device_pager.c revision 58634
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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgment: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93 39 * $FreeBSD: head/sys/vm/device_pager.c 58634 2000-03-26 15:20:23Z charnier $ 40 */ 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/conf.h> 45#include <sys/mman.h> 46 47#include <vm/vm.h> 48#include <vm/vm_object.h> 49#include <vm/vm_page.h> 50#include <vm/vm_pager.h> 51#include <vm/vm_zone.h> 52 53static void dev_pager_init __P((void)); 54static vm_object_t dev_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t, 55 vm_ooffset_t)); 56static void dev_pager_dealloc __P((vm_object_t)); 57static int dev_pager_getpages __P((vm_object_t, vm_page_t *, int, int)); 58static void dev_pager_putpages __P((vm_object_t, vm_page_t *, int, 59 boolean_t, int *)); 60static boolean_t dev_pager_haspage __P((vm_object_t, vm_pindex_t, int *, 61 int *)); 62 63/* list of device pager objects */ 64static struct pagerlst dev_pager_object_list; 65 66static vm_zone_t fakepg_zone; 67static struct vm_zone fakepg_zone_store; 68 69static vm_page_t dev_pager_getfake __P((vm_offset_t)); 70static void dev_pager_putfake __P((vm_page_t)); 71 72static int dev_pager_alloc_lock, dev_pager_alloc_lock_want; 73 74struct pagerops devicepagerops = { 75 dev_pager_init, 76 dev_pager_alloc, 77 dev_pager_dealloc, 78 dev_pager_getpages, 79 dev_pager_putpages, 80 dev_pager_haspage, 81 NULL 82}; 83 84static void 85dev_pager_init() 86{ 87 TAILQ_INIT(&dev_pager_object_list); 88 fakepg_zone = &fakepg_zone_store; 89 zinitna(fakepg_zone, NULL, "DP fakepg", sizeof(struct vm_page), 0, 0, 2); 90} 91 92static vm_object_t 93dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff) 94{ 95 dev_t dev; 96 d_mmap_t *mapfunc; 97 vm_object_t object; 98 unsigned int npages; 99 vm_offset_t off; 100 101 /* 102 * Make sure this device can be mapped. 103 */ 104 dev = handle; 105 mapfunc = devsw(dev)->d_mmap; 106 if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) { 107 printf("obsolete map function %p\n", (void *)mapfunc); 108 return (NULL); 109 } 110 111 /* 112 * Offset should be page aligned. 113 */ 114 if (foff & PAGE_MASK) 115 return (NULL); 116 117 size = round_page(size); 118 119 /* 120 * Check that the specified range of the device allows the desired 121 * protection. 122 * 123 * XXX assumes VM_PROT_* == PROT_* 124 */ 125 npages = OFF_TO_IDX(size); 126 for (off = foff; npages--; off += PAGE_SIZE) 127 if ((*mapfunc) (dev, off, (int) prot) == -1) 128 return (NULL); 129 130 /* 131 * Lock to prevent object creation race condition. 132 */ 133 while (dev_pager_alloc_lock) { 134 dev_pager_alloc_lock_want++; 135 tsleep(&dev_pager_alloc_lock, PVM, "dvpall", 0); 136 dev_pager_alloc_lock_want--; 137 } 138 dev_pager_alloc_lock = 1; 139 140 /* 141 * Look up pager, creating as necessary. 142 */ 143 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 144 if (object == NULL) { 145 /* 146 * Allocate object and associate it with the pager. 147 */ 148 object = vm_object_allocate(OBJT_DEVICE, 149 OFF_TO_IDX(foff + size)); 150 object->handle = handle; 151 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 152 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list); 153 } else { 154 /* 155 * Gain a reference to the object. 156 */ 157 vm_object_reference(object); 158 if (OFF_TO_IDX(foff + size) > object->size) 159 object->size = OFF_TO_IDX(foff + size); 160 } 161 162 dev_pager_alloc_lock = 0; 163 if (dev_pager_alloc_lock_want) 164 wakeup(&dev_pager_alloc_lock); 165 166 return (object); 167} 168 169static void 170dev_pager_dealloc(object) 171 vm_object_t object; 172{ 173 vm_page_t m; 174 175 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 176 /* 177 * Free up our fake pages. 178 */ 179 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 180 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 181 dev_pager_putfake(m); 182 } 183} 184 185static int 186dev_pager_getpages(object, m, count, reqpage) 187 vm_object_t object; 188 vm_page_t *m; 189 int count; 190 int reqpage; 191{ 192 vm_offset_t offset; 193 vm_offset_t paddr; 194 vm_page_t page; 195 dev_t dev; 196 int i, s; 197 d_mmap_t *mapfunc; 198 int prot; 199 200 dev = object->handle; 201 offset = m[reqpage]->pindex; 202 prot = PROT_READ; /* XXX should pass in? */ 203 mapfunc = devsw(dev)->d_mmap; 204 205 if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) 206 panic("dev_pager_getpage: no map function"); 207 208 paddr = pmap_phys_address((*mapfunc) (dev, (vm_offset_t) offset << PAGE_SHIFT, prot)); 209 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error")); 210 /* 211 * Replace the passed in reqpage page with our own fake page and free up the 212 * all of the original pages. 213 */ 214 page = dev_pager_getfake(paddr); 215 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 216 for (i = 0; i < count; i++) { 217 vm_page_free(m[i]); 218 } 219 s = splhigh(); 220 vm_page_insert(page, object, offset); 221 splx(s); 222 223 return (VM_PAGER_OK); 224} 225 226static void 227dev_pager_putpages(object, m, count, sync, rtvals) 228 vm_object_t object; 229 vm_page_t *m; 230 int count; 231 boolean_t sync; 232 int *rtvals; 233{ 234 panic("dev_pager_putpage called"); 235} 236 237static boolean_t 238dev_pager_haspage(object, pindex, before, after) 239 vm_object_t object; 240 vm_pindex_t pindex; 241 int *before; 242 int *after; 243{ 244 if (before != NULL) 245 *before = 0; 246 if (after != NULL) 247 *after = 0; 248 return (TRUE); 249} 250 251static vm_page_t 252dev_pager_getfake(paddr) 253 vm_offset_t paddr; 254{ 255 vm_page_t m; 256 257 m = zalloc(fakepg_zone); 258 259 m->flags = PG_BUSY | PG_FICTITIOUS; 260 m->valid = VM_PAGE_BITS_ALL; 261 m->dirty = 0; 262 m->busy = 0; 263 m->queue = PQ_NONE; 264 m->object = NULL; 265 266 m->wire_count = 1; 267 m->hold_count = 0; 268 m->phys_addr = paddr; 269 270 return (m); 271} 272 273static void 274dev_pager_putfake(m) 275 vm_page_t m; 276{ 277 if (!(m->flags & PG_FICTITIOUS)) 278 panic("dev_pager_putfake: bad page"); 279 zfree(fakepg_zone, m); 280} 281