1 /* $NetBSD: uvm_device.c,v 1.39 2001/11/10 07:36:59 lukem 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 1.39 2001/11/10 07:36:59 lukem 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 struct simplelock udv_lock; 65 66 /* 67 * functions 68 */ 69 70 static void udv_init __P((void)); 71 static void udv_reference __P((struct uvm_object *)); 72 static void udv_detach __P((struct uvm_object *)); 73 static int udv_fault __P((struct uvm_faultinfo *, vaddr_t, 74 struct vm_page **, int, int, vm_fault_t, vm_prot_t, 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 }; 86 87 /* 88 * the ops! 89 */ 90 91 /* 92 * udv_init 93 * 94 * init pager private data structures. 95 */ 96 97 static void 98 udv_init(void) 99 { 100 LIST_INIT(&udv_list); 101 simple_lock_init(&udv_lock); 102 } 103 104 /* 105 * udv_attach 106 * 107 * get a VM object that is associated with a device. allocate a new 108 * one if needed. 109 * 110 * => caller must _not_ already be holding the lock on the uvm_object. 111 * => in fact, nothing should be locked so that we can sleep here. 112 */ 113 114 struct uvm_object * 115 udv_attach(arg, accessprot, off, size) 116 void *arg; 117 vm_prot_t accessprot; 118 voff_t off; /* used only for access check */ 119 vsize_t size; /* used only for access check */ 120 { 121 dev_t device = *((dev_t *)arg); 122 struct uvm_device *udv, *lcv; 123 paddr_t (*mapfn) __P((dev_t, off_t, int)); 124 UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist); 125 126 UVMHIST_LOG(maphist, "(device=0x%x)", device,0,0,0); 127 128 /* 129 * before we do anything, ensure this device supports mmap 130 */ 131 132 mapfn = cdevsw[major(device)].d_mmap; 133 if (mapfn == NULL || 134 mapfn == (paddr_t (*) __P((dev_t, off_t, int))) enodev || 135 mapfn == (paddr_t (*) __P((dev_t, off_t, int))) nullop) 136 return(NULL); 137 138 /* 139 * Negative offsets on the object are not allowed. 140 */ 141 142 if (off < 0) 143 return(NULL); 144 145 /* 146 * Check that the specified range of the device allows the 147 * desired protection. 148 * 149 * XXX assumes VM_PROT_* == PROT_* 150 * XXX clobbers off and size, but nothing else here needs them. 151 */ 152 153 while (size != 0) { 154 if ((*mapfn)(device, off, accessprot) == -1) 155 return (NULL); 156 off += PAGE_SIZE; size -= PAGE_SIZE; 157 } 158 159 /* 160 * keep looping until we get it 161 */ 162 163 for (;;) { 164 165 /* 166 * first, attempt to find it on the main list 167 */ 168 169 simple_lock(&udv_lock); 170 LIST_FOREACH(lcv, &udv_list, u_list) { 171 if (device == lcv->u_device) 172 break; 173 } 174 175 /* 176 * got it on main list. put a hold on it and unlock udv_lock. 177 */ 178 179 if (lcv) { 180 181 /* 182 * if someone else has a hold on it, sleep and start 183 * over again. 184 */ 185 186 if (lcv->u_flags & UVM_DEVICE_HOLD) { 187 lcv->u_flags |= UVM_DEVICE_WANTED; 188 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, 189 "udv_attach",0); 190 continue; 191 } 192 193 /* we are now holding it */ 194 lcv->u_flags |= UVM_DEVICE_HOLD; 195 simple_unlock(&udv_lock); 196 197 /* 198 * bump reference count, unhold, return. 199 */ 200 201 simple_lock(&lcv->u_obj.vmobjlock); 202 lcv->u_obj.uo_refs++; 203 simple_unlock(&lcv->u_obj.vmobjlock); 204 205 simple_lock(&udv_lock); 206 if (lcv->u_flags & UVM_DEVICE_WANTED) 207 wakeup(lcv); 208 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 209 simple_unlock(&udv_lock); 210 return(&lcv->u_obj); 211 } 212 213 /* 214 * did not find it on main list. need to malloc a new one. 215 */ 216 217 simple_unlock(&udv_lock); 218 /* NOTE: we could sleep in the following malloc() */ 219 MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, 220 M_WAITOK); 221 simple_lock(&udv_lock); 222 223 /* 224 * now we have to double check to make sure no one added it 225 * to the list while we were sleeping... 226 */ 227 228 LIST_FOREACH(lcv, &udv_list, u_list) { 229 if (device == lcv->u_device) 230 break; 231 } 232 233 /* 234 * did we lose a race to someone else? 235 * free our memory and retry. 236 */ 237 238 if (lcv) { 239 simple_unlock(&udv_lock); 240 FREE(udv, M_TEMP); 241 continue; 242 } 243 244 /* 245 * we have it! init the data structures, add to list 246 * and return. 