Commit | Line | Data |
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844dd05f MB |
1 | /* |
2 | Added support for the AMD Geode LX RNG | |
3 | (c) Copyright 2004-2005 Advanced Micro Devices, Inc. | |
4 | ||
5 | derived from | |
6 | ||
7 | Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG) | |
8 | (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com> | |
9 | ||
10 | derived from | |
11 | ||
12 | Hardware driver for the AMD 768 Random Number Generator (RNG) | |
13 | (c) Copyright 2001 Red Hat Inc <alan@redhat.com> | |
14 | ||
15 | derived from | |
16 | ||
17 | Hardware driver for Intel i810 Random Number Generator (RNG) | |
18 | Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com> | |
19 | Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com> | |
20 | ||
21 | Added generic RNG API | |
eb032b98 | 22 | Copyright 2006 Michael Buesch <m@bues.ch> |
844dd05f MB |
23 | Copyright 2005 (c) MontaVista Software, Inc. |
24 | ||
25 | Please read Documentation/hw_random.txt for details on use. | |
26 | ||
27 | ---------------------------------------------------------- | |
28 | This software may be used and distributed according to the terms | |
29 | of the GNU General Public License, incorporated herein by reference. | |
30 | ||
31 | */ | |
32 | ||
844dd05f MB |
33 | #include <linux/device.h> |
34 | #include <linux/hw_random.h> | |
35 | #include <linux/module.h> | |
36 | #include <linux/kernel.h> | |
37 | #include <linux/fs.h> | |
914e2637 | 38 | #include <linux/sched.h> |
844dd05f | 39 | #include <linux/miscdevice.h> |
be4000bc | 40 | #include <linux/kthread.h> |
844dd05f | 41 | #include <linux/delay.h> |
f7f154f1 | 42 | #include <linux/slab.h> |
d9e79726 | 43 | #include <linux/random.h> |
3a2c0ba5 | 44 | #include <linux/err.h> |
7c0f6ba6 | 45 | #include <linux/uaccess.h> |
844dd05f | 46 | |
844dd05f MB |
47 | #define RNG_MODULE_NAME "hw_random" |
48 | #define PFX RNG_MODULE_NAME ": " | |
49 | #define RNG_MISCDEV_MINOR 183 /* official */ | |
50 | ||
844dd05f | 51 | static struct hwrng *current_rng; |
be4000bc | 52 | static struct task_struct *hwrng_fill; |
844dd05f | 53 | static LIST_HEAD(rng_list); |
9372b35e | 54 | /* Protects rng_list and current_rng */ |
844dd05f | 55 | static DEFINE_MUTEX(rng_mutex); |
9372b35e RR |
56 | /* Protects rng read functions, data_avail, rng_buffer and rng_fillbuf */ |
57 | static DEFINE_MUTEX(reading_mutex); | |
9996508b | 58 | static int data_avail; |
be4000bc | 59 | static u8 *rng_buffer, *rng_fillbuf; |
0f734e6e TD |
60 | static unsigned short current_quality; |
61 | static unsigned short default_quality; /* = 0; default to "off" */ | |
be4000bc TD |
62 | |
63 | module_param(current_quality, ushort, 0644); | |
64 | MODULE_PARM_DESC(current_quality, | |
65 | "current hwrng entropy estimation per mill"); | |
0f734e6e TD |
66 | module_param(default_quality, ushort, 0644); |
67 | MODULE_PARM_DESC(default_quality, | |
68 | "default entropy content of hwrng per mill"); | |
be4000bc | 69 | |
ff77c150 | 70 | static void drop_current_rng(void); |
90ac41bd | 71 | static int hwrng_init(struct hwrng *rng); |
be4000bc | 72 | static void start_khwrngd(void); |
f7f154f1 | 73 | |
d3cc7996 AS |
74 | static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size, |
75 | int wait); | |
76 | ||
f7f154f1 RR |
77 | static size_t rng_buffer_size(void) |
