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 30 125 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 frp->parent->refcnt++; 204 } 205 mtx_unlock(&firmware_mtx); 206 if (bootverbose) 207 printf("firmware: '%s' version %u: %zu bytes loaded at %p\n", 208 imagename, version, datasize, data); 209 return &frp->fw; 210 } 211 212 /* 213 * Unregister/remove a firmware image. If there are outstanding 214 * references an error is returned and the image is not removed 215 * from the registry. 216 */ 217 int 218 firmware_unregister(const char *imagename) 219 { 220 struct priv_fw *fp; 221 int err; 222 223 mtx_lock(&firmware_mtx); 224 fp = lookup(imagename, NULL); 225 if (fp == NULL) { 226 /* 227 * It is ok for the lookup to fail; this can happen 228 * when a module is unloaded on last reference and the 229 * module unload handler unregister's each of it's 230 * firmware images. 231 */ 232 err = 0; 233 } else if (fp->refcnt != 0) { /* cannot unregister */ 234 err = EBUSY; 235 } else { 236 linker_file_t x = fp->file; /* save value */ 237 238 if (fp->parent != NULL) /* release parent reference */ 239 fp->parent->refcnt--; 240 /* 241 * Clear the whole entry with bzero to make sure we 242 * do not forget anything. Then restore 'file' which is 243 * non-null for autoloaded images. 244 */ 245 bzero(fp, sizeof(struct priv_fw)); 246 fp->file = x; 247 err = 0; 248 } 249 mtx_unlock(&firmware_mtx); 250 return err; 251 } 252 253 static void 254 loadimage(void *arg, int npending) 255 { 256 struct thread *td = curthread; 257 char *imagename = arg; 258 struct priv_fw *fp; 259 linker_file_t result; 260 int error; 261 262 /* synchronize with the thread that dispatched us */ 263 mtx_lock(&firmware_mtx); 264 mtx_unlock(&firmware_mtx); 265 266 if (td->td_proc->p_fd->fd_rdir == NULL) { 267 printf("%s: root not mounted yet, no way to load image\n", 268 imagename); 269 goto done; 270 } 271 error = linker_reference_module(imagename, NULL, &result); 272 if (error != 0) { 273 printf("%s: could not load firmware image, error %d\n", 274 imagename, error); 275 goto done; 276 } 277 278 mtx_lock(&firmware_mtx); 279 fp = lookup(imagename, NULL); 280 if (fp == NULL || fp->file != NULL) { 281 mtx_unlock(&firmware_mtx); 282 if (fp == NULL) 283 printf("%s: firmware image loaded, " 284 "but did not register\n", imagename); 285 (void) linker_release_module(imagename, NULL, NULL); 286 goto done; 287 } 288 fp->file = result; /* record the module identity */ 289 mtx_unlock(&firmware_mtx); 290 done: 291 wakeup_one(imagename); /* we're done */ 292 } 293 294 /* 295 * Lookup and potentially load the specified firmware image. 296 * If the firmware is not found in the registry, try to load a kernel 297 * module named as the image name. 298 * If the firmware is located, a reference is returned. The caller must 299 * release this reference for the image to be eligible for removal/unload. 300 */ 301 const struct firmware * 302 firmware_get(const char *imagename) 303 { 304 struct task fwload_task; 305 struct thread *td; 306 struct priv_fw *fp; 307 308 mtx_lock(&firmware_mtx); 309 fp = lookup(imagename, NULL); 310 if (fp != NULL) 311 goto found; 312 /* 313 * Image not present, try to load the module holding it. 314 */ 315 td = curthread; 316 if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 || 317 securelevel_gt(td->td_ucred, 0) != 0) { 318 mtx_unlock(&firmware_mtx); 319 printf("%s: insufficient privileges to " 320 "load firmware image %s\n", __func__, imagename); 321 return NULL; 322 } 323 /* 324 * Defer load to a thread with known context. linker_reference_module 325 * may do filesystem i/o which requires root & current dirs, etc. 326 * Also we must not hold any mtx's over this call which is problematic. 327 */ 328 TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *, imagename)); 329 taskqueue_enqueue(firmware_tq, &fwload_task); 330 msleep(__DECONST(void *, imagename), &firmware_mtx, 0, "fwload", 0); 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 fp->refcnt++; 341 mtx_unlock(&firmware_mtx); 342 return &fp->fw; 343 } 344 345 /* 346 * Release a reference to a firmware image returned by firmware_get. 347 * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire 348 * to release the resource, but the flag is only advisory. 349 * 350 * If this is the last reference to the firmware image, and this is an 351 * autoloaded module, wake up the firmware_unload_task to figure out 352 * what to do with the associated module. 