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, struct ucred *);
  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 struct pagerops devicepagerops = {
  71         .pgo_init =     dev_pager_init,
  72         .pgo_alloc =    dev_pager_alloc,
  73         .pgo_dealloc =  dev_pager_dealloc,
  74         .pgo_getpages = dev_pager_getpages,
  75         .pgo_putpages = dev_pager_putpages,
  76         .pgo_haspage =  dev_pager_haspage,
  77 };
  78
  79 static void
  80 dev_pager_init()
  81 {
  82         TAILQ_INIT(&dev_pager_object_list);
  83         mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
  84 }
  85
  86 /*
  87  * MPSAFE
  88  */
  89 static vm_object_t
  90 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
  91     vm_ooffset_t foff, struct ucred *cred)
  92 {
  93         struct cdev *dev;
  94         vm_object_t object, object1;
  95         vm_pindex_t pindex;
  96         unsigned int npages;
  97         vm_paddr_t paddr;
  98         vm_ooffset_t off;
  99         vm_memattr_t dummy;
 100         struct cdevsw *csw;
 101         int ref;
 102
 103         /*
 104          * Offset should be page aligned.
 105          */
 106         if (foff & PAGE_MASK)
 107                 return (NULL);
 108
 109         size = round_page(size);
 110         pindex = OFF_TO_IDX(foff + size);
 111
 112         /*
 113          * Make sure this device can be mapped.
 114          */
 115         dev = handle;
 116         csw = dev_refthread(dev, &ref);
 117         if (csw == NULL)
 118                 return (NULL);
 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 (csw->d_mmap(dev, off, &paddr, (int)prot, &dummy) != 0) {
 129                         dev_relthread(dev, ref);
 130                         return (NULL);
 131                 }
 132
 133         mtx_lock(&dev_pager_mtx);
 134
 135         /*
 136          * Look up pager, creating as necessary.
 137          */
 138         object1 = NULL;
 139         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 140         if (object == NULL) {
 141                 /*
 142                  * Allocate object and associate it with the pager.  Initialize
 143                  * the object's pg_color based upon the physical address of the
 144                  * device's memory.
 145                  */
 146                 mtx_unlock(&dev_pager_mtx);
 147                 object1 = vm_object_allocate(OBJT_DEVICE, pindex);
 148                 object1->flags |= OBJ_COLORED;
 149                 object1->pg_color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
 150                 TAILQ_INIT(&object1->un_pager.devp.devp_pglist);
 151                 mtx_lock(&dev_pager_mtx);
 152                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 153                 if (object != NULL) {
 154                         /*
 155                          * We raced with other thread while allocating object.
 156                          */
 157                         if (pindex > object->size)
 158                                 object->size = pindex;
 159                 } else {
 160                         object = object1;
 161                         object1 = NULL;
 162                         object->handle = handle;
 163                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 164                             pager_object_list);
 165                 }
 166         } else {
 167                 if (pindex > object->size)
 168                         object->size = pindex;
 169         }
 170         mtx_unlock(&dev_pager_mtx);
 171         dev_relthread(dev, ref);
 172         if (object1 != NULL) {
 173                 object1->handle = object1;
 174                 mtx_lock(&dev_pager_mtx);
 175                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object1,
 176                     pager_object_list);
 177                 mtx_unlock(&dev_pager_mtx);
 178                 vm_object_deallocate(object1);
 179         }
 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)) != NULL) {
 198                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 199                 vm_page_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 m_paddr, page;
 213         vm_memattr_t memattr;
 214         struct cdev *dev;
 215         int i, ref, ret;
 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         page = m[reqpage];
 223         offset = page->pindex;
 224         memattr = object->memattr;
 225         VM_OBJECT_UNLOCK(object);
 226         csw = dev_refthread(dev, &ref);
 227         if (csw == NULL) {
 228                 VM_OBJECT_LOCK(object);
 229                 return (VM_PAGER_FAIL);
 230         }
 231         td = curthread;
 232         fpop = td->td_fpop;
 233         td->td_fpop = NULL;
 234         ret = csw->d_mmap(dev, (vm_ooffset_t)offset << PAGE_SHIFT, &paddr,
 235             PROT_READ, &memattr);
 236         KASSERT(ret == 0, ("dev_pager_getpage: map function returns error"));
 237         td->td_fpop = fpop;
 238         dev_relthread(dev, ref);
 239         /* If "paddr" is a real page, perform a sanity check on "memattr". */
 240         if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
 241             pmap_page_get_memattr(m_paddr) != memattr) {
 242                 memattr = pmap_page_get_memattr(m_paddr);
 243                 printf(
 244             "WARNING: A device driver has set \"memattr\" inconsistently.\n");
 245         }
 246         if ((page->flags & PG_FICTITIOUS) != 0) {
 247                 /*
 248                  * If the passed in reqpage page is a fake page, update it with
 249                  * the new physical address.
 250                  */
 251                 VM_OBJECT_LOCK(object);
 252                 vm_page_updatefake(page, paddr, memattr);
 253                 if (count > 1) {
 254
 255                         for (i = 0; i < count; i++) {
 256                                 if (i != reqpage) {
 257                                         vm_page_lock(m[i]);
 258                                         vm_page_free(m[i]);
 259                                         vm_page_unlock(m[i]);
 260                                 }
 261                         }
 262                 }
 263         } else {
 264                 /*
 265                  * Replace the passed in reqpage page with our own fake page and
 266                  * free up the all of the original pages.
 267                  */
 268                 page = vm_page_getfake(paddr, memattr);
 269                 VM_OBJECT_LOCK(object);
 270                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
 271                 for (i = 0; i < count; i++) {
 272                         vm_page_lock(m[i]);
 273                         vm_page_free(m[i]);
 274                         vm_page_unlock(m[i]);
 275                 }
 276                 vm_page_insert(page, object, offset);
 277                 m[reqpage] = page;
 278         }
 279         page->valid = VM_PAGE_BITS_ALL;
 280         return (VM_PAGER_OK);
 281 }
 282
 283 static void
 284 dev_pager_putpages(object, m, count, sync, rtvals)
 285         vm_object_t object;
 286         vm_page_t *m;
 287         int count;
 288         boolean_t sync;
 289         int *rtvals;
 290 {
 291         panic("dev_pager_putpage called");
 292 }
 293
 294 static boolean_t
 295 dev_pager_haspage(object, pindex, before, after)
 296         vm_object_t object;
 297         vm_pindex_t pindex;
 298         int *before;
 299         int *after;
 300 {
 301         if (before != NULL)
 302                 *before = 0;
 303         if (after != NULL)
 304                 *after = 0;
 305         return (TRUE);
 306 }