1 /* $NetBSD: uvm_device.c,v 1.38 2001/09/15 20:36:45 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, vm_prot_t, int)); 72 73 /* 74 * master pager structure 75 */ 76 77 struct uvm_pagerops uvm_deviceops = { 78 udv_init, 79 udv_reference, 80 udv_detach, 81 udv_fault, 82 }; 83 84 /* 85 * the ops! 86 */ 87 88 /* 89 * udv_init 90 * 91 * init pager private data structures. 92 */ 93 94 static void 95 udv_init(void) 96 { 97 LIST_INIT(&udv_list); 98 simple_lock_init(&udv_lock); 99 } 100 101 /* 102 * udv_attach 103 * 104 * get a VM object that is associated with a device. allocate a new 105 * one if needed. 106 * 107 * => caller must _not_ already be holding the lock on the uvm_object. 108 * => in fact, nothing should be locked so that we can sleep here. 109 */ 110 111 struct uvm_object * 112 udv_attach(arg, accessprot, off, size) 113 void *arg; 114 vm_prot_t accessprot; 115 voff_t off; /* used only for access check */ 116 vsize_t size; /* used only for access check */ 117 { 118 dev_t device = *((dev_t *)arg); 119 struct uvm_device *udv, *lcv; 120 paddr_t (*mapfn) __P((dev_t, off_t, int)); 121 UVMHIST_FUNC("udv_attach"); UVMHIST_CALLED(maphist); 122 123 UVMHIST_LOG(maphist, "(device=0x%x)", device,0,0,0); 124 125 /* 126 * before we do anything, ensure this device supports mmap 127 */ 128 129 mapfn = cdevsw[major(device)].d_mmap; 130 if (mapfn == NULL || 131 mapfn == (paddr_t (*) __P((dev_t, off_t, int))) enodev || 132 mapfn == (paddr_t (*) __P((dev_t, off_t, int))) nullop) 133 return(NULL); 134 135 /* 136 * Negative offsets on the object are not allowed. 137 */ 138 139 if (off < 0) 140 return(NULL); 141 142 /* 143 * Check that the specified range of the device allows the 144 * desired protection. 145 * 146 * XXX assumes VM_PROT_* == PROT_* 147 * XXX clobbers off and size, but nothing else here needs them. 148 */ 149 150 while (size != 0) { 151 if ((*mapfn)(device, off, accessprot) == -1) 152 return (NULL); 153 off += PAGE_SIZE; size -= PAGE_SIZE; 154 } 155 156 /* 157 * keep looping until we get it 158 */ 159 160 for (;;) { 161 162 /* 163 * first, attempt to find it on the main list 164 */ 165 166 simple_lock(&udv_lock); 167 LIST_FOREACH(lcv, &udv_list, u_list) { 168 if (device == lcv->u_device) 169 break; 170 } 171 172 /* 173 * got it on main list. put a hold on it and unlock udv_lock. 174 */ 175 176 if (lcv) { 177 178 /* 179 * if someone else has a hold on it, sleep and start 180 * over again. 181 */ 182 183 if (lcv->u_flags & UVM_DEVICE_HOLD) { 184 lcv->u_flags |= UVM_DEVICE_WANTED; 185 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, 186 "udv_attach",0); 187 continue; 188 } 189 190 /* we are now holding it */ 191 lcv->u_flags |= UVM_DEVICE_HOLD; 192 simple_unlock(&udv_lock); 193 194 /* 195 * bump reference count, unhold, return. 196 */ 197 198 simple_lock(&lcv->u_obj.vmobjlock); 199 lcv->u_obj.uo_refs++; 200 simple_unlock(&lcv->u_obj.vmobjlock); 201 202 simple_lock(&udv_lock); 203 if (lcv->u_flags & UVM_DEVICE_WANTED) 204 wakeup(lcv); 205 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 206 simple_unlock(&udv_lock); 207 return(&lcv->u_obj); 208 } 209 210 /* 211 * did not find it on main list. need to malloc a new one. 212 */ 213 214 simple_unlock(&udv_lock); 215 /* NOTE: we could sleep in the following malloc() */ 216 MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, 217 M_WAITOK); 218 simple_lock(&udv_lock); 219 220 /* 221 * now we have to double check to make sure no one added it 222 * to the list while we were sleeping... 223 */ 224 225 LIST_FOREACH(lcv, &udv_list, u_list) { 226 if (device == lcv->u_device) 227 break; 228 } 229 230 /* 231 * did we lose a race to someone else? 232 * free our memory and retry. 233 */ 234 235 if (lcv) { 236 simple_unlock(&udv_lock); 237 FREE(udv, M_TEMP); 238 continue; 239 } 240 241 /* 242 * we have it! init the data structures, add to list 243 * and return. 244 */ 245 246 simple_lock_init(&udv->u_obj.vmobjlock); 247 udv->u_obj.pgops = &uvm_deviceops; 248 TAILQ_INIT(&udv->u_obj.memq); 249 udv->u_obj.uo_npages = 0; 250 udv->u_obj.uo_refs = 1; 251 udv->u_flags = 0; 252 udv->u_device = device; 253 LIST_INSERT_HEAD(&udv_list, udv, u_list); 254 simple_unlock(&udv_lock); 255 return(&udv->u_obj); 256 } 257 /*NOTREACHED*/ 258 } 259 260 /* 261 * udv_reference 262 * 263 * add a reference to a VM object. Note that the reference count must 264 * already be one (the passed in reference) so there is no chance of the 265 * udv being released or locked out here. 266 * 267 * => caller must call with object unlocked. 268 */ 269 270 static void 271 udv_reference(uobj) 272 struct uvm_object *uobj; 273 { 274 UVMHIST_FUNC("udv_reference"); UVMHIST_CALLED(maphist); 275 276 simple_lock(&uobj->vmobjlock); 277 uobj->uo_refs++; 278 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 279 uobj, uobj->uo_refs,0,0); 280 simple_unlock(&uobj->vmobjlock); 281 } 282 283 /* 284 * udv_detach 285 * 286 * remove a reference to a VM object. 