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 d_mmap_t *mapfunc; 107 vm_object_t object; 108 vm_pindex_t pindex; 109 unsigned int npages; 110 vm_paddr_t paddr; 111 vm_offset_t off; 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 mtx_lock(&Giant); 127 mapfunc = devsw(dev)->d_mmap; 128 if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) { 129 printf("obsolete map function %p\n", (void *)mapfunc); 130 mtx_unlock(&Giant); 131 return (NULL); 132 } 133 134 /* 135 * Check that the specified range of the device allows the desired 136 * protection. 137 * 138 * XXX assumes VM_PROT_* == PROT_* 139 */ 140 npages = OFF_TO_IDX(size); 141 for (off = foff; npages--; off += PAGE_SIZE) 142 if ((*mapfunc)(dev, off, &paddr, (int)prot) != 0) { 143 mtx_unlock(&Giant); 144 return (NULL); 145 } 146 147 /* 148 * Lock to prevent object creation race condition. 149 */ 150 sx_xlock(&dev_pager_sx); 151 152 /* 153 * Look up pager, creating as necessary. 154 */ 155 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 156 if (object == NULL) { 157 /* 158 * Allocate object and associate it with the pager. 159 */ 160 object = vm_object_allocate(OBJT_DEVICE, pindex); 161 object->handle = handle; 162 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 163 mtx_lock(&dev_pager_mtx); 164 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list); 165 mtx_unlock(&dev_pager_mtx); 166 } else { 167 /* 168 * Gain a reference to the object. 169 */ 170 vm_object_reference(object); 171 if (pindex > object->size) 172 object->size = pindex; 173 } 174 175 sx_xunlock(&dev_pager_sx); 176 mtx_unlock(&Giant); 177 return (object); 178 } 179 180 static void 181 dev_pager_dealloc(object) 182 vm_object_t object; 183 { 184 vm_page_t m; 185 186 mtx_lock(&dev_pager_mtx); 187 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 188 mtx_unlock(&dev_pager_mtx); 189 /* 190 * Free up our fake pages. 191 */ 192 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 193 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 194 dev_pager_putfake(m); 195 } 196 } 197 198 static int 199 dev_pager_getpages(object, m, count, reqpage) 200 vm_object_t object; 201 vm_page_t *m; 202 int count; 203 int reqpage; 204 { 205 vm_pindex_t offset; 206 vm_paddr_t paddr; 207 vm_page_t page; 208 struct cdev *dev; 209 int i, ret; 210 d_mmap_t *mapfunc; 211 int prot; 212 213 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 214 dev = object->handle; 215 offset = m[reqpage]->pindex; 216 VM_OBJECT_UNLOCK(object); 217 mtx_lock(&Giant); 218 prot = PROT_READ; /* XXX should pass in? */ 219 mapfunc = devsw(dev)->d_mmap; 220 221 if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) 222 panic("dev_pager_getpage: no map function"); 223 224 ret = (*mapfunc)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot); 225 KASSERT(ret == 0, ("dev_pager_getpage: map function returns error")); 226 mtx_unlock(&Giant); 227 228 if ((m[reqpage]->flags & PG_FICTITIOUS) != 0) { 229 /* 230 * If the passed in reqpage page is a fake page, update it with 231 * the new physical address. 232 */ 233 dev_pager_updatefake(m[reqpage], paddr); 234 VM_OBJECT_LOCK(object); 235 if (count > 1) { 236 vm_page_lock_queues(); 237 for (i = 0; i < count; i++) { 238 if (i != reqpage) 239 vm_page_free(m[i]); 240 } 241 vm_page_unlock_queues(); 242 } 243 } else { 244 /* 245 * Replace the passed in reqpage page with our own fake page and 246 * free up the all of the original pages. 247 */ 248 page = dev_pager_getfake(paddr); 249 VM_OBJECT_LOCK(object); 250 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 251 vm_page_lock_queues(); 252 for (i = 0; i < count; i++) 253 vm_page_free(m[i]); 254 vm_page_unlock_queues(); 255 vm_page_insert(page, object, offset); 256 m[reqpage] = page; 257 } 258 259 return (VM_PAGER_OK); 260 } 261 262 static void 263 dev_pager_putpages(object, m, count, sync, rtvals) 264 vm_object_t object; 265 vm_page_t *m; 266 int count; 267 boolean_t sync; 268 int *rtvals; 269 { 270 panic("dev_pager_putpage called"); 271 } 272 273 static boolean_t 274 dev_pager_haspage(object, pindex, before, after) 275 vm_object_t object; 276 vm_pindex_t pindex; 277 int *before; 278 int *after; 279 { 280 if (before != NULL) 281 *before = 0; 282 if (after != NULL) 283 *after = 0; 284 return (TRUE); 285 } 286 287 static vm_page_t 288 dev_pager_getfake(paddr) 289 vm_paddr_t paddr; 290 { 291 vm_page_t m; 292 293 m = uma_zalloc(fakepg_zone, M_WAITOK); 294 295 m->flags = PG_BUSY | PG_FICTITIOUS; 296 m->valid = VM_PAGE_BITS_ALL; 297 m->dirty = 0; 298 m->busy = 0; 299 m->queue = PQ_NONE; 300 m->object = NULL; 301 302 m->wire_count = 1; 303 m->hold_count = 0; 304 m->phys_addr = paddr; 305 306 return (m); 307 } 308 309 static void 310 dev_pager_putfake(m) 311 vm_page_t m; 312 { 313 if (!(m->flags & PG_FICTITIOUS)) 314 panic("dev_pager_putfake: bad page"); 315 uma_zfree(fakepg_zone, m); 316 } 317 318 static void 319 dev_pager_updatefake(m, paddr) 320 vm_page_t m; 321 vm_paddr_t paddr; 322 { 323 if (!(m->flags & PG_FICTITIOUS)) 324 panic("dev_pager_updatefake: bad page"); 325 m->phys_addr = paddr; 326 } 327