uvm_device.c revision 1.55
1 /* $NetBSD: uvm_device.c,v 1.55 2008/12/17 20:51:39 cegger 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 1.55 2008/12/17 20:51:39 cegger 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 (off != UVM_UNKNOWN_OFFSET && off < 0) 147 return(NULL); 148 149 /* 150 * Check that the specified range of the device allows the 151 * desired protection. 152 * 153 * XXX assumes VM_PROT_* == PROT_* 154 * XXX clobbers off and size, but nothing else here needs them. 155 */ 156 157 while (size != 0) { 158 if (cdev_mmap(device, off, accessprot) == -1) { 159 return (NULL); 160 } 161 off += PAGE_SIZE; size -= PAGE_SIZE; 162 } 163 164 /* 165 * keep looping until we get it 166 */ 167 168 for (;;) { 169 170 /* 171 * first, attempt to find it on the main list 172 */ 173 174 mutex_enter(&udv_lock); 175 LIST_FOREACH(lcv, &udv_list, u_list) { 176 if (device == lcv->u_device) 177 break; 178 } 179 180 /* 181 * got it on main list. put a hold on it and unlock udv_lock. 182 */ 183 184 if (lcv) { 185 186 /* 187 * if someone else has a hold on it, sleep and start 188 * over again. 189 */ 190 191 if (lcv->u_flags & UVM_DEVICE_HOLD) { 192 lcv->u_flags |= UVM_DEVICE_WANTED; 193 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, false, 194 "udv_attach",0); 195 continue; 196 } 197 198 /* we are now holding it */ 199 lcv->u_flags |= UVM_DEVICE_HOLD; 200 mutex_exit(&udv_lock); 201 202 /* 203 * bump reference count, unhold, return. 204 */ 205 206 mutex_enter(&lcv->u_obj.vmobjlock); 207 lcv->u_obj.uo_refs++; 208 mutex_exit(&lcv->u_obj.vmobjlock); 209 210 mutex_enter(&udv_lock); 211 if (lcv->u_flags & UVM_DEVICE_WANTED) 212 wakeup(lcv); 213 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 214 mutex_exit(&udv_lock); 215 return(&lcv->u_obj); 216 } 217 218 /* 219 * did not find it on main list. need to malloc a new one. 220 */ 221 222 mutex_exit(&udv_lock); 223 /* NOTE: we could sleep in the following malloc() */ 224 udv = malloc(sizeof(*udv), M_TEMP, M_WAITOK); 225 mutex_enter(&udv_lock); 226 227 /* 228 * now we have to double check to make sure no one added it 229 * to the list while we were sleeping... 230 */ 231 232 LIST_FOREACH(lcv, &udv_list, u_list) { 233 if (device == lcv->u_device) 234 break; 235 } 236 237 /* 238 * did we lose a race to someone else? 239 * free our memory and retry. 240 */ 241 242 if (lcv) { 243 mutex_exit(&udv_lock); 244 free(udv, M_TEMP); 245 continue; 246 } 247 248 /* 249 * we have it! init the data structures, add to list 250 * and return. 251 */ 252 253 UVM_OBJ_INIT(&udv->u_obj, &uvm_deviceops, 1); 254 udv->u_flags = 0; 255 udv->u_device = device; 256 LIST_INSERT_HEAD(&udv_list, udv, u_list); 257 mutex_exit(&udv_lock); 258 return(&udv->u_obj); 259 } 260 /*NOTREACHED*/ 261 } 262 263 /* 264 * udv_reference 265 * 266 * add a reference to a VM object. Note that the reference count must 267 * already be one (the passed in reference) so there is no chance of the 268 * udv being released or locked out here. 269 * 270 * => caller must call with object unlocked. 271 */ 272 273 static void 274 udv_reference(struct uvm_object *uobj) 275 { 276 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 277 278 mutex_enter(&uobj->vmobjlock); 279 uobj->uo_refs++; 280 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 281 uobj, uobj->uo_refs,0,0); 282 mutex_exit(&uobj->vmobjlock); 283 } 284 285 /* 286 * udv_detach 287 * 288 * remove a reference to a VM object. 289 * 290 * => caller must call with object unlocked and map locked. 291 */ 292 293 static void 294 udv_detach(struct uvm_object *uobj) 295 { 296 struct uvm_device *udv = (struct uvm_device *)uobj; 297 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 298 299 /* 300 * loop until done 301 */ 302 again: 303 mutex_enter(&uobj->vmobjlock); 304 if (uobj->uo_refs > 1) { 305 uobj->uo_refs--; 306 mutex_exit(&uobj->vmobjlock); 307 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 308 uobj,uobj->uo_refs,0,0); 309 return; 310 } 311 312 /* 313 * is it being held? if so, wait until others are done. 314 */ 315 316 mutex_enter(&udv_lock); 317 if (udv->u_flags & UVM_DEVICE_HOLD) { 318 udv->u_flags |= UVM_DEVICE_WANTED; 319 