, vm_page_t m);
  65
  66 /* list of device pager objects */
  67 static struct pagerlst dev_pager_object_list;
  68 /* protect list manipulation */
  69 static struct mtx dev_pager_mtx;
  70
  71 struct pagerops devicepagerops = {
  72         .pgo_init =     dev_pager_init,
  73         .pgo_alloc =    dev_pager_alloc,
  74         .pgo_dealloc =  dev_pager_dealloc,
  75         .pgo_getpages = dev_pager_getpages,
  76         .pgo_putpages = dev_pager_putpages,
  77         .pgo_haspage =  dev_pager_haspage,
  78 };
  79
  80 struct pagerops mgtdevicepagerops = {
  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 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
  89     vm_ooffset_t foff, struct ucred *cred, u_short *color);
  90 static void old_dev_pager_dtor(void *handle);
  91 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
  92     int prot, vm_page_t *mres);
  93
  94 static struct cdev_pager_ops old_dev_pager_ops = {
  95         .cdev_pg_ctor = old_dev_pager_ctor,
  96         .cdev_pg_dtor = old_dev_pager_dtor,
  97         .cdev_pg_fault = old_dev_pager_fault
  98 };
  99
 100 static void
 101 dev_pager_init()
 102 {
 103         TAILQ_INIT(&dev_pager_object_list);
 104         mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
 105 }
 106
 107 vm_object_t
 108 cdev_pager_lookup(void *handle)
 109 {
 110         vm_object_t object;
 111
 112         mtx_lock(&dev_pager_mtx);
 113         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 114         mtx_unlock(&dev_pager_mtx);
 115         return (object);
 116 }
 117
 118 vm_object_t
 119 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
 120     vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
 121 {
 122         vm_object_t object, object1;
 123         vm_pindex_t pindex;
 124         u_short color;
 125
 126         if (tp != OBJT_DEVICE && tp != OBJT_MGTDEVICE)
 127                 return (NULL);
 128
 129         /*
 130          * Offset should be page aligned.
 131          */
 132         if (foff & PAGE_MASK)
 133                 return (NULL);
 134
 135         size = round_page(size);
 136         pindex = OFF_TO_IDX(foff + size);
 137
 138         if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
 139                 return (NULL);
 140         mtx_lock(&dev_pager_mtx);
 141
 142         /*
 143          * Look up pager, creating as necessary.
 144          */
 145         object1 = NULL;
 146         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 147         if (object == NULL) {
 148                 /*
 149                  * Allocate object and associate it with the pager.  Initialize
 150                  * the object's pg_color based upon the physical address of the
 151                  * device's memory.
 152                  */
 153                 mtx_unlock(&dev_pager_mtx);
 154                 object1 = vm_object_allocate(tp, pindex);
 155                 object1->flags |= OBJ_COLORED;
 156                 object1->pg_color = color;
 157                 object1->handle = handle;
 158                 object1->un_pager.devp.ops = ops;
 159                 TAILQ_INIT(&object1->un_pager.devp.devp_pglist);
 160                 mtx_lock(&dev_pager_mtx);
 161                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 162                 if (object != NULL) {
 163                         /*
 164                          * We raced with other thread while allocating object.
