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 * $DragonFly$ 28 */ 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/spinlock.h> 38 #include <sys/spinlock2.h> 39 #include <sys/errno.h> 40 #include <sys/linker.h> 41 #include <sys/firmware.h> 42 #include <sys/priv.h> 43 #include <sys/proc.h> 44 #include <sys/module.h> 45 #include <sys/eventhandler.h> 46 47 #include <sys/filedesc.h> 48 #include <sys/vnode.h> 49 50 /* 51 * Loadable firmware support. See sys/sys/firmware.h and firmware(9) 52 * form more details on the subsystem. 53 * 54 * 'struct firmware' is the user-visible part of the firmware table. 55 * Additional internal information is stored in a 'struct priv_fw' 56 * (currently a static array). A slot is in use if FW_INUSE is true: 57 */ 58 59 #define FW_INUSE(p) ((p)->file != NULL || (p)->fw.name != NULL) 60 61 /* 62 * fw.name != NULL when an image is registered; file != NULL for 63 * autoloaded images whose handling has not been completed. 64 * 65 * The state of a slot evolves as follows: 66 * firmware_register --> fw.name = image_name 67 * (autoloaded image) --> file = module reference 68 * firmware_unregister --> fw.name = NULL 69 * (unloadentry complete) --> file = NULL 70 * 71 * In order for the above to work, the 'file' field must remain 72 * unchanged in firmware_unregister(). 73 * 74 * Images residing in the same module are linked to each other 75 * through the 'parent' argument of firmware_register(). 76 * One image (typically, one with the same name as the module to let 77 * the autoloading mechanism work) is considered the parent image for 78 * all other images in the same module. Children affect the refcount 79 * on the parent image preventing improper unloading of the image itself. 80 */ 81 82 struct priv_fw { 83 int refcnt; /* reference count */ 84 85 /* 86 * parent entry, see above. Set on firmware_register(), 87 * cleared on firmware_unregister(). 88 */ 89 struct priv_fw *parent; 90 91 int flags; /* record FIRMWARE_UNLOAD requests */ 92 #define FW_UNLOAD 0x100 93 94 /* 95 * 'file' is private info managed by the autoload/unload code. 96 * Set at the end of firmware_get(), cleared only in the 97 * firmware_unload_task, so the latter can depend on its value even 98 * while the lock is not held. 99 */ 100 linker_file_t file; /* module file, if autoloaded */ 101 102 /* 103 * 'fw' is the externally visible image information. 104 * We do not make it the first field in priv_fw, to avoid the 105 * temptation of casting pointers to each other. 106 * Use PRIV_FW(fw) to get a pointer to the cointainer of fw. 107 * Beware, PRIV_FW does not work for a NULL pointer. 108 */ 109 struct firmware fw; /* externally visible information */ 110 }; 111 112 /* 113 * PRIV_FW returns the pointer to the container of struct firmware *x. 114 * Cast to intptr_t to override the 'const' attribute of x 115 */ 116 #define PRIV_FW(x) ((struct priv_fw *) \ 117 ((intptr_t)(x) - offsetof(struct priv_fw, fw)) ) 118 119 /* 120 * At the moment we use a static array as backing store for the registry. 121 * Should we move to a dynamic structure, keep in mind that we cannot 122 * reallocate the array because pointers are held externally. 123 * A list may work, though. 124 */ 125 #define FIRMWARE_MAX 30 126 static struct priv_fw firmware_table[FIRMWARE_MAX]; 127 128 /* 129 * Firmware module operations are handled in a separate task as they 130 * might sleep and they require directory context to do i/o. 131 */ 132 static struct taskqueue *firmware_tq; 133 static struct task firmware_unload_task; 134 135 /* 136 * This mutex protects accesses to the firmware table. 