Merge tag 'pm-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
[linux-block.git] / drivers / char / hw_random / core.c
CommitLineData
844dd05f 1/*
dd801483
CL
2 * hw_random/core.c: HWRNG core API
3 *
4 * Copyright 2006 Michael Buesch <m@bues.ch>
5 * Copyright 2005 (c) MontaVista Software, Inc.
6 *
4f4cfa6c 7 * Please read Documentation/admin-guide/hw_random.rst for details on use.
dd801483
CL
8 *
9 * This software may be used and distributed according to the terms
10 * of the GNU General Public License, incorporated herein by reference.
844dd05f
MB
11 */
12
affdec58 13#include <linux/delay.h>
844dd05f 14#include <linux/device.h>
affdec58
CL
15#include <linux/err.h>
16#include <linux/fs.h>
844dd05f 17#include <linux/hw_random.h>
844dd05f 18#include <linux/kernel.h>
be4000bc 19#include <linux/kthread.h>
affdec58
CL
20#include <linux/miscdevice.h>
21#include <linux/module.h>
d9e79726 22#include <linux/random.h>
affdec58 23#include <linux/sched.h>
d88bdbd9 24#include <linux/sched/signal.h>
affdec58 25#include <linux/slab.h>
78aafb38 26#include <linux/string.h>
7c0f6ba6 27#include <linux/uaccess.h>
844dd05f 28
844dd05f 29#define RNG_MODULE_NAME "hw_random"
844dd05f 30
78aafb38
HX
31#define RNG_BUFFER_SIZE (SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES)
32
844dd05f 33static struct hwrng *current_rng;
10a515dd
HF
34/* the current rng has been explicitly chosen by user via sysfs */
35static int cur_rng_set_by_user;
be4000bc 36static struct task_struct *hwrng_fill;
c90e4539 37/* list of registered rngs */
844dd05f 38static LIST_HEAD(rng_list);
9372b35e 39/* Protects rng_list and current_rng */
844dd05f 40static DEFINE_MUTEX(rng_mutex);
9372b35e
RR
41/* Protects rng read functions, data_avail, rng_buffer and rng_fillbuf */
42static DEFINE_MUTEX(reading_mutex);
9996508b 43static int data_avail;
be4000bc 44static u8 *rng_buffer, *rng_fillbuf;
0f734e6e 45static unsigned short current_quality;
16bdbae3 46static unsigned short default_quality = 1024; /* default to maximum */
be4000bc
TD
47
48module_param(current_quality, ushort, 0644);
49MODULE_PARM_DESC(current_quality,
82082856 50 "current hwrng entropy estimation per 1024 bits of input -- obsolete, use rng_quality instead");
0f734e6e
TD
51module_param(default_quality, ushort, 0644);
52MODULE_PARM_DESC(default_quality,
16bdbae3 53 "default maximum entropy content of hwrng per 1024 bits of input");
be4000bc 54
ff77c150 55static void drop_current_rng(void);
90ac41bd 56static int hwrng_init(struct hwrng *rng);
b006c439 57static int hwrng_fillfn(void *unused);
f7f154f1 58
d3cc7996
AS
59static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
60 int wait);
61
f7f154f1
RR
62static size_t rng_buffer_size(void)
63{
78aafb38 64 return RNG_BUFFER_SIZE;
f7f154f1 65}
844dd05f 66
3a2c0ba5
RR
67static inline void cleanup_rng(struct kref *kref)
68{
69 struct hwrng *rng = container_of(kref, struct hwrng, ref);
70
71 if (rng->cleanup)
72 rng->cleanup(rng);
a027f30d 73
77584ee5 74 complete(&rng->cleanup_done);
3a2c0ba5
RR
75}
76
90ac41bd 77static int set_current_rng(struct hwrng *rng)
3a2c0ba5 78{
