sys/vm/device_pager.c

   1 /*
   2  * (MPSAFE)
   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  * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $
  38  */
  39
  40 #include <sys/param.h>
  41 #include <sys/systm.h>
  42 #include <sys/kernel.h>
  43 #include <sys/conf.h>
  44 #include <sys/mman.h>
  45 #include <sys/device.h>
  46 #include <sys/queue.h>
  47 #include <sys/malloc.h>
  48 #include <sys/thread2.h>
  49 #include <sys/mutex2.h>
  50
  51 #include <vm/vm.h>
  52 #include <vm/vm_object.h>
  53 #include <vm/vm_page.h>
  54 #include <vm/vm_pager.h>
  55 #include <vm/vm_zone.h>
  56 #include <vm/vm_page2.h>
  57
  58 static void dev_pager_dealloc (vm_object_t);
  59 static int dev_pager_getpage (vm_object_t, vm_page_t *, int);
  60 static void dev_pager_putpages (vm_object_t, vm_page_t *, int, int, int *);
  61 static boolean_t dev_pager_haspage (vm_object_t, vm_pindex_t);
  62
  63 /* list of device pager objects */
  64 static TAILQ_HEAD(, vm_page) dev_freepages_list =
  65                 TAILQ_HEAD_INITIALIZER(dev_freepages_list);
  66 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages",
  67                 "Device mapped pages");
  68
  69 static vm_page_t dev_pager_getfake (vm_paddr_t, int);
  70 static void dev_pager_putfake (vm_page_t);
  71
  72 struct pagerops devicepagerops = {
  73         dev_pager_dealloc,
  74         dev_pager_getpage,
  75         dev_pager_putpages,
  76         dev_pager_haspage
  77 };
  78
  79 /* list of device pager objects */
  80 static struct pagerlst dev_pager_object_list =
  81                 TAILQ_HEAD_INITIALIZER(dev_pager_object_list);
  82 /* protect list manipulation */
  83 static struct mtx dev_pager_mtx = MTX_INITIALIZER("devpgr");
  84
  85 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
  86     vm_ooffset_t foff, struct ucred *cred, u_short *pg_color);
  87 static void old_dev_pager_dtor(void *handle);
  88 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
  89     int prot, vm_page_t *mres);
  90
  91 static struct cdev_pager_ops old_dev_pager_ops = {
  92         .cdev_pg_ctor = old_dev_pager_ctor,
  93         .cdev_pg_dtor = old_dev_pager_dtor,
  94         .cdev_pg_fault = old_dev_pager_fault
  95 };
  96
  97 vm_object_t
  98 cdev_pager_lookup(void *handle)
  99 {
 100         vm_object_t object;
 101
 102         mtx_lock(&dev_pager_mtx);
 103         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 104         mtx_unlock(&dev_pager_mtx);
 105
 106         return (object);
 107 }
 108
 109 vm_object_t
 110 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
 111         vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
 112 {
 113         cdev_t dev;
 114         vm_object_t object;
 115         u_short color;
 116
 117         /*
 118          * Offset should be page aligned.
 119          */
 120         if (foff & PAGE_MASK)
 121                 return (NULL);
 122
 123         size = round_page64(size);
 124
 125         if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
 126                 return (NULL);
 127
 128         /*
 129          * Look up pager, creating as necessary.
 130          */
 131         mtx_lock(&dev_pager_mtx);
 132         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 133         if (object == NULL) {
 134                 /*
 135                  * Allocate object and associate it with the pager.
 136                  */
 137                 object = vm_object_allocate_hold(tp,
 138                                                  OFF_TO_IDX(foff + size));
 139                 object->handle = handle;
 140                 object->un_pager.devp.ops = ops;
 141                 object->un_pager.devp.dev = handle;
 142                 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
 143
 144                 /*
 145                  * handle is only a device for old_dev_pager_ctor.
 146                  */
 147                 if (ops->cdev_pg_ctor == old_dev_pager_ctor) {
 148                         dev = handle;
 149                         dev->si_object = object;
 150                 }
 151
 152                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 153                                   pager_object_list);
 154
 155                 vm_object_drop(object);
 156         } else {
 157                 /*
 158                  * Gain a reference to the object.
 159                  */
 160                 vm_object_hold(object);
 161                 vm_object_reference_locked(object);
 162                 if (OFF_TO_IDX(foff + size) > object->size)
 163                         object->size = OFF_TO_IDX(foff + size);
 164                 vm_object_drop(object);
 165         }
 166         mtx_unlock(&dev_pager_mtx);
 167
 168         return (object);
 169 }
 170
 171 /*
 172  * No requirements.
 173  */
 174 vm_object_t
 175 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
 176 {
 177         return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
 178             size, prot, foff, NULL));
 179 }
 180
 181 /*
 182  * Caller must hold object lock.
 183  */
 184 void
 185 cdev_pager_free_page(vm_object_t object, vm_page_t m)
 186 {
 187         if (object->type == OBJT_MGTDEVICE) {
 188                 KKASSERT((m->flags & PG_FICTITIOUS) != 0);
 189                 pmap_page_protect(m, VM_PROT_NONE);
 190                 vm_page_remove(m);
 191                 vm_page_wakeup(m);
 192         } else if (object->type == OBJT_DEVICE) {
 193                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 194                 dev_pager_putfake(m);
 195         }
 196 }
 197
 198 /*
 199  * No requirements.
 200  */
 201 static void
 202 dev_pager_dealloc(vm_object_t object)
 203 {
 204         vm_page_t m;
 205
 206         /*
 207          * NOTE: Callback may recurse into the device pager so do not
 208          * obtain dev_pager_mtx until after it returns.
