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 1.10 2006/03/27 01:54:18 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 #include <sys/device.h>
  48 #include <sys/thread2.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
  56 static void dev_pager_init (void);
  57 static vm_object_t dev_pager_alloc (void *, off_t, vm_prot_t, off_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
  68 static vm_zone_t fakepg_zone;
  69 static struct vm_zone fakepg_zone_store;
  70
  71 static vm_page_t dev_pager_getfake (vm_paddr_t);
  72 static void dev_pager_putfake (vm_page_t);
  73
  74 static int dev_pager_alloc_lock, dev_pager_alloc_lock_want;
  75
  76 struct pagerops devicepagerops = {
  77         dev_pager_init,
  78         dev_pager_alloc,
  79         dev_pager_dealloc,
  80         dev_pager_getpages,
  81         dev_pager_putpages,
  82         dev_pager_haspage,
  83         NULL
  84 };
  85
  86 static void
  87 dev_pager_init(void)
  88 {
  89         TAILQ_INIT(&dev_pager_object_list);
  90         fakepg_zone = &fakepg_zone_store;
  91         zinitna(fakepg_zone, NULL, "DP fakepg", sizeof(struct vm_page), 0, 0, 2);
  92 }
  93
  94 static vm_object_t
  95 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
  96 {
  97         dev_t dev;
  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
 107         /*
 108          * Offset should be page aligned.
 109          */
 110         if (foff & PAGE_MASK)
 111                 return (NULL);
 112
 113         size = round_page(size);
 114
 115         /*
 116          * Check that the specified range of the device allows the desired
 117          * protection.
 118          *
 119          * XXX assumes VM_PROT_* == PROT_*
 120          */
 121         npages = OFF_TO_IDX(size);
 122         for (off = foff; npages--; off += PAGE_SIZE) {
 123                 if (dev_dmmap(dev, off, (int)prot) == -1)
 124                         return (NULL);
 125         }
 126
 127         /*
 128          * Lock to prevent object creation race condition.
 129          */
 130         while (dev_pager_alloc_lock) {
 131                 dev_pager_alloc_lock_want++;
 132                 tsleep(&dev_pager_alloc_lock, 0, "dvpall", 0);
 133                 dev_pager_alloc_lock_want--;
 134         }
 135         dev_pager_alloc_lock = 1;
 136
 137         /*
 138          * Look up pager, creating as necessary.
 139          */
 140         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 141         if (object == NULL) {
 142                 /*
 143                  * Allocate object and associate it with the pager.
 144                  */
 145                 object = vm_object_allocate(OBJT_DEVICE,
 146                         OFF_TO_IDX(foff + size));
 147                 object->handle = handle;
 148                 TAILQ_INIT(&object->un_pager.devp.devp_pglist);
 149                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list);
 150         } else {
 151                 /*
 152                  * Gain a reference to the object.
 153                  */
 154                 vm_object_reference(object);
 155                 if (OFF_TO_IDX(foff + size) > object->size)
 156                         object->size = OFF_TO_IDX(foff + size);
 157         }
 158
 159         dev_pager_alloc_lock = 0;
 160         if (dev_pager_alloc_lock_want)
 161                 wakeup(&dev_pager_alloc_lock);
 162
 163         return (object);
 164 }
 165
 166 static void
 167 dev_pager_dealloc(vm_object_t object)
 168 {
 169         vm_page_t m;
 170
 171         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 172         /*
 173          * Free up our fake pages.
 174          */
 175         while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
 176                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 177                 dev_pager_putfake(m);
 178         }
 179 }
 180
 181 static int
 182 dev_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage)
 183 {
 184         vm_offset_t offset;
 185         vm_paddr_t paddr;
 186         vm_page_t page;
 187         dev_t dev;
 188         int prot;
 189         int i;
 190
 191         dev = object->handle;
 192         offset = m[reqpage]->pindex;
 193         prot = PROT_READ;       /* XXX should pass in? */
 194
 195         paddr = pmap_phys_address(dev_dmmap(dev, (vm_offset_t) offset << PAGE_SHIFT, prot));
 196         KASSERT(paddr != -1,("dev_pager_getpage: map function returns error"));
 197
 198         if (m[reqpage]->flags & PG_FICTITIOUS) {
 199                 /*
 200                  * If the passed in reqpage page is a fake page, update it
 201                  * with the new physical address.
 202                  */
 203                 m[reqpage]->phys_addr = paddr;
 204         } else {
 205                 /*
 206                  * Replace the passed in reqpage page with our own fake page
 207                  * and free up all the original pages.
 208                  */
 209                 page = dev_pager_getfake(paddr);
 210                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
 211                 crit_enter();
 212                 vm_page_free(m[reqpage]);
 213                 vm_page_insert(page, object, offset);
 214                 crit_exit();
 215         }
 216         for (i = 0; i < count; i++) {
 217                 if (i != reqpage)
 218                         vm_page_free(m[i]);
 219         }
 220         return (VM_PAGER_OK);
 221 }
 222
 223 static void
 224 dev_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
 225     int *rtvals)
 226 {
 227         panic("dev_pager_putpage called");
 228 }
 229
 230 static boolean_t
 231 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
 232     int *after)
 233 {
 234         if (before != NULL)
 235                 *before = 0;
 236         if (after != NULL)
 237                 *after = 0;
 238         return (TRUE);
 239 }
 240
 241 static vm_page_t
 242 dev_pager_getfake(vm_paddr_t paddr)
 243 {
 244         vm_page_t m;
 245
 246         m = zalloc(fakepg_zone);
 247
 248         m->flags = PG_BUSY | PG_FICTITIOUS;
 249         m->valid = VM_PAGE_BITS_ALL;
 250         m->dirty = 0;
 251         m->busy = 0;
 252         m->queue = PQ_NONE;
 253         m->object = NULL;
 254
 255         m->wire_count = 1;
 256         m->hold_count = 0;
 257         m->phys_addr = paddr;
 258
 259         return (m);
 260 }
 261
 262 static void
 263 dev_pager_putfake(vm_page_t m)
 264 {
 265         if (!(m->flags & PG_FICTITIOUS))
 266                 panic("dev_pager_putfake: bad page");
 267         KKASSERT(m->object == NULL);
 268         zfree(fakepg_zone, m);
 269 }
 270