Commit | Line | Data |
---|---|---|
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 | * | |
7 | * Please read Documentation/hw_random.txt for details on use. | |
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> |
174cd4b1 | 20 | #include <linux/sched/signal.h> |
affdec58 CL |
21 | #include <linux/miscdevice.h> |
22 | #include <linux/module.h> | |
d9e79726 | 23 | #include <linux/random.h> |
affdec58 CL |
24 | #include <linux/sched.h> |
25 | #include <linux/slab.h> | |
7c0f6ba6 | 26 | #include <linux/uaccess.h> |
844dd05f | 27 | |
844dd05f | 28 | #define RNG_MODULE_NAME "hw_random" |
844dd05f MB |
29 | |
30 | static struct hwrng *current_rng; | |
10a515dd HF |
31 | /* the current rng has been explicitly chosen by user via sysfs */ |
32 | static int cur_rng_set_by_user; | |
be4000bc | 33 | static struct task_struct *hwrng_fill; |
2bbb6983 | 34 | /* list of registered rngs, sorted decending by quality */ |
844dd05f | 35 | static LIST_HEAD(rng_list); |
9372b35e | 36 | /* Protects rng_list and current_rng */ |
844dd05f | 37 | static DEFINE_MUTEX(rng_mutex); |
9372b35e RR |
38 | /* Protects rng read functions, data_avail, rng_buffer and rng_fillbuf */ |
39 | static DEFINE_MUTEX(reading_mutex); | |
9996508b | 40 | static int data_avail; |
be4000bc | 41 | static u8 *rng_buffer, *rng_fillbuf; |
0f734e6e TD |
42 | static unsigned short current_quality; |
43 | static unsigned short default_quality; /* = 0; default to "off" */ | |
be4000bc TD |
44 | |
45 | module_param(current_quality, ushort, 0644); | |
46 | MODULE_PARM_DESC(current_quality, | |
fae29f13 | 47 | "current hwrng entropy estimation per 1024 bits of input"); |
0f734e6e TD |
48 | module_param(default_quality, ushort, 0644); |
49 | MODULE_PARM_DESC(default_quality, | |
fae29f13 | 50 | "default entropy content of hwrng per 1024 bits of input"); |
be4000bc | 51 | |
ff77c150 | 52 | static void drop_current_rng(void); |
90ac41bd | 53 | static int hwrng_init(struct hwrng *rng); |
be4000bc | 54 | static void start_khwrngd(void); |
f7f154f1 | 55 | |
d3cc7996 AS |
56 | static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size, |
57 | int wait); | |
58 | ||
f7f154f1 RR |
59 | static size_t rng_buffer_size(void) |
60 | { | |
61 | return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES; | |
62 | } | |
844dd05f | 63 | |
d3cc7996 AS |
64 | static void add_early_randomness(struct hwrng *rng) |
65 | { | |
d3cc7996 | 66 | int bytes_read; |
6d4952d9 | 67 | size_t size = min_t(size_t, 16, rng_buffer_size()); |
d3cc7996 | 68 | |
9372b35e | 69 | mutex_lock(&reading_mutex); |
6d4952d9 | 70 | bytes_read = rng_get_data(rng, rng_buffer, size, 1); |
9372b35e | 71 | mutex_unlock(&reading_mutex); |
d3cc7996 | 72 | if (bytes_read > 0) |
6d4952d9 | 73 | add_device_randomness(rng_buffer, bytes_read); |
d3cc7996 AS |
74 | } |
75 | ||
3a2c0ba5 RR |
76 | static inline void cleanup_rng(struct kref *kref) |
77 | { | |
78 | struct hwrng *rng = container_of(kref, struct hwrng, ref); | |
79 | ||
80 | if (rng->cleanup) | |
81 | rng->cleanup(rng); | |
a027f30d | 82 | |
77584ee5 | 83 | complete(&rng->cleanup_done); |
3a2c0ba5 RR |
84 | } |
85 | ||
90ac41bd | 86 | static int set_current_rng(struct hwrng *rng) |
3a2c0ba5 | 87 | { |
90ac41bd HX |
88 | int err; |
89 | ||
3a2c0ba5 | 90 | BUG_ON(!mutex_is_locked(&rng_mutex)); |
90ac41bd HX |
91 | |
92 | err = hwrng_init(rng); | |
93 | if (err) | |
94 | return err; | |
95 | ||
ff77c150 | 96 | drop_current_rng(); |
3a2c0ba5 | 97 | current_rng = rng; |
90ac41bd HX |
98 | |
99 | return 0; | |
3a2c0ba5 RR |
100 | } |
101 | ||
102 | static 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(¤t_rng->ref, cleanup_rng); | |
