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("$FreeBSD$");
   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_param.h>
   51 #include <vm/vm_object.h>
   52 #include <vm/vm_page.h>
   53 #include <vm/vm_pager.h>
   54 #include <vm/uma.h>
   55 
   56 static void dev_pager_init(void);
   57 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
   58     vm_ooffset_t, struct ucred *);
   59 static void dev_pager_dealloc(vm_object_t);
   60 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int);
   61 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, 
   62                 boolean_t, int *);
   63 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *,
   64                 int *);
   65 static void dev_pager_free_page(vm_object_t object, vm_page_t m);
   66 
   67 /* list of device pager objects */
   68 static struct pagerlst dev_pager_object_list;
   69 /* protect list manipulation */
   70 static struct mtx dev_pager_mtx;
   71 
   72 struct pagerops devicepagerops = {
   73         .pgo_init =     dev_pager_init,
   74         .pgo_alloc =    dev_pager_alloc,
   75         .pgo_dealloc =  dev_pager_dealloc,
   76         .pgo_getpages = dev_pager_getpages,
   77         .pgo_putpages = dev_pager_putpages,
   78         .pgo_haspage =  dev_pager_haspage,
   79 };
   80 
   81 struct pagerops mgtdevicepagerops = {
   82         .pgo_alloc =    dev_pager_alloc,
   83         .pgo_dealloc =  dev_pager_dealloc,
   84         .pgo_getpages = dev_pager_getpages,
   85         .pgo_putpages = dev_pager_putpages,
   86         .pgo_haspage =  dev_pager_haspage,
   87 };
   88 
   89 static int old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
   90     vm_ooffset_t foff, struct ucred *cred, u_short *color);
   91 static void old_dev_pager_dtor(void *handle);
   92 static int old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset,
   93     int prot, vm_page_t *mres);
   94 
   95 static struct cdev_pager_ops old_dev_pager_ops = {
   96         .cdev_pg_ctor = old_dev_pager_ctor,
   97         .cdev_pg_dtor = old_dev_pager_dtor,
   98         .cdev_pg_fault = old_dev_pager_fault
   99 };
  100 
  101 static void
  102 dev_pager_init()
  103 {
  104         TAILQ_INIT(&dev_pager_object_list);
  105         mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
  106 }
  107 
  108 vm_object_t
  109 cdev_pager_lookup(void *handle)
  110 {
  111         vm_object_t object;
  112 
  113         mtx_lock(&dev_pager_mtx);
  114         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
  115         mtx_unlock(&dev_pager_mtx);
  116         return (object);
  117 }
  118 
  119 vm_object_t
  120 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
  121     vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
  122 {
  123         vm_object_t object, object1;
  124         vm_pindex_t pindex;
  125         u_short color;
  126 
  127         if (tp != OBJT_DEVICE && tp != OBJT_MGTDEVICE)
  128                 return (NULL);
  129 
  130         /*
  131          * Offset should be page aligned.
  132          */
  133         if (foff & PAGE_MASK)
  134                 return (NULL);
  135 
  136         size = round_page(size);
  137         pindex = OFF_TO_IDX(foff + size);
  138 
  139         if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
  140                 return (NULL);
  141         mtx_lock(&dev_pager_mtx);
  142 
  143         /*
  144          * Look up pager, creating as necessary.
  145          */
  146         object1 = NULL;
  147         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
  148         if (object == NULL) {
  149                 /*
  150                  * Allocate object and associate it with the pager.  Initialize
  151                  * the object's pg_color based upon the physical address of the
  152                  * device's memory.
  153                  */
  154                 mtx_unlock(&dev_pager_mtx);
  155                 object1 = vm_object_allocate(tp, pindex);
  156                 object1->flags |= OBJ_COLORED;
  157                 object1->pg_color = color;
  158                 object1->handle = handle;
  159                 object1->un_pager.devp.ops = ops;
  160                 TAILQ_INIT(&object1->un_pager.devp.devp_pglist);
  161                 mtx_lock(&dev_pager_mtx);
  162                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
  163                 if (object != NULL) {
  164                         /*
  165                          * We raced with other thread while allocating object.
