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