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; 178 179 mtx_lock(&firmware_mtx); 180 /* 181 * Do a lookup to make sure the name is unique or find a free slot. 182 */ 183 match = lookup(imagename, &frp); 184 if (match != NULL) { 185 mtx_unlock(&firmware_mtx); 186 printf("%s: image %s already registered!\n", 187 __func__, imagename); 188 return NULL; 189 } 190 if (frp == NULL) { 191 mtx_unlock(&firmware_mtx); 192 printf("%s: cannot register image %s, firmware table full!\n", 193 __func__, imagename); 194 return NULL; 195 } 196 bzero(frp, sizeof(frp)); /* start from a clean record */ 197 frp->fw.name = imagename; 198 frp->fw.data = data; 199 frp->fw.datasize = datasize; 200 frp->fw.version = version; 201 if (parent != NULL) 202 frp->parent = PRIV_FW(parent); 203 mtx_unlock(&firmware_mtx); 204 if (bootverbose) 205 printf("firmware: '%s' version %u: %zu bytes loaded at %p\n", 206 imagename, version, datasize, data); 207 return &frp->fw; 208 } 209 210 /* 211 * Unregister/remove a firmware image. If there are outstanding 212 * references an error is returned and the image is not removed 213 * from the registry. 214 */ 215 int 216 firmware_unregister(const char *imagename) 217 { 218 struct priv_fw *fp; 219 int err; 220 221 mtx_lock(&firmware_mtx); 222 fp = lookup(imagename, NULL); 223 if (fp == NULL) { 224 /* 225 * It is ok for the lookup to fail; this can happen 226 * when a module is unloaded on last reference and the 227 * module unload handler unregister's each of it's 228 * firmware images. 229 */ 230 err = 0; 231 } else if (fp->refcnt != 0) { /* cannot unregister */ 232 err = EBUSY; 233 } else { 234 linker_file_t x = fp->file; /* save value */ 235 236 /* 237 * Clear the whole entry with bzero to make sure we 238 * do not forget anything. Then restore 'file' which is 239 * non-null for autoloaded images. 240 */ 241 bzero(fp, sizeof(struct priv_fw)); 242 fp->file = x; 243 err = 0; 244 } 245 mtx_unlock(&firmware_mtx); 246 return err; 247 } 248 249 static void 250 loadimage(void *arg, int npending) 251 { 252 struct thread *td = curthread; 253 char *imagename = arg; 254 struct priv_fw *fp; 255 linker_file_t result; 256 int error; 257 258 /* synchronize with the thread that dispatched us */ 259 mtx_lock(&firmware_mtx); 260 mtx_unlock(&firmware_mtx); 261 262 if (td->td_proc->p_fd->fd_rdir == NULL) { 263 printf("%s: root not mounted yet, no way to load image\n", 264 imagename); 265 goto done; 266 } 267 error = linker_reference_module(imagename, NULL, &result); 268 if (error != 0) { 269 printf("%s: could not load firmware image, error %d\n", 270 imagename, error); 271 goto done; 272 } 273 274 mtx_lock(&firmware_mtx); 275 fp = lookup(imagename, NULL); 276 if (fp == NULL || fp->file != NULL) { 277 mtx_unlock(&firmware_mtx); 278 if (fp == NULL) 279 printf("%s: firmware image loaded, " 280 "but did not register\n", imagename); 281 (void) linker_release_module(imagename, NULL, NULL); 282 goto done; 283 } 284 fp->file = result; /* record the module identity */ 285 mtx_unlock(&firmware_mtx); 286 done: 287 wakeup_one(imagename); /* we're done */ 288 } 289 290 /* 291 * Lookup and potentially load the specified firmware image. 292 * If the firmware is not found in the registry, try to load a kernel 293 * module named as the image name. 294 * If the firmware is located, a reference is returned. The caller must 295 * release this reference for the image to be eligible for removal/unload. 