90ac41bd
HX
79 int err;
80
3a2c0ba5 81 BUG_ON(!mutex_is_locked(&rng_mutex));
90ac41bd
HX
82
83 err = hwrng_init(rng);
84 if (err)
85 return err;
86
ff77c150 87 drop_current_rng();
3a2c0ba5 88 current_rng = rng;
90ac41bd 89
b006c439
DB
90 /* if necessary, start hwrng thread */
91 if (!hwrng_fill) {
92 hwrng_fill = kthread_run(hwrng_fillfn, NULL, "hwrng");
93 if (IS_ERR(hwrng_fill)) {
94 pr_err("hwrng_fill thread creation failed\n");
95 hwrng_fill = NULL;
96 }
97 }
98
90ac41bd 99 return 0;
3a2c0ba5
RR
100}
101
102static void drop_current_rng(void)
103{
104 BUG_ON(!mutex_is_locked(&rng_mutex));
105 if (!current_rng)
106 return;
107
108 /* decrease last reference for triggering the cleanup */
109 kref_put(&current_rng->ref, cleanup_rng);
110 current_rng = NULL;
111}
112
113/* Returns ERR_PTR(), NULL or refcounted hwrng */
daae28de
LV
114static struct hwrng *get_current_rng_nolock(void)
115{
116 if (current_rng)
117 kref_get(&current_rng->ref);
118
119 return current_rng;
120}
121
3a2c0ba5
RR
122static struct hwrng *get_current_rng(void)
123{
124 struct hwrng *rng;
125
126 if (mutex_lock_interruptible(&rng_mutex))
127 return ERR_PTR(-ERESTARTSYS);
128
daae28de 129 rng = get_current_rng_nolock();
3a2c0ba5
RR
130
131 mutex_unlock(&rng_mutex);
132 return rng;
133}
134
135static void put_rng(struct hwrng *rng)
136{
137 /*
138 * Hold rng_mutex here so we serialize in case they set_current_rng
139 * on rng again immediately.
140 */
141 mutex_lock(&rng_mutex);
142 if (rng)
143 kref_put(&rng->ref, cleanup_rng);
144 mutex_unlock(&rng_mutex);
145}
146
90ac41bd 147static int hwrng_init(struct hwrng *rng)
844dd05f 148{
15b66cd5
HX
149 if (kref_get_unless_zero(&rng->ref))
150 goto skip_init;
151
d3cc7996
AS
152 if (rng->init) {
153 int ret;
154
155 ret = rng->init(rng);
156 if (ret)
157 return ret;
158 }
15b66cd5
HX
159
160 kref_init(&rng->ref);
161 reinit_completion(&rng->cleanup_done);
162
163skip_init:
f0fb6953 164 current_quality = rng->quality; /* obsolete */
0f734e6e 165
d3cc7996 166 return 0;
844dd05f
MB
167}
168
844dd05f
MB
169static int rng_dev_open(struct inode *inode, struct file *filp)
170{
171 /* enforce read-only access to this chrdev */
172 if ((filp->f_mode & FMODE_READ) == 0)
173 return -EINVAL;
174 if (filp->f_mode & FMODE_WRITE)
175 return -EINVAL;
176 return 0;
177}
178
9996508b
IM
179static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
180 int wait) {
181 int present;
182
9372b35e 183 BUG_ON(!mutex_is_locked(&reading_mutex));
fb10c7a8
HX
184 if (rng->read) {
185 int err;
186
187 err = rng->read(rng, buffer, size, wait);
188 if (WARN_ON_ONCE(err > 0 && err > size))
189 err = size;
190
191 return err;
192 }
9996508b
IM
193
194 if (rng->data_present)
195 present = rng->data_present(rng, wait);
196 else
197 present = 1;
198
199 if (present)
200 return rng->data_read(rng, (u32 *)buffer);
201
202 return 0;
203}
204
844dd05f
MB
205static ssize_t rng_dev_read(struct file *filp, char __user *buf,
206 size_t size, loff_t *offp)
207{
78aafb38 208 u8 buffer[RNG_BUFFER_SIZE];
844dd05f 209 ssize_t ret = 0;
984e976f 210 int err = 0;
