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