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/10.4/sys/vm/device_pager.c 320439 2017-06-28 06:13:58Z alc $");
   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/rwlock.h>
   48 #include <sys/sx.h>
   49 
   50 #include <vm/vm.h>
   51 #include <vm/vm_param.h>
   52 #include <vm/vm_object.h>
   53 #include <vm/vm_page.h>
   54 #include <vm/vm_pager.h>
   55 #include <vm/vm_phys.h>
   56 #include <vm/uma.h>
   57 
   58 static void dev_pager_init(void);
   59 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
   60     vm_ooffset_t, struct ucred *);
   61 static void dev_pager_dealloc(vm_object_t);
   62 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int);
   63 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
   64 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *, 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(void)
  103 {
  104 
  105         TAILQ_INIT(&dev_pager_object_list);
  106         mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
  107 }
  108 
  109 vm_object_t
  110 cdev_pager_lookup(void *handle)
  111 {
  112         vm_object_t object;
  113 
  114         mtx_lock(&dev_pager_mtx);
  115         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
  116         mtx_unlock(&dev_pager_mtx);
  117         return (object);
  118 }
  119 
  120 vm_object_t
  121 cdev_pager_allocate(void *handle, enum obj_type tp, struct cdev_pager_ops *ops,
  122     vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
  123 {
  124         vm_object_t object, object1;
  125         vm_pindex_t pindex;
  126         u_short color;
  127 
  128         if (tp != OBJT_DEVICE && tp != OBJT_MGTDEVICE)
  129                 return (NULL);
  130 
  131         /*
  132          * Offset should be page aligned.
  133          */
  134         if (foff & PAGE_MASK)
  135                 return (NULL);
  136 
  137         size = round_page(size);
  138         pindex = OFF_TO_IDX(foff + size);
  139 
  140         if (ops->cdev_pg_ctor(handle, size, prot, foff, cred, &color) != 0)
  141                 return (NULL);
  142         mtx_lock(&dev_pager_mtx);
  143 
  144         /*
  145          * Look up pager, creating as necessary.
  146          */
  147         object1 = NULL;
  148         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
  149         if (object == NULL) {
  150                 /*
  151                  * Allocate object and associate it with the pager.  Initialize
  152                  * the object's pg_color based upon the physical address of the
  153                  * device's memory.
  154                  */
  155                 mtx_unlock(&dev_pager_mtx);
  156                 object1 = vm_object_allocate(tp, pindex);
  157                 object1->flags |= OBJ_COLORED;
  158                 object1->pg_color = color;
  159                 object1->handle = handle;
  160                 object1->un_pager.devp.ops = ops;
  161                 object1->un_pager.devp.dev = handle;
  162                 TAILQ_INIT(&object1->un_pager.devp.devp_pglist);
  163                 mtx_lock(&dev_pager_mtx);
  164                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
  165                 if (object != NULL) {
  166                         /*
  167                          * We raced with other thread while allocating object.
