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,
  61                 boolean_t, int *);
  62 static boolean_t dev_pager_haspage (vm_object_t, vm_pindex_t);
  63
  64 /* list of device pager objects */
  65 static TAILQ_HEAD(, vm_page) dev_freepages_list =
  66                 TAILQ_HEAD_INITIALIZER(dev_freepages_list);
  67 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages",
  68                 "Device mapped pages");
  69
  70 static vm_page_t dev_pager_getfake (vm_paddr_t, int);
  71 static void dev_pager_putfake (vm_page_t);
  72
  73 struct pagerops devicepagerops = {
  74         dev_pager_dealloc,
  75         dev_pager_getpage,
  76         dev_pager_putpages,
  77         dev_pager_haspage
  78 };
  79
  80 /* list of device pager objects */
  81 static struct pagerlst dev_pager_object_list =
  82                 TAILQ_HEAD_INITIALIZER(dev_pager_object_list);
  83 /* protect list manipulation */
  84 static struct mtx dev_pager_mtx = MTX_INITIALIZER;
  85
  86 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
  87     vm_ooffset_t foff, struct ucred *cred, u_short *pg_color);
  88 static void old_dev_pager_dtor(void *handle);
  89 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
  90     int prot, vm_page_t *mres);
  91
  92 static struct cdev_pager_ops old_dev_pager_ops = {
  93         .cdev_pg_ctor = old_dev_pager_ctor,
  94         .cdev_pg_dtor = old_dev_pager_dtor,
  95         .cdev_pg_fault = old_dev_pager_fault
  96 };
  97
  98 vm_object_t
  99 cdev_pager_lookup(void *handle)
 100 {
 101         vm_object_t object;
 102         mtx_lock(&dev_pager_mtx);
 103         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 104         mtx_unlock(&dev_pager_mtx);
 105         return (object);
 106 }
 107
 108 vm_object_t
 109 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
 110         vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
 111 {
 112         cdev_t dev;
 113         vm_object_t object;
 114         u_short color;
 115         dev = handle;
 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                 dev->si_object = object;
 144
 145                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 146                     pager_object_list);
 147
 148                 vm_object_drop(object);
 149         } else {
 150                 /*
 151                  * Gain a reference to the object.
 152                  */
 153                 vm_object_hold(object);
 154                 vm_object_reference_locked(object);
 155                 if (OFF_TO_IDX(foff + size) > object->size)
 156                         object->size = OFF_TO_IDX(foff + size);
 157                 vm_object_drop(object);
 158         }
 159         mtx_unlock(&dev_pager_mtx);
 160
 161         return (object);
 162 }
 163
 164 /*
 165  * No requirements.
 166  */
 167 vm_object_t
 168 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
 169 {
 170         return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
 171             size, prot, foff, NULL));
 172 }
 173
 174 /* XXX */
 175 void
 176 cdev_pager_free_page(vm_object_t object, vm_page_t m)
 177 {
 178         if (object->type == OBJT_MGTDEVICE) {
 179                 KKASSERT((m->flags & PG_FICTITIOUS) != 0);
 180                 pmap_page_protect(m, VM_PROT_NONE);
 181                 vm_page_remove(m);
 182                 vm_page_wakeup(m);
 183         } else if (object->type == OBJT_DEVICE) {
 184                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 185                 dev_pager_putfake(m);
 186         }
 187 }
 188
 189 /*
 190  * No requirements.
 191  */
 192 static void
 193 dev_pager_dealloc(vm_object_t object)
 194 {
 195         vm_page_t m;
 196
 197         mtx_lock(&dev_pager_mtx);
 198         object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev);
 199
 200         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 201
 202         if (object->type == OBJT_DEVICE) {
 203                 /*
 204                  * Free up our fake pages.
 205                  */
 206                 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) !=
 207                        NULL) {
 208                         TAILQ_REMOVE(&object->un_pager.devp.devp_pglist,
 209                                      m, pageq);
 210                         dev_pager_putfake(m);
 211                 }
 212         }
 213         mtx_unlock(&dev_pager_mtx);
 214 }
 215
 216 /*
 217  * No requirements.
 218  */
 219 static int
 220 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
 221 {
 222         vm_page_t page;
 223         int error;
 224
 225         mtx_lock(&dev_pager_mtx);
 226
 227         page = *mpp;
 228
 229         error = object->un_pager.devp.ops->cdev_pg_fault(object,
 230             IDX_TO_OFF(page->pindex), PROT_READ, mpp);
 231
 232         mtx_unlock(&dev_pager_mtx);
 233
 234         return (error);
 235 }
 236
 237 /*
 238  * No requirements.
