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 * $FreeBSD: src/sys/kern/subr_firmware.c,v 1.13.2.2 2010/02/11 18:34:06 mjacob Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/kernel.h> 31 #include <sys/malloc.h> 32 #include <sys/queue.h> 33 #include <sys/taskqueue.h> 34 #include <sys/systm.h> 35 #include <sys/lock.h> 36 #include <sys/spinlock.h> 37 #include <sys/spinlock2.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 lock firmware_lock; 138 #if 0 139 MTX_SYSINIT(firmware, &firmware_lock, "firmware table", MTX_DEF); 140 #endif 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; 180 181 lockmgr(&firmware_lock, LK_EXCLUSIVE); 182 /* 183 * Do a lookup to make sure the name is unique or find a free slot. 184 */ 185 match = lookup(imagename, &frp); 186 if (match != NULL) { 187 lockmgr(&firmware_lock, LK_RELEASE); 188 kprintf("%s: image %s already registered!\n", 189 __func__, imagename); 190 return NULL; 191 } 192 if (frp == NULL) { 193 lockmgr(&firmware_lock, LK_RELEASE); 194 kprintf("%s: cannot register image %s, firmware table full!\n", 195 __func__, imagename); 196 return NULL; 197 } 198 bzero(frp, sizeof(frp)); /* start from a clean record */ 199 frp->fw.name = imagename; 200 frp->fw.data = data; 201 frp->fw.datasize = datasize; 202 frp->fw.version = version; 203 if (parent != NULL) { 204 frp->parent = PRIV_FW(parent); 205 frp->parent->refcnt++; 206 } 207 lockmgr(&firmware_lock, LK_RELEASE); 208 if (bootverbose) 209 kprintf("firmware: '%s' version %u: %zu bytes loaded at %p\n", 210 imagename, version, datasize, data); 211 return &frp->fw; 212 } 213 214 /* 215 * Unregister/remove a firmware image. If there are outstanding 216 * references an error is returned and the image is not removed 217 * from the registry. 218 */ 219 int 220 firmware_unregister(const char *imagename) 221 { 222 struct priv_fw *fp; 223 int err; 224 225 lockmgr(&firmware_lock, LK_EXCLUSIVE); 226 fp = lookup(imagename, NULL); 227 if (fp == NULL) { 228 /* 229 * It is ok for the lookup to fail; this can happen 230 * when a module is unloaded on last reference and the 231 * module unload handler unregister's each of it's 232 * firmware images. 233 */ 234 err = 0; 235 } else if (fp->refcnt != 0) { /* cannot unregister */ 236 err = EBUSY; 237 } else { 238 linker_file_t x = fp->file; /* save value */ 239 240 if (fp->parent != NULL) /* release parent reference */ 241 fp->parent->refcnt--; 242 /* 243 * Clear the whole entry with bzero to make sure we 244 * do not forget anything. Then restore 'file' which is 245 * non-null for autoloaded images. 246 */ 247 bzero(fp, sizeof(struct priv_fw)); 248 fp->file = x; 249 err = 0; 250 } 251 lockmgr(&firmware_lock, LK_RELEASE); 252 return err; 253 } 254 255 static void 256 loadimage(void *arg, int npending) 257 { 258 #ifdef notyet 259 struct thread *td = curthread; 260 #endif 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 lockmgr(&firmware_lock, LK_EXCLUSIVE); 268 lockmgr(&firmware_lock, LK_RELEASE); 269 270 /* JAT 271 if (td->td_proc->p_fd->fd_rdir == NULL) { 272 kprintf("%s: root not mounted yet, no way to load image\n", 273 imagename); 274 goto done; 275 } 276 */ 277 error = linker_reference_module(imagename, NULL, &result); 278 if (error != 0) { 279 kprintf("%s: could not load firmware image, error %d\n", 280 imagename, error); 281 goto done; 282 } 283 284 lockmgr(&firmware_lock, LK_EXCLUSIVE); 285 fp = lookup(imagename, NULL); 286 if (fp == NULL || fp->file != NULL) { 287 lockmgr(&firmware_lock, LK_RELEASE); 288 if (fp == NULL) 289 kprintf("%s: firmware image loaded, " 290 "but did not register\n", imagename); 291 (void) linker_release_module(imagename, NULL, NULL); 292 goto done; 293 } 294 fp->file = result; /* record the module identity */ 295 lockmgr(&firmware_lock, LK_RELEASE); 296 done: 297 wakeup_one(imagename); /* we're done */ 298 } 299 300 /* 301 * Lookup and potentially load the specified firmware image. 