sys/vm/device_pager.c

   1 /*-
   2  * Copyright (c) 1990 University of Utah.
   3  * Copyright (c) 1991, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * the Systems Programming Group of the University of Utah Computer
   8  * Science Department.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)device_pager.c      8.1 (Berkeley) 6/11/93
  35  */
  36
  37 #include <sys/cdefs.h>
  38 __FBSDID("$FreeBSD$");
  39
  40 #include <sys/param.h>
  41 #include <sys/systm.h>
  42 #include <sys/conf.h>
  43 #include <sys/lock.h>
  44 #include <sys/proc.h>
  45 #include <sys/mutex.h>
  46 #include <sys/mman.h>
  47 #include <sys/sx.h>
  48
  49 #include <vm/vm.h>
  50 #include <vm/vm_object.h>
  51 #include <vm/vm_page.h>
  52 #include <vm/vm_pager.h>
  53 #include <vm/uma.h>
  54
  55 static void dev_pager_init(void);
  56 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
  57                 vm_ooffset_t);
  58 static void dev_pager_dealloc(vm_object_t);
  59 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, 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, int *,
  63                 int *);
  64
  65 /* list of device pager objects */
  66 static struct pagerlst dev_pager_object_list;
  67 /* protect list manipulation */
  68 static struct mtx dev_pager_mtx;
  69
  70
  71 static uma_zone_t fakepg_zone;
  72
  73 static vm_page_t dev_pager_getfake(vm_paddr_t);
  74 static void dev_pager_putfake(vm_page_t);
  75 static void dev_pager_updatefake(vm_page_t, vm_paddr_t);
  76
  77 struct pagerops devicepagerops = {
  78         .pgo_init =     dev_pager_init,
  79         .pgo_alloc =    dev_pager_alloc,
  80         .pgo_dealloc =  dev_pager_dealloc,
  81         .pgo_getpages = dev_pager_getpages,
  82         .pgo_putpages = dev_pager_putpages,
  83         .pgo_haspage =  dev_pager_haspage,
  84 };
  85
  86 static void
  87 dev_pager_init()
  88 {
  89         TAILQ_INIT(&dev_pager_object_list);
  90         mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
  91         fakepg_zone = uma_zcreate("DP fakepg", sizeof(struct vm_page),
  92             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
  93             UMA_ZONE_NOFREE|UMA_ZONE_VM);
  94 }
  95
  96 /*
  97  * MPSAFE
  98  */
  99 static vm_object_t
 100 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff)
 101 {
 102         struct cdev *dev;
 103         vm_object_t object, object1;
 104         vm_pindex_t pindex;
 105         unsigned int npages;
 106         vm_paddr_t paddr;
 107         vm_offset_t off;
 108         struct cdevsw *csw;
 109
 110         /*
 111          * Offset should be page aligned.
 112          */
 113         if (foff & PAGE_MASK)
 114                 return (NULL);
 115
 116         size = round_page(size);
 117         pindex = OFF_TO_IDX(foff + size);
 118
 119         /*
 120          * Make sure this device can be mapped.
 121          */
 122         dev = handle;
 123         csw = dev_refthread(dev);
 124         if (csw == NULL)
 125                 return (NULL);
 126
 127         /*
 128          * Check that the specified range of the device allows the desired
 129          * protection.
 130          *
 131          * XXX assumes VM_PROT_* == PROT_*
 132          */
 133         npages = OFF_TO_IDX(size);
 134         for (off = foff; npages--; off += PAGE_SIZE)
 135                 if ((*csw->d_mmap)(dev, off, &paddr, (int)prot) != 0) {
 136                         dev_relthread(dev);
 137                         return (NULL);
 138                 }
 139
 140         mtx_lock(&dev_pager_mtx);
 141
 142         /*
 143          * Look up pager, creating as necessary.
 144          */
 145         object1 = NULL;
 146         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 147         if (object == NULL) {
 148                 /*
 149                  * Allocate object and associate it with the pager.  Initialize
 150                  * the object's pg_color based upon the physical address of the
 151                  * device's memory.
 152                  */
 153                 mtx_unlock(&dev_pager_mtx);
 154                 object1 = vm_object_allocate(OBJT_DEVICE, pindex);
 155                 object1->flags |= OBJ_COLORED;
 156                 object1->pg_color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
 157                 mtx_lock(&dev_pager_mtx);
 158                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 159                 if (object != NULL) {
 160                         /*
 161                          * We raced with other thread while allocating object.
 162                          */
 163                         if (pindex > object->size)
 164                                 object->size = pindex;
 165                 } else {
 166                         object = object1;
 167                         object1 = NULL;
 168                         object->handle = handle;
 169                         TAILQ_INIT(&object->un_pager.devp.devp_pglist);
 170                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 171                             pager_object_list);
 172                 }
 173         } else {
 174                 if (pindex > object->size)
 175                         object->size = pindex;
 176         }
 177         mtx_unlock(&dev_pager_mtx);
 178         dev_relthread(dev);
 179         vm_object_deallocate(object1);
 180         return (object);
 181 }
 182
 183 static void
 184 dev_pager_dealloc(object)
 185         vm_object_t object;
 186 {
 187         vm_page_t m;
 188
 189         VM_OBJECT_UNLOCK(object);
 190         mtx_lock(&dev_pager_mtx);
 191         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 192         mtx_unlock(&dev_pager_mtx);
 193         VM_OBJECT_LOCK(object);
 194         /*
 195          * Free up our fake pages.