78 | { | |
79 | return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES; | |
80 | } | |
844dd05f | 81 | |
d3cc7996 AS |
82 | static void add_early_randomness(struct hwrng *rng) |
83 | { | |
d3cc7996 | 84 | int bytes_read; |
6d4952d9 | 85 | size_t size = min_t(size_t, 16, rng_buffer_size()); |
d3cc7996 | 86 | |
9372b35e | 87 | mutex_lock(&reading_mutex); |
6d4952d9 | 88 | bytes_read = rng_get_data(rng, rng_buffer, size, 1); |
9372b35e | 89 | mutex_unlock(&reading_mutex); |
d3cc7996 | 90 | if (bytes_read > 0) |
6d4952d9 | 91 | add_device_randomness(rng_buffer, bytes_read); |
2cc75154 | 92 | memset(rng_buffer, 0, size); |
d3cc7996 AS |
93 | } |
94 | ||
3a2c0ba5 RR |
95 | static inline void cleanup_rng(struct kref *kref) |
96 | { | |
97 | struct hwrng *rng = container_of(kref, struct hwrng, ref); | |
98 | ||
99 | if (rng->cleanup) | |
100 | rng->cleanup(rng); | |
a027f30d | 101 | |
77584ee5 | 102 | complete(&rng->cleanup_done); |
3a2c0ba5 RR |
103 | } |
104 | ||
90ac41bd | 105 | static int set_current_rng(struct hwrng *rng) |
3a2c0ba5 | 106 | { |
90ac41bd HX |
107 | int err; |
108 | ||
3a2c0ba5 | 109 | BUG_ON(!mutex_is_locked(&rng_mutex)); |
90ac41bd HX |
110 | |
111 | err = hwrng_init(rng); | |
112 | if (err) | |
113 | return err; | |
114 | ||
ff77c150 | 115 | drop_current_rng(); |
3a2c0ba5 | 116 | current_rng = rng; |
90ac41bd HX |
117 | |
118 | return 0; | |
3a2c0ba5 RR |
119 | } |
120 | ||
121 | static void drop_current_rng(void) | |
122 | { | |
123 | BUG_ON(!mutex_is_locked(&rng_mutex)); | |
124 | if (!current_rng) | |
125 | return; | |
126 | ||
127 | /* decrease last reference for triggering the cleanup */ | |
128 | kref_put(¤t_rng->ref, cleanup_rng); | |
129 | current_rng = NULL; | |
130 | } | |
131 | ||
132 | /* Returns ERR_PTR(), NULL or refcounted hwrng */ | |
133 | static struct hwrng *get_current_rng(void) | |
134 | { | |
135 | struct hwrng *rng; | |
136 | ||
137 | if (mutex_lock_interruptible(&rng_mutex)) | |
138 | return ERR_PTR(-ERESTARTSYS); | |
139 | ||
140 | rng = current_rng; | |
141 | if (rng) | |
142 | kref_get(&rng->ref); | |
143 | ||
144 | mutex_unlock(&rng_mutex); | |
145 | return rng; | |
146 | } | |
147 | ||
148 | static void put_rng(struct hwrng *rng) | |
149 | { | |
150 | /* | |
151 | * Hold rng_mutex here so we serialize in case they set_current_rng | |
152 | * on rng again immediately. | |
153 | */ | |
154 | mutex_lock(&rng_mutex); | |
155 | if (rng) | |
156 | kref_put(&rng->ref, cleanup_rng); | |
157 | mutex_unlock(&rng_mutex); | |
158 | } | |
159 | ||
90ac41bd | 160 | static int hwrng_init(struct hwrng *rng) |
844dd05f | 161 | { |
15b66cd5 HX |
162 | if (kref_get_unless_zero(&rng->ref)) |
163 | goto skip_init; | |
164 | ||
d3cc7996 AS |
165 | if (rng->init) { |
166 | int ret; | |
167 | ||
168 | ret = rng->init(rng); | |
169 | if (ret) | |
170 | return ret; | |
171 | } | |
15b66cd5 HX |
172 | |
173 | kref_init(&rng->ref); | |
174 | reinit_completion(&rng->cleanup_done); | |
175 | ||
176 | skip_init: | |
d3cc7996 | 177 | add_early_randomness(rng); |
be4000bc | 178 | |
0f734e6e | 179 | current_quality = rng->quality ? : default_quality; |
506bf0c0 KP |
180 | if (current_quality > 1024) |
181 | current_quality = 1024; | |
0f734e6e TD |
182 | |
183 | if (current_quality == 0 && hwrng_fill) | |
184 | kthread_stop(hwrng_fill); | |
