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  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      @(#)device_pager.c      8.1 (Berkeley) 6/11/93
  39  * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $
  40  * $DragonFly: src/sys/vm/device_pager.c,v 1.2 2003/06/17 04:29:00 dillon Exp $
  41  */
  42
  43 #include <sys/param.h>
  44 #include <sys/systm.h>
  45 #include <sys/conf.h>
  46 #include <sys/mman.h>
  47
  48 #include <vm/vm.h>
  49 #include <vm/vm_object.h>
  50 #include <vm/vm_page.h>
  51 #include <vm/vm_pager.h>
  52 #include <vm/vm_zone.h>
  53
  54 static void dev_pager_init __P((void));
  55 static vm_object_t dev_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t,
  56                 vm_ooffset_t));
  57 static void dev_pager_dealloc __P((vm_object_t));
  58 static int dev_pager_getpages __P((vm_object_t, vm_page_t *, int, int));
  59 static void dev_pager_putpages __P((vm_object_t, vm_page_t *, int,
  60                 boolean_t, int *));
  61 static boolean_t dev_pager_haspage __P((vm_object_t, vm_pindex_t, int *,
  62                 int *));
  63
  64 /* list of device pager objects */
  65 static struct pagerlst dev_pager_object_list;
  66
  67 static vm_zone_t fakepg_zone;
  68 static struct vm_zone fakepg_zone_store;
  69
  70 static vm_page_t dev_pager_getfake __P((vm_offset_t));
  71 static void dev_pager_putfake __P((vm_page_t));
  72
  73 static int dev_pager_alloc_lock, dev_pager_alloc_lock_want;
  74
  75 struct pagerops devicepagerops = {
  76         dev_pager_init,
  77         dev_pager_alloc,
  78         dev_pager_dealloc,
  79         dev_pager_getpages,
  80         dev_pager_putpages,
  81         dev_pager_haspage,
  82         NULL
  83 };
  84
  85 static void
  86 dev_pager_init()
  87 {
  88         TAILQ_INIT(&dev_pager_object_list);
  89         fakepg_zone = &fakepg_zone_store;
  90         zinitna(fakepg_zone, NULL, "DP fakepg", sizeof(struct vm_page), 0, 0, 2);
  91 }
  92
  93 static vm_object_t
  94 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff)
  95 {
  96         dev_t dev;
  97         d_mmap_t *mapfunc;
  98         vm_object_t object;
  99         unsigned int npages;
 100         vm_offset_t off;
 101
 102         /*
 103          * Make sure this device can be mapped.
 104          */
 105         dev = handle;
 106         mapfunc = devsw(dev)->d_mmap;
 107         if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) {
 108                 printf("obsolete map function %p\n", (void *)mapfunc);
 109                 return (NULL);
 110         }
 111
 112         /*
 113          * Offset should be page aligned.
 114          */
 115         if (foff & PAGE_MASK)
 116                 return (NULL);
 117
 118         size = round_page(size);
 119
 120         /*
 121          * Check that the specified range of the device allows the desired
 122          * protection.
 123          *
 124          * XXX assumes VM_PROT_* == PROT_*
 125          */
 126         npages = OFF_TO_IDX(size);
 127         for (off = foff; npages--; off += PAGE_SIZE)
 128                 if ((*mapfunc) (dev, off, (int) prot) == -1)
 129                         return (NULL);
 130
 131         /*
 132          * Lock to prevent object creation race condition.
 133          */
 134         while (dev_pager_alloc_lock) {
 135                 dev_pager_alloc_lock_want++;
 136                 tsleep(&dev_pager_alloc_lock, PVM, "dvpall", 0);
 137                 dev_pager_alloc_lock_want--;
 138         }
 139         dev_pager_alloc_lock = 1;
 140
 141         /*
 142          * Look up pager, creating as necessary.
 143          */
 144         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 145         if (object == NULL) {
 146                 /*
 147                  * Allocate object and associate it with the pager.
