| 1 | /* $NetBSD: uvm_device.c,v 1.64 2014/12/14 23:48:58 chs Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 1997 Charles D. Cranor and Washington University. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 | * |
| 27 | * from: Id: uvm_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp |
| 28 | */ |
| 29 | |
| 30 | /* |
| 31 | * uvm_device.c: the device pager. |
| 32 | */ |
| 33 | |
| 34 | #include <sys/cdefs.h> |
| 35 | __KERNEL_RCSID(0, "$NetBSD: uvm_device.c,v 1.64 2014/12/14 23:48:58 chs Exp $" ); |
| 36 | |
| 37 | #include "opt_uvmhist.h" |
| 38 | |
| 39 | #include <sys/param.h> |
| 40 | #include <sys/systm.h> |
| 41 | #include <sys/conf.h> |
| 42 | #include <sys/proc.h> |
| 43 | #include <sys/kmem.h> |
| 44 | |
| 45 | #include <uvm/uvm.h> |
| 46 | #include <uvm/uvm_device.h> |
| 47 | #include <uvm/uvm_pmap.h> |
| 48 | |
| 49 | /* |
| 50 | * private global data structure |
| 51 | * |
| 52 | * we keep a list of active device objects in the system. |
| 53 | */ |
| 54 | |
| 55 | LIST_HEAD(udv_list_struct, uvm_device); |
| 56 | static struct udv_list_struct udv_list; |
| 57 | static kmutex_t udv_lock; |
| 58 | |
| 59 | /* |
| 60 | * functions |
| 61 | */ |
| 62 | |
| 63 | static void udv_init(void); |
| 64 | static void udv_reference(struct uvm_object *); |
| 65 | static void udv_detach(struct uvm_object *); |
| 66 | static int udv_fault(struct uvm_faultinfo *, vaddr_t, |
| 67 | struct vm_page **, int, int, vm_prot_t, |
| 68 | int); |
| 69 | |
| 70 | /* |
| 71 | * master pager structure |
| 72 | */ |
| 73 | |
| 74 | const struct uvm_pagerops uvm_deviceops = { |
| 75 | .pgo_init = udv_init, |
| 76 | .pgo_reference = udv_reference, |
| 77 | .pgo_detach = udv_detach, |
| 78 | .pgo_fault = udv_fault, |
| 79 | }; |
| 80 | |
| 81 | /* |
| 82 | * the ops! |
| 83 | */ |
| 84 | |
| 85 | /* |
| 86 | * udv_init |
| 87 | * |
| 88 | * init pager private data structures. |
| 89 | */ |
| 90 | |
| 91 | static void |
| 92 | udv_init(void) |
| 93 | { |
| 94 | LIST_INIT(&udv_list); |
| 95 | mutex_init(&udv_lock, MUTEX_DEFAULT, IPL_NONE); |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * udv_attach |
| 100 | * |
| 101 | * get a VM object that is associated with a device. allocate a new |
| 102 | * one if needed. |
| 103 | * |
| 104 | * => caller must _not_ already be holding the lock on the uvm_object. |
| 105 | * => in fact, nothing should be locked so that we can sleep here. |
| 106 | */ |
| 107 | |
| 108 | struct uvm_object * |
| 109 | udv_attach(dev_t device, vm_prot_t accessprot, |
| 110 | voff_t off, /* used only for access check */ |
| 111 | vsize_t size /* used only for access check */) |
| 112 | { |
| 113 | struct uvm_device *udv, *lcv; |
| 114 | const struct cdevsw *cdev; |
| 115 | dev_type_mmap((*mapfn)); |
| 116 | |
| 117 | UVMHIST_FUNC("udv_attach" ); UVMHIST_CALLED(maphist); |
| 118 | |
| 119 | UVMHIST_LOG(maphist, "(device=0x%x)" , device,0,0,0); |
| 120 | |
| 121 | /* |
| 122 | * before we do anything, ensure this device supports mmap |
| 123 | */ |
| 124 | |
| 125 | cdev = cdevsw_lookup(device); |
| 126 | if (cdev == NULL) { |
| 127 | return (NULL); |
| 128 | } |
| 129 | mapfn = cdev->d_mmap; |
| 130 | if (mapfn == NULL || mapfn == nommap || mapfn == nullmmap) { |
| 131 | return(NULL); |
| 132 | } |
| 133 | |
| 134 | /* |
| 135 | * Negative offsets on the object are not allowed. |
| 136 | */ |
| 137 | |
| 138 | if ((cdev->d_flag & D_NEGOFFSAFE) == 0 && |
| 139 | off != UVM_UNKNOWN_OFFSET && 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 (cdev_mmap(device, off, accessprot) == -1) { |
| 152 | return (NULL); |
| 153 | } |
| 154 | off += PAGE_SIZE; size -= PAGE_SIZE; |
| 155 | } |
| 156 | |
| 157 | /* |
| 158 | * keep looping until we get it |
