1 /* $NetBSD: uvm_device.c,v 1.36 2001/05/26 21:27:21 chs 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 #include "opt_uvmhist.h" 38 39 /* 40 * uvm_device.c: the device pager. 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/conf.h> 46 #include <sys/proc.h> 47 #include <sys/malloc.h> 48 #include <sys/vnode.h> 49 50 #include <uvm/uvm.h> 51 #include <uvm/uvm_device.h> 52 53 /* 54 * private global data structure 55 * 56 * we keep a list of active device objects in the system. 57 */ 58 59 LIST_HEAD(udv_list_struct, uvm_device); 60 static struct udv_list_struct udv_list; 61 static struct simplelock udv_lock; 62 63 /* 64 * functions 65 */ 66 67 static void udv_init __P((void)); 68 static void udv_reference __P((struct uvm_object *)); 69 static void udv_detach __P((struct uvm_object *)); 70 static int udv_fault __P((struct uvm_faultinfo *, vaddr_t, 71 struct vm_page **, int, int, vm_fault_t, 72 vm_prot_t, int)); 73 static boolean_t udv_flush __P((struct uvm_object *, voff_t, voff_t, 74 int)); 75 76 /* 77 * master pager structure 78 */ 79 80 struct uvm_pagerops uvm_deviceops = { 81 udv_init, 82 udv_reference, 83 udv_detach, 84 udv_fault, 85 udv_flush, 86 }; 87 88 /* 89 * the ops! 90 */ 91 92 /* 93 * udv_init 94 * 95 * init pager private data structures. 96 */ 97 98 void 99 udv_init() 100 { 101 102 LIST_INIT(&udv_list); 103 simple_lock_init(&udv_lock); 104 } 105 106 /* 107 * udv_attach 108 * 109 * get a VM object that is associated with a device. allocate a new 110 * one if needed. 111 * 112 * => caller must _not_ already be holding the lock on the uvm_object. 113 * => in fact, nothing should be locked so that we can sleep here. 114 */ 115 struct uvm_object * 116 udv_attach(arg, accessprot, off, size) 117 void *arg; 118 vm_prot_t accessprot; 119 voff_t off; /* used only for access check */ 120 vsize_t size; /* used only for access check */ 121 { 122 dev_t device = *((dev_t *)arg); 123 struct uvm_device *udv, *lcv; 124 paddr_t (*mapfn) __P((dev_t, off_t, int)); 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 mapfn = cdevsw[major(device)].d_mmap; 134 if (mapfn == NULL || 135 mapfn == (paddr_t (*) __P((dev_t, off_t, int))) enodev || 136 mapfn == (paddr_t (*) __P((dev_t, off_t, int))) nullop) 137 return(NULL); 138 139 /* 140 * Negative offsets on the object are not allowed. 141 */ 142 143 if (off < 0) 144 return(NULL); 145 146 /* 147 * Check that the specified range of the device allows the 148 * desired protection. 149 * 150 * XXX assumes VM_PROT_* == PROT_* 151 * XXX clobbers off and size, but nothing else here needs them. 152 */ 153 154 while (size != 0) { 155 if ((*mapfn)(device, off, accessprot) == -1) 156 return (NULL); 157 off += PAGE_SIZE; size -= PAGE_SIZE; 158 } 159 160 /* 161 * keep looping until we get it 162 */ 163 164 for (;;) { 165 166 /* 167 * first, attempt to find it on the main list 168 */ 169 170 simple_lock(&udv_lock); 171 LIST_FOREACH(lcv, &udv_list, u_list) { 172 if (device == lcv->u_device) 173 break; 174 } 175 176 /* 177 * got it on main list. put a hold on it and unlock udv_lock. 178 */ 179 180 if (lcv) { 181 182 /* 183 * if someone else has a hold on it, sleep and start 184 * over again. 185 */ 186 187 if (lcv->u_flags & UVM_DEVICE_HOLD) { 188 lcv->u_flags |= UVM_DEVICE_WANTED; 189 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, 190 "udv_attach",0); 191 continue; 192 } 193 194 /* we are now holding it */ 195 lcv->u_flags |= UVM_DEVICE_HOLD; 196 simple_unlock(&udv_lock); 197 198 /* 199 * bump reference count, unhold, return. 