be4000bc TD |
185 | if (current_quality > 0 && !hwrng_fill) |
186 | start_khwrngd(); | |
187 | ||
d3cc7996 | 188 | return 0; |
844dd05f MB |
189 | } |
190 | ||
844dd05f MB |
191 | static int rng_dev_open(struct inode *inode, struct file *filp) |
192 | { | |
193 | /* enforce read-only access to this chrdev */ | |
194 | if ((filp->f_mode & FMODE_READ) == 0) | |
195 | return -EINVAL; | |
196 | if (filp->f_mode & FMODE_WRITE) | |
197 | return -EINVAL; | |
198 | return 0; | |
199 | } | |
200 | ||
9996508b IM |
201 | static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size, |
202 | int wait) { | |
203 | int present; | |
204 | ||
9372b35e | 205 | BUG_ON(!mutex_is_locked(&reading_mutex)); |
9996508b IM |
206 | if (rng->read) |
207 | return rng->read(rng, (void *)buffer, size, wait); | |
208 | ||
209 | if (rng->data_present) | |
210 | present = rng->data_present(rng, wait); | |
211 | else | |
212 | present = 1; | |
213 | ||
214 | if (present) | |
215 | return rng->data_read(rng, (u32 *)buffer); | |
216 | ||
217 | return 0; | |
218 | } | |
219 | ||
844dd05f MB |
220 | static ssize_t rng_dev_read(struct file *filp, char __user *buf, |
221 | size_t size, loff_t *offp) | |
222 | { | |
844dd05f | 223 | ssize_t ret = 0; |
984e976f | 224 | int err = 0; |
9996508b | 225 | int bytes_read, len; |
3a2c0ba5 | 226 | struct hwrng *rng; |
844dd05f MB |
227 | |
228 | while (size) { | |
3a2c0ba5 RR |
229 | rng = get_current_rng(); |
230 | if (IS_ERR(rng)) { | |
231 | err = PTR_ERR(rng); | |
844dd05f | 232 | goto out; |
9996508b | 233 | } |
3a2c0ba5 | 234 | if (!rng) { |
844dd05f | 235 | err = -ENODEV; |
3a2c0ba5 | 236 | goto out; |
844dd05f | 237 | } |
984e976f | 238 | |
1ab87298 JS |
239 | if (mutex_lock_interruptible(&reading_mutex)) { |
240 | err = -ERESTARTSYS; | |
241 | goto out_put; | |
242 | } | |
9996508b | 243 | if (!data_avail) { |
3a2c0ba5 | 244 | bytes_read = rng_get_data(rng, rng_buffer, |
f7f154f1 | 245 | rng_buffer_size(), |
9996508b IM |
246 | !(filp->f_flags & O_NONBLOCK)); |
247 | if (bytes_read < 0) { | |
248 | err = bytes_read; | |
9372b35e | 249 | goto out_unlock_reading; |
9996508b IM |
250 | } |
251 | data_avail = bytes_read; | |
893f1128 | 252 | } |
844dd05f | 253 | |
9996508b IM |
254 | if (!data_avail) { |
255 | if (filp->f_flags & O_NONBLOCK) { | |
256 | err = -EAGAIN; | |
9372b35e | 257 | goto out_unlock_reading; |
9996508b IM |
258 | } |
259 | } else { | |
260 | len = data_avail; | |
261 | if (len > size) | |
262 | len = size; | |
263 | ||
264 | data_avail -= len; | |
265 | ||
266 | if (copy_to_user(buf + ret, rng_buffer + data_avail, | |
267 | len)) { | |
268 | err = -EFAULT; | |
9372b35e | 269 | goto out_unlock_reading; |
9996508b IM |
270 | } |
271 | ||
272 | size -= len; | |
273 | ret += len; | |
844dd05f MB |
274 | } |
275 | ||
9372b35e | 276 | mutex_unlock(&reading_mutex); |
3a2c0ba5 | 277 | put_rng(rng); |
9996508b | 278 | |
844dd05f MB |
279 | if (need_resched()) |
280 | schedule_timeout_interruptible(1); | |
9996508b IM |
281 | |
282 | if (signal_pending(current)) { | |
283 | err = -ERESTARTSYS; | |
844dd05f | 284 | goto out; |
9996508b | 285 | } |
844dd05f MB |
286 | } |
287 | out: | |
2cc75154 | 288 | memset(rng_buffer, 0, rng_buffer_size()); |
844dd05f | 289 | return ret ? : err; |
3a2c0ba5 | 290 | |
9372b35e RR |