 165                          */
 166                         if (pindex > object->size)
 167                                 object->size = pindex;
 168                 } else {
 169                         object = object1;
 170                         object1 = NULL;
 171                         object->handle = handle;
 172                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 173                             pager_object_list);
 174                         KASSERT(object->type == tp,
 175                 ("Inconsistent device pager type %p %d", object, tp));
 176                 }
 177         } else {
 178                 if (pindex > object->size)
 179                         object->size = pindex;
 180         }
 181         mtx_unlock(&dev_pager_mtx);
 182         if (object1 != NULL) {
 183                 object1->handle = object1;
 184                 mtx_lock(&dev_pager_mtx);
 185                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object1,
 186                     pager_object_list);
 187                 mtx_unlock(&dev_pager_mtx);
 188                 vm_object_deallocate(object1);
 189         }
 190         return (object);
 191 }
 192
 193 static vm_object_t
 194 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 195     vm_ooffset_t foff, struct ucred *cred)
 196 {
 197
 198         return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
 199             size, prot, foff, cred));
 200 }
 201
 202 void
 203 cdev_pager_free_page(vm_object_t object, vm_page_t m)
 204 {
 205
 206         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 207         if (object->type == OBJT_MGTDEVICE) {
 208                 KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
 209                 pmap_remove_all(m);
 210                 vm_page_lock(m);
 211                 vm_page_remove(m);
 212                 vm_page_unlock(m);
 213         } else if (object->type == OBJT_DEVICE)
 214                 dev_pager_free_page(object, m);
 215 }
 216
 217 static void
 218 dev_pager_free_page(vm_object_t object, vm_page_t m)
 219 {
 220
 221         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 222         KASSERT((object->type == OBJT_DEVICE &&
 223             (m->oflags & VPO_UNMANAGED) != 0),
 224             ("Managed device or page obj %p m %p", object, m));
 225         TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 226         vm_page_putfake(m);
 227 }
 228
 229 static void
 230 dev_pager_dealloc(object)
 231         vm_object_t object;
 232 {
 233         vm_page_t m;
 234
 235         VM_OBJECT_UNLOCK(object);
 236         object->un_pager.devp.ops->cdev_pg_dtor(object->handle);
 237
 238         mtx_lock(&dev_pager_mtx);
 239         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 240         mtx_unlock(&dev_pager_mtx);
 241         VM_OBJECT_LOCK(object);
 242
 243         if (object->type == OBJT_DEVICE) {
 244                 /*
 245                  * Free up our fake pages.
 246                  */
 247                 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist))
 248                     != NULL)
 249                         dev_pager_free_page(object, m);
 250         }
 251 }
 252
 253 static int
 254 dev_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int reqpage)
 255 {
 256         int error, i;
 257
 258         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 259         error = object->un_pager.devp.ops->cdev_pg_fault(object,
 260             IDX_TO_OFF(ma[reqpage]->pindex), PROT_READ, &ma[reqpage]);
 261
 262         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 263
 264         for (i = 0; i < count; i++) {
 265                 if (i != reqpage) {
 266                         vm_page_lock(ma[i]);
 267                         vm_page_free(ma[i]);
 268                         vm_page_unlock(ma[i]);
 269                 }
 270         }
 271
 272         if (error == VM_PAGER_OK) {
 273                 KASSERT((object->type == OBJT_DEVICE &&
 274                      (ma[reqpage]->oflags & VPO_UNMANAGED) != 0) ||
 275                     (object->type == OBJT_MGTDEVICE &&
 276                      (ma[reqpage]->oflags & VPO_UNMANAGED) == 0),
 277                     ("Wrong page type %p %p", ma[reqpage], object));
 278                 if (object->type == OBJT_DEVICE) {
 279                         TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
 280                             ma[reqpage], pageq);
 281                 }
 282         }
 283
 284         return (error);
 285 }
 286
 287 static int
 288 old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
 289     vm_page_t *mres)
 290 {
 291         vm_pindex_t pidx;
 292         vm_paddr_t paddr;
 293         vm_page_t m_paddr, page;
 294         struct cdev *dev;
 295         struct cdevsw *csw;
 296         struct file *fpop;
 297         struct thread *td;
 298         vm_memattr_t memattr;
 299         int ref, ret;
 300
 301         pidx = OFF_TO_IDX(offset);
 302         memattr = object->memattr;
 303
 304         VM_OBJECT_UNLOCK(object);
 305
 306         dev = object->handle;
 307         csw = dev_refthread(dev, &ref);
 308         if (csw == NULL) {
 309                 VM_OBJECT_LOCK(object);
 310                 return (VM_PAGER_FAIL);
 311         }
 312         td = curthread;
 313         fpop = td->td_fpop;
 314         td->td_fpop = NULL;
 315         ret = csw->d_mmap(dev, offset, &paddr, prot, &memattr);
 316         td->td_fpop = fpop;
 317         dev_relthread(dev, ref);
 318         if (ret != 0) {
 319                 printf(
 320             "WARNING: dev_pager_getpage: map function returns error %d", ret);
 321                 VM_OBJECT_LOCK(object);
 322                 return (VM_PAGER_FAIL);
 323         }
 324
 325         /* If "paddr" is a real page, perform a sanity check on "memattr". */
 326         if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
 327             pmap_page_get_memattr(m_paddr) != memattr) {
 328                 memattr = pmap_page_get_memattr(m_paddr);
 329                 printf(
 330             "WARNING: A device driver has set \"memattr\" inconsistently.\n");
 331         }
 332         if (((*mres)->flags & PG_FICTITIOUS) != 0) {
 333                 /*
 334                  * If the passed in result page is a fake page, update it with
 335                  * the new physical address.