302 * If the firmware is not found in the registry, try to load a kernel 303 * module named as the image name. 304 * If the firmware is located, a reference is returned. The caller must 305 * release this reference for the image to be eligible for removal/unload. 306 */ 307 const struct firmware * 308 firmware_get(const char *imagename) 309 { 310 struct task fwload_task; 311 struct thread *td; 312 struct priv_fw *fp; 313 314 lockmgr(&firmware_lock, LK_EXCLUSIVE); 315 fp = lookup(imagename, NULL); 316 if (fp != NULL) 317 goto found; 318 /* 319 * Image not present, try to load the module holding it. 320 */ 321 td = curthread; 322 if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 || securelevel > 0) { 323 lockmgr(&firmware_lock, LK_RELEASE); 324 kprintf("%s: insufficient privileges to " 325 "load firmware image %s\n", __func__, imagename); 326 return NULL; 327 } 328 /* 329 * Defer load to a thread with known context. linker_reference_module 330 * may do filesystem i/o which requires root & current dirs, etc. 331 * Also we must not hold any lock's over this call which is problematic. 332 */ 333 if (!cold) { 334 TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *, 335 imagename)); 336 taskqueue_enqueue(firmware_tq, &fwload_task); 337 lksleep(__DECONST(void *, imagename), &firmware_lock, 0, 338 "fwload", 0); 339 } 340 /* 341 * After attempting to load the module, see if the image is registered. 342 */ 343 fp = lookup(imagename, NULL); 344 if (fp == NULL) { 345 lockmgr(&firmware_lock, LK_RELEASE); 346 return NULL; 347 } 348 found: /* common exit point on success */ 349 fp->refcnt++; 350 lockmgr(&firmware_lock, LK_RELEASE); 351 return &fp->fw; 352 } 353 354 /* 355 * Release a reference to a firmware image returned by firmware_get. 356 * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire 357 * to release the resource, but the flag is only advisory. 358 * 359 * If this is the last reference to the firmware image, and this is an 360 * autoloaded module, wake up the firmware_unload_task to figure out 361 * what to do with the associated module. 362 */ 363 void 364 firmware_put(const struct firmware *p, int flags) 365 { 366 struct priv_fw *fp = PRIV_FW(p); 367 368 lockmgr(&firmware_lock, LK_EXCLUSIVE); 369 fp->refcnt--; 370 if (fp->refcnt == 0) { 371 if (flags & FIRMWARE_UNLOAD) 372 fp->flags |= FW_UNLOAD; 373 if (fp->file) 374 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 375 } 376 lockmgr(&firmware_lock, LK_RELEASE); 377 } 378 379 #ifdef notyet 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; 388 389 390 #if 0 391 spin_lock_wr(&p->p_fd->fd_spin); 392 if (p->p_fd->fd_cdir == NULL) { 393 p->p_fd->fd_cdir = rootvnode; 394 vref(rootvnode); 395 } 396 if (p->p_fd->fd_rdir == NULL) { 397 p->p_fd->fd_rdir = rootvnode; 398 vref(rootvnode); 399 } 400 spin_unlock_wr(&p->p_fd->fd_spin); 401 402 kfree(arg, M_TEMP); 403 #endif 404 } 405 406 /* 407 * Event handler called on mounting of /; bounce a task 408 * into the task queue thread to setup it's directories. 409 */ 410 static void 411 firmware_mountroot(void *arg) 412 { 413 struct task *setroot_task; 414 415 setroot_task = kmalloc(sizeof(struct task), M_TEMP, M_NOWAIT); 416 if (setroot_task != NULL) { 417 TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task); 418 taskqueue_enqueue(firmware_tq, setroot_task); 419 } else 420 kprintf("%s: no memory for task!