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 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/conf.h> 47 #include <sys/lock.h> 48 #include <sys/proc.h> 49 #include <sys/mutex.h> 50 #include <sys/mman.h> 51 #include <sys/sx.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/uma.h> 58 59 static void dev_pager_init(void); 60 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 61 vm_ooffset_t); 62 static void dev_pager_dealloc(vm_object_t); 63 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int); 64 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, 65 boolean_t, int *); 66 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *, 67 int *); 68 69 /* list of device pager objects */ 70 static struct pagerlst dev_pager_object_list; 71 /* protect against object creation */ 72 static struct sx dev_pager_sx; 73 /* protect list manipulation */ 74 static struct mtx dev_pager_mtx; 75 76 77 static uma_zone_t fakepg_zone; 78 79 static vm_page_t dev_pager_getfake(vm_paddr_t); 80 static void dev_pager_putfake(vm_page_t); 81 82 struct pagerops devicepagerops = { 83 dev_pager_init, 84 dev_pager_alloc, 85 dev_pager_dealloc, 86 dev_pager_getpages, 87 dev_pager_putpages, 88 dev_pager_haspage, 89 NULL 90 }; 91 92 static void 93 dev_pager_init() 94 { 95 TAILQ_INIT(&dev_pager_object_list); 96 sx_init(&dev_pager_sx, "dev_pager create"); 97 mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF); 98 fakepg_zone = uma_zcreate("DP fakepg", sizeof(struct vm_page), 99 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 100 } 101 102 /* 103 * MPSAFE 104 */ 105 static vm_object_t 106 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff) 107 { 108 dev_t dev; 109 d_mmap_t *mapfunc; 110 vm_object_t object; 111 unsigned int npages; 112 vm_paddr_t paddr; 113 vm_offset_t off; 114 115 /* 116 * Offset should be page aligned. 117 */ 118 if (foff & PAGE_MASK) 119 return (NULL); 120 121 size = round_page(size); 122 123 /* 124 * Make sure this device can be mapped. 125 */ 126 dev = handle; 127 mtx_lock(&Giant); 128 mapfunc = devsw(dev)->d_mmap; 129 if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) { 130 printf("obsolete map function %p\n", (void *)mapfunc); 131 mtx_unlock(&Giant); 132 return (NULL); 133 } 134 135 /* 136 * Check that the specified range of the device allows the desired 137 * protection. 138 * 139 * XXX assumes VM_PROT_* == PROT_* 140 */ 141 npages = OFF_TO_IDX(size); 142 for (off = foff; npages--; off += PAGE_SIZE) 143 if ((*mapfunc)(dev, off, &paddr, (int)prot) != 0) { 144 mtx_unlock(&Giant); 145 return (NULL); 146 } 147 148 /* 149 * Lock to prevent object creation race condition. 150 */ 151 sx_xlock(&dev_pager_sx); 152 153 /* 154 * Look up pager, creating as necessary. 155 */ 156 object = vm_pager_object_lookup(&dev_pager_object_list, handle); 157 if (object == NULL) { 158 /* 159 * Allocate object and associate it with the pager. 160 */ 161 object = vm_object_allocate(OBJT_DEVICE, 162 OFF_TO_IDX(foff + size)); 163 object->handle = handle; 164 TAILQ_INIT(&object->un_pager.devp.devp_pglist); 165 mtx_lock(&dev_pager_mtx); 166 TAILQ_INSERT_TAIL(&dev_pager_object_list, object, pager_object_list); 167 mtx_unlock(&dev_pager_mtx); 168 } else { 169 /* 170 * Gain a reference to the object. 171 */ 172 vm_object_reference(object); 173 if (OFF_TO_IDX(foff + size) > object->size) 174 object->size = OFF_TO_IDX(foff + size); 175 } 176 177 sx_xunlock(&dev_pager_sx); 178 mtx_unlock(&Giant); 179 return (object); 180 } 181 182 static void 183 dev_pager_dealloc(object) 184 vm_object_t object; 185 { 186 vm_page_t m; 187 188 mtx_lock(&dev_pager_mtx); 189 TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list); 190 mtx_unlock(&dev_pager_mtx); 191 /* 192 * Free up our fake pages. 193 */ 194 while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) { 195 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq); 196 dev_pager_putfake(m); 197 } 198 } 199 200 static int 201 dev_pager_getpages(object, m, count, reqpage) 202 vm_object_t object; 203 vm_page_t *m; 204 int count; 205 int reqpage; 206 { 207 vm_pindex_t offset; 208 vm_paddr_t paddr; 209 vm_page_t page; 210 dev_t dev; 211 int i, ret; 212 d_mmap_t *mapfunc; 213 int prot; 214 215 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 216 dev = object->handle; 217 offset = m[reqpage]->pindex; 218 VM_OBJECT_UNLOCK(object); 219 prot = PROT_READ; /* XXX should pass in? */ 220 mapfunc = devsw(dev)->d_mmap; 221 222 if (mapfunc == NULL || mapfunc == (d_mmap_t *)nullop) 223 panic("dev_pager_getpage: no map function"); 224 225 ret = (*mapfunc)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot); 226 KASSERT(ret == 0, ("dev_pager_getpage: map function returns error")); 227 /* 228 * Replace the passed in reqpage page with our own fake page and 229 * free up the all of the original pages. 230 */ 231 page = dev_pager_getfake(paddr); 232 VM_OBJECT_LOCK(object); 233 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq); 234 vm_page_lock_queues(); 235 for (i = 0; i < count; i++) 236 vm_page_free(m[i]); 237 vm_page_unlock_queues(); 238 vm_page_insert(page, object, offset); 239 240 return (VM_PAGER_OK); 241 } 242 243 static void 244 dev_pager_putpages(object, m, count, sync, rtvals) 245 vm_object_t object; 246 vm_page_t *m; 247 int count; 248 boolean_t sync; 249 int *rtvals; 250 { 251 panic("dev_pager_putpage called"); 252 } 253 254 static boolean_t 255 dev_pager_haspage(object, pindex, before, after) 256 vm_object_t object; 257 vm_pindex_t pindex; 258 int *before; 259 int *after; 260 { 261 if (before != NULL) 262 *before = 0; 263 if (after != NULL) 264 *after = 0; 265 return (TRUE); 266 } 267 268 static vm_page_t 269 dev_pager_getfake(paddr) 270 vm_paddr_t paddr; 271 { 272 vm_page_t m; 273 274 m = uma_zalloc(fakepg_zone, M_WAITOK); 275 276 m->flags = PG_BUSY | PG_FICTITIOUS; 277 m->valid = VM_PAGE_BITS_ALL; 278 m->dirty = 0; 279 m->busy = 0; 280 m->queue = PQ_NONE; 281 m->object = NULL; 282 283 m->wire_count = 1; 284 m->hold_count = 0; 285 m->phys_addr = paddr; 286 287 return (m); 288 } 289 290 static void 291 dev_pager_putfake(m) 292 vm_page_t m; 293 { 294 if (!(m->flags & PG_FICTITIOUS)) 295 panic("dev_pager_putfake: bad page"); 296 uma_zfree(fakepg_zone, m); 297 } 298