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