  166                          */
  167                         if (pindex > object->size)
  168                                 object->size = pindex;
  169                 } else {
  170                         object = object1;
  171                         object1 = NULL;
  172                         object->handle = handle;
  173                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
  174                             pager_object_list);
  175                         KASSERT(object->type == tp,
  176                 ("Inconsistent device pager type %p %d", object, tp));
  177                 }
  178         } else {
  179                 if (pindex > object->size)
  180                         object->size = pindex;
  181         }
  182         mtx_unlock(&dev_pager_mtx);
  183         if (object1 != NULL) {
  184                 object1->handle = object1;
  185                 mtx_lock(&dev_pager_mtx);
  186                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object1,
  187                     pager_object_list);
  188                 mtx_unlock(&dev_pager_mtx);
  189                 vm_object_deallocate(object1);
  190         }
  191         return (object);
  192 }
  193 
  194 static vm_object_t
  195 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
  196     vm_ooffset_t foff, struct ucred *cred)
  197 {
  198 
  199         return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
  200             size, prot, foff, cred));
  201 }
  202 
  203 void
  204 cdev_pager_free_page(vm_object_t object, vm_page_t m)
  205 {
  206 
  207         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
  208         if (object->type == OBJT_MGTDEVICE) {
  209                 KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
  210                 pmap_remove_all(m);
  211                 vm_page_lock(m);
  212                 vm_page_remove(m);
  213                 vm_page_unlock(m);
  214         } else if (object->type == OBJT_DEVICE)
  215                 dev_pager_free_page(object, m);
  216 }
  217 
  218 static void
  219 dev_pager_free_page(vm_object_t object, vm_page_t m)
  220 {
  221 
  222         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
  223         KASSERT((object->type == OBJT_DEVICE &&
  224             (m->oflags & VPO_UNMANAGED) != 0),
  225             ("Managed device or page obj %p m %p", object, m));
  226         TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
  227         vm_page_putfake(m);
  228 }
  229 
  230 static void
  231 dev_pager_dealloc(object)
  232         vm_object_t object;
  233 {
  234         vm_page_t m;
  235 
  236         VM_OBJECT_UNLOCK(object);
  237         object->un_pager.devp.ops->cdev_pg_dtor(object->handle);
  238 
  239         mtx_lock(&dev_pager_mtx);
  240         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
  241         mtx_unlock(&dev_pager_mtx);
  242         VM_OBJECT_LOCK(object);
  243 
  244         if (object->type == OBJT_DEVICE) {
  245                 /*
  246                  * Free up our fake pages.
  247                  */
  248                 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist))
  249                     != NULL)
  250                         dev_pager_free_page(object, m);
  251         }
  252         object->handle = NULL;
  253         object->type = OBJT_DEAD;
  254 }
  255 
  256 static int
  257 dev_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int reqpage)
  258 {
  259         int error, i;
  260 
  261         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
  262         error = object->un_pager.devp.ops->cdev_pg_fault(object,
  263             IDX_TO_OFF(ma[reqpage]->pindex), PROT_READ, &ma[reqpage]);
  264 
  265         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
  266 
  267         for (i = 0; i < count; i++) {
  268                 if (i != reqpage) {
  269                         vm_page_lock(ma[i]);
  270                         vm_page_free(ma[i]);
  271                         vm_page_unlock(ma[i]);
  272                 }
  273         }
  274 
  275         if (error == VM_PAGER_OK) {
  276                 KASSERT((object->type == OBJT_DEVICE &&
  277                      (ma[reqpage]->oflags & VPO_UNMANAGED) != 0) ||
  278                     (object->type == OBJT_MGTDEVICE &&
  279                      (ma[reqpage]->oflags & VPO_UNMANAGED) == 0),
  280                     ("Wrong page type %p %p", ma[reqpage], object));
  281                 if (object->type == OBJT_DEVICE) {
  282                         TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
  283                             ma[reqpage], pageq);
  284                 }
  285         }
  286 
  287         return (error);
  288 }
  289 
  290 static int
  291 old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
  292     vm_page_t *mres)
  293 {
  294         vm_pindex_t pidx;
  295         vm_paddr_t paddr;