 239  */
 240 static void
 241 dev_pager_putpages(vm_object_t object, vm_page_t *m,
 242                    int count, boolean_t sync, int *rtvals)
 243 {
 244         panic("dev_pager_putpage called");
 245 }
 246
 247 /*
 248  * No requirements.
 249  */
 250 static boolean_t
 251 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex)
 252 {
 253         return (TRUE);
 254 }
 255
 256 /*
 257  * The caller must hold dev_pager_mtx
 258  */
 259 static vm_page_t
 260 dev_pager_getfake(vm_paddr_t paddr, int pat_mode)
 261 {
 262         vm_page_t m;
 263
 264         m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK|M_ZERO);
 265
 266         pmap_page_init(m);
 267
 268         m->flags = PG_BUSY | PG_FICTITIOUS;
 269         m->valid = VM_PAGE_BITS_ALL;
 270         m->dirty = 0;
 271         m->busy = 0;
 272         m->queue = PQ_NONE;
 273         m->object = NULL;
 274
 275         m->wire_count = 1;
 276         m->hold_count = 0;
 277         m->phys_addr = paddr;
 278         m->pat_mode = pat_mode;
 279
 280         return (m);
 281 }
 282
 283 /*
 284  * Synthesized VM pages must be structurally stable for lockless lookups to
 285  * work properly.
 286  *
 287  * The caller must hold dev_pager_mtx
 288  */
 289 static void
 290 dev_pager_putfake(vm_page_t m)
 291 {
 292         if (!(m->flags & PG_FICTITIOUS))
 293                 panic("dev_pager_putfake: bad page");
 294         KKASSERT(m->object == NULL);
 295         KKASSERT(m->hold_count == 0);
 296         kfree(m, M_FICTITIOUS_PAGES);
 297 }
 298
 299 static int
 300 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
 301     vm_ooffset_t foff, struct ucred *cred,  u_short *color)
 302 {
 303         unsigned int npages;
 304         vm_offset_t off;
 305         cdev_t dev;
 306
 307         dev = handle;
 308
 309         /*
 310          * Check that the specified range of the device allows the desired
 311          * protection.
 312          *
 313          * XXX assumes VM_PROT_* == PROT_*
 314          */
 315         npages = OFF_TO_IDX(size);
 316         for (off = foff; npages--; off += PAGE_SIZE) {
 317                 if (dev_dmmap(dev, off, (int)prot, NULL) == -1)
 318                         return (EINVAL);
 319         }
 320
 321         return (0);
 322 }
 323
 324 static void old_dev_pager_dtor(void *handle)
 325 {
 326         cdev_t dev;
 327
 328         dev = handle;
 329         if (dev != NULL) {
 330                 KKASSERT(dev->si_object);
 331                 dev->si_object = NULL;
 332         }
 333 }
 334
 335 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
 336     int prot, vm_page_t *mres)
 337 {
 338         vm_paddr_t paddr;
 339         vm_page_t page;
 340         vm_offset_t pidx = OFF_TO_IDX(offset);
 341         cdev_t dev;
 342
 343         page = *mres;
 344         dev = object->handle;
 345
 346         paddr = pmap_phys_address(
 347                     dev_dmmap(dev, offset, prot, NULL));
 348         KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
 349         KKASSERT(object->type == OBJT_DEVICE);
 350
 351         if (page->flags & PG_FICTITIOUS) {
 352                 /*
 353                  * If the passed in reqpage page is already a fake page,
 354                  * update it with the new physical address.
 355                  */
 356                 page->phys_addr = paddr;
 357                 page->valid = VM_PAGE_BITS_ALL;
 358         } else {
 359                 /*
 360                  * Replace the passed in reqpage page with our own fake page
 361                  * and free up all the original pages.
 362                  */
 363                 page = dev_pager_getfake(paddr, object->memattr);
 364                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
 365                                   page, pageq);
 366                 vm_object_hold(object);
 367                 vm_page_free(*mres);
 368                 if (vm_page_insert(page, object, pidx) == FALSE) {
 369                         panic("dev_pager_getpage: page (%p,%016jx) exists",
 370                               object, (uintmax_t)pidx);
 371                 }
 372                 vm_object_drop(object);
 373         }
 374
 375         return (VM_PAGER_OK);
 376 }
 377