1 /* $NetBSD: uvm_device.c,v 1.56 2009/06/20 19:24:27 mrg Exp $ */ 2 3 /* 4 * 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Charles D. Cranor and 19 * Washington University. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 * 34 * from: Id: uvm_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp 35 */ 36 37 /* 38 * uvm_device.c: the device pager. 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: uvm_device.c,v 1.56 2009/06/20 19:24:27 mrg Exp $"); 43 44 #include "opt_uvmhist.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/conf.h> 49 #include <sys/proc.h> 50 #include <sys/malloc.h> 51 #include <sys/vnode.h> 52 53 #include <uvm/uvm.h> 54 #include <uvm/uvm_device.h> 55 56 /* 57 * private global data structure 58 * 59 * we keep a list of active device objects in the system. 60 */ 61 62 LIST_HEAD(udv_list_struct, uvm_device); 63 static struct udv_list_struct udv_list; 64 static kmutex_t udv_lock; 65 66 /* 67 * functions 68 */ 69 70 static void udv_init(void); 71 static void udv_reference(struct uvm_object *); 72 static void udv_detach(struct uvm_object *); 73 static int udv_fault(struct uvm_faultinfo *, vaddr_t, 74 struct vm_page **, int, int, vm_prot_t, 75 int); 76 77 /* 78 * master pager structure 79 */ 80 81 const struct uvm_pagerops uvm_deviceops = { 82 .pgo_init = udv_init, 83 .pgo_reference = udv_reference, 84 .pgo_detach = udv_detach, 85 .pgo_fault = udv_fault, 86 }; 87 88 /* 89 * the ops! 90 */ 91 92 /* 93 * udv_init 94 * 95 * init pager private data structures. 96 */ 97 98 static void 99 udv_init(void) 100 { 101 LIST_INIT(&udv_list); 102 mutex_init(&udv_lock, MUTEX_DEFAULT, IPL_NONE); 103 } 104 105 /* 106 * udv_attach 107 * 108 * get a VM object that is associated with a device. allocate a new 109 * one if needed. 110 * 111 * => caller must _not_ already be holding the lock on the uvm_object. 112 * => in fact, nothing should be locked so that we can sleep here. 113 */ 114 115 struct uvm_object * 116 udv_attach(void *arg, vm_prot_t accessprot, 117 voff_t off, /* used only for access check */ 118 vsize_t size /* used only for access check */) 119 { 120 dev_t device = *((dev_t *)arg); 121 struct uvm_device *udv, *lcv; 122 const struct cdevsw *cdev; 123 dev_type_mmap((*mapfn)); 124 125 UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist); 126 127 UVMHIST_LOG(maphist, "(device=0x%x)", device,0,0,0); 128 129 /* 130 * before we do anything, ensure this device supports mmap 131 */ 132 133 cdev = cdevsw_lookup(device); 134 if (cdev == NULL) { 135 return (NULL); 136 } 137 mapfn = cdev->d_mmap; 138 if (mapfn == NULL || mapfn == nommap || mapfn == nullmmap) { 139 return(NULL); 140 } 141 142 /* 143 * Negative offsets on the object are not allowed. 144 */ 145 146 if ((cdev->d_flag & D_NEGOFFSAFE) == 0 && 147 off != UVM_UNKNOWN_OFFSET && off < 0) 148 return(NULL); 149 150 /* 151 * Check that the specified range of the device allows the 152 * desired protection. 153 * 154 * XXX assumes VM_PROT_* == PROT_* 155 * XXX clobbers off and size, but nothing else here needs them. 156 */ 157 158 while (size != 0) { 159 if (cdev_mmap(device, off, accessprot) == -1) { 160 return (NULL); 161 } 162 off += PAGE_SIZE; size -= PAGE_SIZE; 163 } 164 165 /* 166 * keep looping until we get it 167 */ 168 169 for (;;) { 170 171 /* 172 * first, attempt to find it on the main list 173 */ 174 175 mutex_enter(&udv_lock); 176 LIST_FOREACH(lcv, &udv_list, u_list) { 177 if (device == lcv->u_device) 178 break; 179 } 180 181 /* 182 * got it on main list. put a hold on it and unlock udv_lock. 183 */ 184 185 if (lcv) { 186 187 /* 188 * if someone else has a hold on it, sleep and start 189 * over again. 