1 /*- 2 * Copyright (c) 2005-2008, Sam Leffler <sam@errno.com> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/kernel.h> 32 #include <sys/malloc.h> 33 #include <sys/queue.h> 34 #include <sys/taskqueue.h> 35 #include <sys/systm.h> 36 #include <sys/lock.h> 37 #include <sys/mutex.h> 38 #include <sys/errno.h> 39 #include <sys/linker.h> 40 #include <sys/firmware.h> 41 #include <sys/priv.h> 42 #include <sys/proc.h> 43 #include <sys/module.h> 44 #include <sys/eventhandler.h> 45 46 #include <sys/filedesc.h> 47 #include <sys/vnode.h> 48 49 /* 50 * Loadable firmware support. See sys/sys/firmware.h and firmware(9) 51 * form more details on the subsystem. 52 * 53 * 'struct firmware' is the user-visible part of the firmware table. 54 * Additional internal information is stored in a 'struct priv_fw' 55 * (currently a static array). A slot is in use if FW_INUSE is true: 56 */ 57 58 #define FW_INUSE(p) ((p)->file != NULL || (p)->fw.name != NULL) 59 60 /* 61 * fw.name != NULL when an image is registered; file != NULL for 62 * autoloaded images whose handling has not been completed. 63 * 64 * The state of a slot evolves as follows: 65 * firmware_register --> fw.name = image_name 66 * (autoloaded image) --> file = module reference 67 * firmware_unregister --> fw.name = NULL 68 * (unloadentry complete) --> file = NULL 69 * 70 * In order for the above to work, the 'file' field must remain 71 * unchanged in firmware_unregister(). 72 * 73 * Images residing in the same module are linked to each other 74 * through the 'parent' argument of firmware_register(). 75 * One image (typically, one with the same name as the module to let 76 * the autoloading mechanism work) is considered the parent image for 77 * all other images in the same module. Children affect the refcount 78 * on the parent image preventing improper unloading of the image itself. 79 */ 80 81 struct priv_fw { 82 int refcnt; /* reference count */ 83 84 /* 85 * parent entry, see above. Set on firmware_register(), 86 * cleared on firmware_unregister(). 87 */ 88 struct priv_fw *parent; 89 90 int flags; /* record FIRMWARE_UNLOAD requests */ 91 #define FW_UNLOAD 0x100 92 93 /* 94 * 'file' is private info managed by the autoload/unload code. 95 * Set at the end of firmware_get(), cleared only in the 96 * firmware_unload_task, so the latter can depend on its value even 97 * while the lock is not held. 98 */ 99 linker_file_t file; /* module file, if autoloaded */ 100 101 /* 102 * 'fw' is the externally visible image information. 103 * We do not make it the first field in priv_fw, to avoid the 104 * temptation of casting pointers to each other. 105 * Use PRIV_FW(fw) to get a pointer to the cointainer of fw. 106 * Beware, PRIV_FW does not work for a NULL pointer. 107 */ 108 struct firmware fw; /* externally visible information */ 109 }; 110 111 /* 112 * PRIV_FW returns the pointer to the container of struct firmware *x. 113 * Cast to intptr_t to override the 'const' attribute of x 114 */ 115 #define PRIV_FW(x) ((struct priv_fw *) \ 116 ((intptr_t)(x) - offsetof(struct priv_fw, fw)) ) 117 118 /* 119 * At the moment we use a static array as backing store for the registry. 120 * Should we move to a dynamic structure, keep in mind that we cannot 121 * reallocate the array because pointers are held externally. 122 * A list may work, though. 123 */ 124 #define FIRMWARE_MAX 50 125 static struct priv_fw firmware_table[FIRMWARE_MAX]; 126 127 /* 128 * Firmware module operations are handled in a separate task as they 129 * might sleep and they require directory context to do i/o. 130 */ 131 static struct taskqueue *firmware_tq; 132 static struct task firmware_unload_task; 133 134 /* 135 * This mutex protects accesses to the firmware table. 