 196          */
 197         while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
 198                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 199                 dev_pager_putfake(m);
 200         }
 201 }
 202
 203 static int
 204 dev_pager_getpages(object, m, count, reqpage)
 205         vm_object_t object;
 206         vm_page_t *m;
 207         int count;
 208         int reqpage;
 209 {
 210         vm_pindex_t offset;
 211         vm_paddr_t paddr;
 212         vm_page_t page;
 213         struct cdev *dev;
 214         int i, ret;
 215         int prot;
 216         struct cdevsw *csw;
 217         struct thread *td;
 218         struct file *fpop;
 219
 220         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 221         dev = object->handle;
 222         offset = m[reqpage]->pindex;
 223         VM_OBJECT_UNLOCK(object);
 224         csw = dev_refthread(dev);
 225         if (csw == NULL)
 226                 panic("dev_pager_getpage: no cdevsw");
 227         prot = PROT_READ;       /* XXX should pass in? */
 228
 229         td = curthread;
 230         fpop = td->td_fpop;
 231         td->td_fpop = NULL;
 232         ret = (*csw->d_mmap)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot);
 233         KASSERT(ret == 0, ("dev_pager_getpage: map function returns error"));
 234         td->td_fpop = fpop;
 235         dev_relthread(dev);
 236
 237         if ((m[reqpage]->flags & PG_FICTITIOUS) != 0) {
 238                 /*
 239                  * If the passed in reqpage page is a fake page, update it with
 240                  * the new physical address.
 241                  */
 242                 VM_OBJECT_LOCK(object);
 243                 dev_pager_updatefake(m[reqpage], paddr);
 244                 if (count > 1) {
 245                         vm_page_lock_queues();
 246                         for (i = 0; i < count; i++) {
 247                                 if (i != reqpage)
 248                                         vm_page_free(m[i]);
 249                         }
 250                         vm_page_unlock_queues();
 251                 }
 252         } else {
 253                 /*
 254                  * Replace the passed in reqpage page with our own fake page and
 255                  * free up the all of the original pages.
 256                  */
 257                 page = dev_pager_getfake(paddr);
 258                 VM_OBJECT_LOCK(object);
 259                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
 260                 vm_page_lock_queues();
 261                 for (i = 0; i < count; i++)
 262                         vm_page_free(m[i]);
 263                 vm_page_unlock_queues();
 264                 vm_page_insert(page, object, offset);
 265                 m[reqpage] = page;
 266         }
 267
 268         return (VM_PAGER_OK);
 269 }
 270
 271 static void
 272 dev_pager_putpages(object, m, count, sync, rtvals)
 273         vm_object_t object;
 274         vm_page_t *m;
 275         int count;
 276         boolean_t sync;
 277         int *rtvals;
 278 {
 279         panic("dev_pager_putpage called");
 280 }
 281
 282 static boolean_t
 283 dev_pager_haspage(object, pindex, before, after)
 284         vm_object_t object;
 285         vm_pindex_t pindex;
 286         int *before;
 287         int *after;
 288 {
 289         if (before != NULL)
 290                 *before = 0;
 291         if (after != NULL)
 292                 *after = 0;
 293         return (TRUE);
 294 }
 295
 296 /*
 297  * Instantiate a fictitious page.  Unlike physical memory pages, only
 298  * the machine-independent fields must be initialized.
 299  */
 300 static vm_page_t
 301 dev_pager_getfake(paddr)
 302         vm_paddr_t paddr;
 303 {
 304         vm_page_t m;
 305
 306         m = uma_zalloc(fakepg_zone, M_WAITOK);
 307
 308         m->flags = PG_FICTITIOUS;
 309         m->oflags = VPO_BUSY;
 310         m->valid = VM_PAGE_BITS_ALL;
 311         m->dirty = 0;
 312         m->busy = 0;
 313         m->queue = PQ_NONE;
 314         m->object = NULL;
 315
 316         m->wire_count = 1;
 317         m->hold_count = 0;
 318         m->phys_addr = paddr;
 319
 320         return (m);
 321 }
 322
 323 static void
 324 dev_pager_putfake(m)
 325         vm_page_t m;
 326 {
 327         if (!(m->flags & PG_FICTITIOUS))
 328                 panic("dev_pager_putfake: bad page");
 329         uma_zfree(fakepg_zone, m);
 330 }
 331
 332 static void
 333 dev_pager_updatefake(m, paddr)
 334         vm_page_t m;
 335         vm_paddr_t paddr;
 336 {
 337         if (!(m->flags & PG_FICTITIOUS))
 338                 panic("dev_pager_updatefake: bad page");
 339         m->phys_addr = paddr;
 340         m->valid = VM_PAGE_BITS_ALL;
 341 }