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