  296         vm_page_t m_paddr, page;
  297         struct cdev *dev;
  298         struct cdevsw *csw;
  299         struct file *fpop;
  300         struct thread *td;
  301         vm_memattr_t memattr;
  302         int ref, ret;
  303 
  304         pidx = OFF_TO_IDX(offset);
  305         memattr = object->memattr;
  306 
  307         VM_OBJECT_UNLOCK(object);
  308 
  309         dev = object->handle;
  310         csw = dev_refthread(dev, &ref);
  311         if (csw == NULL) {
  312                 VM_OBJECT_LOCK(object);
  313                 return (VM_PAGER_FAIL);
  314         }
  315         td = curthread;
  316         fpop = td->td_fpop;
  317         td->td_fpop = NULL;
  318         ret = csw->d_mmap(dev, offset, &paddr, prot, &memattr);
  319         td->td_fpop = fpop;
  320         dev_relthread(dev, ref);
  321         if (ret != 0) {
  322                 printf(
  323             "WARNING: dev_pager_getpage: map function returns error %d", ret);
  324                 VM_OBJECT_LOCK(object);
  325                 return (VM_PAGER_FAIL);
  326         }
  327 
  328         /* If "paddr" is a real page, perform a sanity check on "memattr". */
  329         if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
  330             pmap_page_get_memattr(m_paddr) != memattr) {
  331                 memattr = pmap_page_get_memattr(m_paddr);
  332                 printf(
  333             "WARNING: A device driver has set \"memattr\" inconsistently.\n");
  334         }
  335         if (((*mres)->flags & PG_FICTITIOUS) != 0) {
  336                 /*
  337                  * If the passed in result page is a fake page, update it with
  338                  * the new physical address.
  339                  */
  340                 page = *mres;
  341                 VM_OBJECT_LOCK(object);
  342                 vm_page_updatefake(page, paddr, memattr);
  343         } else {
  344                 /*
  345                  * Replace the passed in reqpage page with our own fake page and
  346                  * free up the all of the original pages.
  347                  */
  348                 page = vm_page_getfake(paddr, memattr);
  349                 VM_OBJECT_LOCK(object);
  350                 vm_page_lock(*mres);
  351                 vm_page_free(*mres);
  352                 vm_page_unlock(*mres);
  353                 *mres = page;
  354                 vm_page_insert(page, object, pidx);
  355         }
  356         page->valid = VM_PAGE_BITS_ALL;
  357         return (VM_PAGER_OK);
  358 }
  359 
  360 static void
  361 dev_pager_putpages(object, m, count, sync, rtvals)
  362         vm_object_t object;
  363         vm_page_t *m;
  364         int count;
  365         boolean_t sync;
  366         int *rtvals;
  367 {
  368 
  369         panic("dev_pager_putpage called");
  370 }
  371 
  372 static boolean_t
  373 dev_pager_haspage(object, pindex, before, after)
  374         vm_object_t object;
  375         vm_pindex_t pindex;
  376         int *before;
  377         int *after;
  378 {
  379         if (before != NULL)
  380                 *before = 0;
  381         if (after != NULL)
  382                 *after = 0;
  383         return (TRUE);
  384 }
  385 
  386 static int
  387 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
  388     vm_ooffset_t foff, struct ucred *cred, u_short *color)
  389 {
  390         struct cdev *dev;
  391         struct cdevsw *csw;
  392         vm_memattr_t dummy;
  393         vm_ooffset_t off;
  394         vm_paddr_t paddr;
  395         unsigned int npages;
  396         int ref;
  397 
  398         /*
  399          * Make sure this device can be mapped.
  400          */
  401         dev = handle;
  402         csw = dev_refthread(dev, &ref);
  403         if (csw == NULL)
  404                 return (ENXIO);
  405 
  406         /*
  407          * Check that the specified range of the device allows the desired
  408          * protection.
  409          *
  410          * XXX assumes VM_PROT_* == PROT_*
  411          */
  412         npages = OFF_TO_IDX(size);
  413         paddr = 0; /* Make paddr initialized for the case of size == 0. */
  414         for (off = foff; npages--; off += PAGE_SIZE) {
  415                 if (csw->d_mmap(dev, off, &paddr, (int)prot, &dummy) != 0) {
  416                         dev_relthread(dev, ref);
  417                         return (EINVAL);
  418                 }
  419         }
  420 
  421         dev_ref(dev);
  422         dev_relthread(dev, ref);
  423         *color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
  424         return (0);
  425 }
  426 
  427 static void
  428 old_dev_pager_dtor(void *handle)
  429 {
  430 
  431         dev_rel(handle);
  432 }
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FreeBSD/Linux Kernel Cross Reference sys/vm/device_pager.c

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