190 */ 191 192 if (lcv->u_flags & UVM_DEVICE_HOLD) { 193 lcv->u_flags |= UVM_DEVICE_WANTED; 194 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, false, 195 "udv_attach",0); 196 continue; 197 } 198 199 /* we are now holding it */ 200 lcv->u_flags |= UVM_DEVICE_HOLD; 201 mutex_exit(&udv_lock); 202 203 /* 204 * bump reference count, unhold, return. 205 */ 206 207 mutex_enter(&lcv->u_obj.vmobjlock); 208 lcv->u_obj.uo_refs++; 209 mutex_exit(&lcv->u_obj.vmobjlock); 210 211 mutex_enter(&udv_lock); 212 if (lcv->u_flags & UVM_DEVICE_WANTED) 213 wakeup(lcv); 214 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 215 mutex_exit(&udv_lock); 216 return(&lcv->u_obj); 217 } 218 219 /* 220 * did not find it on main list. need to malloc a new one. 221 */ 222 223 mutex_exit(&udv_lock); 224 /* NOTE: we could sleep in the following malloc() */ 225 udv = malloc(sizeof(*udv), M_TEMP, M_WAITOK); 226 mutex_enter(&udv_lock); 227 228 /* 229 * now we have to double check to make sure no one added it 230 * to the list while we were sleeping... 231 */ 232 233 LIST_FOREACH(lcv, &udv_list, u_list) { 234 if (device == lcv->u_device) 235 break; 236 } 237 238 /* 239 * did we lose a race to someone else? 240 * free our memory and retry. 241 */ 242 243 if (lcv) { 244 mutex_exit(&udv_lock); 245 free(udv, M_TEMP); 246 continue; 247 } 248 249 /* 250 * we have it! init the data structures, add to list 251 * and return. 252 */ 253 254 UVM_OBJ_INIT(&udv->u_obj, &uvm_deviceops, 1); 255 udv->u_flags = 0; 256 udv->u_device = device; 257 LIST_INSERT_HEAD(&udv_list, udv, u_list); 258 mutex_exit(&udv_lock); 259 return(&udv->u_obj); 260 } 261 /*NOTREACHED*/ 262 } 263 264 /* 265 * udv_reference 266 * 267 * add a reference to a VM object. Note that the reference count must 268 * already be one (the passed in reference) so there is no chance of the 269 * udv being released or locked out here. 270 * 271 * => caller must call with object unlocked. 272 */ 273 274 static void 275 udv_reference(struct uvm_object *uobj) 276 { 277 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 278 279 mutex_enter(&uobj->vmobjlock); 280 uobj->uo_refs++; 281 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 282 uobj, uobj->uo_refs,0,0); 283 mutex_exit(&uobj->vmobjlock); 284 } 285 286 /* 287 * udv_detach 288 * 289 * remove a reference to a VM object. 290 * 291 * => caller must call with object unlocked and map locked. 292 */ 293 294 static void 295 udv_detach(struct uvm_object *uobj) 296 { 297 struct uvm_device *udv = (struct uvm_device *)uobj; 298 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 299 300 /* 301 * loop until done 302 */ 303 again: 304 mutex_enter(&uobj->vmobjlock); 305 if (uobj->uo_refs > 1) { 306 uobj->uo_refs--; 307 mutex_exit(&uobj->vmobjlock); 308 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 309 uobj,uobj->uo_refs,0,0); 310 return; 311 } 312 313 /* 314 * is it being held? if so, wait until others are done. 315 */ 316 317 mutex_enter(&udv_lock); 318 if (udv->u_flags & UVM_DEVICE_HOLD) { 319 udv->u_flags |= UVM_DEVICE_WANTED; 320 mutex_exit(&uobj->vmobjlock); 321 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, false, "udv_detach",0); 322 goto again; 323 } 324 325 /* 326 * got it! nuke it now. 327 */ 328 329 LIST_REMOVE(udv, u_list); 330 if (udv->u_flags & UVM_DEVICE_WANTED) 331 wakeup(udv); 332 mutex_exit(&udv_lock); 333 mutex_exit(&uobj->vmobjlock); 334 UVM_OBJ_DESTROY(uobj); 335 free(udv, M_TEMP); 336 UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); 337 } 338 339 /* 340 * udv_fault: non-standard fault routine for device "pages" 341 * 342 * => rather than having a "get" function, we have a fault routine 343 * since we don't return vm_pages we need full control over the 344 * pmap_enter map in 345 * => all the usual fault data structured are locked by the caller 346 * (i.e. maps(read), amap (if any), uobj) 347 * => on return, we unlock all fault data structures 348 * => flags: PGO_ALLPAGES: get all of the pages 349 * PGO_LOCKED: fault data structures are locked 350 * XXX: currently PGO_LOCKED is always required ... consider removing 351 * it as a flag 352 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 353 */ 354 355 static int 356 udv_fault(struct uvm_faultinfo *ufi, vaddr_t vaddr, struct vm_page **pps, 357 int npages, int centeridx, vm_prot_t access_type, 358 int flags) 359 { 360 struct vm_map_entry *entry = ufi->entry; 361 struct uvm_object *uobj = entry->object.uvm_obj; 362 struct uvm_device *udv = (struct uvm_device *)uobj; 363 vaddr_t curr_va; 364 off_t curr_offset; 365 paddr_t paddr, mdpgno; 366 int lcv, retval; 367 dev_t device; 368 vm_prot_t mapprot; 369 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 370 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 371 372 /* 373 * we do not allow device mappings to be mapped copy-on-write 374 * so we kill any attempt to do so here. 375 */ 376 377 if (UVM_ET_ISCOPYONWRITE(entry)) { 378 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 379 entry->etype, 0,0,0); 380 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 381 return(EIO); 382 } 383 384 /* 385 * get device map function. 386 */ 387 388 device = udv->u_device; 389 if (cdevsw_lookup(device) == NULL) { 390 /* XXX This should not happen */ 391 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 392 return (EIO); 393 } 394 395 /* 396 * now we must determine the offset in udv to use and the VA to 397 * use for pmap_enter. note that we always use orig_map's pmap 398 * for pmap_enter (even if we have a submap). since virtual 399 * addresses in a submap must match the main map, this is ok. 400 */ 401 402 /* udv offset = (offset from start of entry) + entry's offset */ 403 curr_offset = entry->offset + (vaddr - entry->start); 404 /* pmap va = vaddr (virtual address of pps[0]) */ 405 curr_va = vaddr; 406 407 /* 408 * loop over the page range entering in as needed 409 */ 410 411 retval = 0; 412 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 413 curr_va += PAGE_SIZE) { 414 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 415 continue; 416 417 if (pps[lcv] == PGO_DONTCARE) 418 continue; 419 420 mdpgno = cdev_mmap(device, curr_offset, access_type); 421 if (mdpgno == -1) { 422 retval = EIO; 423 break; 424 } 425 paddr = pmap_phys_address(mdpgno); 426 mapprot = ufi->entry->protection; 427 UVMHIST_LOG(maphist, 428 " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d", 429 ufi->orig_map->pmap, curr_va, paddr, mapprot); 430 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 431 mapprot, PMAP_CANFAIL | mapprot) != 0) { 432 /* 433 * pmap_enter() didn't have the resource to 434 * enter this mapping. Unlock everything, 435 * wait for the pagedaemon to free up some 436 * pages, and then tell uvm_fault() to start 437 * the fault again. 438 * 439 * XXX Needs some rethinking for the PGO_ALLPAGES 440 * XXX case. 441 */ 442 pmap_update(ufi->orig_map->pmap); /* sync what we have so far */ 443 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 444 uobj, NULL); 445 uvm_wait("udv_fault"); 446 return (ERESTART); 447 } 448 } 449 450 pmap_update(ufi->orig_map->pmap); 451 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 452 return (retval); 453 } 454