200 */ 201 202 simple_lock(&lcv->u_obj.vmobjlock); 203 lcv->u_obj.uo_refs++; 204 simple_unlock(&lcv->u_obj.vmobjlock); 205 206 simple_lock(&udv_lock); 207 if (lcv->u_flags & UVM_DEVICE_WANTED) 208 wakeup(lcv); 209 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 210 simple_unlock(&udv_lock); 211 return(&lcv->u_obj); 212 } 213 214 /* 215 * did not find it on main list. need to malloc a new one. 216 */ 217 218 simple_unlock(&udv_lock); 219 /* NOTE: we could sleep in the following malloc() */ 220 MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, 221 M_WAITOK); 222 simple_lock(&udv_lock); 223 224 /* 225 * now we have to double check to make sure no one added it 226 * to the list while we were sleeping... 227 */ 228 229 LIST_FOREACH(lcv, &udv_list, u_list) { 230 if (device == lcv->u_device) 231 break; 232 } 233 234 /* 235 * did we lose a race to someone else? 236 * free our memory and retry. 237 */ 238 239 if (lcv) { 240 simple_unlock(&udv_lock); 241 FREE(udv, M_TEMP); 242 continue; 243 } 244 245 /* 246 * we have it! init the data structures, add to list 247 * and return. 248 */ 249 250 simple_lock_init(&udv->u_obj.vmobjlock); 251 udv->u_obj.pgops = &uvm_deviceops; 252 TAILQ_INIT(&udv->u_obj.memq); 253 udv->u_obj.uo_npages = 0; 254 udv->u_obj.uo_refs = 1; 255 udv->u_flags = 0; 256 udv->u_device = device; 257 LIST_INSERT_HEAD(&udv_list, udv, u_list); 258 simple_unlock(&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(uobj) 276 struct uvm_object *uobj; 277 { 278 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 279 280 simple_lock(&uobj->vmobjlock); 281 uobj->uo_refs++; 282 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 283 uobj, uobj->uo_refs,0,0); 284 simple_unlock(&uobj->vmobjlock); 285 } 286 287 /* 288 * udv_detach 289 * 290 * remove a reference to a VM object. 291 * 292 * => caller must call with object unlocked and map locked. 293 */ 294 295 static void 296 udv_detach(uobj) 297 struct uvm_object *uobj; 298 { 299 struct uvm_device *udv = (struct uvm_device *)uobj; 300 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 301 302 /* 303 * loop until done 304 */ 305 again: 306 simple_lock(&uobj->vmobjlock); 307 if (uobj->uo_refs > 1) { 308 uobj->uo_refs--; 309 simple_unlock(&uobj->vmobjlock); 310 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 311 uobj,uobj->uo_refs,0,0); 312 return; 313 } 314 KASSERT(uobj->uo_npages == 0 && TAILQ_EMPTY(&uobj->memq)); 315 316 /* 317 * is it being held? if so, wait until others are done. 318 */ 319 320 simple_lock(&udv_lock); 321 if (udv->u_flags & UVM_DEVICE_HOLD) { 322 udv->u_flags |= UVM_DEVICE_WANTED; 323 simple_unlock(&uobj->vmobjlock); 324 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); 325 goto again; 326 } 327 328 /* 329 * got it! nuke it now. 330 */ 331 332 LIST_REMOVE(udv, u_list); 333 if (udv->u_flags & UVM_DEVICE_WANTED) 334 wakeup(udv); 335 simple_unlock(&udv_lock); 336 simple_unlock(&uobj->vmobjlock); 337 FREE(udv, M_TEMP); 338 UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); 339 } 340 341 342 /* 343 * udv_flush 344 * 345 * flush pages out of a uvm object. a no-op for devices. 