9996508b 211 int bytes_read, len;
3a2c0ba5 212 struct hwrng *rng;
844dd05f
MB
213
214 while (size) {
3a2c0ba5
RR
215 rng = get_current_rng();
216 if (IS_ERR(rng)) {
217 err = PTR_ERR(rng);
844dd05f 218 goto out;
9996508b 219 }
3a2c0ba5 220 if (!rng) {
844dd05f 221 err = -ENODEV;
3a2c0ba5 222 goto out;
844dd05f 223 }
984e976f 224
1ab87298
JS
225 if (mutex_lock_interruptible(&reading_mutex)) {
226 err = -ERESTARTSYS;
227 goto out_put;
228 }
9996508b 229 if (!data_avail) {
3a2c0ba5 230 bytes_read = rng_get_data(rng, rng_buffer,
f7f154f1 231 rng_buffer_size(),
9996508b
IM
232 !(filp->f_flags & O_NONBLOCK));
233 if (bytes_read < 0) {
234 err = bytes_read;
9372b35e 235 goto out_unlock_reading;
78aafb38
HX
236 } else if (bytes_read == 0 &&
237 (filp->f_flags & O_NONBLOCK)) {
238 err = -EAGAIN;
239 goto out_unlock_reading;
9996508b 240 }
78aafb38 241
9996508b 242 data_avail = bytes_read;
893f1128 243 }
844dd05f 244
78aafb38
HX
245 len = data_avail;
246 if (len) {
9996508b
IM
247 if (len > size)
248 len = size;
249
250 data_avail -= len;
251
78aafb38
HX
252 memcpy(buffer, rng_buffer + data_avail, len);
253 }
254 mutex_unlock(&reading_mutex);
255 put_rng(rng);
256
257 if (len) {
258 if (copy_to_user(buf + ret, buffer, len)) {
9996508b 259 err = -EFAULT;
78aafb38 260 goto out;
9996508b
IM
261 }
262
263 size -= len;
264 ret += len;
844dd05f
MB
265 }
266
9996508b 267
844dd05f
MB
268 if (need_resched())
269 schedule_timeout_interruptible(1);
9996508b
IM
270
271 if (signal_pending(current)) {
272 err = -ERESTARTSYS;
844dd05f 273 goto out;
9996508b 274 }
844dd05f
MB
275 }
276out:
78aafb38 277 memzero_explicit(buffer, sizeof(buffer));
844dd05f 278 return ret ? : err;
3a2c0ba5 279
9372b35e
RR
280out_unlock_reading:
281 mutex_unlock(&reading_mutex);
1ab87298 282out_put:
3a2c0ba5
RR
283 put_rng(rng);
284 goto out;
844dd05f
MB
285}
286
62322d25 287static const struct file_operations rng_chrdev_ops = {
844dd05f
MB
288 .owner = THIS_MODULE,
289 .open = rng_dev_open,
290 .read = rng_dev_read,
6038f373 291 .llseek = noop_llseek,
844dd05f
MB
292};
293
0daa7a0a
TI
294static const struct attribute_group *rng_dev_groups[];
295
844dd05f 296static struct miscdevice rng_miscdev = {
fd50d71f 297 .minor = HWRNG_MINOR,
844dd05f 298 .name = RNG_MODULE_NAME,
e454cea2 299 .nodename = "hwrng",
844dd05f 300 .fops = &rng_chrdev_ops,
0daa7a0a 301 .groups = rng_dev_groups,
844dd05f
MB
302};
303
142a27f0
PM
304static int enable_best_rng(void)
305{
c90e4539 306 struct hwrng *rng, *new_rng = NULL;
142a27f0
PM
307 int ret = -ENODEV;
308
309 BUG_ON(!mutex_is_locked(&rng_mutex));
310
c90e4539
DB
311 /* no rng to use? */
312 if (list_empty(&rng_list)) {
0e4b5294
GH
313 drop_current_rng();
314 cur_rng_set_by_user = 0;
c90e4539
DB
315 return 0;
316 }
317
318 /* use the rng which offers the best quality */
319 list_for_each_entry(rng, &rng_list, list) {
320 if (!new_rng || rng->quality > new_rng->quality)
321 new_rng = rng;
142a27f0
PM
322 }
323
c90e4539
DB
324 ret = ((new_rng == current_rng) ? 0 : set_current_rng(new_rng));
325 if (!ret)
326 cur_rng_set_by_user = 0;
327
142a27f0
PM