291 | out_unlock_reading: |
292 | mutex_unlock(&reading_mutex); | |
1ab87298 | 293 | out_put: |
3a2c0ba5 RR |
294 | put_rng(rng); |
295 | goto out; | |
844dd05f MB |
296 | } |
297 | ||
62322d25 | 298 | static const struct file_operations rng_chrdev_ops = { |
844dd05f MB |
299 | .owner = THIS_MODULE, |
300 | .open = rng_dev_open, | |
301 | .read = rng_dev_read, | |
6038f373 | 302 | .llseek = noop_llseek, |
844dd05f MB |
303 | }; |
304 | ||
0daa7a0a TI |
305 | static const struct attribute_group *rng_dev_groups[]; |
306 | ||
844dd05f MB |
307 | static struct miscdevice rng_miscdev = { |
308 | .minor = RNG_MISCDEV_MINOR, | |
309 | .name = RNG_MODULE_NAME, | |
e454cea2 | 310 | .nodename = "hwrng", |
844dd05f | 311 | .fops = &rng_chrdev_ops, |
0daa7a0a | 312 | .groups = rng_dev_groups, |
844dd05f MB |
313 | }; |
314 | ||
94fbcded GKH |
315 | static ssize_t hwrng_attr_current_store(struct device *dev, |
316 | struct device_attribute *attr, | |
844dd05f MB |
317 | const char *buf, size_t len) |
318 | { | |
319 | int err; | |
320 | struct hwrng *rng; | |
321 | ||
322 | err = mutex_lock_interruptible(&rng_mutex); | |
323 | if (err) | |
324 | return -ERESTARTSYS; | |
325 | err = -ENODEV; | |
326 | list_for_each_entry(rng, &rng_list, list) { | |
d9a53b01 | 327 | if (sysfs_streq(rng->name, buf)) { |
844dd05f | 328 | err = 0; |
90ac41bd HX |
329 | if (rng != current_rng) |
330 | err = set_current_rng(rng); | |
844dd05f MB |
331 | break; |
332 | } | |
333 | } | |
334 | mutex_unlock(&rng_mutex); | |
335 | ||
336 | return err ? : len; | |
337 | } | |
338 | ||
94fbcded GKH |
339 | static ssize_t hwrng_attr_current_show(struct device *dev, |
340 | struct device_attribute *attr, | |
844dd05f MB |
341 | char *buf) |
342 | { | |
844dd05f | 343 | ssize_t ret; |
3a2c0ba5 | 344 | struct hwrng *rng; |
844dd05f | 345 | |
3a2c0ba5 RR |
346 | rng = get_current_rng(); |
347 | if (IS_ERR(rng)) | |
348 | return PTR_ERR(rng); | |
349 | ||
350 | ret = snprintf(buf, PAGE_SIZE, "%s\n", rng ? rng->name : "none"); | |
351 | put_rng(rng); | |
844dd05f MB |
352 | |
353 | return ret; | |
354 | } | |
355 | ||
94fbcded GKH |
356 | static ssize_t hwrng_attr_available_show(struct device *dev, |
357 | struct device_attribute *attr, | |
844dd05f MB |
358 | char *buf) |
359 | { | |
360 | int err; | |
844dd05f MB |
361 | struct hwrng *rng; |
362 | ||
363 | err = mutex_lock_interruptible(&rng_mutex); | |
364 | if (err) | |
365 | return -ERESTARTSYS; | |
366 | buf[0] = '\0'; | |
367 | list_for_each_entry(rng, &rng_list, list) { | |
61daf055 RS |
368 | strlcat(buf, rng->name, PAGE_SIZE); |
369 | strlcat(buf, " ", PAGE_SIZE); | |
844dd05f | 370 | } |
61daf055 | 371 | strlcat(buf, "\n", PAGE_SIZE); |
844dd05f MB |
372 | mutex_unlock(&rng_mutex); |
373 | ||
61daf055 | 374 | return strlen(buf); |
844dd05f MB |
375 | } |
376 | ||
94fbcded GKH |
377 | static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR, |
378 | hwrng_attr_current_show, | |
379 | hwrng_attr_current_store); | |
380 | static DEVICE_ATTR(rng_available, S_IRUGO, | |
381 | hwrng_attr_available_show, | |
382 | NULL); | |
844dd05f | 383 | |
0daa7a0a TI |
384 | static struct attribute *rng_dev_attrs[] = { |
385 | &dev_attr_rng_current.attr, | |
386 | &dev_attr_rng_available.attr, | |
387 | NULL | |
388 | }; | |
389 | ||
390 | ATTRIBUTE_GROUPS(rng_dev); | |