110 | current_rng = NULL; | |
111 | } | |
112 | ||
113 | /* Returns ERR_PTR(), NULL or refcounted hwrng */ | |
114 | static struct hwrng *get_current_rng(void) | |
115 | { | |
116 | struct hwrng *rng; | |
117 | ||
118 | if (mutex_lock_interruptible(&rng_mutex)) | |
119 | return ERR_PTR(-ERESTARTSYS); | |
120 | ||
121 | rng = current_rng; | |
122 | if (rng) | |
123 | kref_get(&rng->ref); | |
124 | ||
125 | mutex_unlock(&rng_mutex); | |
126 | return rng; | |
127 | } | |
128 | ||
129 | static void put_rng(struct hwrng *rng) | |
130 | { | |
131 | /* | |
132 | * Hold rng_mutex here so we serialize in case they set_current_rng | |
133 | * on rng again immediately. | |
134 | */ | |
135 | mutex_lock(&rng_mutex); | |
136 | if (rng) | |
137 | kref_put(&rng->ref, cleanup_rng); | |
138 | mutex_unlock(&rng_mutex); | |
139 | } | |
140 | ||
90ac41bd | 141 | static int hwrng_init(struct hwrng *rng) |
844dd05f | 142 | { |
15b66cd5 HX |
143 | if (kref_get_unless_zero(&rng->ref)) |
144 | goto skip_init; | |
145 | ||
d3cc7996 AS |
146 | if (rng->init) { |
147 | int ret; | |
148 | ||
149 | ret = rng->init(rng); | |
150 | if (ret) | |
151 | return ret; | |
152 | } | |
15b66cd5 HX |
153 | |
154 | kref_init(&rng->ref); | |
155 | reinit_completion(&rng->cleanup_done); | |
156 | ||
157 | skip_init: | |
d3cc7996 | 158 | add_early_randomness(rng); |
be4000bc | 159 | |
0f734e6e | 160 | current_quality = rng->quality ? : default_quality; |
506bf0c0 KP |
161 | if (current_quality > 1024) |
162 | current_quality = 1024; | |
0f734e6e TD |
163 | |
164 | if (current_quality == 0 && hwrng_fill) | |
165 | kthread_stop(hwrng_fill); | |
be4000bc TD |
166 | if (current_quality > 0 && !hwrng_fill) |
167 | start_khwrngd(); | |
168 | ||
d3cc7996 | 169 | return 0; |
844dd05f MB |
170 | } |
171 | ||
844dd05f MB |
172 | static int rng_dev_open(struct inode *inode, struct file *filp) |
173 | { | |
174 | /* enforce read-only access to this chrdev */ | |
175 | if ((filp->f_mode & FMODE_READ) == 0) | |
176 | return -EINVAL; | |
177 | if (filp->f_mode & FMODE_WRITE) | |
178 | return -EINVAL; | |
179 | return 0; | |
180 | } | |
181 | ||
9996508b IM |
182 | static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size, |
183 | int wait) { | |
184 | int present; | |
185 | ||
9372b35e | 186 | BUG_ON(!mutex_is_locked(&reading_mutex)); |
9996508b IM |
187 | if (rng->read) |
188 | return rng->read(rng, (void *)buffer, size, wait); | |
189 | ||
190 | if (rng->data_present) | |
191 | present = rng->data_present(rng, wait); | |
192 | else | |
193 | present = 1; | |
194 | ||
195 | if (present) | |
196 | return rng->data_read(rng, (u32 *)buffer); | |
197 | ||
198 | return 0; | |
199 | } | |
200 | ||
844dd05f MB |
201 | static ssize_t rng_dev_read(struct file *filp, char __user *buf, |
202 | size_t size, loff_t *offp) | |
203 | { | |
844dd05f | 204 | ssize_t ret = 0; |
984e976f | 205 | int err = 0; |
9996508b | 206 | int bytes_read, len; |
3a2c0ba5 | 207 | struct hwrng *rng; |
844dd05f MB |
208 | |
209 | while (size) { | |
3a2c0ba5 RR |
210 | rng = get_current_rng(); |
211 | if (IS_ERR(rng)) { | |
212 | err = PTR_ERR(rng); | |
844dd05f | 213 | goto out; |
9996508b | 214 | } |
3a2c0ba5 | 215 | if (!rng) { |
844dd05f | 216 | err = -ENODEV; |
3a2c0ba5 | 217 | goto out; |
844dd05f | 218 | } |
984e976f | 219 | |
1ab87298 JS |
220 | if (mutex_lock_interruptible(&reading_mutex)) { |
221 | err = -ERESTARTSYS; | |
222 | goto out_put; | |
223 | } | |
9996508b | 224 | if (!data_avail) { |
3a2c0ba5 | 225 | bytes_read = rng_get_data(rng, rng_buffer, |
f7f154f1 | 226 | rng_buffer_size(), |
9996508b IM |
227 | !(filp->f_flags & O_NONBLOCK)); |
