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
  71 static uma_zone_t fakepg_zone;
  72
  73 static vm_page_t dev_pager_getfake(vm_paddr_t, vm_memattr_t);
  74 static void dev_pager_putfake(vm_page_t);
  75 static void dev_pager_updatefake(vm_page_t, vm_paddr_t, vm_memattr_t);
  76
  77 struct pagerops devicepagerops = {
  78         .pgo_init =     dev_pager_init,
  79         .pgo_alloc =    dev_pager_alloc,
  80         .pgo_dealloc =  dev_pager_dealloc,
  81         .pgo_getpages = dev_pager_getpages,
  82         .pgo_putpages = dev_pager_putpages,
  83         .pgo_haspage =  dev_pager_haspage,
  84 };
  85
  86 static void
  87 dev_pager_init()
  88 {
  89         TAILQ_INIT(&dev_pager_object_list);
  90         mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
  91         fakepg_zone = uma_zcreate("DP fakepg", sizeof(struct vm_page),
  92             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
  93             UMA_ZONE_NOFREE|UMA_ZONE_VM);
  94 }
  95
  96 /*
  97  * MPSAFE
  98  */
  99 static vm_object_t
 100 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 101     vm_ooffset_t foff, struct ucred *cred)
 102 {
 103         struct cdev *dev;
 104         vm_object_t object, object1;
 105         vm_pindex_t pindex;
 106         unsigned int npages;
 107         vm_paddr_t paddr;
 108         vm_offset_t off;
 109         struct cdevsw *csw;
 110
 111         /*
 112          * Offset should be page aligned.
 113          */
 114         if (foff & PAGE_MASK)
 115                 return (NULL);
 116
 117         size = round_page(size);
 118         pindex = OFF_TO_IDX(foff + size);
 119
 120         /*
 121          * Make sure this device can be mapped.
 122          */
 123         dev = handle;
 124         csw = dev_refthread(dev);
 125         if (csw == NULL)
 126                 return (NULL);
 127
 128         /*
 129          * Check that the specified range of the device allows the desired
 130          * protection.
 131          *
 132          * XXX assumes VM_PROT_* == PROT_*
 133          */
 134         npages = OFF_TO_IDX(size);
 135         for (off = foff; npages--; off += PAGE_SIZE)
 136                 if ((*csw->d_mmap)(dev, off, &paddr, (int)prot) != 0) {
 137                         dev_relthread(dev);
 138                         return (NULL);
 139                 }
 140
 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(OBJT_DEVICE, pindex);
 156                 object1->flags |= OBJ_COLORED;
 157                 object1->pg_color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
 158                 mtx_lock(&dev_pager_mtx);
 159                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 160                 if (object != NULL) {
 161                         /*
 162                          * We raced with other thread while allocating object.
 163                          */
 164                         if (pindex > object->size)
 165                                 object->size = pindex;
 166                 } else {
 167                         object = object1;
 168                         object1 = NULL;
 169                         object->handle = handle;
 170                         TAILQ_INIT(&object->un_pager.devp.devp_pglist);
 171                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 172                             pager_object_list);
 173                 }
 174         } else {
 175                 if (pindex > object->size)
 176                         object->size = pindex;
 177         }
 178         mtx_unlock(&dev_pager_mtx);
 179         dev_relthread(dev);
 180         vm_object_deallocate(object1);
 181         return (object);
 182 }
 183
 184 static void
 185 dev_pager_dealloc(object)
 186         vm_object_t object;
 187 {
 188         vm_page_t m;
 189
 190         VM_OBJECT_UNLOCK(object);
 191         mtx_lock(&dev_pager_mtx);
 192         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 193         mtx_unlock(&dev_pager_mtx);
 194         VM_OBJECT_LOCK(object);
 195         /*
 196          * Free up our fake pages.