328 return ret;
329}
330
98f481f2
Y
331static ssize_t rng_current_store(struct device *dev,
332 struct device_attribute *attr,
333 const char *buf, size_t len)
844dd05f 334{
cb028f16 335 int err;
67ec8cdf 336 struct hwrng *rng, *new_rng;
844dd05f
MB
337
338 err = mutex_lock_interruptible(&rng_mutex);
339 if (err)
340 return -ERESTARTSYS;
142a27f0
PM
341
342 if (sysfs_streq(buf, "")) {
343 err = enable_best_rng();
344 } else {
345 list_for_each_entry(rng, &rng_list, list) {
346 if (sysfs_streq(rng->name, buf)) {
90ac41bd 347 err = set_current_rng(rng);
f41aa47c
DB
348 if (!err)
349 cur_rng_set_by_user = 1;
142a27f0
PM
350 break;
351 }
844dd05f
MB
352 }
353 }
daae28de 354 new_rng = get_current_rng_nolock();
844dd05f
MB
355 mutex_unlock(&rng_mutex);
356
67ec8cdf 357 if (new_rng)
daae28de 358 put_rng(new_rng);
daae28de 359
844dd05f
MB
360 return err ? : len;
361}
362
98f481f2
Y
363static ssize_t rng_current_show(struct device *dev,
364 struct device_attribute *attr,
365 char *buf)
844dd05f 366{
844dd05f 367 ssize_t ret;
3a2c0ba5 368 struct hwrng *rng;
844dd05f 369
3a2c0ba5
RR
370 rng = get_current_rng();
371 if (IS_ERR(rng))
372 return PTR_ERR(rng);
373
90d012fb 374 ret = sysfs_emit(buf, "%s\n", rng ? rng->name : "none");
3a2c0ba5 375 put_rng(rng);
844dd05f
MB
376
377 return ret;
378}
379
98f481f2
Y
380static ssize_t rng_available_show(struct device *dev,
381 struct device_attribute *attr,
382 char *buf)
844dd05f
MB
383{
384 int err;
844dd05f
MB
385 struct hwrng *rng;
386
387 err = mutex_lock_interruptible(&rng_mutex);
388 if (err)
389 return -ERESTARTSYS;
390 buf[0] = '\0';
391 list_for_each_entry(rng, &rng_list, list) {
61daf055
RS
392 strlcat(buf, rng->name, PAGE_SIZE);
393 strlcat(buf, " ", PAGE_SIZE);
844dd05f 394 }
61daf055 395 strlcat(buf, "\n", PAGE_SIZE);
844dd05f
MB
396 mutex_unlock(&rng_mutex);
397
61daf055 398 return strlen(buf);
844dd05f
MB
399}
400
98f481f2
Y
401static ssize_t rng_selected_show(struct device *dev,
402 struct device_attribute *attr,
403 char *buf)
10a515dd 404{
91253022 405 return sysfs_emit(buf, "%d\n", cur_rng_set_by_user);
10a515dd
HF
406}
407
82082856
DB
408static ssize_t rng_quality_show(struct device *dev,
409 struct device_attribute *attr,
410 char *buf)
411{
412 ssize_t ret;
413 struct hwrng *rng;
414
415 rng = get_current_rng();
416 if (IS_ERR(rng))
417 return PTR_ERR(rng);
418
419 if (!rng) /* no need to put_rng */
420 return -ENODEV;
421
422 ret = sysfs_emit(buf, "%hu\n", rng->quality);
423 put_rng(rng);
424
425 return ret;
426}
427
428static ssize_t rng_quality_store(struct device *dev,
429 struct device_attribute *attr,
430 const char *buf, size_t len)
431{
432 u16 quality;
433 int ret = -EINVAL;
434
435 if (len < 2)
436 return -EINVAL;
437
438 ret = mutex_lock_interruptible(&rng_mutex);
439 if (ret)
440 return -ERESTARTSYS;
441
442 ret = kstrtou16(buf, 0, &quality);
443 if (ret || quality > 1024) {
444 ret = -EINVAL;
445 goto out;
446 }
447
448 if (!current_rng) {
449 ret = -ENODEV;
450 goto out;
451 }
452
453 current_rng->quality = quality;
454 current_quality = quality; /* obsolete */
455
