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/caps.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 lock protects accesses to the firmware table.
136 */
137 static struct lock firmware_lock;
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 *
lookup(const char * name,struct priv_fw ** empty_slot)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 *
firmware_register(const char * imagename,const void * data,size_t datasize,unsigned int version,const struct firmware * parent)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 lockmgr(&firmware_lock, LK_EXCLUSIVE);
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 lockmgr(&firmware_lock, LK_RELEASE);
185 kprintf("%s: image %s already registered!\n",
186 __func__, imagename);
187 return NULL;
188 }
189 if (frp == NULL) {
190 lockmgr(&firmware_lock, LK_RELEASE);
191 kprintf("%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 lockmgr(&firmware_lock, LK_RELEASE);
205 if (bootverbose)
206 kprintf("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
firmware_unregister(const char * imagename)217 firmware_unregister(const char *imagename)
218 {
219 struct priv_fw *fp;
220 int err;
221
222 lockmgr(&firmware_lock, LK_EXCLUSIVE);
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 lockmgr(&firmware_lock, LK_RELEASE);
249 return err;
250 }
251
252 static void
loadimage(void * arg,int npending)253 loadimage(void *arg, int npending)
254 {
255 #ifdef notyet
256 struct thread *td = curthread;
257 #endif
258 char *imagename = arg;
259 struct priv_fw *fp;
260 linker_file_t result;
261 int error;
262
263 /* synchronize with the thread that dispatched us */
264 lockmgr(&firmware_lock, LK_EXCLUSIVE);
265 lockmgr(&firmware_lock, LK_RELEASE);
266
267 /* JAT
268 if (td->td_proc->p_fd->fd_rdir == NULL) {
269 kprintf("%s: root not mounted yet, no way to load image\n",
270 imagename);
271 goto done;
272 }
273 */
274 error = linker_reference_module(imagename, NULL, &result);
275 if (error != 0) {
276 kprintf("%s: could not load firmware image, error %d\n",
277 imagename, error);
278 goto done;
279 }
280
281 lockmgr(&firmware_lock, LK_EXCLUSIVE);
282 fp = lookup(imagename, NULL);
283 if (fp == NULL || fp->file != NULL) {
284 lockmgr(&firmware_lock, LK_RELEASE);
285 if (fp == NULL)
286 kprintf("%s: firmware image loaded, "
287 "but did not register\n", imagename);
288 (void) linker_release_module(imagename, NULL, NULL);
289 goto done;
290 }
291 fp->file = result; /* record the module identity */
292 lockmgr(&firmware_lock, LK_RELEASE);
293 done:
294 wakeup_one(imagename); /* we're done */
295 }
296
297 /*
298 * Lookup and potentially load the specified firmware image.
299 * If the firmware is not found in the registry, try to load a kernel
300 * module named as the image name.
301 * If the firmware is located, a reference is returned. The caller must
302 * release this reference for the image to be eligible for removal/unload.
303 */
304 const struct firmware *
firmware_get(const char * imagename)305 firmware_get(const char *imagename)
306 {
307 struct task fwload_task;
308 struct priv_fw *fp;
309
310 lockmgr(&firmware_lock, LK_EXCLUSIVE);
311 fp = lookup(imagename, NULL);
312 if (fp != NULL)
313 goto found;
314 /*
315 * Image not present, try to load the module holding it.
316 */
317 if (caps_priv_check_self(SYSCAP_NOKLD) != 0 || securelevel > 0) {
318 lockmgr(&firmware_lock, LK_RELEASE);
319 kprintf("%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 lock's over this call which is problematic.
327 */
328 if (!cold) {
329 TASK_INIT(&fwload_task, 0, loadimage, __DECONST(void *,
330 imagename));
331 taskqueue_enqueue(firmware_tq, &fwload_task);
332 lksleep(__DECONST(void *, imagename), &firmware_lock, 0,
333 "fwload", 0);
334 }
335 /*
336 * After attempting to load the module, see if the image is registered.
337 */
338 fp = lookup(imagename, NULL);
339 if (fp == NULL) {
340 lockmgr(&firmware_lock, LK_RELEASE);
341 return NULL;
342 }
343 found: /* common exit point on success */
344 fp->refcnt++;
345 lockmgr(&firmware_lock, LK_RELEASE);
346 return &fp->fw;
347 }
348
349 /*
350 * Release a reference to a firmware image returned by firmware_get.
351 * The caller may specify, with the FIRMWARE_UNLOAD flag, its desire
352 * to release the resource, but the flag is only advisory.
353 *
354 * If this is the last reference to the firmware image, and this is an
355 * autoloaded module, wake up the firmware_unload_task to figure out
356 * what to do with the associated module.
357 */
358 void
firmware_put(const struct firmware * p,int flags)359 firmware_put(const struct firmware *p, int flags)
360 {
361 struct priv_fw *fp = PRIV_FW(p);
362
363 lockmgr(&firmware_lock, LK_EXCLUSIVE);
364 fp->refcnt--;
365 if (fp->refcnt == 0) {
366 if (flags & FIRMWARE_UNLOAD)
367 fp->flags |= FW_UNLOAD;
368 if (fp->file)
369 taskqueue_enqueue(firmware_tq, &firmware_unload_task);
370 }
371 lockmgr(&firmware_lock, LK_RELEASE);
372 }
373
374 #ifdef notyet
375 /*
376 * Setup directory state for the firmware_tq thread so we can do i/o.