\n", __func__); 421 } 422 EVENTHANDLER_DECLARE(mountroot, firmware_mountroot); 423 #endif 424 425 /* 426 * The body of the task in charge of unloading autoloaded modules 427 * that are not needed anymore. 428 * Images can be cross-linked so we may need to make multiple passes, 429 * but the time we spend in the loop is bounded because we clear entries 430 * as we touch them. 431 */ 432 static void 433 unloadentry(void *unused1, int unused2) 434 { 435 int limit = FIRMWARE_MAX; 436 int i; /* current cycle */ 437 438 lockmgr(&firmware_lock, LK_EXCLUSIVE); 439 /* 440 * Scan the table. limit is set to make sure we make another 441 * full sweep after matching an entry that requires unloading. 442 */ 443 for (i = 0; i < limit; i++) { 444 struct priv_fw *fp; 445 int err; 446 447 fp = &firmware_table[i % FIRMWARE_MAX]; 448 if (fp->fw.name == NULL || fp->file == NULL || 449 fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0) 450 continue; 451 452 /* 453 * Found an entry. Now: 454 * 1. bump up limit to make sure we make another full round; 455 * 2. clear FW_UNLOAD so we don't try this entry again. 456 * 3. release the lock while trying to unload the module. 457 * 'file' remains set so that the entry cannot be reused 458 * in the meantime (it also means that fp->file will 459 * not change while we release the lock). 460 */ 461 limit = i + FIRMWARE_MAX; /* make another full round */ 462 fp->flags &= ~FW_UNLOAD; /* do not try again */ 463 464 lockmgr(&firmware_lock, LK_RELEASE); 465 err = linker_release_module(NULL, NULL, fp->file); 466 lockmgr(&firmware_lock, LK_EXCLUSIVE); 467 468 /* 469 * We rely on the module to call firmware_unregister() 470 * on unload to actually release the entry. 471 * If err = 0 we can drop our reference as the system 472 * accepted it. Otherwise unloading failed (e.g. the 473 * module itself gave an error) so our reference is 474 * still valid. 475 */ 476 if (err == 0) 477 fp->file = NULL; 478 } 479 lockmgr(&firmware_lock, LK_RELEASE); 480 } 481 482 /* 483 * Module glue. 484 */ 485 static int 486 firmware_modevent(module_t mod, int type, void *unused) 487 { 488 struct priv_fw *fp; 489 int i, err; 490 491 switch (type) { 492 case MOD_LOAD: 493 TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL); 494 lockinit(&firmware_lock, "firmware table", 0, LK_CANRECURSE); 495 firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK, 496 taskqueue_thread_enqueue, &firmware_tq); 497 /* NB: use our own loop routine that sets up context */ 498 (void) taskqueue_start_threads(&firmware_tq, 1, TDPRI_KERN_DAEMON, 499 -1, "firmware taskq"); 500 if (rootvnode != NULL) { 501 /* 502 * Root is already mounted so we won't get an event; 503 * simulate one here. 504 */ 505 #ifdef notyet 506 firmware_mountroot(NULL); 507 #endif 508 } 509 return 0; 510 511 case MOD_UNLOAD: 512 /* request all autoloaded modules to be released */ 513 lockmgr(&firmware_lock, LK_EXCLUSIVE); 514 for (i = 0; i < FIRMWARE_MAX; i++) { 515 fp = &firmware_table[i]; 516 fp->flags |= FW_UNLOAD; 517 } 518 lockmgr(&firmware_lock, LK_RELEASE); 519 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 520 taskqueue_drain(firmware_tq, &firmware_unload_task); 521 err = 0; 522 for (i = 0; i < FIRMWARE_MAX; i++) { 523 fp = &firmware_table[i]; 524 if (fp->fw.name != NULL) { 525 kprintf("%s: image %p ref %d still active slot %d\n", 526 __func__, fp->fw.name, 527 fp->refcnt, i); 528 err = EINVAL; 529 } 530 } 531 if (err == 0) 532 taskqueue_free(firmware_tq); 533 return err; 534 } 535 return EINVAL; 536 } 537 538 static moduledata_t firmware_mod = { 539 "firmware", 540 firmware_modevent, 541 NULL 542 }; 543 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 544 MODULE_VERSION(firmware, 1); 545