1 /* $NetBSD: uvm_device.c,v 1.46 2005/12/11 12:25:29 christos 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 1.46 2005/12/11 12:25:29 christos 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(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_fault_t, vm_prot_t, 75 int); 76 77 /* 78 * master pager structure 79 */ 80 81 struct uvm_pagerops uvm_deviceops = { 82 udv_init, 83 udv_reference, 84 udv_detach, 85 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 simple_lock_init(&udv_lock); 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 mapfn = cdev->d_mmap; 137 if (mapfn == NULL || mapfn == nommap || mapfn == nullmmap) 138 return(NULL); 139 140 /* 141 * Negative offsets on the object are not allowed. 142 */ 143 144 if (off < 0) 145 return(NULL); 146 147 /* 148 * Check that the specified range of the device allows the 149 * desired protection. 150 * 151 * XXX assumes VM_PROT_* == PROT_* 152 * XXX clobbers off and size, but nothing else here needs them. 153 */ 154 155 while (size != 0) { 156 if ((*mapfn)(device, off, accessprot) == -1) 157 return (NULL); 158 off += PAGE_SIZE; size -= PAGE_SIZE; 159 } 160 161 /* 162 * keep looping until we get it 163 */ 164 165 for (;;) { 166 167 /* 168 * first, attempt to find it on the main list 169 */ 170 171 simple_lock(&udv_lock); 172 LIST_FOREACH(lcv, &udv_list, u_list) { 173 if (device == lcv->u_device) 174 break; 175 } 176 177 /* 178 * got it on main list. put a hold on it and unlock udv_lock. 179 */ 180 181 if (lcv) { 182 183 /* 184 * if someone else has a hold on it, sleep and start 185 * over again. 186 */ 187 188 if (lcv->u_flags & UVM_DEVICE_HOLD) { 189 lcv->u_flags |= UVM_DEVICE_WANTED; 190 UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, FALSE, 191 "udv_attach",0); 192 continue; 193 } 194 195 /* we are now holding it */ 196 lcv->u_flags |= UVM_DEVICE_HOLD; 197 simple_unlock(&udv_lock); 198 199 /* 200 * bump reference count, unhold, return. 201 */ 202 203 simple_lock(&lcv->u_obj.vmobjlock); 204 lcv->u_obj.uo_refs++; 205 simple_unlock(&lcv->u_obj.vmobjlock); 206 207 simple_lock(&udv_lock); 208 if (lcv->u_flags & UVM_DEVICE_WANTED) 209 wakeup(lcv); 210 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 211 simple_unlock(&udv_lock); 212 return(&lcv->u_obj); 213 } 214 215 /* 216 * did not find it on main list. need to malloc a new one. 217 */ 218 219 simple_unlock(&udv_lock); 220 /* NOTE: we could sleep in the following malloc() */ 221 MALLOC(udv, struct uvm_device *, sizeof(*udv), M_TEMP, 222 M_WAITOK); 223 simple_lock(&udv_lock); 224 225 /* 226 * now we have to double check to make sure no one added it 227 * to the list while we were sleeping... 228 */ 229 230 LIST_FOREACH(lcv, &udv_list, u_list) { 231 if (device == lcv->u_device) 232 break; 233 } 234 235 /* 236 * did we lose a race to someone else? 237 * free our memory and retry. 238 */ 239 240 if (lcv) { 241 simple_unlock(&udv_lock); 242 FREE(udv, M_TEMP); 243 continue; 244 } 245 246 /* 247 * we have it! init the data structures, add to list 248 * and return. 249 */ 250 251 UVM_OBJ_INIT(&udv->u_obj, &uvm_deviceops, 1); 252 udv->u_flags = 0; 253 udv->u_device = device; 254 LIST_INSERT_HEAD(&udv_list, udv, u_list); 255 simple_unlock(&udv_lock); 256 return(&udv->u_obj); 257 } 258 /*NOTREACHED*/ 259 } 260 261 /* 262 * udv_reference 263 * 264 * add a reference to a VM object. Note that the reference count must 265 * already be one (the passed in reference) so there is no chance of the 266 * udv being released or locked out here. 267 * 268 * => caller must call with object unlocked. 