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;
  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         mtx_lock(&dev_pager_mtx);
 102         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 103         mtx_unlock(&dev_pager_mtx);
 104         return (object);
 105 }
 106
 107 vm_object_t
 108 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
 109         vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
 110 {
 111         cdev_t dev;
 112         vm_object_t object;
 113         u_short color;
 114
 115         /*
 116          * Offset should be page aligned.
 117          */
 118         if (foff & PAGE_MASK)
 119                 return (NULL);
 120
 121         size = round_page64(size);
 122
 123         if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
 124                 return (NULL);
 125
 126         /*
 127          * Look up pager, creating as necessary.
 128          */
 129         mtx_lock(&dev_pager_mtx);
 130         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 131         if (object == NULL) {
 132                 /*
 133                  * Allocate object and associate it with the pager.
 134                  */
 135                 object = vm_object_allocate_hold(tp,
 136                                                  OFF_TO_IDX(foff + size));
 137                 object->handle = handle;
 138                 object->un_pager.devp.ops = ops;
 139                 object->un_pager.devp.dev = handle;
 140                 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
 141
 142                 /*
 143                  * handle is only a device for old_dev_pager_ctor.
 144                  */
 145                 if (ops->cdev_pg_ctor == old_dev_pager_ctor) {
 146                         dev = handle;
 147                         dev->si_object = object;
 148                 }
 149
 150                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 151                     pager_object_list);
 152
 153                 vm_object_drop(object);
 154         } else {
 155                 /*
 156                  * Gain a reference to the object.
 157                  */
 158                 vm_object_hold(object);
 159                 vm_object_reference_locked(object);
 160                 if (OFF_TO_IDX(foff + size) > object->size)
 161                         object->size = OFF_TO_IDX(foff + size);
 162                 vm_object_drop(object);
 163         }
 164         mtx_unlock(&dev_pager_mtx);
 165
 166         return (object);
 167 }
 168
 169 /*
 170  * No requirements.
 171  */
 172 vm_object_t
 173 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
 174 {
 175         return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
 176             size, prot, foff, NULL));
 177 }
 178
 179 /* XXX */
 180 void
 181 cdev_pager_free_page(vm_object_t object, vm_page_t m)
 182 {
 183         if (object->type == OBJT_MGTDEVICE) {
 184                 KKASSERT((m->flags & PG_FICTITIOUS) != 0);
 185                 pmap_page_protect(m, VM_PROT_NONE);
 186                 vm_page_remove(m);
 187                 vm_page_wakeup(m);
 188         } else if (object->type == OBJT_DEVICE) {
 189                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 190                 dev_pager_putfake(m);
 191         }
 192 }
 193
 194 /*
 195  * No requirements.
 196  */
 197 static void
 198 dev_pager_dealloc(vm_object_t object)
 199 {
 200         vm_page_t m;
 201
 202         mtx_lock(&dev_pager_mtx);
 203         object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev);
 204
 205         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 206
 207         if (object->type == OBJT_DEVICE) {
 208                 /*
 209                  * Free up our fake pages.
 210                  */
 211                 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) !=
 212                        NULL) {
 213                         TAILQ_REMOVE(&object->un_pager.devp.devp_pglist,
 214                                      m, pageq);
 215                         dev_pager_putfake(m);
 216                 }
 217         }
 218         mtx_unlock(&dev_pager_mtx);
 219 }
 220
 221 /*
 222  * No requirements.
 223  */
 224 static int
 225 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
 226 {
 227         vm_page_t page;
 228         int error;
 229
 230         mtx_lock(&dev_pager_mtx);
 231
 232         page = *mpp;
 233
 234         error = object->un_pager.devp.ops->cdev_pg_fault(object,
 235             IDX_TO_OFF(page->pindex), PROT_READ, mpp);
 236
 237         mtx_unlock(&dev_pager_mtx);
 238
 239         return (error);
 240 }
 241
 242 /*
 243  * No requirements.
 244  */
 245 static void
 246 dev_pager_putpages(vm_object_t object, vm_page_t *m,
 247                    int count, int sync, int *rtvals)
 248 {
 249         panic("dev_pager_putpage called");
 250 }
 251
 252 /*
 253  * No requirements.