 197          */
 198         while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != NULL) {
 199                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 200                 dev_pager_putfake(m);
 201         }
 202 }
 203
 204 static int
 205 dev_pager_getpages(object, m, count, reqpage)
 206         vm_object_t object;
 207         vm_page_t *m;
 208         int count;
 209         int reqpage;
 210 {
 211         vm_pindex_t offset;
 212         vm_paddr_t paddr;
 213         vm_page_t m_paddr, page;
 214         vm_memattr_t memattr;
 215         struct cdev *dev;
 216         int i, ret;
 217         int prot;
 218         struct cdevsw *csw;
 219         struct thread *td;
 220         struct file *fpop;
 221
 222         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 223         dev = object->handle;
 224         page = m[reqpage];
 225         offset = page->pindex;
 226         memattr = object->memattr;
 227         VM_OBJECT_UNLOCK(object);
 228         csw = dev_refthread(dev);
 229         if (csw == NULL)
 230                 panic("dev_pager_getpage: no cdevsw");
 231         prot = PROT_READ;       /* XXX should pass in? */
 232
 233         td = curthread;
 234         fpop = td->td_fpop;
 235         td->td_fpop = NULL;
 236         ret = (*csw->d_mmap)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot);
 237         KASSERT(ret == 0, ("dev_pager_getpage: map function returns error"));
 238         td->td_fpop = fpop;
 239         dev_relthread(dev);
 240         /* If "paddr" is a real page, perform a sanity check on "memattr". */
 241         if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
 242             pmap_page_get_memattr(m_paddr) != memattr) {
 243                 memattr = pmap_page_get_memattr(m_paddr);
 244                 printf(
 245             "WARNING: A device driver has set \"memattr\" inconsistently.\n");
 246         }
 247         if ((page->flags & PG_FICTITIOUS) != 0) {
 248                 /*
 249                  * If the passed in reqpage page is a fake page, update it with
 250                  * the new physical address.
 251                  */
 252                 VM_OBJECT_LOCK(object);
 253                 dev_pager_updatefake(page, paddr, memattr);
 254                 if (count > 1) {
 255                         vm_page_lock_queues();
 256                         for (i = 0; i < count; i++) {
 257                                 if (i != reqpage)
 258                                         vm_page_free(m[i]);
 259                         }
 260                         vm_page_unlock_queues();
 261                 }
 262         } else {
 263                 /*
 264                  * Replace the passed in reqpage page with our own fake page and
 265                  * free up the all of the original pages.
 266                  */
 267                 page = dev_pager_getfake(paddr, memattr);
 268                 VM_OBJECT_LOCK(object);
 269                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
 270                 vm_page_lock_queues();
 271                 for (i = 0; i < count; i++)
 272                         vm_page_free(m[i]);
 273                 vm_page_unlock_queues();
 274                 vm_page_insert(page, object, offset);
 275                 m[reqpage] = page;
 276         }
 277         page->valid = VM_PAGE_BITS_ALL;
 278         return (VM_PAGER_OK);
 279 }
 280
 281 static void
 282 dev_pager_putpages(object, m, count, sync, rtvals)
 283         vm_object_t object;
 284         vm_page_t *m;
 285         int count;
 286         boolean_t sync;
 287         int *rtvals;
 288 {
 289         panic("dev_pager_putpage called");
 290 }
 291
 292 static boolean_t
 293 dev_pager_haspage(object, pindex, before, after)
 294         vm_object_t object;
 295         vm_pindex_t pindex;
 296         int *before;
 297         int *after;
 298 {
 299         if (before != NULL)
 300                 *before = 0;
 301         if (after != NULL)
 302                 *after = 0;
 303         return (TRUE);
 304 }
 305
 306 /*
 307  * Create a fictitious page with the specified physical address and memory
 308  * attribute.  The memory attribute is the only the machine-dependent aspect
 309  * of a fictitious page that must be initialized.
 310  */
 311 static vm_page_t
 312 dev_pager_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
 313 {
 314         vm_page_t m;
 315
 316         m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO);
 317         m->phys_addr = paddr;
 318         /* Fictitious pages don't use "segind". */
 319         m->flags = PG_FICTITIOUS;
 320         /* Fictitious pages don't use "order" or "pool". */
 321         m->oflags = VPO_BUSY;
 322         m->wire_count = 1;
 323         pmap_page_set_memattr(m, memattr);
 324         return (m);
 325 }
 326
 327 /*
 328  * Release a fictitious page.
 329  */
 330 static void
 331 dev_pager_putfake(vm_page_t m)
 332 {
 333
 334         if (!(m->flags & PG_FICTITIOUS))
 335                 panic("dev_pager_putfake: bad page");
 336         uma_zfree(fakepg_zone, m);
 337 }
 338
 339 /*
 340  * Update the given fictitious page to the specified physical address and
 341  * memory attribute.
 342  */
 343 static void
 344 dev_pager_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
 345 {
 346
 347         if (!(m->flags & PG_FICTITIOUS))
 348                 panic("dev_pager_updatefake: bad page");
 349         m->phys_addr = paddr;
 350         pmap_page_set_memattr(m, memattr);
 351 }