296 */ 297 const struct firmware * 298 firmware_get(const char *imagename) 299 { 300 struct task fwload_task; 301 struct thread *td; 302 struct priv_fw *fp; 303 304 mtx_lock(&firmware_mtx); 305 fp = lookup(imagename, NULL); 306 if (fp != NULL) 307 goto found; 308 /* 309 * Image not present, try to load the module holding it. 310 */ 311 td = curthread; 312 if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 || 313 securelevel_gt(td->td_ucred, 0) != 0) { 314 mtx_unlock(&firmware_mtx); 315 printf("%s: insufficient privileges to " 316 "load firmware image %s\n", __func__, imagename); 317 return NULL; 318 } 319 /* 320 * Defer load to a thread with known context. linker_reference_module 321 * may do filesystem i/o which requires root & current dirs, etc. 322 * Also we must not hold any mtx's over this call which is problematic. 323 */ 324 if (!cold) { 325 TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *, 326 imagename)); 327 taskqueue_enqueue(firmware_tq, &fwload_task); 328 msleep(__DECONST(void *, imagename), &firmware_mtx, 0, 329 "fwload", 0); 330 } 331 /* 332 * After attempting to load the module, see if the image is registered. 333 */ 334 fp = lookup(imagename, NULL); 335 if (fp == NULL) { 336 mtx_unlock(&firmware_mtx); 337 return NULL; 338 } 339 found: /* common exit point on success */ 340 if (fp->refcnt == 0 && fp->parent != NULL) 341 fp->parent->refcnt++; 342 fp->refcnt++; 343 mtx_unlock(&firmware_mtx); 344 return &fp->fw; 345 } 346 347 /* 348 * Release a reference to a firmware image returned by firmware_get. 349 * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire 350 * to release the resource, but the flag is only advisory. 351 * 352 * If this is the last reference to the firmware image, and this is an 353 * autoloaded module, wake up the firmware_unload_task to figure out 354 * what to do with the associated module. 355 */ 356 void 357 firmware_put(const struct firmware *p, int flags) 358 { 359 struct priv_fw *fp = PRIV_FW(p); 360 361 mtx_lock(&firmware_mtx); 362 fp->refcnt--; 363 if (fp->refcnt == 0) { 364 if (fp->parent != NULL) 365 fp->parent->refcnt--; 366 if (flags & FIRMWARE_UNLOAD) 367 fp->flags |= FW_UNLOAD; 368 if (fp->file) 369 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 370 } 371 mtx_unlock(&firmware_mtx); 372 } 373 374 /* 375 * Setup directory state for the firmware_tq thread so we can do i/o. 376 */ 377 static void 378 set_rootvnode(void *arg, int npending) 379 { 380 struct thread *td = curthread; 381 struct proc *p = td->td_proc; 382 383 FILEDESC_XLOCK(p->p_fd); 384 if (p->p_fd->fd_cdir == NULL) { 385 p->p_fd->fd_cdir = rootvnode; 386 VREF(rootvnode); 387 } 388 if (p->p_fd->fd_rdir == NULL) { 389 p->p_fd->fd_rdir = rootvnode; 390 VREF(rootvnode); 391 } 392 FILEDESC_XUNLOCK(p->p_fd); 393 394 free(arg, M_TEMP); 395 } 396 397 /* 398 * Event handler called on mounting of /; bounce a task 399 * into the task queue thread to setup it's directories. 400 */ 401 static void 402 firmware_mountroot(void *arg) 403 { 404 struct task *setroot_task; 405 406 setroot_task = malloc(sizeof(struct task), M_TEMP, M_NOWAIT); 407 if (setroot_task != NULL) { 408 TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task); 409 taskqueue_enqueue(firmware_tq, setroot_task); 410 } else 411 printf("%s: no memory for task!\n", __func__); 412 } 413 EVENTHANDLER_DEFINE(mountroot, firmware_mountroot, NULL, 0); 414 415 /* 416 * The body of the task in charge of unloading autoloaded modules 417 * that are not needed anymore. 