| 159 | */ |
| 160 | |
| 161 | for (;;) { |
| 162 | |
| 163 | /* |
| 164 | * first, attempt to find it on the main list |
| 165 | */ |
| 166 | |
| 167 | mutex_enter(&udv_lock); |
| 168 | LIST_FOREACH(lcv, &udv_list, u_list) { |
| 169 | if (device == lcv->u_device) |
| 170 | break; |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * got it on main list. put a hold on it and unlock udv_lock. |
| 175 | */ |
| 176 | |
| 177 | if (lcv) { |
| 178 | |
| 179 | /* |
| 180 | * if someone else has a hold on it, sleep and start |
| 181 | * over again. |
| 182 | */ |
| 183 | |
| 184 | if (lcv->u_flags & UVM_DEVICE_HOLD) { |
| 185 | lcv->u_flags |= UVM_DEVICE_WANTED; |
| 186 | UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, false, |
| 187 | "udv_attach" ,0); |
| 188 | continue; |
| 189 | } |
| 190 | |
| 191 | /* we are now holding it */ |
| 192 | lcv->u_flags |= UVM_DEVICE_HOLD; |
| 193 | mutex_exit(&udv_lock); |
| 194 | |
| 195 | /* |
| 196 | * bump reference count, unhold, return. |
| 197 | */ |
| 198 | |
| 199 | mutex_enter(lcv->u_obj.vmobjlock); |
| 200 | lcv->u_obj.uo_refs++; |
| 201 | mutex_exit(lcv->u_obj.vmobjlock); |
| 202 | |
| 203 | mutex_enter(&udv_lock); |
| 204 | if (lcv->u_flags & UVM_DEVICE_WANTED) |
| 205 | wakeup(lcv); |
| 206 | lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); |
| 207 | mutex_exit(&udv_lock); |
| 208 | return(&lcv->u_obj); |
| 209 | } |
| 210 | |
| 211 | /* |
| 212 | * Did not find it on main list. Need to allocate a new one. |
| 213 | */ |
| 214 | |
| 215 | mutex_exit(&udv_lock); |
| 216 | |
| 217 | /* Note: both calls may allocate memory and sleep. */ |
| 218 | udv = kmem_alloc(sizeof(*udv), KM_SLEEP); |
| 219 | uvm_obj_init(&udv->u_obj, &uvm_deviceops, true, 1); |
| 220 | |
| 221 | mutex_enter(&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 | mutex_exit(&udv_lock); |
| 240 | uvm_obj_destroy(&udv->u_obj, true); |
| 241 | kmem_free(udv, sizeof(*udv)); |
| 242 | continue; |
| 243 | } |
| 244 | |
| 245 | /* |
| 246 | * we have it! init the data structures, add to list |
| 247 | * and return. |
| 248 | */ |
| 249 | |
| 250 | udv->u_flags = 0; |
| 251 | udv->u_device = device; |
| 252 | LIST_INSERT_HEAD(&udv_list, udv, u_list); |
| 253 | mutex_exit(&udv_lock); |
| 254 | return(&udv->u_obj); |
| 255 | } |
| 256 | /*NOTREACHED*/ |
| 257 | } |
| 258 | |
| 259 | /* |
| 260 | * udv_reference |
| 261 | * |
| 262 | * add a reference to a VM object. Note that the reference count must |
| 263 | * already be one (the passed in reference) so there is no chance of the |
| 264 | * udv being released or locked out here. |
| 265 | * |
| 266 | * => caller must call with object unlocked. |
| 267 | */ |
| 268 | |
| 269 | static void |
| 270 | udv_reference(struct uvm_object *uobj) |
| 271 | { |
| 272 | UVMHIST_FUNC("udv_reference" ); UVMHIST_CALLED(maphist); |
| 273 | |
| 274 | mutex_enter(uobj->vmobjlock); |
| 275 | uobj->uo_refs++; |
| 276 | UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)" , |
| 277 | uobj, uobj->uo_refs,0,0); |
| 278 | mutex_exit(uobj->vmobjlock); |
| 279 | } |
| 280 | |
| 281 | /* |
| 282 | * udv_detach |
| 283 | * |
| 284 | * remove a reference to a VM object. |
| 285 | * |
| 286 | * => caller must call with object unlocked and map locked. |
| 287 | */ |
| 288 | |
| 289 | static void |
| 290 | udv_detach(struct uvm_object *uobj) |
| 291 | { |
| 292 | struct uvm_device *udv = (struct uvm_device *)uobj; |
| 293 | UVMHIST_FUNC("udv_detach" ); UVMHIST_CALLED(maphist); |
| 294 | |
| 295 | /* |
| 296 | * loop until done |
| 297 | */ |
| 298 | again: |
| 299 | mutex_enter(uobj->vmobjlock); |
| 300 | if (uobj->uo_refs > 1) { |
| 301 | uobj->uo_refs--; |
| 302 | mutex_exit(uobj->vmobjlock); |