844dd05f | 391 | |
ac3a497f | 392 | static void __exit unregister_miscdev(void) |
844dd05f | 393 | { |
b844eba2 | 394 | misc_deregister(&rng_miscdev); |
844dd05f MB |
395 | } |
396 | ||
ac3a497f | 397 | static int __init register_miscdev(void) |
844dd05f | 398 | { |
0daa7a0a | 399 | return misc_register(&rng_miscdev); |
844dd05f MB |
400 | } |
401 | ||
be4000bc TD |
402 | static int hwrng_fillfn(void *unused) |
403 | { | |
404 | long rc; | |
405 | ||
406 | while (!kthread_should_stop()) { | |
3a2c0ba5 RR |
407 | struct hwrng *rng; |
408 | ||
409 | rng = get_current_rng(); | |
410 | if (IS_ERR(rng) || !rng) | |
be4000bc | 411 | break; |
9372b35e | 412 | mutex_lock(&reading_mutex); |
3a2c0ba5 | 413 | rc = rng_get_data(rng, rng_fillbuf, |
be4000bc | 414 | rng_buffer_size(), 1); |
9372b35e | 415 | mutex_unlock(&reading_mutex); |
3a2c0ba5 | 416 | put_rng(rng); |
be4000bc TD |
417 | if (rc <= 0) { |
418 | pr_warn("hwrng: no data available\n"); | |
419 | msleep_interruptible(10000); | |
420 | continue; | |
421 | } | |
9372b35e | 422 | /* Outside lock, sure, but y'know: randomness. */ |
be4000bc | 423 | add_hwgenerator_randomness((void *)rng_fillbuf, rc, |
e02b8765 | 424 | rc * current_quality * 8 >> 10); |
2cc75154 | 425 | memset(rng_fillbuf, 0, rng_buffer_size()); |
be4000bc | 426 | } |
9dda727d | 427 | hwrng_fill = NULL; |
be4000bc TD |
428 | return 0; |
429 | } | |
430 | ||
431 | static void start_khwrngd(void) | |
432 | { | |
433 | hwrng_fill = kthread_run(hwrng_fillfn, NULL, "hwrng"); | |
17fb874d | 434 | if (IS_ERR(hwrng_fill)) { |
be4000bc TD |
435 | pr_err("hwrng_fill thread creation failed"); |
436 | hwrng_fill = NULL; | |
437 | } | |
438 | } | |
439 | ||
844dd05f MB |
440 | int hwrng_register(struct hwrng *rng) |
441 | { | |
844dd05f MB |
442 | int err = -EINVAL; |
443 | struct hwrng *old_rng, *tmp; | |
444 | ||
445 | if (rng->name == NULL || | |
9996508b | 446 | (rng->data_read == NULL && rng->read == NULL)) |
844dd05f MB |
447 | goto out; |
448 | ||
449 | mutex_lock(&rng_mutex); | |
844dd05f MB |
450 | /* Must not register two RNGs with the same name. */ |
451 | err = -EEXIST; | |
452 | list_for_each_entry(tmp, &rng_list, list) { | |
453 | if (strcmp(tmp->name, rng->name) == 0) | |
454 | goto out_unlock; | |
455 | } | |
456 | ||
15b66cd5 HX |
457 | init_completion(&rng->cleanup_done); |
458 | complete(&rng->cleanup_done); | |
459 | ||
844dd05f | 460 | old_rng = current_rng; |
ebbbfa24 | 461 | err = 0; |
844dd05f | 462 | if (!old_rng) { |
90ac41bd | 463 | err = set_current_rng(rng); |
844dd05f MB |
464 | if (err) |
465 | goto out_unlock; | |
844dd05f | 466 | } |
844dd05f | 467 | list_add_tail(&rng->list, &rng_list); |
d9e79726 | 468 | |
d3cc7996 AS |
469 | if (old_rng && !rng->init) { |
470 | /* | |
471 | * Use a new device's input to add some randomness to | |
472 | * the system. If this rng device isn't going to be | |
473 | * used right away, its init function hasn't been | |
474 | * called yet; so only use the randomness from devices | |
475 | * that don't need an init callback. | |
476 | */ | |
477 | add_early_randomness(rng); | |
478 | } | |
479 | ||
844dd05f MB |
480 | out_unlock: |
481 | mutex_unlock(&rng_mutex); | |
482 | out: | |
483 | return err; | |
484 | } | |
485 | EXPORT_SYMBOL_GPL(hwrng_register); | |
486 | ||
