device_pager.c

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    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: releng/9.0/sys/vm/device_pager.c 224522 2011-07-30 14:13:57Z kib $");
   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 }
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FreeBSD/Linux Kernel Cross Reference sys/vm/device_pager.c

FreeBSD/Linux Kernel Cross Reference
sys/vm/device_pager.c
