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_dealloc (vm_object_t); 60 static int dev_pager_getpage (vm_object_t, vm_page_t *, int); 61 static void dev_pager_putpages (vm_object_t, vm_page_t *, int, 62 boolean_t, int *); 63 static boolean_t dev_pager_haspage (vm_object_t, vm_pindex_t); 64 65 /* list of device pager objects */ 66 static TAILQ_HEAD(, vm_page) dev_freepages_list = 67 TAILQ_HEAD_INITIALIZER(dev_freepages_list); 68 static MALLOC_DEFINE(M_FICTITIOUS_PAGES, "device-mapped pages", "Device mapped pages"); 69 70 static vm_page_t dev_pager_getfake (vm_paddr_t); 71 static void dev_pager_putfake (vm_page_t); 72 73 static int dev_pager_alloc_lock, dev_pager_alloc_lock_want; 74 75 struct pagerops devicepagerops = { 76 dev_pager_dealloc, 77 dev_pager_getpage, 78 dev_pager_putpages, 79 dev_pager_haspage 80 }; 81 82 vm_object_t 83 dev_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff) 84 { 85 cdev_t dev; 86 vm_object_t object; 87 unsigned int npages; 88 vm_offset_t off; 89 90 /* 91 * Make sure this device can be mapped. 92 */ 93 dev = handle; 94 95 /* 96 * Offset should be page aligned. 97 */ 98 if (foff & PAGE_MASK) 99 return (NULL); 100 101 size = round_page64(size); 102 103 /* 104 * Check that the specified range of the device allows the desired 105 * protection. 106 * 107 * XXX assumes VM_PROT_* == PROT_* 108 */ 109 npages = OFF_TO_IDX(size); 110 for (off = foff; npages--; off += PAGE_SIZE) { 111 if (dev_dmmap(dev, off, (int)prot) == -1) 112 return (NULL); 113 } 114 115 /* 116 * Lock to prevent object creation race condition. 117 */ 118 while (dev_pager_alloc_lock) { 119 dev_pager_alloc_lock_want++; 120 tsleep(&dev_pager_alloc_lock, 0, "dvpall", 0); 121 dev_pager_alloc_lock_want--; 122 } 123 dev_pager_alloc_lock = 1; 124 125 /* 126 * Look up pager, creating as necessary. 127 */ 128 object = dev->si_object; 129 if (object == NULL) { 130 /* 131 * Allocate object and associate it with the pager. 132 */ 133 object = vm_object_allocate(OBJT_DEVICE, 134 OFF_TO_IDX(foff + size)); 135 object->handle = handle; 136 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 137 dev->si_object = object; 138 } else { 139 /* 140 * Gain a reference to the object. 141 */ 142 vm_object_reference(object); 143 if (OFF_TO_IDX(foff + size) > object->size) 144 object->size = OFF_TO_IDX(foff + size); 145 } 146 147 dev_pager_alloc_lock = 0; 148 if (dev_pager_alloc_lock_want) 149 wakeup(&dev_pager_alloc_lock); 150 151 return (object); 152 } 153 154 static void 155 dev_pager_dealloc(vm_object_t object) 156 { 157 vm_page_t m; 158 cdev_t dev; 159 160 if ((dev = object->handle) != NULL) { 161 KKASSERT(dev->si_object); 162 dev->si_object = NULL; 163 } 164 KKASSERT(object->swblock_count == 0); 165 166 /* 167 * Free up our fake pages. 168 */ 169 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 170 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 171 dev_pager_putfake(m); 172 } 173 } 174 175 static int 176 dev_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess) 177 { 178 vm_offset_t offset; 179 vm_paddr_t paddr; 180 vm_page_t page; 181 cdev_t dev; 182 int prot; 183 184 page = *mpp; 185 dev = object->handle; 186 offset = page->pindex; 187 prot = PROT_READ; /* XXX should pass in? */ 188 189 paddr = pmap_phys_address( 190 dev_dmmap(dev, (vm_offset_t)offset << PAGE_SHIFT, prot)); 191 KASSERT(paddr != -1,("dev_pager_getpage: map function returns error")); 192 193 if (page->flags & PG_FICTITIOUS) { 194 /* 195 * If the passed in reqpage page is a fake page, update it 196 * with the new physical address. 197 */ 198 page->phys_addr = paddr; 199 page->valid = VM_PAGE_BITS_ALL; 200 } else { 201 /* 202 * Replace the passed in reqpage page with our own fake page 203 * and free up all the original pages. 204 */ 205 page = dev_pager_getfake(paddr); 206 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 207 crit_enter(); 208 vm_page_free(*mpp); 209 vm_page_insert(page, object, offset); 210 crit_exit(); 211 } 212 return (VM_PAGER_OK); 213 } 214 215 static void 216 dev_pager_putpages(vm_object_t object, vm_page_t *m, 217 int count, boolean_t sync, int *rtvals) 218 { 219 panic("dev_pager_putpage called"); 220 } 221 222 static boolean_t 223 dev_pager_haspage(vm_object_t object, vm_pindex_t pindex) 224 { 225 return (TRUE); 226 } 227 228 static vm_page_t 229 dev_pager_getfake(vm_paddr_t paddr) 230 { 231 vm_page_t m; 232 233 if ((m = TAILQ_FIRST(&dev_freepages_list)) != NULL) { 234 TAILQ_REMOVE(&dev_freepages_list, m, pageq); 235 } else { 236 m = kmalloc(sizeof(*m), M_FICTITIOUS_PAGES, M_WAITOK); 237 } 238 bzero(m, sizeof(*m)); 239 240 m->flags = PG_BUSY | PG_FICTITIOUS; 241 m->valid = VM_PAGE_BITS_ALL; 242 m->dirty = 0; 243 m->busy = 0; 244 m->queue = PQ_NONE; 245 m->object = NULL; 246 247 m->wire_count = 1; 248 m->hold_count = 0; 249 m->phys_addr = paddr; 250 251 return (m); 252 } 253 254 /* 255 * Synthesized VM pages must be structurally stable for lockless lookups to 256 * work properly. 257 */ 258 static void 259 dev_pager_putfake(vm_page_t m) 260 { 261 if (!(m->flags & PG_FICTITIOUS)) 262 panic("dev_pager_putfake: bad page"); 263 KKASSERT(m->object == NULL); 264 TAILQ_INSERT_HEAD(&dev_freepages_list, m, pageq); 265 } 266 267