418 * Images can be cross-linked so we may need to make multiple passes, 419 * but the time we spend in the loop is bounded because we clear entries 420 * as we touch them. 421 */ 422 static void 423 unloadentry(void *unused1, int unused2) 424 { 425 int limit = FIRMWARE_MAX; 426 int i; /* current cycle */ 427 428 mtx_lock(&firmware_mtx); 429 /* 430 * Scan the table. limit is set to make sure we make another 431 * full sweep after matching an entry that requires unloading. 432 */ 433 for (i = 0; i < limit; i++) { 434 struct priv_fw *fp; 435 int err; 436 437 fp = &firmware_table[i % FIRMWARE_MAX]; 438 if (fp->fw.name == NULL || fp->file == NULL || 439 fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0) 440 continue; 441 442 /* 443 * Found an entry. Now: 444 * 1. bump up limit to make sure we make another full round; 445 * 2. clear FW_UNLOAD so we don't try this entry again. 446 * 3. release the lock while trying to unload the module. 447 * 'file' remains set so that the entry cannot be reused 448 * in the meantime (it also means that fp->file will 449 * not change while we release the lock). 450 */ 451 limit = i + FIRMWARE_MAX; /* make another full round */ 452 fp->flags &= ~FW_UNLOAD; /* do not try again */ 453 454 mtx_unlock(&firmware_mtx); 455 err = linker_release_module(NULL, NULL, fp->file); 456 mtx_lock(&firmware_mtx); 457 458 /* 459 * We rely on the module to call firmware_unregister() 460 * on unload to actually release the entry. 461 * If err = 0 we can drop our reference as the system 462 * accepted it. Otherwise unloading failed (e.g. the 463 * module itself gave an error) so our reference is 464 * still valid. 465 */ 466 if (err == 0) 467 fp->file = NULL; 468 } 469 mtx_unlock(&firmware_mtx); 470 } 471 472 /* 473 * Module glue. 474 */ 475 static int 476 firmware_modevent(module_t mod, int type, void *unused) 477 { 478 struct priv_fw *fp; 479 int i, err; 480 481 switch (type) { 482 case MOD_LOAD: 483 TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL); 484 firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK, 485 taskqueue_thread_enqueue, &firmware_tq); 486 /* NB: use our own loop routine that sets up context */ 487 (void) taskqueue_start_threads(&firmware_tq, 1, PWAIT, 488 "firmware taskq"); 489 if (rootvnode != NULL) { 490 /* 491 * Root is already mounted so we won't get an event; 492 * simulate one here. 493 */ 494 firmware_mountroot(NULL); 495 } 496 return 0; 497 498 case MOD_UNLOAD: 499 /* request all autoloaded modules to be released */ 500 mtx_lock(&firmware_mtx); 501 for (i = 0; i < FIRMWARE_MAX; i++) { 502 fp = &firmware_table[i]; 503 fp->flags |= FW_UNLOAD; 504 } 505 mtx_unlock(&firmware_mtx); 506 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 507 taskqueue_drain(firmware_tq, &firmware_unload_task); 508 err = 0; 509 for (i = 0; i < FIRMWARE_MAX; i++) { 510 fp = &firmware_table[i]; 511 if (fp->fw.name != NULL) { 512 printf("%s: image %p ref %d still active slot %d\n", 513 __func__, fp->fw.name, 514 fp->refcnt, i); 515 err = EINVAL; 516 } 517 } 518 if (err == 0) 519 taskqueue_free(firmware_tq); 520 return err; 521 } 522 return EINVAL; 523 } 524 525 static moduledata_t firmware_mod = { 526 "firmware", 527 firmware_modevent, 528 NULL 529 }; 530 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 531 MODULE_VERSION(firmware, 1); 532