456 /* the best available RNG may have changed */
457 ret = enable_best_rng();
458
82082856
DB
459out:
460 mutex_unlock(&rng_mutex);
461 return ret ? ret : len;
462}
463
98f481f2
Y
464static DEVICE_ATTR_RW(rng_current);
465static DEVICE_ATTR_RO(rng_available);
466static DEVICE_ATTR_RO(rng_selected);
82082856 467static DEVICE_ATTR_RW(rng_quality);
844dd05f 468
0daa7a0a
TI
469static struct attribute *rng_dev_attrs[] = {
470 &dev_attr_rng_current.attr,
471 &dev_attr_rng_available.attr,
10a515dd 472 &dev_attr_rng_selected.attr,
82082856 473 &dev_attr_rng_quality.attr,
0daa7a0a
TI
474 NULL
475};
476
477ATTRIBUTE_GROUPS(rng_dev);
844dd05f 478
be4000bc
TD
479static int hwrng_fillfn(void *unused)
480{
a43bed82 481 size_t entropy, entropy_credit = 0; /* in 1/1024 of a bit */
be4000bc
TD
482 long rc;
483
08e97aec 484 while (!kthread_should_stop()) {
f0fb6953 485 unsigned short quality;
3a2c0ba5
RR
486 struct hwrng *rng;
487
488 rng = get_current_rng();
489 if (IS_ERR(rng) || !rng)
be4000bc 490 break;
9372b35e 491 mutex_lock(&reading_mutex);
3a2c0ba5 492 rc = rng_get_data(rng, rng_fillbuf,
be4000bc 493 rng_buffer_size(), 1);
f0fb6953
DB
494 if (current_quality != rng->quality)
495 rng->quality = current_quality; /* obsolete */
496 quality = rng->quality;
9372b35e 497 mutex_unlock(&reading_mutex);
36cb6494
JD
498
499 if (rc <= 0)
500 hwrng_msleep(rng, 10000);
501
3a2c0ba5 502 put_rng(rng);
f0fb6953 503
36cb6494 504 if (rc <= 0)
be4000bc 505 continue;
a43bed82
DB
506
507 /* If we cannot credit at least one bit of entropy,
508 * keep track of the remainder for the next iteration
509 */
f0fb6953 510 entropy = rc * quality * 8 + entropy_credit;
a43bed82
DB
511 if ((entropy >> 10) == 0)
512 entropy_credit = entropy;
513
9372b35e 514 /* Outside lock, sure, but y'know: randomness. */
be4000bc 515 add_hwgenerator_randomness((void *)rng_fillbuf, rc,
db516da9 516 entropy >> 10, true);
be4000bc 517 }
9dda727d 518 hwrng_fill = NULL;
be4000bc
TD
519 return 0;
520}
521
844dd05f
MB
522int hwrng_register(struct hwrng *rng)
523{
844dd05f 524 int err = -EINVAL;
28443671 525 struct hwrng *tmp;
844dd05f 526
2a971e3b 527 if (!rng->name || (!rng->data_read && !rng->read))
844dd05f
MB
528 goto out;
529
530 mutex_lock(&rng_mutex);
daae28de 531
844dd05f
MB
532 /* Must not register two RNGs with the same name. */
533 err = -EEXIST;
534 list_for_each_entry(tmp, &rng_list, list) {
535 if (strcmp(tmp->name, rng->name) == 0)
536 goto out_unlock;
537 }
c90e4539 538 list_add_tail(&rng->list, &rng_list);
844dd05f 539
15b66cd5
HX
540 init_completion(&rng->cleanup_done);
541 complete(&rng->cleanup_done);
36cb6494 542 init_completion(&rng->dying);
15b66cd5 543
95c0f5c3
HF
544 /* Adjust quality field to always have a proper value */
545 rng->quality = min_t(u16, min_t(u16, default_quality, 1024), rng->quality ?: 1024);
546
28443671
LV
547 if (!current_rng ||
548 (!cur_rng_set_by_user && rng->quality > current_rng->quality)) {
2bbb6983
HF
549 /*
550 * Set new rng as current as the new rng source
10a515dd
HF
551 * provides better entropy quality and was not
552 * chosen by userspace.
