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 acknowledgement: 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: src/sys/vm/device_pager.c,v 1.46.2.1 2000/08/02 21:54:37 peter Exp $ 40 * $DragonFly: src/sys/vm/device_pager.c,v 1.13 2008/01/21 10:25:18 corecode Exp $ 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/kernel.h> 46 #include <sys/conf.h> 47 #include <sys/mman.h> 48 #include <sys/device.h> 49 #include <sys/queue.h> 50 #include <sys/malloc.h> 51 #include <sys/thread2.h> 52 53 #include <vm/vm.h> 54 #include <vm/vm_object.h> 55 #include <vm/vm_page.h> 56 #include <vm/vm_pager.h> 57 #include <vm/vm_zone.h> 58 59 static void dev_pager_init (void); 60 static vm_object_t dev_pager_alloc (void *, off_t, vm_prot_t, off_t); 61 static void dev_pager_dealloc (vm_object_t); 62 static int dev_pager_getpages (vm_object_t, vm_page_t *, int, 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, int *, 66 int *); 67 68 /* list of device pager objects */ 69 static struct pagerlst dev_pager_object_list; 70 static TAILQ_HEAD(, vm_page) dev_freepages_list; 71 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages", "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 static int dev_pager_alloc_lock, dev_pager_alloc_lock_want; 77 78 struct pagerops devicepagerops = { 79 dev_pager_init, 80 dev_pager_alloc, 81 dev_pager_dealloc, 82 dev_pager_getpages, 83 dev_pager_putpages, 84 dev_pager_haspage, 85 NULL 86 }; 87 88 static void 89 dev_pager_init(void) 90 { 91 TAILQ_INIT(&dev_pager_object_list); 92 TAILQ_INIT(&dev_freepages_list); 93 } 94 95 static vm_object_t 96 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff) 97 { 98 cdev_t dev; 99 vm_object_t object; 100 unsigned int npages; 101 vm_offset_t off; 102 103 /* 104 * Make sure this device can be mapped. 105 */ 106 dev = handle; 107 108 /* 109 * Offset should be page aligned. 110 */ 111 if (foff & PAGE_MASK) 112 return (NULL); 113 114 size = round_page(size); 115 116 /* 117 * Check that the specified range of the device allows the desired 118 * protection. 119 * 120 * XXX assumes VM_PROT_* == PROT_* 121 */ 122 npages = OFF_TO_IDX(size); 123 for (off = foff; npages--; off += PAGE_SIZE) { 124 if (dev_dmmap(dev, off, (int)prot) == -1) 125 return (NULL); 126 } 127 128 /* 129 * Lock to prevent object creation race condition. 130 */ 131 while (dev_pager_alloc_lock) { 132 dev_pager_alloc_lock_want++; 133 tsleep(&dev_pager_alloc_lock, 0, "dvpall", 0); 134 dev_pager_alloc_lock_want--; 135 } 136 dev_pager_alloc_lock = 1; 137 138 /* 139 * Look up pager, creating as necessary. 140 */ 141 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 142 if (object == NULL) { 143 /* 144 * Allocate object and associate it with the pager. 145 */ 146 object = vm_object_allocate(OBJT_DEVICE, 147 OFF_TO_IDX(foff + size)); 148 object->handle = handle; 149 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 150 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list); 151 } else { 152 /* 153 * Gain a reference to the object. 154 */ 155 vm_object_reference(object); 156 if (OFF_TO_IDX(foff + size) > object->size) 157 object->size = OFF_TO_IDX(foff + size); 158 } 159 160 dev_pager_alloc_lock = 0; 161 if (dev_pager_alloc_lock_want) 162 wakeup(&dev_pager_alloc_lock); 163 164 return (object); 165 } 166 167 static void 168 dev_pager_dealloc(vm_object_t object) 169 { 170 vm_page_t m; 171 172 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 173 /* 174 * Free up our fake pages. 175 */ 176 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 177 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 178 dev_pager_putfake(m); 179 } 180 } 181 182 static int 183 dev_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 184 { 185 vm_offset_t offset; 186 vm_paddr_t paddr; 187 vm_page_t page; 188 cdev_t dev; 189 int prot; 190 int i; 191 192 dev = object->handle; 193 offset = m[reqpage]->pindex; 194 prot = PROT_READ; /* XXX should pass in? */ 195 196 paddr = pmap_phys_address(dev_dmmap(dev, (vm_offset_t) offset << PAGE_SHIFT, prot)); 197 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error")); 198 199 if (m[reqpage]->flags & PG_FICTITIOUS) { 200 /* 201 * If the passed in reqpage page is a fake page, update it 202 * with the new physical address. 203 */ 204 m[reqpage]->phys_addr = paddr; 205 m[reqpage]->valid = VM_PAGE_BITS_ALL; 206 } else { 207 /* 208 * Replace the passed in reqpage page with our own fake page 209 * and free up all the original pages. 210 */ 211 page = dev_pager_getfake(paddr); 212 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 213 crit_enter(); 214 vm_page_free(m[reqpage]); 215 vm_page_insert(page, object, offset); 216 crit_exit(); 217 } 218 for (i = 0; i < count; i++) { 219 if (i != reqpage) 220 vm_page_free(m[i]); 221 } 222 return (VM_PAGER_OK); 223 } 224 225 static void 226 dev_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 227 int *rtvals) 228 { 229 panic("dev_pager_putpage called"); 230 } 231 232 static boolean_t 233 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 234 int *after) 235 { 236 if (before != NULL) 237 *before = 0; 238 if (after != NULL) 239 *after = 0; 240 return (TRUE); 241 } 242 243 static vm_page_t 244 dev_pager_getfake(vm_paddr_t paddr) 245 { 246 vm_page_t m; 247 248 if ((m = TAILQ_FIRST(&dev_freepages_list)) != NULL) { 249 TAILQ_REMOVE(&dev_freepages_list, m, pageq); 250 } else { 251 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK); 252 } 253 bzero(m, sizeof(*m)); 254 255 m->flags = PG_BUSY | PG_FICTITIOUS; 256 m->valid = VM_PAGE_BITS_ALL; 257 m->dirty = 0; 258 m->busy = 0; 259 m->queue = PQ_NONE; 260 m->object = NULL; 261 262 m->wire_count = 1; 263 m->hold_count = 0; 264 m->phys_addr = paddr; 265 266 return (m); 267 } 268 269 /* 270 * Synthesized VM pages must be structurally stable for lockless lookups to 271 * work properly. 272 */ 273 static void 274 dev_pager_putfake(vm_page_t m) 275 { 276 if (!(m->flags & PG_FICTITIOUS)) 277 panic("dev_pager_putfake: bad page"); 278 KKASSERT(m->object == NULL); 279 TAILQ_INSERT_HEAD(&dev_freepages_list, m, pageq); 280 } 281 282