 148                  */
 149                 object = vm_object_allocate(OBJT_DEVICE,
 150                         OFF_TO_IDX(foff + size));
 151                 object->handle = handle;
 152                 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
 153                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list);
 154         } else {
 155                 /*
 156                  * Gain a reference to the object.
 157                  */
 158                 vm_object_reference(object);
 159                 if (OFF_TO_IDX(foff + size) > object->size)
 160                         object->size = OFF_TO_IDX(foff + size);
 161         }
 162
 163         dev_pager_alloc_lock = 0;
 164         if (dev_pager_alloc_lock_want)
 165                 wakeup(&dev_pager_alloc_lock);
 166
 167         return (object);
 168 }
 169
 170 static void
 171 dev_pager_dealloc(object)
 172         vm_object_t object;
 173 {
 174         vm_page_t m;
 175
 176         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 177         /*
 178          * Free up our fake pages.
 179          */
 180         while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
 181                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 182                 dev_pager_putfake(m);
 183         }
 184 }
 185
 186 static int
 187 dev_pager_getpages(object, m, count, reqpage)
 188         vm_object_t object;
 189         vm_page_t *m;
 190         int count;
 191         int reqpage;
 192 {
 193         vm_offset_t offset;
 194         vm_offset_t paddr;
 195         vm_page_t page;
 196         dev_t dev;
 197         int i, s;
 198         d_mmap_t *mapfunc;
 199         int prot;
 200
 201         dev = object->handle;
 202         offset = m[reqpage]->pindex;
 203         prot = PROT_READ;       /* XXX should pass in? */
 204         mapfunc = devsw(dev)->d_mmap;
 205
 206         if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop)
 207                 panic("dev_pager_getpage: no map function");
 208
 209         paddr = pmap_phys_address((*mapfunc) (dev, (vm_offset_t) offset << PAGE_SHIFT, prot));
 210         KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
 211         /*
 212          * Replace the passed in reqpage page with our own fake page and free up the
 213          * all of the original pages.
 214          */
 215         page = dev_pager_getfake(paddr);
 216         TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
 217         for (i = 0; i < count; i++) {
 218                 vm_page_free(m[i]);
 219         }
 220         s = splhigh();
 221         vm_page_insert(page, object, offset);
 222         splx(s);
 223
 224         return (VM_PAGER_OK);
 225 }
 226
 227 static void
 228 dev_pager_putpages(object, m, count, sync, rtvals)
 229         vm_object_t object;
 230         vm_page_t *m;
 231         int count;
 232         boolean_t sync;
 233         int *rtvals;
 234 {
 235         panic("dev_pager_putpage called");
 236 }
 237
 238 static boolean_t
 239 dev_pager_haspage(object, pindex, before, after)
 240         vm_object_t object;
 241         vm_pindex_t pindex;
 242         int *before;
 243         int *after;
 244 {
 245         if (before != NULL)
 246                 *before = 0;
 247         if (after != NULL)
 248                 *after = 0;
 249         return (TRUE);
 250 }
 251
 252 static vm_page_t
 253 dev_pager_getfake(paddr)
 254         vm_offset_t paddr;
 255 {
 256         vm_page_t m;
 257
 258         m = zalloc(fakepg_zone);
 259
 260         m->flags = PG_BUSY | PG_FICTITIOUS;
 261         m->valid = VM_PAGE_BITS_ALL;
 262         m->dirty = 0;
 263         m->busy = 0;
 264         m->queue = PQ_NONE;
 265         m->object = NULL;
 266
 267         m->wire_count = 1;
 268         m->hold_count = 0;
 269         m->phys_addr = paddr;
 270
 271         return (m);
 272 }
 273
 274 static void
 275 dev_pager_putfake(m)
 276         vm_page_t m;
 277 {
 278         if (!(m->flags & PG_FICTITIOUS))
 279                 panic("dev_pager_putfake: bad page");
 280         zfree(fakepg_zone, m);
 281 }