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/proc.h>
42 #include <sys/module.h>
43 #include <sys/eventhandler.h>
44
45 #include <sys/filedesc.h>
46 #include <sys/vnode.h>
47
48 /*
49 * Loadable firmware support. See sys/sys/firmware.h and firmware(9)
50 * form more details on the subsystem.
51 *
52 * 'struct firmware' is the user-visible part of the firmware table.
53 * Additional internal information is stored in a 'struct priv_fw'
54 * (currently a static array). A slot is in use if FW_INUSE is true:
55 */
56
57 #define FW_INUSE(p) ((p)->file != NULL || (p)->fw.name != NULL)
58
59 /*
60 * fw.name != NULL when an image is registered; file != NULL for
61 * autoloaded images whose handling has not been completed.
62 *
63 * The state of a slot evolves as follows:
64 * firmware_register --> fw.name = image_name
65 * (autoloaded image) --> file = module reference
66 * firmware_unregister --> fw.name = NULL
67 * (unloadentry complete) --> file = NULL
68 *
69 * In order for the above to work, the 'file' field must remain
70 * unchanged in firmware_unregister().
71 *
72 * Images residing in the same module are linked to each other
73 * through the 'parent' argument of firmware_register().
74 * One image (typically, one with the same name as the module to let
75 * the autoloading mechanism work) is considered the parent image for
76 * all other images in the same module. Children affect the refcount
77 * on the parent image preventing improper unloading of the image itself.
78 */
79
80 struct priv_fw {
81 int refcnt; /* reference count */
82
83 /*
84 * parent entry, see above. Set on firmware_register(),
85 * cleared on firmware_unregister().
86 */
87 struct priv_fw *parent;
88
89 int flags; /* record FIRMWARE_UNLOAD requests */
90 #define FW_UNLOAD 0x100
91
92 /*
93 * 'file' is private info managed by the autoload/unload code.
94 * Set at the end of firmware_get(), cleared only in the
95 * firmware_unload_task, so the latter can depend on its value even
96 * while the lock is not held.
97 */
98 linker_file_t file; /* module file, if autoloaded */
99
100 /*
101 * 'fw' is the externally visible image information.
102 * We do not make it the first field in priv_fw, to avoid the
103 * temptation of casting pointers to each other.
104 * Use PRIV_FW(fw) to get a pointer to the cointainer of fw.
105 * Beware, PRIV_FW does not work for a NULL pointer.
106 */
107 struct firmware fw; /* externally visible information */
108 };
109
110 /*
111 * PRIV_FW returns the pointer to the container of struct firmware *x.
112 * Cast to intptr_t to override the 'const' attribute of x
113 */
114 #define PRIV_FW(x) ((struct priv_fw *) \
115 ((intptr_t)(x) - offsetof(struct priv_fw, fw)) )
116
117 /*
118 * At the moment we use a static array as backing store for the registry.
119 * Should we move to a dynamic structure, keep in mind that we cannot
120 * reallocate the array because pointers are held externally.
121 * A list may work, though.
122 */
123 #define FIRMWARE_MAX 30
124 static struct priv_fw firmware_table[FIRMWARE_MAX];
125
126 /*
127 * Firmware module operations are handled in a separate task as they
128 * might sleep and they require directory context to do i/o.
129 */
130 static struct taskqueue *firmware_tq;
131 static struct task firmware_unload_task;
132
133 /*
134 * This mutex protects accesses to the firmware table.
135 */
136 static struct mtx firmware_mtx;
137 MTX_SYSINIT(firmware, &firmware_mtx, "firmware table", MTX_DEF);
138
139 /*
140 * Helper function to lookup a name.
141 * As a side effect, it sets the pointer to a free slot, if any.
142 * This way we can concentrate most of the registry scanning in
143 * this function, which makes it easier to replace the registry
144 * with some other data structure.
