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  */
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/conf.h>
  45 #include <sys/mman.h>
  46
  47 #include <vm/vm.h>
  48 #include <vm/vm_object.h>
  49 #include <vm/vm_page.h>
  50 #include <vm/vm_pager.h>
  51 #include <vm/vm_zone.h>
  52
  53 static void dev_pager_init __P((void));
  54 static vm_object_t dev_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t,
  55                 vm_ooffset_t));
  56 static void dev_pager_dealloc __P((vm_object_t));
  57 static int dev_pager_getpages __P((vm_object_t, vm_page_t *, int, int));
  58 static void dev_pager_putpages __P((vm_object_t, vm_page_t *, int,
  59                 boolean_t, int *));
  60 static boolean_t dev_pager_haspage __P((vm_object_t, vm_pindex_t, int *,
  61                 int *));
  62
  63 /* list of device pager objects */
  64 static struct pagerlst dev_pager_object_list;
  65
  66 static vm_zone_t fakepg_zone;
  67 static struct vm_zone fakepg_zone_store;
  68
  69 static vm_page_t dev_pager_getfake __P((vm_offset_t));
  70 static void dev_pager_putfake __P((vm_page_t));
  71
  72 static int dev_pager_alloc_lock, dev_pager_alloc_lock_want;
  73
  74 struct pagerops devicepagerops = {
  75         dev_pager_init,
  76         dev_pager_alloc,
  77         dev_pager_dealloc,
  78         dev_pager_getpages,
  79         dev_pager_putpages,
  80         dev_pager_haspage,
  81         NULL
  82 };
  83
  84 static void
  85 dev_pager_init()
  86 {
  87         TAILQ_INIT(&dev_pager_object_list);
  88         fakepg_zone = &fakepg_zone_store;
  89         zinitna(fakepg_zone, NULL, "DP fakepg", sizeof(struct vm_page), 0, 0, 2);
  90 }
  91
  92 static vm_object_t
  93 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff)
  94 {
  95         dev_t dev;
  96         d_mmap_t *mapfunc;
  97         vm_object_t object;
  98         unsigned int npages;
  99         vm_offset_t off;
 100
 101         /*
 102          * Make sure this device can be mapped.
 103          */
 104         dev = handle;
 105         mapfunc = devsw(dev)->d_mmap;
 106         if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) {
 107                 printf("obsolete map function %p\n", (void *)mapfunc);
 108                 return (NULL);
 109         }
 110
 111         /*
 112          * Offset should be page aligned.
 113          */
 114         if (foff & PAGE_MASK)
 115                 return (NULL);
 116
 117         size = round_page(size);
 118
 119         /*
 120          * Check that the specified range of the device allows the desired
 121          * protection.
 122          *
 123          * XXX assumes VM_PROT_* == PROT_*
 124          */
 125         npages = OFF_TO_IDX(size);
 126         for (off = foff; npages--; off += PAGE_SIZE)
 127                 if ((*mapfunc) (dev, off, (int) prot) == -1)
 128                         return (NULL);
 129
 130         /*
 131          * Lock to prevent object creation race condition.
 132          */
 133         while (dev_pager_alloc_lock) {
 134                 dev_pager_alloc_lock_want++;
 135                 tsleep(&dev_pager_alloc_lock, PVM, "dvpall", 0);
 136                 dev_pager_alloc_lock_want--;
 137         }
 138         dev_pager_alloc_lock = 1;
 139
 140         /*
 141          * Look up pager, creating as necessary.
 142          */
 143         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 144         if (object == NULL) {
 145                 /*
 146                  * Allocate object and associate it with the pager.
 147                  */
 148                 object = vm_object_allocate(OBJT_DEVICE,
 149                         OFF_TO_IDX(foff + size));
 150                 object->handle = handle;
 151                 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
 152                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list);
 153         } else {
 154                 /*
 155                  * Gain a reference to the object.
 156                  */
 157                 vm_object_reference(object);
 158                 if (OFF_TO_IDX(foff + size) > object->size)
 159                         object->size = OFF_TO_IDX(foff + size);
 160         }
 161
 162         dev_pager_alloc_lock = 0;
 163         if (dev_pager_alloc_lock_want)
 164                 wakeup(&dev_pager_alloc_lock);
 165
 166         return (object);
 167 }
 168
 169 static void
 170 dev_pager_dealloc(object)
 171         vm_object_t object;
 172 {
 173         vm_page_t m;
 174
 175         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 176         /*
 177          * Free up our fake pages.
 178          */
 179         while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
 180                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 181                 dev_pager_putfake(m);
 182         }
 183 }
 184
 185 static int
 186 dev_pager_getpages(object, m, count, reqpage)
 187         vm_object_t object;
 188         vm_page_t *m;
 189         int count;
 190         int reqpage;
 191 {
 192         vm_offset_t offset;
 193         vm_offset_t paddr;
 194         vm_page_t page;
 195         dev_t dev;
 196         int i, s;
 197         d_mmap_t *mapfunc;
 198         int prot;
 199
 200         dev = object->handle;
 201         offset = m[reqpage]->pindex;
 202         prot = PROT_READ;       /* XXX should pass in? */
 203         mapfunc = devsw(dev)->d_mmap;
 204
 205         if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop)
 206                 panic("dev_pager_getpage: no map function");
 207
 208         paddr = pmap_phys_address((*mapfunc) (dev, (vm_offset_t) offset << PAGE_SHIFT, prot));
 209         KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
 210         /*
 211          * Replace the passed in reqpage page with our own fake page and free up the
 212          * all of the original pages.
 213          */
 214         page = dev_pager_getfake(paddr);
 215         TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
 216         for (i = 0; i < count; i++) {
 217                 vm_page_free(m[i]);
 218         }
 219         s = splhigh();
 220         vm_page_insert(page, object, offset);
 221         splx(s);
 222
 223         return (VM_PAGER_OK);
 224 }
 225
 226 static void
 227 dev_pager_putpages(object, m, count, sync, rtvals)
 228         vm_object_t object;
 229         vm_page_t *m;
 230         int count;
 231         boolean_t sync;
 232         int *rtvals;
 233 {
 234         panic("dev_pager_putpage called");
 235 }
 236
 237 static boolean_t
 238 dev_pager_haspage(object, pindex, before, after)
 239         vm_object_t object;
 240         vm_pindex_t pindex;
 241         int *before;
 242         int *after;
 243 {
 244         if (before != NULL)
 245                 *before = 0;
 246         if (after != NULL)
 247                 *after = 0;
 248         return (TRUE);
 249 }
 250
 251 static vm_page_t
 252 dev_pager_getfake(paddr)
 253         vm_offset_t paddr;
 254 {
 255         vm_page_t m;
 256
 257         m = zalloc(fakepg_zone);
 258
 259         m->flags = PG_BUSY | PG_FICTITIOUS;
 260         m->valid = VM_PAGE_BITS_ALL;
 261         m->dirty = 0;
 262         m->busy = 0;
 263         m->queue = PQ_NONE;
 264         m->object = NULL;
 265
 266         m->wire_count = 1;
 267         m->hold_count = 0;
 268         m->phys_addr = paddr;
 269
 270         return (m);
 271 }
 272
 273 static void
 274 dev_pager_putfake(m)
 275         vm_page_t m;
 276 {
 277         if (!(m->flags & PG_FICTITIOUS))
 278                 panic("dev_pager_putfake: bad page");
 279         zfree(fakepg_zone, m);
 280 }