287 * 288 * => caller must call with object unlocked and map locked. 289 */ 290 291 static void 292 udv_detach(uobj) 293 struct uvm_object *uobj; 294 { 295 struct uvm_device *udv = (struct uvm_device *)uobj; 296 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 297 298 /* 299 * loop until done 300 */ 301 again: 302 simple_lock(&uobj->vmobjlock); 303 if (uobj->uo_refs > 1) { 304 uobj->uo_refs--; 305 simple_unlock(&uobj->vmobjlock); 306 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 307 uobj,uobj->uo_refs,0,0); 308 return; 309 } 310 311 /* 312 * is it being held? if so, wait until others are done. 313 */ 314 315 simple_lock(&udv_lock); 316 if (udv->u_flags & UVM_DEVICE_HOLD) { 317 udv->u_flags |= UVM_DEVICE_WANTED; 318 simple_unlock(&uobj->vmobjlock); 319 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); 320 goto again; 321 } 322 323 /* 324 * got it! nuke it now. 325 */ 326 327 LIST_REMOVE(udv, u_list); 328 if (udv->u_flags & UVM_DEVICE_WANTED) 329 wakeup(udv); 330 simple_unlock(&udv_lock); 331 simple_unlock(&uobj->vmobjlock); 332 FREE(udv, M_TEMP); 333 UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); 334 } 335 336 /* 337 * udv_fault: non-standard fault routine for device "pages" 338 * 339 * => rather than having a "get" function, we have a fault routine 340 * since we don't return vm_pages we need full control over the 341 * pmap_enter map in 342 * => all the usual fault data structured are locked by the caller 343 * (i.e. maps(read), amap (if any), uobj) 344 * => on return, we unlock all fault data structures 345 * => flags: PGO_ALLPAGES: get all of the pages 346 * PGO_LOCKED: fault data structures are locked 347 * XXX: currently PGO_LOCKED is always required ... consider removing 348 * it as a flag 349 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 350 */ 351 352 static int 353 udv_fault(ufi, vaddr, pps, npages, centeridx, fault_type, access_type, flags) 354 struct uvm_faultinfo *ufi; 355 vaddr_t vaddr; 356 struct vm_page **pps; 357 int npages, centeridx, flags; 358 vm_fault_t fault_type; 359 vm_prot_t access_type; 360 { 361 struct vm_map_entry *entry = ufi->entry; 362 struct uvm_object *uobj = entry->object.uvm_obj; 363 struct uvm_device *udv = (struct uvm_device *)uobj; 364 vaddr_t curr_va; 365 off_t curr_offset; 366 paddr_t paddr, mdpgno; 367 int lcv, retval; 368 dev_t device; 369 paddr_t (*mapfn) __P((dev_t, off_t, int)); 370 vm_prot_t mapprot; 371 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 372 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 373 374 /* 375 * we do not allow device mappings to be mapped copy-on-write 376 * so we kill any attempt to do so here. 377 */ 378 379 if (UVM_ET_ISCOPYONWRITE(entry)) { 380 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 381 entry->etype, 0,0,0); 382 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 383 return(EIO); 384 } 385 386 /* 387 * get device map function. 388 */ 389 390 device = udv->u_device; 391 mapfn = cdevsw[major(device)].d_mmap; 392 393 /* 394 * now we must determine the offset in udv to use and the VA to 395 * use for pmap_enter. note that we always use orig_map's pmap 396 * for pmap_enter (even if we have a submap). since virtual 397 * addresses in a submap must match the main map, this is ok. 398 */ 399 400 /* udv offset = (offset from start of entry) + entry's offset */ 401 curr_offset = entry->offset + (vaddr - entry->start); 402 /* pmap va = vaddr (virtual address of pps[0]) */ 403 curr_va = vaddr; 404 405 /* 406 * loop over the page range entering in as needed 407 */ 408 409 retval = 0; 410 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 411 curr_va += PAGE_SIZE) { 412 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 413 continue; 414 415 if (pps[lcv] == PGO_DONTCARE) 416 continue; 417 418 mdpgno = (*mapfn)(device, curr_offset, access_type); 419 if (mdpgno == -1) { 420 retval = EIO; 421 break; 422 } 423 paddr = pmap_phys_address(mdpgno); 424 mapprot = ufi->entry->protection; 425 UVMHIST_LOG(maphist, 426 " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d", 427 ufi->orig_map->pmap, curr_va, paddr, mapprot); 428 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 429 mapprot, PMAP_CANFAIL | mapprot) != 0) { 430 /* 431 * pmap_enter() didn't have the resource to 432 * enter this mapping. Unlock everything, 433 * wait for the pagedaemon to free up some 434 * pages, and then tell uvm_fault() to start 435 * the fault again. 436 * 437 * XXX Needs some rethinking for the PGO_ALLPAGES 438 * XXX case. 439 */ 440 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 441 uobj, NULL); 442 pmap_update(ufi->orig_map->pmap); /* sync what we have so far */ 443 uvm_wait("udv_fault"); 444 return (ERESTART); 445 } 446 } 447 448 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 449 pmap_update(ufi->orig_map->pmap); 450 return (retval); 451 } 452