1 /* 2 * (MPSAFE) 3 * 4 * Copyright (c) 1990 University of Utah. 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * the Systems Programming Group of the University of Utah Computer 10 * Science Department. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93 37 * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $ 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/kernel.h> 43 #include <sys/conf.h> 44 #include <sys/mman.h> 45 #include <sys/device.h> 46 #include <sys/queue.h> 47 #include <sys/malloc.h> 48 #include <sys/thread2.h> 49 #include <sys/mutex2.h> 50 51 #include <vm/vm.h> 52 #include <vm/vm_object.h> 53 #include <vm/vm_page.h> 54 #include <vm/vm_pager.h> 55 #include <vm/vm_zone.h> 56 57 static void dev_pager_dealloc (vm_object_t); 58 static int dev_pager_getpage (vm_object_t, vm_page_t *, int); 59 static void dev_pager_putpages (vm_object_t, vm_page_t *, int, 60 boolean_t, int *); 61 static boolean_t dev_pager_haspage (vm_object_t, vm_pindex_t); 62 63 /* list of device pager objects */ 64 static TAILQ_HEAD(, vm_page) dev_freepages_list = 65 TAILQ_HEAD_INITIALIZER(dev_freepages_list); 66 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages", 67 "Device mapped pages"); 68 69 static vm_page_t dev_pager_getfake (vm_paddr_t); 70 static void dev_pager_putfake (vm_page_t); 71 72 struct pagerops devicepagerops = { 73 dev_pager_dealloc, 74 dev_pager_getpage, 75 dev_pager_putpages, 76 dev_pager_haspage 77 }; 78 79 static struct mtx dev_pager_mtx = MTX_INITIALIZER; 80 81 /* 82 * No requirements. 83 */ 84 vm_object_t 85 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff) 86 { 87 cdev_t dev; 88 vm_object_t object; 89 unsigned int npages; 90 vm_offset_t off; 91 92 /* 93 * Make sure this device can be mapped. 94 */ 95 dev = handle; 96 97 /* 98 * Offset should be page aligned. 99 */ 100 if (foff & PAGE_MASK) 101 return (NULL); 102 103 size = round_page64(size); 104 105 /* 106 * Check that the specified range of the device allows the desired 107 * protection. 108 * 109 * XXX assumes VM_PROT_* == PROT_* 110 */ 111 npages = OFF_TO_IDX(size); 112 for (off = foff; npages--; off += PAGE_SIZE) { 113 if (dev_dmmap(dev, off, (int)prot) == -1) 114 return (NULL); 115 } 116 117 /* 118 * Look up pager, creating as necessary. 119 */ 120 mtx_lock(&dev_pager_mtx); 121 object = dev->si_object; 122 if (object == NULL) { 123 /* 124 * Allocate object and associate it with the pager. 125 */ 126 object = vm_object_allocate_hold(OBJT_DEVICE, 127 OFF_TO_IDX(foff + size)); 128 object->handle = handle; 129 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 130 dev->si_object = object; 131 vm_object_drop(object); 132 } else { 133 /* 134 * Gain a reference to the object. 135 */ 136 vm_object_hold(object); 137 vm_object_reference_locked(object); 138 if (OFF_TO_IDX(foff + size) > object->size) 139 object->size = OFF_TO_IDX(foff + size); 140 vm_object_drop(object); 141 } 142 mtx_unlock(&dev_pager_mtx); 143 144 return (object); 145 } 146 147 /* 148 * No requirements. 149 */ 150 static void 151 dev_pager_dealloc(vm_object_t object) 152 { 153 vm_page_t m; 154 cdev_t dev; 155 156 mtx_lock(&dev_pager_mtx); 157 158 if ((dev = object->handle) != NULL) { 159 KKASSERT(dev->si_object); 160 dev->si_object = NULL; 161 } 162 KKASSERT(object->swblock_count == 0); 163 164 /* 165 * Free up our fake pages. 166 */ 167 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 168 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 169 dev_pager_putfake(m); 170 } 171 mtx_unlock(&dev_pager_mtx); 172 } 173 174 /* 175 * No requirements. 176 */ 177 static int 178 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 179 { 180 vm_offset_t offset; 181 vm_paddr_t paddr; 182 vm_page_t page; 183 cdev_t dev; 184 int prot; 185 186 mtx_lock(&dev_pager_mtx); 187 188 page = *mpp; 189 dev = object->handle; 190 offset = page->pindex; 191 prot = PROT_READ; /* XXX should pass in? */ 192 193 paddr = pmap_phys_address( 194 dev_dmmap(dev, offset << PAGE_SHIFT, prot)); 195 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error")); 196 197 if (page->flags & PG_FICTITIOUS) { 198 /* 199 * If the passed in reqpage page is a fake page, update it 200 * with the new physical address. 201 */ 202 page->phys_addr = paddr; 203 page->valid = VM_PAGE_BITS_ALL; 204 } else { 205 /* 206 * Replace the passed in reqpage page with our own fake page 207 * and free up all the original pages. 208 */ 209 page = dev_pager_getfake(paddr); 210 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, 211 page, pageq); 212 vm_object_hold(object); 213 vm_page_free(*mpp); 214 if (vm_page_insert(page, object, offset) == FALSE) { 215 panic("dev_pager_getpage: page (%p,%ld) exists", 216 object, offset); 217 } 218 vm_object_drop(object); 219 } 220 mtx_unlock(&dev_pager_mtx); 221 return (VM_PAGER_OK); 222 } 223 224 /* 225 * No requirements. 226 */ 227 static void 228 dev_pager_putpages(vm_object_t object, vm_page_t *m, 229 int count, boolean_t sync, int *rtvals) 230 { 231 panic("dev_pager_putpage called"); 232 } 233 234 /* 235 * No requirements. 236 */ 237 static boolean_t 238 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex) 239 { 240 return (TRUE); 241 } 242 243 /* 244 * The caller must hold dev_pager_mtx 245 */ 246 static vm_page_t 247 dev_pager_getfake(vm_paddr_t paddr) 248 { 249 vm_page_t m; 250 251 if ((m = TAILQ_FIRST(&dev_freepages_list)) != NULL) { 252 TAILQ_REMOVE(&dev_freepages_list, m, pageq); 253 } else { 254 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK); 255 } 256 bzero(m, sizeof(*m)); 257 258 m->flags = PG_BUSY | PG_FICTITIOUS; 259 m->valid = VM_PAGE_BITS_ALL; 260 m->dirty = 0; 261 m->busy = 0; 262 m->queue = PQ_NONE; 263 m->object = NULL; 264 265 m->wire_count = 1; 266 m->hold_count = 0; 267 m->phys_addr = paddr; 268 269 return (m); 270 } 271 272 /* 273 * Synthesized VM pages must be structurally stable for lockless lookups to 274 * work properly. 275 * 276 * The caller must hold dev_pager_mtx 277 */ 278 static void 279 dev_pager_putfake(vm_page_t m) 280 { 281 if (!(m->flags & PG_FICTITIOUS)) 282 panic("dev_pager_putfake: bad page"); 283 KKASSERT(m->object == NULL); 284 TAILQ_INSERT_HEAD(&dev_freepages_list, m, pageq); 285 } 286 287