  168                          */
  169                         if (pindex > object->size)
  170                                 object->size = pindex;
  171                 } else {
  172                         object = object1;
  173                         object1 = NULL;
  174                         object->handle = handle;
  175                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
  176                             pager_object_list);
  177                         KASSERT(object->type == tp,
  178                 ("Inconsistent device pager type %p %d", object, tp));
  179                 }
  180         } else {
  181                 if (pindex > object->size)
  182                         object->size = pindex;
  183         }
  184         mtx_unlock(&dev_pager_mtx);
  185         if (object1 != NULL) {
  186                 object1->handle = object1;
  187                 mtx_lock(&dev_pager_mtx);
  188                 TAILQ_INSERT_TAIL(&dev_pager_object_list, object1,
  189                     pager_object_list);
  190                 mtx_unlock(&dev_pager_mtx);
  191                 vm_object_deallocate(object1);
  192         }
  193         return (object);
  194 }
  195 
  196 static vm_object_t
  197 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
  198     vm_ooffset_t foff, struct ucred *cred)
  199 {
  200 
  201         return (cdev_pager_allocate(handle, OBJT_DEVICE, &old_dev_pager_ops,
  202             size, prot, foff, cred));
  203 }
  204 
  205 void
  206 cdev_pager_free_page(vm_object_t object, vm_page_t m)
  207 {
  208 
  209         VM_OBJECT_ASSERT_WLOCKED(object);
  210         if (object->type == OBJT_MGTDEVICE) {
  211                 KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("unmanaged %p", m));
  212                 pmap_remove_all(m);
  213                 vm_page_lock(m);
  214                 vm_page_remove(m);
  215                 vm_page_unlock(m);
  216         } else if (object->type == OBJT_DEVICE)
  217                 dev_pager_free_page(object, m);
  218 }
  219 
  220 static void
  221 dev_pager_free_page(vm_object_t object, vm_page_t m)
  222 {
  223 
  224         VM_OBJECT_ASSERT_WLOCKED(object);
  225         KASSERT((object->type == OBJT_DEVICE &&
  226             (m->oflags & VPO_UNMANAGED) != 0),
  227             ("Managed device or page obj %p m %p", object, m));
  228         TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, plinks.q);
  229         vm_page_putfake(m);
  230 }
  231 
  232 static void
  233 dev_pager_dealloc(vm_object_t object)
  234 {
  235         vm_page_t m;
  236 
  237         VM_OBJECT_WUNLOCK(object);
  238         object->un_pager.devp.ops->cdev_pg_dtor(object->un_pager.devp.dev);
  239 
  240         mtx_lock(&dev_pager_mtx);
  241         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
  242         mtx_unlock(&dev_pager_mtx);
  243         VM_OBJECT_WLOCK(object);
  244 
  245         if (object->type == OBJT_DEVICE) {
  246                 /*
  247                  * Free up our fake pages.
  248                  */
  249                 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist))
  250                     != NULL)
  251                         dev_pager_free_page(object, m);
  252         }
  253         object->handle = NULL;
  254         object->type = OBJT_DEAD;
  255 }
  256 
  257 static int
  258 dev_pager_getpages(vm_object_t object, vm_page_t *ma, int count, int reqpage)
  259 {
  260         int error, i;
  261 
  262         VM_OBJECT_ASSERT_WLOCKED(object);
  263         error = object->un_pager.devp.ops->cdev_pg_fault(object,
  264             IDX_TO_OFF(ma[reqpage]->pindex), PROT_READ, &ma[reqpage]);
  265 
  266         VM_OBJECT_ASSERT_WLOCKED(object);
  267 
  268         for (i = 0; i < count; i++) {
  269                 if (i != reqpage) {
  270                         vm_page_lock(ma[i]);
  271                         vm_page_free(ma[i]);
  272                         vm_page_unlock(ma[i]);
  273                 }
  274         }
  275 
  276         if (error == VM_PAGER_OK) {
  277                 KASSERT((object->type == OBJT_DEVICE &&
  278                      (ma[reqpage]->oflags & VPO_UNMANAGED) != 0) ||
  279                     (object->type == OBJT_MGTDEVICE &&
  280                      (ma[reqpage]->oflags & VPO_UNMANAGED) == 0),
  281                     ("Wrong page type %p %p", ma[reqpage], object));
  282                 if (object->type == OBJT_DEVICE) {
  283                         TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist,
  284                             ma[reqpage], plinks.q);
  285                 }
  286         }
  287 
  288         return (error);
  289 }
  290 
  291 static int
  292 old_dev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
  293     vm_page_t *mres)
  294 {
  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, memattr1;
  302         int ref, ret;
  303 
  304         memattr = object->memattr;
  305 
  306         VM_OBJECT_WUNLOCK(object);
  307 
  308         dev = object->handle;
  309         csw = dev_refthread(dev, &ref);
  310         if (csw == NULL) {
  311                 VM_OBJECT_WLOCK(object);
  312                 return (VM_PAGER_FAIL);
  313         }
  314         td = curthread;
  315         fpop = td->td_fpop;
  316         td->td_fpop = NULL;
  317         ret = csw->d_mmap(dev, offset, &paddr, prot, &memattr);
  318         td->td_fpop = fpop;
  319         dev_relthread(dev, ref);
  320         if (ret != 0) {
  321                 printf(
  322             "WARNING: dev_pager_getpage: map function returns error %d", ret);
  323                 VM_OBJECT_WLOCK(object);
  324                 return (VM_PAGER_FAIL);
  325         }
  326 
  327         /* If "paddr" is a real page, perform a sanity check on "memattr". */
  328         if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
  329             (memattr1 = pmap_page_get_memattr(m_paddr)) != memattr) {
  330                 /*
  331                  * For the /dev/mem d_mmap routine to return the
  332                  * correct memattr, pmap_page_get_memattr() needs to
  333                  * be called, which we do there.