2bbb6983 553 */
90ac41bd 554 err = set_current_rng(rng);
844dd05f
MB
555 if (err)
556 goto out_unlock;
844dd05f 557 }
daae28de 558 mutex_unlock(&rng_mutex);
28443671 559 return 0;
844dd05f
MB
560out_unlock:
561 mutex_unlock(&rng_mutex);
562out:
563 return err;
564}
565EXPORT_SYMBOL_GPL(hwrng_register);
566
b844eba2 567void hwrng_unregister(struct hwrng *rng)
844dd05f 568{
67ec8cdf 569 struct hwrng *new_rng;
837bf7cc
MB
570 int err;
571
844dd05f
MB
572 mutex_lock(&rng_mutex);
573
574 list_del(&rng->list);
36cb6494 575 complete_all(&rng->dying);
837bf7cc
MB
576 if (current_rng == rng) {
577 err = enable_best_rng();
578 if (err) {
579 drop_current_rng();
580 cur_rng_set_by_user = 0;
581 }
582 }
3a2c0ba5 583
daae28de 584 new_rng = get_current_rng_nolock();
be4000bc 585 if (list_empty(&rng_list)) {
1dacb395 586 mutex_unlock(&rng_mutex);
be4000bc
TD
587 if (hwrng_fill)
588 kthread_stop(hwrng_fill);
1dacb395
AK
589 } else
590 mutex_unlock(&rng_mutex);
a027f30d 591
67ec8cdf 592 if (new_rng)
daae28de 593 put_rng(new_rng);
daae28de 594
77584ee5 595 wait_for_completion(&rng->cleanup_done);
844dd05f 596}
b844eba2 597EXPORT_SYMBOL_GPL(hwrng_unregister);
844dd05f 598
4d9b519c
DT
599static void devm_hwrng_release(struct device *dev, void *res)
600{
601 hwrng_unregister(*(struct hwrng **)res);
602}
603
604static int devm_hwrng_match(struct device *dev, void *res, void *data)
605{
606 struct hwrng **r = res;
607
608 if (WARN_ON(!r || !*r))
609 return 0;
610
611 return *r == data;
612}
613
614int devm_hwrng_register(struct device *dev, struct hwrng *rng)
615{
616 struct hwrng **ptr;
617 int error;
618
619 ptr = devres_alloc(devm_hwrng_release, sizeof(*ptr), GFP_KERNEL);
620 if (!ptr)
621 return -ENOMEM;
622
623 error = hwrng_register(rng);
624 if (error) {
625 devres_free(ptr);
626 return error;
627 }
628
629 *ptr = rng;
630 devres_add(dev, ptr);
631 return 0;
632}
633EXPORT_SYMBOL_GPL(devm_hwrng_register);
634
635void devm_hwrng_unregister(struct device *dev, struct hwrng *rng)
636{
637 devres_release(dev, devm_hwrng_release, devm_hwrng_match, rng);
638}
639EXPORT_SYMBOL_GPL(devm_hwrng_unregister);
640
36cb6494
JD
641long hwrng_msleep(struct hwrng *rng, unsigned int msecs)
642{
643 unsigned long timeout = msecs_to_jiffies(msecs) + 1;
644
645 return wait_for_completion_interruptible_timeout(&rng->dying, timeout);
646}
647EXPORT_SYMBOL_GPL(hwrng_msleep);
648
b58a3600
SW
649long hwrng_yield(struct hwrng *rng)
650{
651 return wait_for_completion_interruptible_timeout(&rng->dying, 1);
652}
653EXPORT_SYMBOL_GPL(hwrng_yield);
654
ac3a497f
HX
655static int __init hwrng_modinit(void)
656{
45645709 657 int ret;
58b022ac
PM
658
659 /* kmalloc makes this safe for virt_to_page() in virtio_rng.c */
660 rng_buffer = kmalloc(rng_buffer_size(), GFP_KERNEL);
661 if (!rng_buffer)
662 return -ENOMEM;
663
664 rng_fillbuf = kmalloc(rng_buffer_size(), GFP_KERNEL);
665 if (!rng_fillbuf) {
666 kfree(rng_buffer);
667 return -ENOMEM;
668 }
669
df1e9791 670 ret = misc_register(&rng_miscdev);
58b022ac
PM
671 if (ret) {
672 kfree(rng_fillbuf);
673 kfree(rng_buffer);
674 }
675
676 return ret;
ac3a497f
HX
677}
678
679static void __exit hwrng_modexit(void)
b7d44d94
ST
680{
681 mutex_lock(&rng_mutex);
682 BUG_ON(current_rng);
683 kfree(rng_buffer);
be4000bc 684 kfree(rng_fillbuf);
b7d44d94 685 mutex_unlock(&rng_mutex);
ac3a497f 686
df1e9791 687 misc_deregister(&rng_miscdev);
b7d44d94
ST
688}
689
26a03981 690fs_initcall(hwrng_modinit); /* depends on misc_register() */
ac3a497f 691module_exit(hwrng_modexit);
844dd05f
MB
692
693MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver");
694MODULE_LICENSE("GPL");