377 */
378 static void
set_rootvnode(void * arg,int npending)379 set_rootvnode(void *arg, int npending)
380 {
381 struct thread *td = curthread;
382 struct proc *p = td->td_proc;
383
384
385 #if 0
386 spin_lock_wr(&p->p_fd->fd_spin);
387 if (p->p_fd->fd_cdir == NULL) {
388 p->p_fd->fd_cdir = rootvnode;
389 vref(rootvnode);
390 }
391 if (p->p_fd->fd_rdir == NULL) {
392 p->p_fd->fd_rdir = rootvnode;
393 vref(rootvnode);
394 }
395 spin_unlock_wr(&p->p_fd->fd_spin);
396
397 kfree(arg, M_TEMP);
398 #endif
399 }
400
401 /*
402 * Event handler called on mounting of /; bounce a task
403 * into the task queue thread to setup it's directories.
404 */
405 static void
firmware_mountroot(void * arg)406 firmware_mountroot(void *arg)
407 {
408 struct task *setroot_task;
409
410 setroot_task = kmalloc(sizeof(struct task), M_TEMP, M_NOWAIT);
411 if (setroot_task != NULL) {
412 TASK_INIT(setroot_task, 0, set_rootvnode, setroot_task);
413 taskqueue_enqueue(firmware_tq, setroot_task);
414 } else
415 kprintf("%s: no memory for task!\n", __func__);
416 }
417 EVENTHANDLER_DECLARE(mountroot, firmware_mountroot);
418 #endif
419
420 /*
421 * The body of the task in charge of unloading autoloaded modules
422 * that are not needed anymore.
423 * Images can be cross-linked so we may need to make multiple passes,
424 * but the time we spend in the loop is bounded because we clear entries
425 * as we touch them.
426 */
427 static void
unloadentry(void * unused1,int unused2)428 unloadentry(void *unused1, int unused2)
429 {
430 int limit = FIRMWARE_MAX;
431 int i; /* current cycle */
432
433 lockmgr(&firmware_lock, LK_EXCLUSIVE);
434 /*
435 * Scan the table. limit is set to make sure we make another
436 * full sweep after matching an entry that requires unloading.
437 */
438 for (i = 0; i < limit; i++) {
439 struct priv_fw *fp;
440 int err;
441
442 fp = &firmware_table[i % FIRMWARE_MAX];
443 if (fp->fw.name == NULL || fp->file == NULL ||
444 fp->refcnt != 0 || (fp->flags & FW_UNLOAD) == 0)
445 continue;
446
447 /*
448 * Found an entry. Now:
449 * 1. bump up limit to make sure we make another full round;
450 * 2. clear FW_UNLOAD so we don't try this entry again.
451 * 3. release the lock while trying to unload the module.
452 * 'file' remains set so that the entry cannot be reused
453 * in the meantime (it also means that fp->file will
454 * not change while we release the lock).
455 */
456 limit = i + FIRMWARE_MAX; /* make another full round */
457 fp->flags &= ~FW_UNLOAD; /* do not try again */
458
459 lockmgr(&firmware_lock, LK_RELEASE);
460 err = linker_release_module(NULL, NULL, fp->file);
461 lockmgr(&firmware_lock, LK_EXCLUSIVE);
462
463 /*
464 * We rely on the module to call firmware_unregister()
465 * on unload to actually release the entry.
466 * If err = 0 we can drop our reference as the system
467 * accepted it. Otherwise unloading failed (e.g. the
468 * module itself gave an error) so our reference is
469 * still valid.
470 */
471 if (err == 0)
472 fp->file = NULL;
473 }
474 lockmgr(&firmware_lock, LK_RELEASE);
475 }
476
477 /*
478 * Module glue.
479 */
480 static int
firmware_modevent(module_t mod,int type,void * unused)481 firmware_modevent(module_t mod, int type, void *unused)
482 {
483 struct priv_fw *fp;
484 int i, err;
485
486 switch (type) {
487 case MOD_LOAD:
488 TASK_INIT(&firmware_unload_task, 0, unloadentry, NULL);
489 lockinit(&firmware_lock, "firmware table", 0, LK_CANRECURSE);
490 firmware_tq = taskqueue_create("taskqueue_firmware", M_WAITOK,
491 taskqueue_thread_enqueue, &firmware_tq);
492 /* NB: use our own loop routine that sets up context */
493 (void) taskqueue_start_threads(&firmware_tq, 1, TDPRI_KERN_DAEMON,
494 -1, "firmware taskq");
495 if (rootvnode != NULL) {
496 /*
497 * Root is already mounted so we won't get an event;
498 * simulate one here.
499 */
500 #ifdef notyet
501 firmware_mountroot(NULL);
502 #endif
503 }
504 return 0;
505
506 case MOD_UNLOAD:
507 /* request all autoloaded modules to be released */
508 lockmgr(&firmware_lock, LK_EXCLUSIVE);
509 for (i = 0; i < FIRMWARE_MAX; i++) {
510 fp = &firmware_table[i];
511 fp->flags |= FW_UNLOAD;
512 }
513 lockmgr(&firmware_lock, LK_RELEASE);
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 kprintf("%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 NULL
537 };
538 DECLARE_MODULE(firmware, firmware_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
539 MODULE_VERSION(firmware, 1);
540