269 */ 270 271 static void 272 udv_reference(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(struct uvm_object *uobj) 293 { 294 struct uvm_device *udv = (struct uvm_device *)uobj; 295 UVMHIST_FUNC("udv_detach"); UVMHIST_CALLED(maphist); 296 297 /* 298 * loop until done 299 */ 300 again: 301 simple_lock(&uobj->vmobjlock); 302 if (uobj->uo_refs > 1) { 303 uobj->uo_refs--; 304 simple_unlock(&uobj->vmobjlock); 305 UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d", 306 uobj,uobj->uo_refs,0,0); 307 return; 308 } 309 310 /* 311 * is it being held? if so, wait until others are done. 312 */ 313 314 simple_lock(&udv_lock); 315 if (udv->u_flags & UVM_DEVICE_HOLD) { 316 udv->u_flags |= UVM_DEVICE_WANTED; 317 simple_unlock(&uobj->vmobjlock); 318 UVM_UNLOCK_AND_WAIT(udv, &udv_lock, FALSE, "udv_detach",0); 319 goto again; 320 } 321 322 /* 323 * got it! nuke it now. 324 */ 325 326 LIST_REMOVE(udv, u_list); 327 if (udv->u_flags & UVM_DEVICE_WANTED) 328 wakeup(udv); 329 simple_unlock(&udv_lock); 330 simple_unlock(&uobj->vmobjlock); 331 FREE(udv, M_TEMP); 332 UVMHIST_LOG(maphist," <- done, freed uobj=0x%x", uobj,0,0,0); 333 } 334 335 /* 336 * udv_fault: non-standard fault routine for device "pages" 337 * 338 * => rather than having a "get" function, we have a fault routine 339 * since we don't return vm_pages we need full control over the 340 * pmap_enter map in 341 * => all the usual fault data structured are locked by the caller 342 * (i.e. maps(read), amap (if any), uobj) 343 * => on return, we unlock all fault data structures 344 * => flags: PGO_ALLPAGES: get all of the pages 345 * PGO_LOCKED: fault data structures are locked 346 * XXX: currently PGO_LOCKED is always required ... consider removing 347 * it as a flag 348 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 349 */ 350 351 static int 352 udv_fault(struct uvm_faultinfo *ufi, vaddr_t vaddr, struct vm_page **pps, 353 int npages, int centeridx, vm_fault_t fault_type, vm_prot_t access_type, 354 int flags) 355 { 356 struct vm_map_entry *entry = ufi->entry; 357 struct uvm_object *uobj = entry->object.uvm_obj; 358 struct uvm_device *udv = (struct uvm_device *)uobj; 359 const struct cdevsw *cdev; 360 vaddr_t curr_va; 361 off_t curr_offset; 362 paddr_t paddr, mdpgno; 363 int lcv, retval; 364 dev_t device; 365 paddr_t (*mapfn)(dev_t, off_t, int); 366 vm_prot_t mapprot; 367 UVMHIST_FUNC("udv_fault"); UVMHIST_CALLED(maphist); 368 UVMHIST_LOG(maphist," flags=%d", flags,0,0,0); 369 370 /* 371 * we do not allow device mappings to be mapped copy-on-write 372 * so we kill any attempt to do so here. 373 */ 374 375 if (UVM_ET_ISCOPYONWRITE(entry)) { 376 UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)", 377 entry->etype, 0,0,0); 378 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 379 return(EIO); 380 } 381 382 /* 383 * get device map function. 384 */ 385 386 device = udv->u_device; 387 cdev = cdevsw_lookup(device); 388 if (cdev == NULL) { 389 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 390 return (EIO); 391 } 392 mapfn = cdev->d_mmap; 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 = (*mapfn)(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 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 442 uobj, NULL); 443 pmap_update(ufi->orig_map->pmap); /* sync what we have so far */ 444 uvm_wait("udv_fault"); 445 return (ERESTART); 446 } 447 } 448 449 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 450 pmap_update(ufi->orig_map->pmap); 451 return (retval); 452 } 453