247 */ 248 249 simple_lock_init(&udv->u_obj.vmobjlock); 250 udv->u_obj.pgops = &uvm_deviceops; 251 TAILQ_INIT(&udv->u_obj.memq); 252 udv->u_obj.uo_npages = 0; 253 udv->u_obj.uo_refs = 1; 254 udv->u_flags = 0; 255 udv->u_device = device; 256 LIST_INSERT_HEAD(&udv_list, udv, u_list); 257 simple_unlock(&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(uobj) 275 struct uvm_object *uobj; 276 { 277 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 278 279 simple_lock(&uobj->vmobjlock); 280 uobj->uo_refs++; 281 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 282 uobj, uobj->uo_refs,0,0); 283 simple_unlock(&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(uobj) 296 struct uvm_object *uobj; 297 { 298 struct uvm_device *udv = (struct uvm_device *)uobj; 299 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 300 301 /* 302 * loop until done 303 */ 304 again: 305 simple_lock(&uobj->vmobjlock); 306 if (uobj->uo_refs > 1) { 307 uobj->uo_refs--; 308 simple_unlock(&uobj->vmobjlock); 309 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 310 uobj,uobj->uo_refs,0,0); 311 return; 312 } 313 314 /* 315 * is it being held? if so, wait until others are done. 316 */ 317 318 simple_lock(&udv_lock); 319 if (udv->u_flags & UVM_DEVICE_HOLD) { 320 udv->u_flags |= UVM_DEVICE_WANTED; 321 simple_unlock(&uobj->vmobjlock); 322 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); 323 goto again; 324 } 325 326 /* 327 * got it! nuke it now. 328 */ 329 330 LIST_REMOVE(udv, u_list); 331 if (udv->u_flags & UVM_DEVICE_WANTED) 332 wakeup(udv); 333 simple_unlock(&udv_lock); 334 simple_unlock(&uobj->vmobjlock); 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(ufi, vaddr, pps, npages, centeridx, fault_type, access_type, flags) 357 struct uvm_faultinfo *ufi; 358 vaddr_t vaddr; 359 struct vm_page **pps; 360 int npages, centeridx, flags; 361 vm_fault_t fault_type; 362 vm_prot_t access_type; 363 { 364 struct vm_map_entry *entry = ufi->entry; 365 struct uvm_object *uobj = entry->object.uvm_obj; 366 struct uvm_device *udv = (struct uvm_device *)uobj; 367 vaddr_t curr_va; 368 off_t curr_offset; 369 paddr_t paddr, mdpgno; 370 int lcv, retval; 371 dev_t device; 372 paddr_t (*mapfn) __P((dev_t, off_t, int)); 373 vm_prot_t mapprot; 374 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 375 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 376 377 /* 378 * we do not allow device mappings to be mapped copy-on-write 379 * so we kill any attempt to do so here. 380 */ 381 382 if (UVM_ET_ISCOPYONWRITE(entry)) { 383 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 384 entry->etype, 0,0,0); 385 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 386 return(EIO); 387 } 388 389 /* 390 * get device map function. 391 */ 392 393 device = udv->u_device; 394 mapfn = cdevsw[major(device)].d_mmap; 395 396 /* 397 * now we must determine the offset in udv to use and the VA to 398 * use for pmap_enter. note that we always use orig_map's pmap 399 * for pmap_enter (even if we have a submap). since virtual 400 * addresses in a submap must match the main map, this is ok. 401 */ 402 403 /* udv offset = (offset from start of entry) + entry's offset */ 404 curr_offset = entry->offset + (vaddr - entry->start); 405 /* pmap va = vaddr (virtual address of pps[0]) */ 406 curr_va = vaddr; 407 408 /* 409 * loop over the page range entering in as needed 410 */ 411 412 retval = 0; 413 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 414 curr_va += PAGE_SIZE) { 415 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 416 continue; 417 418 if (pps[lcv] == PGO_DONTCARE) 419 continue; 420 421 mdpgno = (*mapfn)(device, curr_offset, access_type); 422 if (mdpgno == -1) { 423 retval = EIO; 424 break; 425 } 426 paddr = pmap_phys_address(mdpgno); 427 mapprot = ufi->entry->protection; 428 UVMHIST_LOG(maphist, 429 " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d", 430 ufi->orig_map->pmap, curr_va, paddr, mapprot); 431 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 432 mapprot, PMAP_CANFAIL | mapprot) != 0) { 433 /* 434 * pmap_enter() didn't have the resource to 435 * enter this mapping. Unlock everything, 436 * wait for the pagedaemon to free up some 437 * pages, and then tell uvm_fault() to start 438 * the fault again. 439 * 440 * XXX Needs some rethinking for the PGO_ALLPAGES 441 * XXX case. 442 */ 443 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 444 uobj, NULL); 445 pmap_update(ufi->orig_map->pmap); /* sync what we have so far */ 446 uvm_wait("udv_fault"); 447 return (ERESTART); 448 } 449 } 450 451 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 452 pmap_update(ufi->orig_map->pmap); 453 return (retval); 454 } 455