 336                  */
 337                 page = *mres;
 338                 VM_OBJECT_LOCK(object);
 339                 vm_page_updatefake(page, paddr, memattr);
 340         } else {
 341                 /*
 342                  * Replace the passed in reqpage page with our own fake page and
 343                  * free up the all of the original pages.
 344                  */
 345                 page = vm_page_getfake(paddr, memattr);
 346                 VM_OBJECT_LOCK(object);
 347                 vm_page_lock(*mres);
 348                 vm_page_free(*mres);
 349                 vm_page_unlock(*mres);
 350                 *mres = page;
 351                 vm_page_insert(page, object, pidx);
 352         }
 353         page->valid = VM_PAGE_BITS_ALL;
 354         return (VM_PAGER_OK);
 355 }
 356
 357 static void
 358 dev_pager_putpages(object, m, count, sync, rtvals)
 359         vm_object_t object;
 360         vm_page_t *m;
 361         int count;
 362         boolean_t sync;
 363         int *rtvals;
 364 {
 365
 366         panic("dev_pager_putpage called");
 367 }
 368
 369 static boolean_t
 370 dev_pager_haspage(object, pindex, before, after)
 371         vm_object_t object;
 372         vm_pindex_t pindex;
 373         int *before;
 374         int *after;
 375 {
 376         if (before != NULL)
 377                 *before = 0;
 378         if (after != NULL)
 379                 *after = 0;
 380         return (TRUE);
 381 }
 382
 383 static int
 384 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
 385     vm_ooffset_t foff, struct ucred *cred, u_short *color)
 386 {
 387         struct cdev *dev;
 388         struct cdevsw *csw;
 389         vm_memattr_t dummy;
 390         vm_ooffset_t off;
 391         vm_paddr_t paddr;
 392         unsigned int npages;
 393         int ref;
 394
 395         /*
 396          * Make sure this device can be mapped.
 397          */
 398         dev = handle;
 399         csw = dev_refthread(dev, &ref);
 400         if (csw == NULL)
 401                 return (ENXIO);
 402
 403         /*
 404          * Check that the specified range of the device allows the desired
 405          * protection.
 406          *
 407          * XXX assumes VM_PROT_* == PROT_*
 408          */
 409         npages = OFF_TO_IDX(size);
 410         for (off = foff; npages--; off += PAGE_SIZE) {
 411                 if (csw->d_mmap(dev, off, &paddr, (int)prot, &dummy) != 0) {
 412                         dev_relthread(dev, ref);
 413                         return (EINVAL);
 414                 }
 415         }
 416
 417         dev_ref(dev);
 418         dev_relthread(dev, ref);
 419         *color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
 420         return (0);
 421 }
 422
 423 static void
 424 old_dev_pager_dtor(void *handle)
 425 {
 426
 427         dev_rel(handle);
 428 }