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 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)device_pager.c 8.1 (Berkeley) 6/11/93 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/conf.h> 43 #include <sys/lock.h> 44 #include <sys/proc.h> 45 #include <sys/mutex.h> 46 #include <sys/mman.h> 47 #include <sys/sx.h> 48 49 #include <vm/vm.h> 50 #include <vm/vm_object.h> 51 #include <vm/vm_page.h> 52 #include <vm/vm_pager.h> 53 #include <vm/uma.h> 54 55 static void dev_pager_init(void); 56 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 57 vm_ooffset_t); 58 static void dev_pager_dealloc(vm_object_t); 59 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int); 60 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, 61 boolean_t, int *); 62 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *, 63 int *); 64 65 /* list of device pager objects */ 66 static struct pagerlst dev_pager_object_list; 67 /* protect against object creation */ 68 static struct sx dev_pager_sx; 69 /* protect list manipulation */ 70 static struct mtx dev_pager_mtx; 71 72 73 static uma_zone_t fakepg_zone; 74 75 static vm_page_t dev_pager_getfake(vm_paddr_t); 76 static void dev_pager_putfake(vm_page_t); 77 static void dev_pager_updatefake(vm_page_t, vm_paddr_t); 78 79 struct pagerops devicepagerops = { 80 .pgo_init = dev_pager_init, 81 .pgo_alloc = dev_pager_alloc, 82 .pgo_dealloc = dev_pager_dealloc, 83 .pgo_getpages = dev_pager_getpages, 84 .pgo_putpages = dev_pager_putpages, 85 .pgo_haspage = dev_pager_haspage, 86 }; 87 88 static void 89 dev_pager_init() 90 { 91 TAILQ_INIT(&dev_pager_object_list); 92 sx_init(&dev_pager_sx, "dev_pager create"); 93 mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF); 94 fakepg_zone = uma_zcreate("DP fakepg", sizeof(struct vm_page), 95 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 96 UMA_ZONE_NOFREE|UMA_ZONE_VM); 97 } 98 99 /* 100 * MPSAFE 101 */ 102 static vm_object_t 103 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff) 104 { 105 struct cdev *dev; 106 vm_object_t object; 107 vm_pindex_t pindex; 108 unsigned int npages; 109 vm_paddr_t paddr; 110 vm_offset_t off; 111 struct cdevsw *csw; 112 113 /* 114 * Offset should be page aligned. 115 */ 116 if (foff & PAGE_MASK) 117 return (NULL); 118 119 size = round_page(size); 120 pindex = OFF_TO_IDX(foff + size); 121 122 /* 123 * Make sure this device can be mapped. 124 */ 125 dev = handle; 126 csw = dev_refthread(dev); 127 if (csw == NULL) 128 return (NULL); 129 mtx_lock(&Giant); 130 131 /* 132 * Check that the specified range of the device allows the desired 133 * protection. 134 * 135 * XXX assumes VM_PROT_* == PROT_* 136 */ 137 npages = OFF_TO_IDX(size); 138 for (off = foff; npages--; off += PAGE_SIZE) 139 if ((*csw->d_mmap)(dev, off, &paddr, (int)prot) != 0) { 140 mtx_unlock(&Giant); 141 dev_relthread(dev); 142 return (NULL); 143 } 144 145 /* 146 * Lock to prevent object creation race condition. 147 */ 148 sx_xlock(&dev_pager_sx); 149 150 /* 151 * Look up pager, creating as necessary. 152 */ 153 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 154 if (object == NULL) { 155 /* 156 * Allocate object and associate it with the pager. 157 */ 158 object = vm_object_allocate(OBJT_DEVICE, pindex); 159 object->handle = handle; 160 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 161 mtx_lock(&dev_pager_mtx); 162 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list); 163 mtx_unlock(&dev_pager_mtx); 164 } else { 165 /* 166 * Gain a reference to the object. 