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. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93 41 * $FreeBSD: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $ 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/conf.h> 48 #include <sys/mman.h> 49 #include <sys/device.h> 50 #include <sys/queue.h> 51 #include <sys/malloc.h> 52 #include <sys/thread2.h> 53 #include <sys/mutex2.h> 54 55 #include <vm/vm.h> 56 #include <vm/vm_object.h> 57 #include <vm/vm_page.h> 58 #include <vm/vm_pager.h> 59 #include <vm/vm_zone.h> 60 61 static void dev_pager_dealloc (vm_object_t); 62 static int dev_pager_getpage (vm_object_t, vm_page_t *, int); 63 static void dev_pager_putpages (vm_object_t, vm_page_t *, int, 64 boolean_t, int *); 65 static boolean_t dev_pager_haspage (vm_object_t, vm_pindex_t); 66 67 /* list of device pager objects */ 68 static TAILQ_HEAD(, vm_page) dev_freepages_list = 69 TAILQ_HEAD_INITIALIZER(dev_freepages_list); 70 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages", 71 "Device mapped pages"); 72 73 static vm_page_t dev_pager_getfake (vm_paddr_t); 74 static void dev_pager_putfake (vm_page_t); 75 76 struct pagerops devicepagerops = { 77 dev_pager_dealloc, 78 dev_pager_getpage, 79 dev_pager_putpages, 80 dev_pager_haspage 81 }; 82 83 static struct mtx dev_pager_mtx = MTX_INITIALIZER; 84 85 /* 86 * No requirements. 87 */ 88 vm_object_t 89 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff) 90 { 91 cdev_t dev; 92 vm_object_t object; 93 unsigned int npages; 94 vm_offset_t off; 95 96 /* 97 * Make sure this device can be mapped. 98 */ 99 dev = handle; 100 101 /* 102 * Offset should be page aligned. 103 */ 104 if (foff & PAGE_MASK) 105 return (NULL); 106 107 size = round_page64(size); 108 109 /* 110 * Check that the specified range of the device allows the desired 111 * protection. 112 * 113 * XXX assumes VM_PROT_* == PROT_* 114 */ 115 npages = OFF_TO_IDX(size); 116 for (off = foff; npages--; off += PAGE_SIZE) { 117 if (dev_dmmap(dev, off, (int)prot) == -1) 118 return (NULL); 119 } 120 121 /* 122 * Look up pager, creating as necessary. 123 */ 124 mtx_lock(&dev_pager_mtx); 125 object = dev->si_object; 126 if (object == NULL) { 127 /* 128 * Allocate object and associate it with the pager. 129 */ 130 object = vm_object_allocate_hold(OBJT_DEVICE, 131 OFF_TO_IDX(foff + size)); 132 object->handle = handle; 133 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 134 dev->si_object = object; 135 vm_object_drop(object); 136 } else { 137 /* 138 * Gain a reference to the object. 139 */ 140 vm_object_hold(object); 141 vm_object_reference_locked(object); 142 if (OFF_TO_IDX(foff + size) > object->size) 143 object->size = OFF_TO_IDX(foff + size); 144 vm_object_drop(object); 145 } 146 mtx_unlock(&dev_pager_mtx); 147 148 return (object); 149 } 150 151 /* 152 * No requirements. 153 */ 154 static void 155 dev_pager_dealloc(vm_object_t object) 156 { 157 vm_page_t m; 158 cdev_t dev; 159 160 mtx_lock(&dev_pager_mtx); 161 162 if ((dev = object->handle) != NULL) { 163 KKASSERT(dev->si_object); 164 dev->si_object = NULL; 165 } 166 KKASSERT(object->swblock_count == 0); 167 168 /* 169 * Free up our fake pages. 170 */ 171 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 172 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 173 dev_pager_putfake(m); 174 } 175 mtx_unlock(&dev_pager_mtx); 176 } 177 178 /* 179 * No requirements. 180 */ 181 static int 182 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 183 { 184 vm_offset_t offset; 185 vm_paddr_t paddr; 186 vm_page_t page; 187 cdev_t dev; 188 int prot; 189 190 mtx_lock(&dev_pager_mtx); 191 192 page = *mpp; 193 dev = object->handle; 194 offset = page->pindex; 195 prot = PROT_READ; /* XXX should pass in? */ 196 197 paddr = pmap_phys_address( 198 dev_dmmap(dev, (vm_offset_t)offset << PAGE_SHIFT, prot)); 199 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error")); 200 201 if (page->flags & PG_FICTITIOUS) { 202 /* 203 * If the passed in reqpage page is a fake page, update it 204 * with the new physical address. 205 */ 206 page->phys_addr = paddr; 207 page->valid = VM_PAGE_BITS_ALL; 208 } else { 209 /* 210 * Replace the passed in reqpage page with our own fake page 211 * and free up all the original pages. 212 */ 213 page = dev_pager_getfake(paddr); 214 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, 215 page, pageq); 216 vm_object_hold(object); 217 vm_page_free(*mpp); 218 if (vm_page_insert(page, object, offset) == FALSE) { 219 panic("dev_pager_getpage: page (%p,%ld) exists", 220 object, offset); 221 } 222 vm_object_drop(object); 223 } 224 mtx_unlock(&dev_pager_mtx); 225 return (VM_PAGER_OK); 226 } 227 228 /* 229 * No requirements. 230 */ 231 static void 232 dev_pager_putpages(vm_object_t object, vm_page_t *m, 233 int count, boolean_t sync, int *rtvals) 234 { 235 panic("dev_pager_putpage called"); 236 } 237 238 /* 239 * No requirements. 240 */ 241 static boolean_t 242 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex) 243 { 244 return (TRUE); 245 } 246 247 /* 248 * The caller must hold dev_pager_mtx 249 */ 250 static vm_page_t 251 dev_pager_getfake(vm_paddr_t paddr) 252 { 253 vm_page_t m; 254 255 if ((m = TAILQ_FIRST(&dev_freepages_list)) != NULL) { 256 TAILQ_REMOVE(&dev_freepages_list, m, pageq); 257 } else { 258 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK); 259 } 260 bzero(m, sizeof(*m)); 261 262 m->flags = PG_BUSY | PG_FICTITIOUS; 263 m->valid = VM_PAGE_BITS_ALL; 264 m->dirty = 0; 265 m->busy = 0; 266 m->queue = PQ_NONE; 267 m->object = NULL; 268 269 m->wire_count = 1; 270 m->hold_count = 0; 271 m->phys_addr = paddr; 272 273 return (m); 274 } 275 276 /* 277 * Synthesized VM pages must be structurally stable for lockless lookups to 278 * work properly. 279 * 280 * The caller must hold dev_pager_mtx 281 */ 282 static void 283 dev_pager_putfake(vm_page_t m) 284 { 285 if (!(m->flags & PG_FICTITIOUS)) 286 panic("dev_pager_putfake: bad page"); 287 KKASSERT(m->object == NULL); 288 TAILQ_INSERT_HEAD(&dev_freepages_list, m, pageq); 289 } 290 291