353 */ 354 void 355 firmware_put(const struct firmware *p, int flags) 356 { 357 struct priv_fw *fp = PRIV_FW(p); 358 359 mtx_lock(&firmware_mtx); 360 fp->refcnt--; 361 if (fp->refcnt == 0) { 362 if (flags & FIRMWARE_UNLOAD) 363 fp->flags |= FW_UNLOAD; 364 if (fp->file) 365 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 366 } 367 mtx_unlock(&firmware_mtx); 368 } 369 370 /* 371 * Setup directory state for the firmware_tq thread so we can do i/o. 372 */ 373 static void 374 set_rootvnode(void *arg, int npending) 375 { 376 struct thread *td = curthread; 377 struct proc *p = td->td_proc; 378 379 FILEDESC_XLOCK(p->p_fd); 380 if (p->p_fd->fd_cdir == NULL) { 381 p->p_fd->fd_cdir = rootvnode; 382 VREF(rootvnode); 383 } 384 if (p->p_fd->fd_rdir == NULL) { 385 p->p_fd->fd_rdir = rootvnode; 386 VREF(rootvnode); 387 } 388 FILEDESC_XUNLOCK(p->p_fd); 389 } 390 391 /* 392 * Event handler called on mounting of /; bounce a task 393 * into the task queue thread to setup it's directories. 394 */ 395 static void 396 firmware_mountroot(void *arg) 397 { 398 static struct task setroot_task; 399 400 TASK_INIT(&setroot_task, 0, set_rootvnode, NULL); 401 taskqueue_enqueue(firmware_tq, &setroot_task); 402 } 403 EVENTHANDLER_DEFINE(mountroot, firmware_mountroot, NULL, 0); 404 405 /* 406 * The body of the task in charge of unloading autoloaded modules 407 * that are not needed anymore. 408 * Images can be cross-linked so we may need to make multiple passes, 409 * but the time we spend in the loop is bounded because we clear entries 410 * as we touch them. 411 */ 412 static void 413 unloadentry(void *unused1, int unused2) 414 { 415 int limit = FIRMWARE_MAX; 416 int i; /* current cycle */ 417 418 mtx_lock(&firmware_mtx); 419 /* 420 * Scan the table. limit is set to make sure we make another 421 * full sweep after matching an entry that requires unloading. 422 */ 423 for (i = 0; i < limit; i++) { 424 struct priv_fw *fp; 425 int err; 426 427 fp = &firmware_table[i % FIRMWARE_MAX]; 428 if (fp->fw.name == NULL || fp->file == NULL || 429 fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0) 430 continue; 431 432 /* 433 * Found an entry. Now: 434 * 1. bump up limit to make sure we make another full round; 435 * 2. clear FW_UNLOAD so we don't try this entry again. 436 * 3. release the lock while trying to unload the module. 437 * 'file' remains set so that the entry cannot be reused 438 * in the meantime (it also means that fp->file will 439 * not change while we release the lock). 440 */ 441 limit = i + FIRMWARE_MAX; /* make another full round */ 442 fp->flags &= ~FW_UNLOAD; /* do not try again */ 443 444 mtx_unlock(&firmware_mtx); 445 err = linker_release_module(NULL, NULL, fp->file); 446 mtx_lock(&firmware_mtx); 447 448 /* 449 * We rely on the module to call firmware_unregister() 450 * on unload to actually release the entry. 451 * If err = 0 we can drop our reference as the system 452 * accepted it. Otherwise unloading failed (e.g. the 453 * module itself gave an error) so our reference is 454 * still valid. 455 */ 456 if (err == 0) 457 fp->file = NULL; 458 } 459 mtx_unlock(&firmware_mtx); 460 } 461 462 /* 463 * Module glue. 464 */ 465 static int 466 firmware_modevent(module_t mod, int type, void *unused) 467 { 468 struct priv_fw *fp; 469 int i, err; 470 471 switch (type) { 472 case MOD_LOAD: 473 TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL); 474 firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK, 475 taskqueue_thread_enqueue, &firmware_tq); 476 /* NB: use our own loop routine that sets up context */ 477 (void) taskqueue_start_threads(&firmware_tq, 1, PWAIT, 478 "firmware taskq"); 479 if (rootvnode != NULL) { 480 /* 481 * Root is already mounted so we won't get an event; 482 * simulate one here. 483 */ 484 firmware_mountroot(NULL); 485 } 486 return 0; 487 488 case MOD_UNLOAD: 489 /* request all autoloaded modules to be released */ 490 mtx_lock(&firmware_mtx); 491 for (i = 0; i < FIRMWARE_MAX; i++) { 492 fp = &firmware_table[i]; 493 fp->flags |= FW_UNLOAD;; 494 } 495 mtx_unlock(&firmware_mtx); 496 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 497 taskqueue_drain(firmware_tq, &firmware_unload_task); 498 err = 0; 499 for (i = 0; i < FIRMWARE_MAX; i++) { 500 fp = &firmware_table[i]; 501 if (fp->fw.name != NULL) { 502 printf("%s: image %p ref %d still active slot %d\n", 503 __func__, fp->fw.name, 504 fp->refcnt, i); 505 err = EINVAL; 506 } 507 } 508 if (err == 0) 509 taskqueue_free(firmware_tq); 510 return err; 511 } 512 return EINVAL; 513 } 514 515 static moduledata_t firmware_mod = { 516 "firmware", 517 firmware_modevent, 518 0 519 }; 520 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 521 MODULE_VERSION(firmware, 1); 522