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