mutex_exit(&uobj->vmobjlock); 320 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, false, "udv_detach",0); 321 goto again; 322 } 323 324 /* 325 * got it! nuke it now. 326 */ 327 328 LIST_REMOVE(udv, u_list); 329 if (udv->u_flags & UVM_DEVICE_WANTED) 330 wakeup(udv); 331 mutex_exit(&udv_lock); 332 mutex_exit(&uobj->vmobjlock); 333 UVM_OBJ_DESTROY(uobj); 334 free(udv, M_TEMP); 335 UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); 336 } 337 338 /* 339 * udv_fault: non-standard fault routine for device "pages" 340 * 341 * => rather than having a "get" function, we have a fault routine 342 * since we don't return vm_pages we need full control over the 343 * pmap_enter map in 344 * => all the usual fault data structured are locked by the caller 345 * (i.e. maps(read), amap (if any), uobj) 346 * => on return, we unlock all fault data structures 347 * => flags: PGO_ALLPAGES: get all of the pages 348 * PGO_LOCKED: fault data structures are locked 349 * XXX: currently PGO_LOCKED is always required ... consider removing 350 * it as a flag 351 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 352 */ 353 354 static int 355 udv_fault(struct uvm_faultinfo *ufi, vaddr_t vaddr, struct vm_page **pps, 356 int npages, int centeridx, vm_prot_t access_type, 357 int flags) 358 { 359 struct vm_map_entry *entry = ufi->entry; 360 struct uvm_object *uobj = entry->object.uvm_obj; 361 struct uvm_device *udv = (struct uvm_device *)uobj; 362 vaddr_t curr_va; 363 off_t curr_offset; 364 paddr_t paddr, mdpgno; 365 int lcv, retval; 366 dev_t device; 367 vm_prot_t mapprot; 368 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 369 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 370 371 /* 372 * we do not allow device mappings to be mapped copy-on-write 373 * so we kill any attempt to do so here. 374 */ 375 376 if (UVM_ET_ISCOPYONWRITE(entry)) { 377 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 378 entry->etype, 0,0,0); 379 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 380 return(EIO); 381 } 382 383 /* 384 * get device map function. 385 */ 386 387 device = udv->u_device; 388 if (cdevsw_lookup(device) == NULL) { 389 /* XXX This should not happen */ 390 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 391 return (EIO); 392 } 393 394 /* 395 * now we must determine the offset in udv to use and the VA to 396 * use for pmap_enter. note that we always use orig_map's pmap 397 * for pmap_enter (even if we have a submap). since virtual 398 * addresses in a submap must match the main map, this is ok. 399 */ 400 401 /* udv offset = (offset from start of entry) + entry's offset */ 402 curr_offset = entry->offset + (vaddr - entry->start); 403 /* pmap va = vaddr (virtual address of pps[0]) */ 404 curr_va = vaddr; 405 406 /* 407 * loop over the page range entering in as needed 408 */ 409 410 retval = 0; 411 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 412 curr_va += PAGE_SIZE) { 413 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 414 continue; 415 416 if (pps[lcv] == PGO_DONTCARE) 417 continue; 418 419 mdpgno = cdev_mmap(device, curr_offset, access_type); 420 if (mdpgno == -1) { 421 retval = EIO; 422 break; 423 } 424 paddr = pmap_phys_address(mdpgno); 425 mapprot = ufi->entry->protection; 426 UVMHIST_LOG(maphist, 427 " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d", 428 ufi->orig_map->pmap, curr_va, paddr, mapprot); 429 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 430 mapprot, PMAP_CANFAIL | mapprot) != 0) { 431 /* 432 * pmap_enter() didn't have the resource to 433 * enter this mapping. Unlock everything, 434 * wait for the pagedaemon to free up some 435 * pages, and then tell uvm_fault() to start 436 * the fault again. 437 * 438 * XXX Needs some rethinking for the PGO_ALLPAGES 439 * XXX case. 440 */ 441 pmap_update(ufi->orig_map->pmap); /* sync what we have so far */ 442 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 443 uobj, NULL); 444 uvm_wait("udv_fault"); 445 return (ERESTART); 446 } 447 } 448 449 pmap_update(ufi->orig_map->pmap); 450 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 451 return (retval); 452 } 453
Indexes created Tue Sep 30 11:09:46 GMT 2025