 209          *
 210          * The mutex should only be needed when manipulating the list.
 211          */
 212         object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev);
 213
 214         mtx_lock(&dev_pager_mtx);
 215         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 216         mtx_unlock(&dev_pager_mtx);
 217
 218         if (object->type == OBJT_DEVICE) {
 219                 /*
 220                  * Free up our fake pages.
 221                  */
 222                 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) !=
 223                        NULL) {
 224                         TAILQ_REMOVE(&object->un_pager.devp.devp_pglist,
 225                                      m, pageq);
 226                         dev_pager_putfake(m);
 227                 }
 228         }
 229 }
 230
 231 /*
 232  * No requirements.
 233  *
 234  * WARNING! Do not obtain dev_pager_mtx here, doing so will cause a
 235  *          deadlock in DRMs VM paging code.
 236  */
 237 static int
 238 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
 239 {
 240         vm_page_t page;
 241         int error;
 242
 243         page = *mpp;
 244
 245         error = object->un_pager.devp.ops->cdev_pg_fault(
 246                         object, IDX_TO_OFF(page->pindex),
 247                         PROT_READ, mpp);
 248
 249         return (error);
 250 }
 251
 252 /*
 253  * No requirements.
 254  */
 255 static void
 256 dev_pager_putpages(vm_object_t object, vm_page_t *m,
 257                    int count, int sync, int *rtvals)
 258 {
 259         panic("dev_pager_putpage called");
 260 }
 261
 262 /*
 263  * No requirements.
 264  */
 265 static boolean_t
 266 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex)
 267 {
 268         return (TRUE);
 269 }
 270
 271 /*
 272  * The caller does not need to hold dev_pager_mtx() but caller must ensure
 273  * no page-use collision.
 274  */
 275 static vm_page_t
 276 dev_pager_getfake(vm_paddr_t paddr, int pat_mode)
 277 {
 278         vm_page_t m;
 279
 280         m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK|M_ZERO);
 281
 282         pmap_page_init(m);
 283
 284         m->flags = PG_BUSY | PG_FICTITIOUS;
 285         m->valid = VM_PAGE_BITS_ALL;
 286         m->dirty = 0;
 287         m->busy = 0;
 288         m->queue = PQ_NONE;
 289         m->object = NULL;
 290
 291         m->wire_count = 1;
 292         m->hold_count = 0;
 293         m->phys_addr = paddr;
 294         m->pat_mode = pat_mode;
 295
 296         spin_init(&m->spin, "dev_page");
 297
 298         return (m);
 299 }
 300
 301 /*
 302  * The caller does not need to hold dev_pager_mtx() but caller must ensure
 303  * no page-use collision within the object.
 304  */
 305 static void
 306 dev_pager_putfake(vm_page_t m)
 307 {
 308         if (!(m->flags & PG_FICTITIOUS))
 309                 panic("dev_pager_putfake: bad page");
 310         KKASSERT(m->object == NULL);
 311         KKASSERT(m->hold_count == 0);
 312         kfree(m, M_FICTITIOUS_PAGES);
 313 }
 314
 315 static int
 316 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
 317     vm_ooffset_t foff, struct ucred *cred,  u_short *color)
 318 {
 319         unsigned int npages;
 320         vm_offset_t off;
 321         cdev_t dev;
 322
 323         dev = handle;
 324
 325         /*
 326          * Check that the specified range of the device allows the desired
 327          * protection.
 328          *
 329          * XXX assumes VM_PROT_* == PROT_*
 330          */
 331         npages = OFF_TO_IDX(size);
 332         for (off = foff; npages--; off += PAGE_SIZE) {
 333                 if (dev_dmmap(dev, off, (int)prot, NULL) == -1)
 334                         return (EINVAL);
 335         }
 336
 337         return (0);
 338 }
 339
 340 static void old_dev_pager_dtor(void *handle)
 341 {
 342         cdev_t dev;
 343
 344         dev = handle;
 345         if (dev != NULL) {
 346                 KKASSERT(dev->si_object);
 347                 dev->si_object = NULL;
 348         }
 349 }
 350
 351 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
 352     int prot, vm_page_t *mres)
 353 {
 354         vm_paddr_t paddr;
 355         vm_page_t page;
 356         vm_offset_t pidx = OFF_TO_IDX(offset);
 357         cdev_t dev;
 358
 359         page = *mres;
 360         dev = object->handle;
 361
 362         paddr = pmap_phys_address(dev_dmmap(dev, offset, prot, NULL));
 363         KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
 364         KKASSERT(object->type == OBJT_DEVICE);
 365
 366         if (page->flags & PG_FICTITIOUS) {
 367                 /*
 368                  * If the passed in reqpage page is already a fake page,
 369                  * update it with the new physical address.
 370                  */
 371                 page->phys_addr = paddr;
 372                 page->valid = VM_PAGE_BITS_ALL;
 373         } else {
 374                 /*
 375                  * Replace the passed in reqpage page with our own fake page
 376                  * and free up all the original pages.  Object lock must be
 377                  * held when manipulating devp_pglist and inserting the
 378                  * page.
 379                  */
 380                 page = dev_pager_getfake(paddr, object->memattr);
 381                 vm_object_hold(object);
 382                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
 383                                   page, pageq);
 384                 vm_page_free(*mres);
 385                 if (vm_page_insert(page, object, pidx) == FALSE) {
 386                         panic("dev_pager_getpage: page (%p,%016jx) exists",
 387                               object, (uintmax_t)pidx);
 388                 }
 389                 vm_object_drop(object);
 390         }
 391
 392         return (VM_PAGER_OK);
 393 }
 394