145 */
146 static struct priv_fw *
147 lookup(const char *name, struct priv_fw **empty_slot)
148 {
149 struct priv_fw *fp = NULL;
150 struct priv_fw *dummy;
151 int i;
152
153 if (empty_slot == NULL)
154 empty_slot = &dummy;
155 *empty_slot = NULL;
156 for (i = 0; i < FIRMWARE_MAX; i++) {
157 fp = &firmware_table[i];
158 if (fp->fw.name != NULL && strcasecmp(name, fp->fw.name) == 0)
159 break;
160 else if (!FW_INUSE(fp))
161 *empty_slot = fp;
162 }
163 return (i < FIRMWARE_MAX ) ? fp : NULL;
164 }
165
166 /*
167 * Register a firmware image with the specified name. The
168 * image name must not already be registered. If this is a
169 * subimage then parent refers to a previously registered
170 * image that this should be associated with.
171 */
172 const struct firmware *
173 firmware_register(const char *imagename, const void *data, size_t datasize,
174 unsigned int version, const struct firmware *parent)
175 {
176 struct priv_fw *match, *frp;
177
178 mtx_lock(&firmware_mtx);
179 /*
180 * Do a lookup to make sure the name is unique or find a free slot.
181 */
182 match = lookup(imagename, &frp);
183 if (match != NULL) {
184 mtx_unlock(&firmware_mtx);
185 printf("%s: image %s already registered!\n",
186 __func__, imagename);
187 return NULL;
188 }
189 if (frp == NULL) {
190 mtx_unlock(&firmware_mtx);
191 printf("%s: cannot register image %s, firmware table full!\n",
192 __func__, imagename);
193 return NULL;
194 }
195 bzero(frp, sizeof(frp)); /* start from a clean record */
196 frp->fw.name = imagename;
197 frp->fw.data = data;
198 frp->fw.datasize = datasize;
199 frp->fw.version = version;
200 if (parent != NULL) {
201 frp->parent = PRIV_FW(parent);
202 frp->parent->refcnt++;
203 }
204 mtx_unlock(&firmware_mtx);
205 if (bootverbose)
206 printf("firmware: '%s' version %u: %zu bytes loaded at %p\n",
207 imagename, version, datasize, data);
208 return &frp->fw;
209 }
210
211 /*
212 * Unregister/remove a firmware image. If there are outstanding
213 * references an error is returned and the image is not removed
214 * from the registry.
215 */
216 int
217 firmware_unregister(const char *imagename)
218 {
219 struct priv_fw *fp;
220 int err;
221
222 mtx_lock(&firmware_mtx);
223 fp = lookup(imagename, NULL);
224 if (fp == NULL) {
225 /*
226 * It is ok for the lookup to fail; this can happen
227 * when a module is unloaded on last reference and the
228 * module unload handler unregister's each of it's
229 * firmware images.
230 */
231 err = 0;
232 } else if (fp->refcnt != 0) { /* cannot unregister */
233 err = EBUSY;
234 } else {
235 linker_file_t x = fp->file; /* save value */
236
237 if (fp->parent != NULL) /* release parent reference */
238 fp->parent->refcnt--;
239 /*
240 * Clear the whole entry with bzero to make sure we
241 * do not forget anything. Then restore 'file' which is
242 * non-null for autoloaded images.
243 */
244 bzero(fp, sizeof(struct priv_fw));
245 fp->file = x;
246 err = 0;
247 }
248 mtx_unlock(&firmware_mtx);
249 return err;
250 }
251
252 static void
253 loadimage(void *arg, int npending)
254 {
255 struct thread *td = curthread;
256 char *imagename = arg;
257 struct priv_fw *fp;
258 linker_file_t result;
259 int error;
260
261 /* synchronize with the thread that dispatched us */
262 mtx_lock(&firmware_mtx);
263 mtx_unlock(&firmware_mtx);
264
265 if (td->td_proc->p_fd->fd_rdir == NULL) {
266 printf("%s: root not mounted yet, no way to load image\n",
267 imagename);
268 goto done;
269 }
270 error = linker_reference_module(imagename, NULL, &result);
271 if (error != 0) {
272 printf("%s: could not load firmware image, error %d\n",
273 imagename, error);
274 goto done;
275 }
276
277 mtx_lock(&firmware_mtx);
278 fp = lookup(imagename, NULL);
279 if (fp == NULL || fp->file != NULL) {
280 mtx_unlock(&firmware_mtx);
281 if (fp == NULL)
282 printf("%s: firmware image loaded, "
283 "but did not register\n", imagename);
284 (void) linker_release_module(imagename, NULL, NULL);
285 goto done;
286 }
287 fp->file = result; /* record the module identity */
288 mtx_unlock(&firmware_mtx);
289 done:
290 wakeup_one(imagename); /* we're done */
291 }
292
293 /*
294 * Lookup and potentially load the specified firmware image.