137 */ 138 static struct lock firmware_lock; 139 #if 0 140 MTX_SYSINIT(firmware, &firmware_lock, "firmware table", MTX_DEF); 141 #endif 142 143 /* 144 * Helper function to lookup a name. 145 * As a side effect, it sets the pointer to a free slot, if any. 146 * This way we can concentrate most of the registry scanning in 147 * this function, which makes it easier to replace the registry 148 * with some other data structure. 149 */ 150 static struct priv_fw * 151 lookup(const char *name, struct priv_fw **empty_slot) 152 { 153 struct priv_fw *fp = NULL; 154 struct priv_fw *dummy; 155 int i; 156 157 if (empty_slot == NULL) 158 empty_slot = &dummy; 159 *empty_slot = NULL; 160 for (i = 0; i < FIRMWARE_MAX; i++) { 161 fp = &firmware_table[i]; 162 if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0) 163 break; 164 else if (!FW_INUSE(fp)) 165 *empty_slot = fp; 166 } 167 return (i < FIRMWARE_MAX ) ? fp : NULL; 168 } 169 170 /* 171 * Register a firmware image with the specified name. The 172 * image name must not already be registered. If this is a 173 * subimage then parent refers to a previously registered 174 * image that this should be associated with. 175 */ 176 const struct firmware * 177 firmware_register(const char *imagename, const void *data, size_t datasize, 178 unsigned int version, const struct firmware *parent) 179 { 180 struct priv_fw *match, *frp; 181 182 lockmgr(&firmware_lock, LK_EXCLUSIVE); 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 lockmgr(&firmware_lock, LK_RELEASE); 189 kprintf("%s: image %s already registered!\n", 190 __func__, imagename); 191 return NULL; 192 } 193 if (frp == NULL) { 194 lockmgr(&firmware_lock, LK_RELEASE); 195 kprintf("%s: cannot register image %s, firmware table full!\n", 196 __func__, imagename); 197 return NULL; 198 } 199 bzero(frp, sizeof(frp)); /* start from a clean record */ 200 frp->fw.name = imagename; 201 frp->fw.data = data; 202 frp->fw.datasize = datasize; 203 frp->fw.version = version; 204 if (parent != NULL) { 205 frp->parent = PRIV_FW(parent); 206 frp->parent->refcnt++; 207 } 208 lockmgr(&firmware_lock, LK_RELEASE); 209 if (bootverbose) 210 kprintf("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 lockmgr(&firmware_lock, LK_EXCLUSIVE); 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 if (fp->parent != NULL) /* release parent reference */ 242 fp->parent->refcnt--; 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 bzero(fp, sizeof(struct priv_fw)); 249 fp->file = x; 250 err = 0; 251 } 252 lockmgr(&firmware_lock, LK_RELEASE); 253 return err; 254 } 255 256 static void 257 loadimage(void *arg, int npending) 258 { 259 #ifdef notyet 260 struct thread *td = curthread; 261 #endif 262 char *imagename = arg; 263 struct priv_fw *fp; 264 linker_file_t result; 265 int error; 266 267 /* synchronize with the thread that dispatched us */ 268 lockmgr(&firmware_lock, LK_EXCLUSIVE); 269 lockmgr(&firmware_lock, LK_RELEASE); 270 271 /* JAT 272 if (td->td_proc->p_fd->fd_rdir == NULL) { 273 kprintf("%s: root not mounted yet, no way to load image\n", 274 imagename); 275 goto done; 276 } 277 */ 278 error = linker_reference_module(imagename, NULL, &result); 279 if (error != 0) { 280 kprintf("%s: could not load firmware image, error %d\n", 281 imagename, error); 282 goto done; 283 } 284 285 lockmgr(&firmware_lock, LK_EXCLUSIVE); 286 fp = lookup(imagename, NULL); 287 if (fp == NULL || fp->file != NULL) { 288 lockmgr(&firmware_lock, LK_RELEASE); 289 if (fp == NULL) 290 kprintf("%s: firmware image loaded, " 291 "but did not register\n", imagename); 292 (void) linker_release_module(imagename, NULL, NULL); 293 goto done; 294 } 295 fp->file = result; /* record the module identity */ 296 lockmgr(&firmware_lock, LK_RELEASE); 297 done: 298 wakeup_one(imagename); /* we're done */ 299 } 300 301 /* 302 * Lookup and potentially load the specified firmware image. 