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 static __inline int
  97 dev_mmap(struct cdevsw *csw, struct cdev *dev, vm_offset_t offset,
  98     vm_paddr_t *paddr, int nprot, vm_memattr_t *memattr)
  99 {
 100
 101         if (csw->d_flags & D_MMAP2)
 102                 return (csw->d_mmap2(dev, offset, paddr, nprot, memattr));
 103         else
 104                 return (csw->d_mmap(dev, offset, paddr, nprot));
 105 }
 106
 107 /*
 108  * MPSAFE
 109  */
 110 static vm_object_t
 111 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 112     vm_ooffset_t foff, struct ucred *cred)
 113 {
 114         struct cdev *dev;
 115         vm_object_t object, object1;
 116         vm_pindex_t pindex;
 117         unsigned int npages;
 118         vm_paddr_t paddr;
 119         vm_offset_t off;
 120         vm_memattr_t dummy;
 121         struct cdevsw *csw;
 122         int ref;
 123
 124         /*
 125          * Offset should be page aligned.
 126          */
 127         if (foff & PAGE_MASK)
 128                 return (NULL);
 129
 130         size = round_page(size);
 131         pindex = OFF_TO_IDX(foff + size);
 132
 133         /*
 134          * Make sure this device can be mapped.
 135          */
 136         dev = handle;
 137         csw = dev_refthread(dev, &ref);
 138         if (csw == NULL)
 139                 return (NULL);
 140
 141         /*
 142          * Check that the specified range of the device allows the desired
 143          * protection.
 144          *
 145          * XXX assumes VM_PROT_* == PROT_*
 146          */
 147         npages = OFF_TO_IDX(size);
 148         for (off = foff; npages--; off += PAGE_SIZE)
 149                 if (dev_mmap(csw, dev, off, &paddr, (int)prot, &dummy) != 0) {
 150                         dev_relthread(dev, ref);
 151                         return (NULL);
 152                 }
 153
 154         mtx_lock(&dev_pager_mtx);
 155
 156         /*
 157          * Look up pager, creating as necessary.
 158          */
 159         object1 = NULL;
 160         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 161         if (object == NULL) {
 162                 /*
 163                  * Allocate object and associate it with the pager.  Initialize
 164                  * the object's pg_color based upon the physical address of the
 165                  * device's memory.
 166                  */
 167                 mtx_unlock(&dev_pager_mtx);
 168                 object1 = vm_object_allocate(OBJT_DEVICE, pindex);
 169                 object1->flags |= OBJ_COLORED;
 170                 object1->pg_color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
 171                 mtx_lock(&dev_pager_mtx);
 172                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
 173                 if (object != NULL) {
 174                         /*
 175                          * We raced with other thread while allocating object.
 176                          */
 177                         if (pindex > object->size)
 178                                 object->size = pindex;
 179                 } else {
 180                         object = object1;
 181                         object1 = NULL;
 182                         object->handle = handle;
 183                         TAILQ_INIT(&object->un_pager.devp.devp_pglist);
 184                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
 185                             pager_object_list);
 186                 }
 187         } else {
 188                 if (pindex > object->size)
 189                         object->size = pindex;
 190         }
 191         mtx_unlock(&dev_pager_mtx);
 192         dev_relthread(dev, ref);
 193         vm_object_deallocate(object1);
 194         return (object);
 195 }
 196
 197 static void
 198 dev_pager_dealloc(object)
 199         vm_object_t object;
 200 {
 201         vm_page_t m;
 202
 203         VM_OBJECT_UNLOCK(object);
 204         mtx_lock(&dev_pager_mtx);
 205         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
 206         mtx_unlock(&dev_pager_mtx);
 207         VM_OBJECT_LOCK(object);
 208         /*
 209          * Free up our fake pages.