 254  */
 255 static boolean_t
 256 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex)
 257 {
 258         return (TRUE);
 259 }
 260
 261 /*
 262  * The caller must hold dev_pager_mtx
 263  */
 264 static vm_page_t
 265 dev_pager_getfake(vm_paddr_t paddr, int pat_mode)
 266 {
 267         vm_page_t m;
 268
 269         m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK|M_ZERO);
 270
 271         pmap_page_init(m);
 272
 273         m->flags = PG_BUSY | PG_FICTITIOUS;
 274         m->valid = VM_PAGE_BITS_ALL;
 275         m->dirty = 0;
 276         m->busy = 0;
 277         m->queue = PQ_NONE;
 278         m->object = NULL;
 279
 280         m->wire_count = 1;
 281         m->hold_count = 0;
 282         m->phys_addr = paddr;
 283         m->pat_mode = pat_mode;
 284
 285         return (m);
 286 }
 287
 288 /*
 289  * Synthesized VM pages must be structurally stable for lockless lookups to
 290  * work properly.
 291  *
 292  * The caller must hold dev_pager_mtx
 293  */
 294 static void
 295 dev_pager_putfake(vm_page_t m)
 296 {
 297         if (!(m->flags & PG_FICTITIOUS))
 298                 panic("dev_pager_putfake: bad page");
 299         KKASSERT(m->object == NULL);
 300         KKASSERT(m->hold_count == 0);
 301         kfree(m, M_FICTITIOUS_PAGES);
 302 }
 303
 304 static int
 305 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
 306     vm_ooffset_t foff, struct ucred *cred,  u_short *color)
 307 {
 308         unsigned int npages;
 309         vm_offset_t off;
 310         cdev_t dev;
 311
 312         dev = handle;
 313
 314         /*
 315          * Check that the specified range of the device allows the desired
 316          * protection.
 317          *
 318          * XXX assumes VM_PROT_* == PROT_*
 319          */
 320         npages = OFF_TO_IDX(size);
 321         for (off = foff; npages--; off += PAGE_SIZE) {
 322                 if (dev_dmmap(dev, off, (int)prot, NULL) == -1)
 323                         return (EINVAL);
 324         }
 325
 326         return (0);
 327 }
 328
 329 static void old_dev_pager_dtor(void *handle)
 330 {
 331         cdev_t dev;
 332
 333         dev = handle;
 334         if (dev != NULL) {
 335                 KKASSERT(dev->si_object);
 336                 dev->si_object = NULL;
 337         }
 338 }
 339
 340 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
 341     int prot, vm_page_t *mres)
 342 {
 343         vm_paddr_t paddr;
 344         vm_page_t page;
 345         vm_offset_t pidx = OFF_TO_IDX(offset);
 346         cdev_t dev;
 347
 348         page = *mres;
 349         dev = object->handle;
 350
 351         paddr = pmap_phys_address(
 352                     dev_dmmap(dev, offset, prot, NULL));
 353         KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
 354         KKASSERT(object->type == OBJT_DEVICE);
 355
 356         if (page->flags & PG_FICTITIOUS) {
 357                 /*
 358                  * If the passed in reqpage page is already a fake page,
 359                  * update it with the new physical address.
 360                  */
 361                 page->phys_addr = paddr;
 362                 page->valid = VM_PAGE_BITS_ALL;
 363         } else {
 364                 /*
 365                  * Replace the passed in reqpage page with our own fake page
 366                  * and free up all the original pages.
 367                  */
 368                 page = dev_pager_getfake(paddr, object->memattr);
 369                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
 370                                   page, pageq);
 371                 vm_object_hold(object);
 372                 vm_page_free(*mres);
 373                 if (vm_page_insert(page, object, pidx) == FALSE) {
 374                         panic("dev_pager_getpage: page (%p,%016jx) exists",
 375                               object, (uintmax_t)pidx);
 376                 }
 377                 vm_object_drop(object);
 378         }
 379
 380         return (VM_PAGER_OK);
 381 }
 382