303 * If the firmware is not found in the registry, try to load a kernel 304 * module named as the image name. 305 * If the firmware is located, a reference is returned. The caller must 306 * release this reference for the image to be eligible for removal/unload. 307 */ 308 const struct firmware * 309 firmware_get(const char *imagename) 310 { 311 struct task fwload_task; 312 struct thread *td; 313 struct priv_fw *fp; 314 315 lockmgr(&firmware_lock, LK_EXCLUSIVE); 316 fp = lookup(imagename, NULL); 317 if (fp != NULL) 318 goto found; 319 /* 320 * Image not present, try to load the module holding it. 321 */ 322 td = curthread; 323 if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 || 324 priv_check_cred(td->td_ucred, 0, 0)) { 325 lockmgr(&firmware_lock, LK_RELEASE); 326 kprintf("%s: insufficient privileges to " 327 "load firmware image %s\n", __func__, imagename); 328 return NULL; 329 } 330 /* 331 * Defer load to a thread with known context. linker_reference_module 332 * may do filesystem i/o which requires root & current dirs, etc. 333 * Also we must not hold any lock's over this call which is problematic. 334 */ 335 if (!cold) { 336 TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *, 337 imagename)); 338 taskqueue_enqueue(firmware_tq, &fwload_task); 339 lksleep(__DECONST(void *, imagename), &firmware_lock, 0, 340 "fwload", 0); 341 } 342 /* 343 * After attempting to load the module, see if the image is registered. 344 */ 345 fp = lookup(imagename, NULL); 346 if (fp == NULL) { 347 lockmgr(&firmware_lock, LK_RELEASE); 348 return NULL; 349 } 350 found: /* common exit point on success */ 351 fp->refcnt++; 352 lockmgr(&firmware_lock, LK_RELEASE); 353 return &fp->fw; 354 } 355 356 /* 357 * Release a reference to a firmware image returned by firmware_get. 358 * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire 359 * to release the resource, but the flag is only advisory. 360 * 361 * If this is the last reference to the firmware image, and this is an 362 * autoloaded module, wake up the firmware_unload_task to figure out 363 * what to do with the associated module. 364 */ 365 void 366 firmware_put(const struct firmware *p, int flags) 367 { 368 struct priv_fw *fp = PRIV_FW(p); 369 370 lockmgr(&firmware_lock, LK_EXCLUSIVE); 371 fp->refcnt--; 372 if (fp->refcnt == 0) { 373 if (flags & FIRMWARE_UNLOAD) 374 fp->flags |= FW_UNLOAD; 375 if (fp->file) 376 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 377 } 378 lockmgr(&firmware_lock, LK_RELEASE); 379 } 380 381 #ifdef notyet 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 struct thread *td = curthread; 389 struct proc *p = td->td_proc; 390 391 392 kprintf("JAT: arg = %p, p = %p\n", arg, p); 393 #if 0 394 kprintf("JAT: arg = %p, p = %p, p_fd = %p, fd_spin = %p\n", 395 arg, p, p->p_fd, &p->p_fd->fd_spin); 396 #endif 397 398 #if 0 399 spin_lock_wr(&p->p_fd->fd_spin); 400 kprintf("JAT: after spin_lock_wr\n"); 401 if (p->p_fd->fd_cdir == NULL) { 402 p->p_fd->fd_cdir = rootvnode; 403 vref(rootvnode); 404 } 405 if (p->p_fd->fd_rdir == NULL) { 406 p->p_fd->fd_rdir = rootvnode; 407 vref(rootvnode); 408 } 409 spin_unlock_wr(&p->p_fd->fd_spin); 410 kprintf("JAT: after spin_unlock_wr\n"); 411 412 kfree(arg, M_TEMP); 413 #endif 414 } 415 416 /* 417 * Event handler called on mounting of /; bounce a task 418 * into the task queue thread to setup it's directories. 419 */ 420 static void 421 firmware_mountroot(void *arg) 422 { 423 struct task *setroot_task; 424 425 setroot_task = kmalloc(sizeof(struct task), M_TEMP, M_NOWAIT); 426 if (setroot_task != NULL) { 427 TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task); 428 taskqueue_enqueue(firmware_tq, setroot_task); 429 } else 430 kprintf("%s: no memory for task!