  334                  */
  335                 if ((csw->d_flags & D_MEM) == 0) {
  336                         printf("WARNING: Device driver %s has set "
  337                             "\"memattr\" inconsistently (drv %u pmap %u).\n",
  338                             csw->d_name, memattr, memattr1);
  339                 }
  340                 memattr = memattr1;
  341         }
  342         if (((*mres)->flags & PG_FICTITIOUS) != 0) {
  343                 /*
  344                  * If the passed in result page is a fake page, update it with
  345                  * the new physical address.
  346                  */
  347                 page = *mres;
  348                 VM_OBJECT_WLOCK(object);
  349                 vm_page_updatefake(page, paddr, memattr);
  350         } else {
  351                 /*
  352                  * Replace the passed in reqpage page with our own fake page and
  353                  * free up the all of the original pages.
  354                  */
  355                 page = vm_page_getfake(paddr, memattr);
  356                 VM_OBJECT_WLOCK(object);
  357                 if (vm_page_replace(page, object, (*mres)->pindex) != *mres)
  358                         panic("old_dev_pager_fault: invalid page replacement");
  359                 vm_page_lock(*mres);
  360                 vm_page_free(*mres);
  361                 vm_page_unlock(*mres);
  362                 *mres = page;
  363         }
  364         page->valid = VM_PAGE_BITS_ALL;
  365         return (VM_PAGER_OK);
  366 }
  367 
  368 static void
  369 dev_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
  370     int *rtvals)
  371 {
  372 
  373         panic("dev_pager_putpage called");
  374 }
  375 
  376 static boolean_t
  377 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
  378     int *after)
  379 {
  380 
  381         if (before != NULL)
  382                 *before = 0;
  383         if (after != NULL)
  384                 *after = 0;
  385         return (TRUE);
  386 }
  387 
  388 static int
  389 old_dev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
  390     vm_ooffset_t foff, struct ucred *cred, u_short *color)
  391 {
  392         struct cdev *dev;
  393         struct cdevsw *csw;
  394         vm_memattr_t dummy;
  395         vm_ooffset_t off;
  396         vm_paddr_t paddr;
  397         unsigned int npages;
  398         int ref;
  399 
  400         /*
  401          * Make sure this device can be mapped.
  402          */
  403         dev = handle;
  404         csw = dev_refthread(dev, &ref);
  405         if (csw == NULL)
  406                 return (ENXIO);
  407 
  408         /*
  409          * Check that the specified range of the device allows the desired
  410          * protection.
  411          *
  412          * XXX assumes VM_PROT_* == PROT_*
  413          */
  414         npages = OFF_TO_IDX(size);
  415         paddr = 0; /* Make paddr initialized for the case of size == 0. */
  416         for (off = foff; npages--; off += PAGE_SIZE) {
  417                 if (csw->d_mmap(dev, off, &paddr, (int)prot, &dummy) != 0) {
  418                         dev_relthread(dev, ref);
  419                         return (EINVAL);
  420                 }
  421         }
  422 
  423         dev_ref(dev);
  424         dev_relthread(dev, ref);
  425         *color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
  426         return (0);
  427 }
  428 
  429 static void
  430 old_dev_pager_dtor(void *handle)
  431 {
  432 
  433         dev_rel(handle);
  434 }
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FreeBSD/Linux Kernel Cross Reference sys/vm/device_pager.c

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