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 * $Id: device_pager.c,v 1.12 1995/07/13 08:48:10 davidg Exp $ 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/conf.h> 45 #include <sys/mman.h> 46 #include <sys/malloc.h> 47 #include <sys/proc.h> 48 49 #include <vm/vm.h> 50 #include <vm/vm_kern.h> 51 #include <vm/vm_page.h> 52 #include <vm/vm_pager.h> 53 #include <vm/device_pager.h> 54 55 struct pagerlst dev_pager_object_list; /* list of device pager objects */ 56 TAILQ_HEAD(, vm_page) dev_pager_fakelist; /* list of available vm_page_t's */ 57 58 static vm_page_t dev_pager_getfake __P((vm_offset_t)); 59 static void dev_pager_putfake __P((vm_page_t)); 60 61 static int dev_pager_alloc_lock, dev_pager_alloc_lock_want; 62 63 struct pagerops devicepagerops = { 64 dev_pager_init, 65 dev_pager_alloc, 66 dev_pager_dealloc, 67 dev_pager_getpages, 68 dev_pager_putpages, 69 dev_pager_haspage, 70 NULL 71 }; 72 73 void 74 dev_pager_init() 75 { 76 TAILQ_INIT(&dev_pager_object_list); 77 TAILQ_INIT(&dev_pager_fakelist); 78 } 79 80 vm_object_t 81 dev_pager_alloc(handle, size, prot, foff) 82 void *handle; 83 vm_size_t size; 84 vm_prot_t prot; 85 vm_offset_t foff; 86 { 87 dev_t dev; 88 int (*mapfunc) (); 89 vm_object_t object; 90 unsigned int npages, off; 91 92 /* 93 * Make sure this device can be mapped. 94 */ 95 dev = (dev_t) (u_long) handle; 96 mapfunc = cdevsw[major(dev)].d_mmap; 97 if (mapfunc == NULL || mapfunc == nullop) 98 return (NULL); 99 100 /* 101 * Offset should be page aligned. 102 */ 103 if (foff & (PAGE_SIZE - 1)) 104 return (NULL); 105 106 /* 107 * Check that the specified range of the device allows the desired 108 * protection. 109 * 110 * XXX assumes VM_PROT_* == PROT_* 111 */ 112 npages = atop(round_page(size)); 113 for (off = foff; npages--; off += PAGE_SIZE) 114 if ((*mapfunc) (dev, off, (int) prot) == -1) 115 return (NULL); 116 117 /* 118 * Lock to prevent object creation race contion. 119 */ 120 while (dev_pager_alloc_lock) { 121 dev_pager_alloc_lock_want++; 122 tsleep(&dev_pager_alloc_lock, PVM, "dvpall", 0); 123 dev_pager_alloc_lock_want--; 124 } 125 dev_pager_alloc_lock = 1; 126 127 /* 128 * Look up pager, creating as necessary. 129 */ 130 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 131 if (object == NULL) { 132 /* 133 * Allocate object and associate it with the pager. 134 */ 135 object = vm_object_allocate(OBJT_DEVICE, foff + size); 136 object->handle = handle; 137 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 138 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list); 139 } else { 140 /* 141 * Gain a reference to the object. 142 */ 143 vm_object_reference(object); 144 if (foff + size > object->size) 145 object->size = foff + size; 146 } 147 148 dev_pager_alloc_lock = 0; 149 if (dev_pager_alloc_lock_want) 150 wakeup(&dev_pager_alloc_lock); 151 152 return (object); 153 } 154 155 void 156 dev_pager_dealloc(object) 157 vm_object_t object; 158 { 159 vm_page_t m; 160 161 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 162 /* 163 * Free up our fake pages. 164 */ 165 while ((m = object->un_pager.devp.devp_pglist.tqh_first) != 0) { 166 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 167 dev_pager_putfake(m); 168 } 169 } 170 171 int 172 dev_pager_getpages(object, m, count, reqpage) 173 vm_object_t object; 174 vm_page_t *m; 175 int count; 176 int reqpage; 177 { 178 vm_offset_t offset, paddr; 179 vm_page_t page; 180 dev_t dev; 181 int i, s; 182 int (*mapfunc) (), prot; 183 184 dev = (dev_t) (u_long) object->handle; 185 offset = m[reqpage]->offset + object->paging_offset; 186 prot = PROT_READ; /* XXX should pass in? */ 187 mapfunc = cdevsw[major(dev)].d_mmap; 188 189 if (mapfunc == NULL || mapfunc == nullop) 190 panic("dev_pager_getpage: no map function"); 191 192 paddr = pmap_phys_address((*mapfunc) ((dev_t) dev, (int) offset, prot)); 193 #ifdef DIAGNOSTIC 194 if (paddr == -1) 195 panic("dev_pager_getpage: map function returns error"); 196 #endif 197 /* 198 * Replace the passed in reqpage page with our own fake page and free up the 199 * all of the original pages. 200 */ 201 page = dev_pager_getfake(paddr); 202 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 203 for (i = 0; i < count; i++) { 204 PAGE_WAKEUP(m[i]); 205 vm_page_free(m[i]); 206 } 207 s = splhigh(); 208 vm_page_insert(page, object, offset); 209 splx(s); 210 211 return (VM_PAGER_OK); 212 } 213 214 int 215 dev_pager_putpages(object, m, count, sync, rtvals) 216 vm_object_t object; 217 vm_page_t *m; 218 int count; 219 boolean_t sync; 220 int *rtvals; 221 { 222 panic("dev_pager_putpage called"); 223 } 224 225 boolean_t 226 dev_pager_haspage(object, offset, before, after) 227 vm_object_t object; 228 vm_offset_t offset; 229 int *before; 230 int *after; 231 { 232 if (before != NULL) 233 *before = 0; 234 if (after != NULL) 235 *after = 0; 236 return (TRUE); 237 } 238 239 static vm_page_t 240 dev_pager_getfake(paddr) 241 vm_offset_t paddr; 242 { 243 vm_page_t m; 244 int i; 245 246 if (dev_pager_fakelist.tqh_first == NULL) { 247 m = (vm_page_t) malloc(PAGE_SIZE * 2, M_VMPGDATA, M_WAITOK); 248 for (i = (PAGE_SIZE * 2) / sizeof(*m); i > 0; i--) { 249 TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq); 250 m++; 251 } 252 } 253 m = dev_pager_fakelist.tqh_first; 254 TAILQ_REMOVE(&dev_pager_fakelist, m, pageq); 255 256 m->flags = PG_BUSY | PG_FICTITIOUS; 257 m->valid = VM_PAGE_BITS_ALL; 258 m->dirty = 0; 259 m->busy = 0; 260 m->bmapped = 0; 261 262 m->wire_count = 1; 263 m->phys_addr = paddr; 264 265 return (m); 266 } 267 268 static void 269 dev_pager_putfake(m) 270 vm_page_t m; 271 { 272 if (!(m->flags & PG_FICTITIOUS)) 273 panic("dev_pager_putfake: bad page"); 274 TAILQ_INSERT_TAIL(&dev_pager_fakelist, m, pageq); 275 } 276