\n", __func__); 431 } 432 EVENTHANDLER_DECLARE(mountroot, firmware_mountroot); 433 #endif 434 435 /* 436 * The body of the task in charge of unloading autoloaded modules 437 * that are not needed anymore. 438 * Images can be cross-linked so we may need to make multiple passes, 439 * but the time we spend in the loop is bounded because we clear entries 440 * as we touch them. 441 */ 442 static void 443 unloadentry(void *unused1, int unused2) 444 { 445 int limit = FIRMWARE_MAX; 446 int i; /* current cycle */ 447 448 lockmgr(&firmware_lock, LK_EXCLUSIVE); 449 /* 450 * Scan the table. limit is set to make sure we make another 451 * full sweep after matching an entry that requires unloading. 452 */ 453 for (i = 0; i < limit; i++) { 454 struct priv_fw *fp; 455 int err; 456 457 fp = &firmware_table[i % FIRMWARE_MAX]; 458 if (fp->fw.name == NULL || fp->file == NULL || 459 fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0) 460 continue; 461 462 /* 463 * Found an entry. Now: 464 * 1. bump up limit to make sure we make another full round; 465 * 2. clear FW_UNLOAD so we don't try this entry again. 466 * 3. release the lock while trying to unload the module. 467 * 'file' remains set so that the entry cannot be reused 468 * in the meantime (it also means that fp->file will 469 * not change while we release the lock). 470 */ 471 limit = i + FIRMWARE_MAX; /* make another full round */ 472 fp->flags &= ~FW_UNLOAD; /* do not try again */ 473 474 lockmgr(&firmware_lock, LK_RELEASE); 475 err = linker_release_module(NULL, NULL, fp->file); 476 lockmgr(&firmware_lock, LK_EXCLUSIVE); 477 478 /* 479 * We rely on the module to call firmware_unregister() 480 * on unload to actually release the entry. 481 * If err = 0 we can drop our reference as the system 482 * accepted it. Otherwise unloading failed (e.g. the 483 * module itself gave an error) so our reference is 484 * still valid. 485 */ 486 if (err == 0) 487 fp->file = NULL; 488 } 489 lockmgr(&firmware_lock, LK_RELEASE); 490 } 491 492 /* 493 * Module glue. 494 */ 495 static int 496 firmware_modevent(module_t mod, int type, void *unused) 497 { 498 struct priv_fw *fp; 499 int i, err; 500 501 switch (type) { 502 case MOD_LOAD: 503 TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL); 504 lockinit(&firmware_lock, "firmware table", 0, LK_CANRECURSE); 505 firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK, 506 taskqueue_thread_enqueue, &firmware_tq); 507 /* NB: use our own loop routine that sets up context */ 508 (void) taskqueue_start_threads(&firmware_tq, 1, TDPRI_KERN_DAEMON, 509 -1, "firmware taskq"); 510 if (rootvnode != NULL) { 511 /* 512 * Root is already mounted so we won't get an event; 513 * simulate one here. 514 */ 515 #ifdef notyet 516 firmware_mountroot(NULL); 517 #endif 518 } 519 return 0; 520 521 case MOD_UNLOAD: 522 /* request all autoloaded modules to be released */ 523 lockmgr(&firmware_lock, LK_EXCLUSIVE); 524 for (i = 0; i < FIRMWARE_MAX; i++) { 525 fp = &firmware_table[i]; 526 fp->flags |= FW_UNLOAD; 527 } 528 lockmgr(&firmware_lock, LK_RELEASE); 529 taskqueue_enqueue(firmware_tq, &firmware_unload_task); 530 taskqueue_drain(firmware_tq, &firmware_unload_task); 531 err = 0; 532 for (i = 0; i < FIRMWARE_MAX; i++) { 533 fp = &firmware_table[i]; 534 if (fp->fw.name != NULL) { 535 kprintf("%s: image %p ref %d still active slot %d\n", 536 __func__, fp->fw.name, 537 fp->refcnt, i); 538 err = EINVAL; 539 } 540 } 541 if (err == 0) 542 taskqueue_free(firmware_tq); 543 return err; 544 } 545 return EINVAL; 546 } 547 548 static moduledata_t firmware_mod = { 549 "firmware", 550 firmware_modevent, 551 NULL 552 }; 553 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 554 MODULE_VERSION(firmware, 1); 555