295 * If the firmware is not found in the registry, try to load a kernel
296 * module named as the image name.
297 * If the firmware is located, a reference is returned. The caller must
298 * release this reference for the image to be eligible for removal/unload.
299 */
300 const struct firmware *
301 firmware_get(const char *imagename)
302 {
303 struct task fwload_task;
304 struct thread *td;
305 struct priv_fw *fp;
306
307 mtx_lock(&firmware_mtx);
308 fp = lookup(imagename, NULL);
309 if (fp != NULL)
310 goto found;
311 /*
312 * Image not present, try to load the module holding it.
313 */
314 td = curthread;
315 if (suser(td) != 0 ||
316 securelevel_gt(td->td_ucred, 0) != 0) {
317 mtx_unlock(&firmware_mtx);
318 printf("%s: insufficient privileges to "
319 "load firmware image %s\n", __func__, imagename);
320 return NULL;
321 }
322 /*
323 * Defer load to a thread with known context. linker_reference_module
324 * may do filesystem i/o which requires root & current dirs, etc.
325 * Also we must not hold any mtx's over this call which is problematic.
326 */
327 if (!cold) {
328 TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *,
329 imagename));
330 taskqueue_enqueue(firmware_tq, &fwload_task);
331 msleep(__DECONST(void *, imagename), &firmware_mtx, 0,
332 "fwload", 0);
333 }
334 /*
335 * After attempting to load the module, see if the image is registered.
336 */
337 fp = lookup(imagename, NULL);
338 if (fp == NULL) {
339 mtx_unlock(&firmware_mtx);
340 return NULL;
341 }
342 found: /* common exit point on success */
343 fp->refcnt++;
344 mtx_unlock(&firmware_mtx);
345 return &fp->fw;
346 }
347
348 /*
349 * Release a reference to a firmware image returned by firmware_get.
350 * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire
351 * to release the resource, but the flag is only advisory.
352 *
353 * If this is the last reference to the firmware image, and this is an
354 * autoloaded module, wake up the firmware_unload_task to figure out
355 * what to do with the associated module.
356 */
357 void
358 firmware_put(const struct firmware *p, int flags)
359 {
360 struct priv_fw *fp = PRIV_FW(p);
361
362 mtx_lock(&firmware_mtx);
363 fp->refcnt--;
364 if (fp->refcnt == 0) {
365 if (flags & FIRMWARE_UNLOAD)
366 fp->flags |= FW_UNLOAD;
367 if (fp->file)
368 taskqueue_enqueue(firmware_tq, &firmware_unload_task);
369 }
370 mtx_unlock(&firmware_mtx);
371 }
372
373 /*
374 * Setup directory state for the firmware_tq thread so we can do i/o.
375 */
376 static void
377 set_rootvnode(void *arg, int npending)
378 {
379 struct thread *td = curthread;
380 struct proc *p = td->td_proc;
381
382 FILEDESC_LOCK(p->p_fd);
383 if (p->p_fd->fd_cdir == NULL) {
384 p->p_fd->fd_cdir = rootvnode;
385 VREF(rootvnode);
386 }
387 if (p->p_fd->fd_rdir == NULL) {
388 p->p_fd->fd_rdir = rootvnode;
389 VREF(rootvnode);
390 }
391 FILEDESC_UNLOCK(p->p_fd);
392
393 free(arg, M_TEMP);
394 }
395
396 /*
397 * Event handler called on mounting of /; bounce a task
398 * into the task queue thread to setup it's directories.
399 */
400 static void
401 firmware_mountroot(void *arg)
402 {
403 struct task *setroot_task;
404
405 setroot_task = malloc(sizeof(struct task), M_TEMP, M_NOWAIT);
406 if (setroot_task != NULL) {
407 TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task);
408 taskqueue_enqueue(firmware_tq, setroot_task);
409 } else
410 printf("%s: no memory for task!\n", __func__);
411 }
412
413 static eventhandler_tag mountroot_tag;
414 static void
415 mountroot_evh_init(void *ctx)
416 {
417 mountroot_tag = EVENTHANDLER_REGISTER(mountroot,
418 firmware_mountroot, ctx, 0);
419 }
420 SYSINIT(mountroot_evh_init, SI_SUB_CONFIGURE, SI_ORDER_ANY,
421 mountroot_evh_init, NULL);
422
423 /*
424 * The body of the task in charge of unloading autoloaded modules
425 * that are not needed anymore.