136 */ 137 static struct mtx firmware_mtx; 138 MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF); 139 140 /* 141 * Helper function to lookup a name. 142 * As a side effect, it sets the pointer to a free slot, if any. 143 * This way we can concentrate most of the registry scanning in 144 * this function, which makes it easier to replace the registry 145 * with some other data structure. 146 */ 147 static struct priv_fw * 148 lookup(const char *name, struct priv_fw **empty_slot) 149 { 150 struct priv_fw *fp = NULL; 151 struct priv_fw *dummy; 152 int i; 153 154 if (empty_slot == NULL) 155 empty_slot = &dummy; 156 *empty_slot = NULL; 157 for (i = 0; i < FIRMWARE_MAX; i++) { 158 fp = &firmware_table[i]; 159 if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0) 160 break; 161 else if (!FW_INUSE(fp)) 162 *empty_slot = fp; 163 } 164 return (i < FIRMWARE_MAX ) ? fp : NULL; 165 } 166 167 /* 168 * Register a firmware image with the specified name. The 169 * image name must not already be registered. If this is a 170 * subimage then parent refers to a previously registered 171 * image that this should be associated with. 172 */ 173 const struct firmware * 174 firmware_register(const char *imagename, const void *data, size_t datasize, 175 unsigned int version, const struct firmware *parent) 176 { 177 struct priv_fw *match, *frp; 178 char *str; 179 180 str = strdup(imagename, M_TEMP); 181 182 mtx_lock(&firmware_mtx); 183 /* 184 * Do a lookup to make sure the name is unique or find a free slot. 185 */ 186 match = lookup(imagename, &frp); 187 if (match != NULL) { 188 mtx_unlock(&firmware_mtx); 189 printf("%s: image %s already registered!\n", 190 __func__, imagename); 191 free(str, M_TEMP); 192 return NULL; 193 } 194 if (frp == NULL) { 195 mtx_unlock(&firmware_mtx); 196 printf("%s: cannot register image %s, firmware table full!\n", 197 __func__, imagename); 198 free(str, M_TEMP); 199 return NULL; 200 } 201 bzero(frp, sizeof(*frp)); /* start from a clean record */ 202 frp->fw.name = str; 203 frp->fw.data = data; 204 frp->fw.datasize = datasize; 205 frp->fw.version = version; 206 if (parent != NULL) 207 frp->parent = PRIV_FW(parent); 208 mtx_unlock(&firmware_mtx); 209 if (bootverbose) 210 printf("firmware: '%s' version %u: %zu bytes loaded at %p\n", 211 imagename, version, datasize, data); 212 return &frp->fw; 213 } 214 215 /* 216 * Unregister/remove a firmware image. If there are outstanding 217 * references an error is returned and the image is not removed 218 * from the registry. 219 */ 220 int 221 firmware_unregister(const char *imagename) 222 { 223 struct priv_fw *fp; 224 int err; 225 226 mtx_lock(&firmware_mtx); 227 fp = lookup(imagename, NULL); 228 if (fp == NULL) { 229 /* 230 * It is ok for the lookup to fail; this can happen 231 * when a module is unloaded on last reference and the 232 * module unload handler unregister's each of it's 233 * firmware images. 234 */ 235 err = 0; 236 } else if (fp->refcnt != 0) { /* cannot unregister */ 237 err = EBUSY; 238 } else { 239 linker_file_t x = fp->file; /* save value */ 240 241 /* 242 * Clear the whole entry with bzero to make sure we 243 * do not forget anything. Then restore 'file' which is 244 * non-null for autoloaded images. 245 */ 246 free((void *) (uintptr_t) fp->fw.name, M_TEMP); 247 bzero(fp, sizeof(struct priv_fw)); 248 fp->file = x; 249 err = 0; 250 } 251 mtx_unlock(&firmware_mtx); 252 return err; 253 } 254 255 static void 256 loadimage(void *arg, int npending) 257 { 258 struct thread *td = curthread; 259 char *imagename = arg; 260 struct priv_fw *fp; 261 linker_file_t result; 262 int error; 263 264 /* synchronize with the thread that dispatched us */ 265 mtx_lock(&firmware_mtx); 266 mtx_unlock(&firmware_mtx); 267 268 if (td->td_proc->p_fd->fd_rdir == NULL) { 269 printf("%s: root not mounted yet, no way to load image\n", 270 imagename); 271 goto done; 272 } 273 error = linker_reference_module(imagename, NULL, &result); 274 if (error != 0) { 275 printf("%s: could