 210          */
 211         while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != NULL) {
 212                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
 213                 dev_pager_putfake(m);
 214         }
 215 }
 216
 217 static int
 218 dev_pager_getpages(object, m, count, reqpage)
 219         vm_object_t object;
 220         vm_page_t *m;
 221         int count;
 222         int reqpage;
 223 {
 224         vm_pindex_t offset;
 225         vm_paddr_t paddr;
 226         vm_page_t m_paddr, page;
 227         vm_memattr_t memattr;
 228         struct cdev *dev;
 229         int i, ref, ret;
 230         struct cdevsw *csw;
 231         struct thread *td;
 232         struct file *fpop;
 233
 234         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 235         dev = object->handle;
 236         page = m[reqpage];
 237         offset = page->pindex;
 238         memattr = object->memattr;
 239         VM_OBJECT_UNLOCK(object);
 240         csw = dev_refthread(dev, &ref);
 241         if (csw == NULL)
 242                 panic("dev_pager_getpage: no cdevsw");
 243         td = curthread;
 244         fpop = td->td_fpop;
 245         td->td_fpop = NULL;
 246         ret = dev_mmap(csw, dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr,
 247             PROT_READ, &memattr);
 248         KASSERT(ret == 0, ("dev_pager_getpage: map function returns error"));
 249         td->td_fpop = fpop;
 250         dev_relthread(dev, ref);
 251         /* If "paddr" is a real page, perform a sanity check on "memattr". */
 252         if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL &&
 253             pmap_page_get_memattr(m_paddr) != memattr) {
 254                 memattr = pmap_page_get_memattr(m_paddr);
 255                 printf(
 256             "WARNING: A device driver has set \"memattr\" inconsistently.\n");
 257         }
 258         if ((page->flags & PG_FICTITIOUS) != 0) {
 259                 /*
 260                  * If the passed in reqpage page is a fake page, update it with
 261                  * the new physical address.
 262                  */
 263                 VM_OBJECT_LOCK(object);
 264                 dev_pager_updatefake(page, paddr, memattr);
 265                 if (count > 1) {
 266                         vm_page_lock_queues();
 267                         for (i = 0; i < count; i++) {
 268                                 if (i != reqpage)
 269                                         vm_page_free(m[i]);
 270                         }
 271                         vm_page_unlock_queues();
 272                 }
 273         } else {
 274                 /*
 275                  * Replace the passed in reqpage page with our own fake page and
 276                  * free up the all of the original pages.
 277                  */
 278                 page = dev_pager_getfake(paddr, memattr);
 279                 VM_OBJECT_LOCK(object);
 280                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
 281                 vm_page_lock_queues();
 282                 for (i = 0; i < count; i++)
 283                         vm_page_free(m[i]);
 284                 vm_page_unlock_queues();
 285                 vm_page_insert(page, object, offset);
 286                 m[reqpage] = page;
 287         }
 288         page->valid = VM_PAGE_BITS_ALL;
 289         return (VM_PAGER_OK);
 290 }
 291
 292 static void
 293 dev_pager_putpages(object, m, count, sync, rtvals)
 294         vm_object_t object;
 295         vm_page_t *m;
 296         int count;
 297         boolean_t sync;
 298         int *rtvals;
 299 {
 300         panic("dev_pager_putpage called");
 301 }
 302
 303 static boolean_t
 304 dev_pager_haspage(object, pindex, before, after)
 305         vm_object_t object;
 306         vm_pindex_t pindex;
 307         int *before;
 308         int *after;
 309 {
 310         if (before != NULL)
 311                 *before = 0;
 312         if (after != NULL)
 313                 *after = 0;
 314         return (TRUE);
 315 }
 316
 317 /*
 318  * Create a fictitious page with the specified physical address and memory
 319  * attribute.  The memory attribute is the only the machine-dependent aspect
 320  * of a fictitious page that must be initialized.
 321  */
 322 static vm_page_t
 323 dev_pager_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
 324 {
 325         vm_page_t m;
 326
 327         m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO);
 328         m->phys_addr = paddr;
 329         /* Fictitious pages don't use "segind". */
 330         m->flags = PG_FICTITIOUS;
 331         /* Fictitious pages don't use "order" or "pool". */
 332         m->oflags = VPO_BUSY;
 333         m->wire_count = 1;
 334         pmap_page_set_memattr(m, memattr);
 335         return (m);
 336 }
 337
 338 /*
 339  * Release a fictitious page.
 340  */
 341 static void
 342 dev_pager_putfake(vm_page_t m)
 343 {
 344
 345         if (!(m->flags & PG_FICTITIOUS))
 346                 panic("dev_pager_putfake: bad page");
 347         uma_zfree(fakepg_zone, m);
 348 }
 349
 350 /*
 351  * Update the given fictitious page to the specified physical address and
 352  * memory attribute.
 353  */
 354 static void
 355 dev_pager_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
 356 {
 357
 358         if (!(m->flags & PG_FICTITIOUS))
 359                 panic("dev_pager_updatefake: bad page");
 360         m->phys_addr = paddr;
 361         pmap_page_set_memattr(m, memattr);
 362 }