b844eba2 | 487 | void hwrng_unregister(struct hwrng *rng) |
844dd05f | 488 | { |
844dd05f MB |
489 | mutex_lock(&rng_mutex); |
490 | ||
491 | list_del(&rng->list); | |
492 | if (current_rng == rng) { | |
3a2c0ba5 RR |
493 | drop_current_rng(); |
494 | if (!list_empty(&rng_list)) { | |
495 | struct hwrng *tail; | |
496 | ||
497 | tail = list_entry(rng_list.prev, struct hwrng, list); | |
498 | ||
90ac41bd | 499 | set_current_rng(tail); |
844dd05f MB |
500 | } |
501 | } | |
3a2c0ba5 | 502 | |
be4000bc | 503 | if (list_empty(&rng_list)) { |
1dacb395 | 504 | mutex_unlock(&rng_mutex); |
be4000bc TD |
505 | if (hwrng_fill) |
506 | kthread_stop(hwrng_fill); | |
1dacb395 AK |
507 | } else |
508 | mutex_unlock(&rng_mutex); | |
a027f30d | 509 | |
77584ee5 | 510 | wait_for_completion(&rng->cleanup_done); |
844dd05f | 511 | } |
b844eba2 | 512 | EXPORT_SYMBOL_GPL(hwrng_unregister); |
844dd05f | 513 | |
4d9b519c DT |
514 | static void devm_hwrng_release(struct device *dev, void *res) |
515 | { | |
516 | hwrng_unregister(*(struct hwrng **)res); | |
517 | } | |
518 | ||
519 | static int devm_hwrng_match(struct device *dev, void *res, void *data) | |
520 | { | |
521 | struct hwrng **r = res; | |
522 | ||
523 | if (WARN_ON(!r || !*r)) | |
524 | return 0; | |
525 | ||
526 | return *r == data; | |
527 | } | |
528 | ||
529 | int devm_hwrng_register(struct device *dev, struct hwrng *rng) | |
530 | { | |
531 | struct hwrng **ptr; | |
532 | int error; | |
533 | ||
534 | ptr = devres_alloc(devm_hwrng_release, sizeof(*ptr), GFP_KERNEL); | |
535 | if (!ptr) | |
536 | return -ENOMEM; | |
537 | ||
538 | error = hwrng_register(rng); | |
539 | if (error) { | |
540 | devres_free(ptr); | |
541 | return error; | |
542 | } | |
543 | ||
544 | *ptr = rng; | |
545 | devres_add(dev, ptr); | |
546 | return 0; | |
547 | } | |
548 | EXPORT_SYMBOL_GPL(devm_hwrng_register); | |
549 | ||
550 | void devm_hwrng_unregister(struct device *dev, struct hwrng *rng) | |
551 | { | |
552 | devres_release(dev, devm_hwrng_release, devm_hwrng_match, rng); | |
553 | } | |
554 | EXPORT_SYMBOL_GPL(devm_hwrng_unregister); | |
555 | ||
ac3a497f HX |
556 | static int __init hwrng_modinit(void) |
557 | { | |
58b022ac PM |
558 | int ret = -ENOMEM; |
559 | ||
560 | /* kmalloc makes this safe for virt_to_page() in virtio_rng.c */ | |
561 | rng_buffer = kmalloc(rng_buffer_size(), GFP_KERNEL); | |
562 | if (!rng_buffer) | |
563 | return -ENOMEM; | |
564 | ||
565 | rng_fillbuf = kmalloc(rng_buffer_size(), GFP_KERNEL); | |
566 | if (!rng_fillbuf) { | |
567 | kfree(rng_buffer); | |
568 | return -ENOMEM; | |
569 | } | |
570 | ||
571 | ret = register_miscdev(); | |
572 | if (ret) { | |
573 | kfree(rng_fillbuf); | |
574 | kfree(rng_buffer); | |
575 | } | |
576 | ||
577 | return ret; | |
ac3a497f HX |
578 | } |
579 | ||
580 | static void __exit hwrng_modexit(void) | |
b7d44d94 ST |
581 | { |
582 | mutex_lock(&rng_mutex); | |
583 | BUG_ON(current_rng); | |
584 | kfree(rng_buffer); | |
be4000bc | 585 | kfree(rng_fillbuf); |
b7d44d94 | 586 | mutex_unlock(&rng_mutex); |
ac3a497f HX |
587 | |
588 | unregister_miscdev(); | |
b7d44d94 ST |
589 | } |
590 | ||
ac3a497f HX |
591 | module_init(hwrng_modinit); |
592 | module_exit(hwrng_modexit); | |
844dd05f MB |
593 | |
594 | MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver"); | |
595 | MODULE_LICENSE("GPL"); |