not load firmware image, error %d\n", 276 imagename, error); 277 goto done; 278 } 279 280 mtx_lock(&firmware_mtx); 281 fp = lookup(imagename, NULL); 282 if (fp == NULL || fp->file != NULL) { 283 mtx_unlock(&firmware_mtx); 284 if (fp == NULL) 285 printf("%s: firmware image loaded, " 286 "but did not register\n", imagename); 287 (void) linker_release_module(imagename, NULL, NULL); 288 goto done; 289 } 290 fp->file = result; /* record the module identity */ 291 mtx_unlock(&firmware_mtx); 292 done: 293 wakeup_one(imagename); /* we're done */ 294 } 295 296 /* 297 * Lookup and potentially load the specified firmware image. 298 * If the firmware is not found in the registry, try to load a kernel 299 * module named as the image name. 300 * If the firmware is located, a reference is returned. The caller must 301 * release this reference for the image to be eligible for removal/unload. 302 */ 303 const struct firmware * 304 firmware_get(const char *imagename) 305 { 306 struct task fwload_task; 307 struct thread *td; 308 struct priv_fw *fp; 309 310 mtx_lock(&firmware_mtx); 311 fp = lookup(imagename, NULL); 312 if (fp != NULL) 313 goto found; 314 /* 315 * Image not present, try to load the module holding it. 316 */ 317 td = curthread; 318 if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 || 319 securelevel_gt(td->td_ucred, 0) != 0) { 320 mtx_unlock(&firmware_mtx); 321 printf("%s: insufficient privileges to " 322 "load firmware image %s\n", __func__, imagename); 323 return NULL; 324 } 325 /* 326 * Defer load to a thread with known context. linker_reference_module 327 * may do filesystem i/o which requires root & current dirs, etc. 328 * Also we must not hold any mtx's over this call which is problematic. 329 */ 330 if (!cold) { 331 TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *, 332 imagename)); 333 taskqueue_enqueue(firmware_tq, &fwload_task); 334 msleep(__DECONST(void *, imagename), &firmware_mtx, 0, 335 "fwload", 0); 336 } 337 /* 338 * After attempting to load the module, see if the image is registered. 339 */ 340 fp = lookup(imagename, NULL); 341 if (fp == NULL) { 342 mtx_unlock(&firmware_mtx); 343 return NULL; 344 } 345 found: /* common exit point on success */ 346 if (fp->refcnt == 0 && fp->parent != NULL) 347 fp->parent->refcnt++; 348 fp->refcnt++; 349 mtx_unlock(&firmware_mtx); 350 return &fp->fw; 351 } 352 353 /* 354 * Release a reference to a firmware image returned by firmware_get. 355 * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire 356 * to release the resource, but the flag is only advisory. 357 * 358 * If this is the last reference to the firmware image, and this is an 359 * autoloaded module, wake up the firmware_unload_task to figure out 360 * what to do with the associated module. 361 */ 362 void 363 firmware_put(const struct firmware *p, int flags) 364 { 365 struct priv_fw *fp = PRIV_FW(p); 366 367 mtx_lock(&firmware_mtx); 368 fp->refcnt--; 369 if (fp->refcnt == 0) { 370 if (fp->parent != NULL) 371 fp->parent->refcnt--; 372 if (flags & FIRMWARE_UNLOAD) 373 fp->flags |= FW_UNLOAD; 374 if (fp->file) 375 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 376 } 377 mtx_unlock(&firmware_mtx); 378 } 379 380 /* 381 * Setup directory state for the firmware_tq thread so we can do i/o. 382 */ 383 static void 384 set_rootvnode(void *arg, int npending) 385 { 386 struct thread *td = curthread; 387 struct proc *p = td->td_proc; 388 389 FILEDESC_XLOCK(p->p_fd); 390 if (p->p_fd->fd_cdir == NULL) { 391 p->p_fd->fd_cdir = rootvnode; 392 VREF(rootvnode); 393 } 394 if (p->p_fd->fd_rdir == NULL) { 395 p->p_fd->fd_rdir = rootvnode; 396 VREF(rootvnode); 397 } 398 FILEDESC_XUNLOCK(p->p_fd); 399 400 free(arg, M_TEMP); 401 } 402 403 /* 404 * Event handler called on mounting of /; bounce a task 405 * into the task queue thread to setup it's directories. 