426 * Images can be cross-linked so we may need to make multiple passes,
427 * but the time we spend in the loop is bounded because we clear entries
428 * as we touch them.
429 */
430 static void
431 unloadentry(void *unused1, int unused2)
432 {
433 int limit = FIRMWARE_MAX;
434 int i; /* current cycle */
435
436 mtx_lock(&firmware_mtx);
437 /*
438 * Scan the table. limit is set to make sure we make another
439 * full sweep after matching an entry that requires unloading.
440 */
441 for (i = 0; i < limit; i++) {
442 struct priv_fw *fp;
443 int err;
444
445 fp = &firmware_table[i % FIRMWARE_MAX];
446 if (fp->fw.name == NULL || fp->file == NULL ||
447 fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0)
448 continue;
449
450 /*
451 * Found an entry. Now:
452 * 1. bump up limit to make sure we make another full round;
453 * 2. clear FW_UNLOAD so we don't try this entry again.
454 * 3. release the lock while trying to unload the module.
455 * 'file' remains set so that the entry cannot be reused
456 * in the meantime (it also means that fp->file will
457 * not change while we release the lock).
458 */
459 limit = i + FIRMWARE_MAX; /* make another full round */
460 fp->flags &= ~FW_UNLOAD; /* do not try again */
461
462 mtx_unlock(&firmware_mtx);
463 err = linker_release_module(NULL, NULL, fp->file);
464 mtx_lock(&firmware_mtx);
465
466 /*
467 * We rely on the module to call firmware_unregister()
468 * on unload to actually release the entry.
469 * If err = 0 we can drop our reference as the system
470 * accepted it. Otherwise unloading failed (e.g. the
471 * module itself gave an error) so our reference is
472 * still valid.
473 */
474 if (err == 0)
475 fp->file = NULL;
476 }
477 mtx_unlock(&firmware_mtx);
478 }
479
480 /*
481 * Module glue.
482 */
483 static int
484 firmware_modevent(module_t mod, int type, void *unused)
485 {
486 struct priv_fw *fp;
487 int i, err;
488
489 switch (type) {
490 case MOD_LOAD:
491 TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL);
492 firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK,
493 taskqueue_thread_enqueue, &firmware_tq, NULL);
494 /* NB: use our own loop routine that sets up context */
495 (void) taskqueue_start_threads(&firmware_tq, 1, PWAIT,
496 "firmware taskq");
497 if (rootvnode != NULL) {
498 /*
499 * Root is already mounted so we won't get an event;
500 * simulate one here.
501 */
502 firmware_mountroot(NULL);
503 }
504 return 0;
505
506 case MOD_UNLOAD:
507 /* request all autoloaded modules to be released */
508 mtx_lock(&firmware_mtx);
509 for (i = 0; i < FIRMWARE_MAX; i++) {
510 fp = &firmware_table[i];
511 fp->flags |= FW_UNLOAD;;
512 }
513 mtx_unlock(&firmware_mtx);
514 taskqueue_enqueue(firmware_tq, &firmware_unload_task);
515 taskqueue_drain(firmware_tq, &firmware_unload_task);
516 err = 0;
517 for (i = 0; i < FIRMWARE_MAX; i++) {
518 fp = &firmware_table[i];
519 if (fp->fw.name != NULL) {
520 printf("%s: image %p ref %d still active slot %d\n",
521 __func__, fp->fw.name,
522 fp->refcnt, i);
523 err = EINVAL;
524 }
525 }
526 if (err == 0)
527 taskqueue_free(firmware_tq);
528 return err;
529 }
530 return EINVAL;
531 }
532
533 static moduledata_t firmware_mod = {
534 "firmware",
535 firmware_modevent,
536 0
537 };
538 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
539 MODULE_VERSION(firmware, 1);
Cache object: 5a1c55924af6e860c1a7a73baa227ebb
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