| 303 | UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d" , |
| 304 | uobj,uobj->uo_refs,0,0); |
| 305 | return; |
| 306 | } |
| 307 | |
| 308 | /* |
| 309 | * is it being held? if so, wait until others are done. |
| 310 | */ |
| 311 | |
| 312 | mutex_enter(&udv_lock); |
| 313 | if (udv->u_flags & UVM_DEVICE_HOLD) { |
| 314 | udv->u_flags |= UVM_DEVICE_WANTED; |
| 315 | mutex_exit(uobj->vmobjlock); |
| 316 | UVM_UNLOCK_AND_WAIT(udv, &udv_lock, false, "udv_detach" ,0); |
| 317 | goto again; |
| 318 | } |
| 319 | |
| 320 | /* |
| 321 | * got it! nuke it now. |
| 322 | */ |
| 323 | |
| 324 | LIST_REMOVE(udv, u_list); |
| 325 | if (udv->u_flags & UVM_DEVICE_WANTED) |
| 326 | wakeup(udv); |
| 327 | mutex_exit(&udv_lock); |
| 328 | mutex_exit(uobj->vmobjlock); |
| 329 | |
| 330 | uvm_obj_destroy(uobj, true); |
| 331 | kmem_free(udv, sizeof(*udv)); |
| 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_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 | vaddr_t curr_va; |
| 360 | off_t curr_offset; |
| 361 | paddr_t paddr, mdpgno; |
| 362 | u_int mmapflags; |
| 363 | int lcv, retval; |
| 364 | dev_t device; |
| 365 | vm_prot_t mapprot; |
| 366 | UVMHIST_FUNC("udv_fault" ); UVMHIST_CALLED(maphist); |
| 367 | UVMHIST_LOG(maphist," flags=%d" , flags,0,0,0); |
| 368 | |
| 369 | /* |
| 370 | * we do not allow device mappings to be mapped copy-on-write |
| 371 | * so we kill any attempt to do so here. |
| 372 | */ |
| 373 | |
| 374 | if (UVM_ET_ISCOPYONWRITE(entry)) { |
| 375 | UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)" , |
| 376 | entry->etype, 0,0,0); |
| 377 | uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj); |
| 378 | return(EIO); |
| 379 | } |
| 380 | |
| 381 | /* |
| 382 | * get device map function. |
| 383 | */ |
| 384 | |
| 385 | device = udv->u_device; |
| 386 | if (cdevsw_lookup(device) == NULL) { |
| 387 | /* XXX This should not happen */ |
| 388 | uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj); |
| 389 | return (EIO); |
| 390 | } |
| 391 | |
| 392 | /* |
| 393 | * now we must determine the offset in udv to use and the VA to |
| 394 | * use for pmap_enter. note that we always use orig_map's pmap |
| 395 | * for pmap_enter (even if we have a submap). since virtual |
| 396 | * addresses in a submap must match the main map, this is ok. |
| 397 | */ |
| 398 | |
| 399 | /* udv offset = (offset from start of entry) + entry's offset */ |
| 400 | curr_offset = entry->offset + (vaddr - entry->start); |
| 401 | /* pmap va = vaddr (virtual address of pps[0]) */ |
| 402 | curr_va = vaddr; |
| 403 | |
| 404 | /* |
| 405 | * loop over the page range entering in as needed |
| 406 | */ |
| 407 | |
| 408 | retval = 0; |
| 409 | for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, |
| 410 | curr_va += PAGE_SIZE) { |
| 411 | if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) |
| 412 | continue; |
| 413 | |
| 414 | if (pps[lcv] == PGO_DONTCARE) |
| 415 | continue; |
| 416 | |
| 417 | mdpgno = cdev_mmap(device, curr_offset, access_type); |
| 418 | if (mdpgno == -1) { |
| 419 | retval = EIO; |
| 420 | break; |
| 421 | } |
| 422 | paddr = pmap_phys_address(mdpgno); |
| 423 | mmapflags = pmap_mmap_flags(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, mapprot, |
| 429 | PMAP_CANFAIL | mapprot | mmapflags) != 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 | pmap_update(ufi->orig_map->pmap); /* sync what we have so far */ |
| 441 | uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, |
| 442 | uobj); |
| 443 | uvm_wait("udv_fault" ); |
| 444 | return (ERESTART); |
| 445 | } |
| 446 | } |
| 447 | |
| 448 | pmap_update(ufi->orig_map->pmap); |
| 449 | uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj); |
| 450 | return (retval); |
| 451 | } |
| 452 | |