167 */ 168 vm_object_reference(object); 169 if (pindex > object->size) 170 object->size = pindex; 171 } 172 173 sx_xunlock(&dev_pager_sx); 174 mtx_unlock(&Giant); 175 dev_relthread(dev); 176 return (object); 177 } 178 179 static void 180 dev_pager_dealloc(object) 181 vm_object_t object; 182 { 183 vm_page_t m; 184 185 mtx_lock(&dev_pager_mtx); 186 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 187 mtx_unlock(&dev_pager_mtx); 188 /* 189 * Free up our fake pages. 190 */ 191 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 192 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 193 dev_pager_putfake(m); 194 } 195 } 196 197 static int 198 dev_pager_getpages(object, m, count, reqpage) 199 vm_object_t object; 200 vm_page_t *m; 201 int count; 202 int reqpage; 203 { 204 vm_pindex_t offset; 205 vm_paddr_t paddr; 206 vm_page_t page; 207 struct cdev *dev; 208 int i, ret; 209 int prot; 210 struct cdevsw *csw; 211 212 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 213 dev = object->handle; 214 offset = m[reqpage]->pindex; 215 VM_OBJECT_UNLOCK(object); 216 csw = dev_refthread(dev); 217 if (csw == NULL) 218 panic("dev_pager_getpage: no cdevsw"); 219 mtx_lock(&Giant); 220 prot = PROT_READ; /* XXX should pass in? */ 221 222 ret = (*csw->d_mmap)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot); 223 KASSERT(ret == 0, ("dev_pager_getpage: map function returns error")); 224 mtx_unlock(&Giant); 225 dev_relthread(dev); 226 227 if ((m[reqpage]->flags & PG_FICTITIOUS) != 0) { 228 /* 229 * If the passed in reqpage page is a fake page, update it with 230 * the new physical address. 231 */ 232 VM_OBJECT_LOCK(object); 233 dev_pager_updatefake(m[reqpage], paddr); 234 if (count > 1) { 235 vm_page_lock_queues(); 236 for (i = 0; i < count; i++) { 237 if (i != reqpage) 238 vm_page_free(m[i]); 239 } 240 vm_page_unlock_queues(); 241 } 242 } else { 243 /* 244 * Replace the passed in reqpage page with our own fake page and 245 * free up the all of the original pages. 246 */ 247 page = dev_pager_getfake(paddr); 248 VM_OBJECT_LOCK(object); 249 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 250 vm_page_lock_queues(); 251 for (i = 0; i < count; i++) 252 vm_page_free(m[i]); 253 vm_page_unlock_queues(); 254 vm_page_insert(page, object, offset); 255 m[reqpage] = page; 256 } 257 258 return (VM_PAGER_OK); 259 } 260 261 static void 262 dev_pager_putpages(object, m, count, sync, rtvals) 263 vm_object_t object; 264 vm_page_t *m; 265 int count; 266 boolean_t sync; 267 int *rtvals; 268 { 269 panic("dev_pager_putpage called"); 270 } 271 272 static boolean_t 273 dev_pager_haspage(object, pindex, before, after) 274 vm_object_t object; 275 vm_pindex_t pindex; 276 int *before; 277 int *after; 278 { 279 if (before != NULL) 280 *before = 0; 281 if (after != NULL) 282 *after = 0; 283 return (TRUE); 284 } 285 286 /* 287 * Instantiate a fictitious page. Unlike physical memory pages, only 288 * the machine-independent fields must be initialized. 289 */ 290 static vm_page_t 291 dev_pager_getfake(paddr) 292 vm_paddr_t paddr; 293 { 294 vm_page_t m; 295 296 m = uma_zalloc(fakepg_zone, M_WAITOK); 297 298 m->flags = PG_BUSY | PG_FICTITIOUS; 299 m->valid = VM_PAGE_BITS_ALL; 300 m->dirty = 0; 301 m->busy = 0; 302 m->queue = PQ_NONE; 303 m->object = NULL; 304 305 m->wire_count = 1; 306 m->hold_count = 0; 307 m->phys_addr = paddr; 308 309 return (m); 310 } 311 312 static void 313 dev_pager_putfake(m) 314 vm_page_t m; 315 { 316 if (!(m->flags & PG_FICTITIOUS)) 317 panic("dev_pager_putfake: bad page"); 318 uma_zfree(fakepg_zone, m); 319 } 320 321 static void 322 dev_pager_updatefake(m, paddr) 323 vm_page_t m; 324 vm_paddr_t paddr; 325 { 326 if (!(m->flags & PG_FICTITIOUS)) 327 panic("dev_pager_updatefake: bad page"); 328 m->phys_addr = paddr; 329 m->valid = VM_PAGE_BITS_ALL; 330 } 331