406 */ 407 static void 408 firmware_mountroot(void *arg) 409 { 410 struct task *setroot_task; 411 412 setroot_task = malloc(sizeof(struct task), M_TEMP, M_NOWAIT); 413 if (setroot_task != NULL) { 414 TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task); 415 taskqueue_enqueue(firmware_tq, setroot_task); 416 } else 417 printf("%s: no memory for task!\n", __func__); 418 } 419 EVENTHANDLER_DEFINE(mountroot, firmware_mountroot, NULL, 0); 420 421 /* 422 * The body of the task in charge of unloading autoloaded modules 423 * that are not needed anymore. 424 * Images can be cross-linked so we may need to make multiple passes, 425 * but the time we spend in the loop is bounded because we clear entries 426 * as we touch them. 427 */ 428 static void 429 unloadentry(void *unused1, int unused2) 430 { 431 int limit = FIRMWARE_MAX; 432 int i; /* current cycle */ 433 434 mtx_lock(&firmware_mtx); 435 /* 436 * Scan the table. limit is set to make sure we make another 437 * full sweep after matching an entry that requires unloading. 438 */ 439 for (i = 0; i < limit; i++) { 440 struct priv_fw *fp; 441 int err; 442 443 fp = &firmware_table[i % FIRMWARE_MAX]; 444 if (fp->fw.name == NULL || fp->file == NULL || 445 fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0) 446 continue; 447 448 /* 449 * Found an entry. Now: 450 * 1. bump up limit to make sure we make another full round; 451 * 2. clear FW_UNLOAD so we don't try this entry again. 452 * 3. release the lock while trying to unload the module. 453 * 'file' remains set so that the entry cannot be reused 454 * in the meantime (it also means that fp->file will 455 * not change while we release the lock). 456 */ 457 limit = i + FIRMWARE_MAX; /* make another full round */ 458 fp->flags &= ~FW_UNLOAD; /* do not try again */ 459 460 mtx_unlock(&firmware_mtx); 461 err = linker_release_module(NULL, NULL, fp->file); 462 mtx_lock(&firmware_mtx); 463 464 /* 465 * We rely on the module to call firmware_unregister() 466 * on unload to actually release the entry. 467 * If err = 0 we can drop our reference as the system 468 * accepted it. Otherwise unloading failed (e.g. the 469 * module itself gave an error) so our reference is 470 * still valid. 471 */ 472 if (err == 0) 473 fp->file = NULL; 474 } 475 mtx_unlock(&firmware_mtx); 476 } 477 478 /* 479 * Module glue. 480 */ 481 static int 482 firmware_modevent(module_t mod, int type, void *unused) 483 { 484 struct priv_fw *fp; 485 int i, err; 486 487 switch (type) { 488 case MOD_LOAD: 489 TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL); 490 firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK, 491 taskqueue_thread_enqueue, &firmware_tq); 492 /* NB: use our own loop routine that sets up context */ 493 (void) taskqueue_start_threads(&firmware_tq, 1, PWAIT, 494 "firmware taskq"); 495 if (rootvnode != NULL) { 496 /* 497 * Root is already mounted so we won't get an event; 498 * simulate one here. 499 */ 500 firmware_mountroot(NULL); 501 } 502 return 0; 503 504 case MOD_UNLOAD: 505 /* request all autoloaded modules to be released */ 506 mtx_lock(&firmware_mtx); 507 for (i = 0; i < FIRMWARE_MAX; i++) { 508 fp = &firmware_table[i]; 509 fp->flags |= FW_UNLOAD; 510 } 511 mtx_unlock(&firmware_mtx); 512 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 513 taskqueue_drain(firmware_tq, &firmware_unload_task); 514 err = 0; 515 for (i = 0; i < FIRMWARE_MAX; i++) { 516 fp = &firmware_table[i]; 517 if (fp->fw.name != NULL) { 518 printf("%s: image %p ref %d still active slot %d\n", 519 __func__, fp->fw.name, 520 fp->refcnt, i); 521 err = EINVAL; 522 } 523 } 524 if (err == 0) 525 taskqueue_free(firmware_tq); 526 return err; 527 } 528 return EINVAL; 529 } 530 531 static moduledata_t firmware_mod = { 532 "firmware", 533 firmware_modevent, 534 NULL 535 }; 536 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 537 MODULE_VERSION(firmware, 1); 538