346 */ 347 348 static boolean_t 349 udv_flush(uobj, start, stop, flags) 350 struct uvm_object *uobj; 351 voff_t start, stop; 352 int flags; 353 { 354 355 return(TRUE); 356 } 357 358 /* 359 * udv_fault: non-standard fault routine for device "pages" 360 * 361 * => rather than having a "get" function, we have a fault routine 362 * since we don't return vm_pages we need full control over the 363 * pmap_enter map in 364 * => all the usual fault data structured are locked by the caller 365 * (i.e. maps(read), amap (if any), uobj) 366 * => on return, we unlock all fault data structures 367 * => flags: PGO_ALLPAGES: get all of the pages 368 * PGO_LOCKED: fault data structures are locked 369 * XXX: currently PGO_LOCKED is always required ... consider removing 370 * it as a flag 371 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 372 */ 373 374 static int 375 udv_fault(ufi, vaddr, pps, npages, centeridx, fault_type, access_type, flags) 376 struct uvm_faultinfo *ufi; 377 vaddr_t vaddr; 378 struct vm_page **pps; 379 int npages, centeridx, flags; 380 vm_fault_t fault_type; 381 vm_prot_t access_type; 382 { 383 struct vm_map_entry *entry = ufi->entry; 384 struct uvm_object *uobj = entry->object.uvm_obj; 385 struct uvm_device *udv = (struct uvm_device *)uobj; 386 vaddr_t curr_va; 387 off_t curr_offset; 388 paddr_t paddr, mdpgno; 389 int lcv, retval; 390 dev_t device; 391 paddr_t (*mapfn) __P((dev_t, off_t, int)); 392 vm_prot_t mapprot; 393 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 394 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 395 396 /* 397 * we do not allow device mappings to be mapped copy-on-write 398 * so we kill any attempt to do so here. 399 */ 400 401 if (UVM_ET_ISCOPYONWRITE(entry)) { 402 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 403 entry->etype, 0,0,0); 404 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 405 return(EIO); 406 } 407 408 /* 409 * get device map function. 410 */ 411 412 device = udv->u_device; 413 mapfn = cdevsw[major(device)].d_mmap; 414 415 /* 416 * now we must determine the offset in udv to use and the VA to 417 * use for pmap_enter. note that we always use orig_map's pmap 418 * for pmap_enter (even if we have a submap). since virtual 419 * addresses in a submap must match the main map, this is ok. 420 */ 421 422 /* udv offset = (offset from start of entry) + entry's offset */ 423 curr_offset = entry->offset + (vaddr - entry->start); 424 /* pmap va = vaddr (virtual address of pps[0]) */ 425 curr_va = vaddr; 426 427 /* 428 * loop over the page range entering in as needed 429 */ 430 431 retval = 0; 432 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 433 curr_va += PAGE_SIZE) { 434 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 435 continue; 436 437 if (pps[lcv] == PGO_DONTCARE) 438 continue; 439 440 mdpgno = (*mapfn)(device, curr_offset, access_type); 441 if (mdpgno == -1) { 442 retval = EIO; 443 break; 444 } 445 paddr = pmap_phys_address(mdpgno); 446 mapprot = ufi->entry->protection; 447 UVMHIST_LOG(maphist, 448 " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d", 449 ufi->orig_map->pmap, curr_va, paddr, mapprot); 450 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 451 mapprot, PMAP_CANFAIL | mapprot) != 0) { 452 /* 453 * pmap_enter() didn't have the resource to 454 * enter this mapping. Unlock everything, 455 * wait for the pagedaemon to free up some 456 * pages, and then tell uvm_fault() to start 457 * the fault again. 458 * 459 * XXX Needs some rethinking for the PGO_ALLPAGES 460 * XXX case. 461 */ 462 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 463 uobj, NULL); 464 pmap_update(); /* sync what we have so far */ 465 uvm_wait("udv_fault"); 466 return (ERESTART); 467 } 468 } 469 470 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 471 pmap_update(); 472 return (retval); 473 } 474