228 | if (bytes_read < 0) { | |
229 | err = bytes_read; | |
9372b35e | 230 | goto out_unlock_reading; |
9996508b IM |
231 | } |
232 | data_avail = bytes_read; | |
893f1128 | 233 | } |
844dd05f | 234 | |
9996508b IM |
235 | if (!data_avail) { |
236 | if (filp->f_flags & O_NONBLOCK) { | |
237 | err = -EAGAIN; | |
9372b35e | 238 | goto out_unlock_reading; |
9996508b IM |
239 | } |
240 | } else { | |
241 | len = data_avail; | |
242 | if (len > size) | |
243 | len = size; | |
244 | ||
245 | data_avail -= len; | |
246 | ||
247 | if (copy_to_user(buf + ret, rng_buffer + data_avail, | |
248 | len)) { | |
249 | err = -EFAULT; | |
9372b35e | 250 | goto out_unlock_reading; |
9996508b IM |
251 | } |
252 | ||
253 | size -= len; | |
254 | ret += len; | |
844dd05f MB |
255 | } |
256 | ||
9372b35e | 257 | mutex_unlock(&reading_mutex); |
3a2c0ba5 | 258 | put_rng(rng); |
9996508b | 259 | |
844dd05f MB |
260 | if (need_resched()) |
261 | schedule_timeout_interruptible(1); | |
9996508b IM |
262 | |
263 | if (signal_pending(current)) { | |
264 | err = -ERESTARTSYS; | |
844dd05f | 265 | goto out; |
9996508b | 266 | } |
844dd05f MB |
267 | } |
268 | out: | |
269 | return ret ? : err; | |
3a2c0ba5 | 270 | |
9372b35e RR |
271 | out_unlock_reading: |
272 | mutex_unlock(&reading_mutex); | |
1ab87298 | 273 | out_put: |
3a2c0ba5 RR |
274 | put_rng(rng); |
275 | goto out; | |
844dd05f MB |
276 | } |
277 | ||
62322d25 | 278 | static const struct file_operations rng_chrdev_ops = { |
844dd05f MB |
279 | .owner = THIS_MODULE, |
280 | .open = rng_dev_open, | |
281 | .read = rng_dev_read, | |
6038f373 | 282 | .llseek = noop_llseek, |
844dd05f MB |
283 | }; |
284 | ||
0daa7a0a TI |
285 | static const struct attribute_group *rng_dev_groups[]; |
286 | ||
844dd05f | 287 | static struct miscdevice rng_miscdev = { |
fd50d71f | 288 | .minor = HWRNG_MINOR, |
844dd05f | 289 | .name = RNG_MODULE_NAME, |
e454cea2 | 290 | .nodename = "hwrng", |
844dd05f | 291 | .fops = &rng_chrdev_ops, |
0daa7a0a | 292 | .groups = rng_dev_groups, |
844dd05f MB |
293 | }; |
294 | ||
142a27f0 PM |
295 | static int enable_best_rng(void) |
296 | { | |
297 | int ret = -ENODEV; | |
298 | ||
299 | BUG_ON(!mutex_is_locked(&rng_mutex)); | |
300 | ||
301 | /* rng_list is sorted by quality, use the best (=first) one */ | |
302 | if (!list_empty(&rng_list)) { | |
303 | struct hwrng *new_rng; | |
304 | ||
305 | new_rng = list_entry(rng_list.next, struct hwrng, list); | |
306 | ret = ((new_rng == current_rng) ? 0 : set_current_rng(new_rng)); | |
307 | if (!ret) | |
308 | cur_rng_set_by_user = 0; | |
0e4b5294 GH |
309 | } else { |
310 | drop_current_rng(); | |
311 | cur_rng_set_by_user = 0; | |
312 | ret = 0; | |
142a27f0 PM |
313 | } |
314 | ||
315 | return ret; | |
316 | } | |
317 | ||
94fbcded GKH |
318 | static ssize_t hwrng_attr_current_store(struct device *dev, |
319 | struct device_attribute *attr, | |
844dd05f MB |
320 | const char *buf, size_t len) |
321 | { | |
142a27f0 | 322 | int err = -ENODEV; |
844dd05f MB |
323 | struct hwrng *rng; |
324 | ||
325 | err = mutex_lock_interruptible(&rng_mutex); | |
326 | if (err) | |
327 | return -ERESTARTSYS; | |
142a27f0 PM |
328 | |
329 | if (sysfs_streq(buf, "")) { | |
330 | err = enable_best_rng(); | |
331 | } else { | |
332 | list_for_each_entry(rng, &rng_list, list) { | |
333 | if (sysfs_streq(rng->name, buf)) { | |
334 | cur_rng_set_by_user = 1; | |
90ac41bd | 335 | err = set_current_rng(rng); |
142a27f0 PM |
336 | break; |
337 | } | |
844dd05f MB |
338 | } |
339 | } | |
142a27f0 | 340 | |
844dd05f MB |
341 | mutex_unlock(&rng_mutex); |
342 | ||
343 | return err ? : len; | |
344 | } | |
345 | ||
94fbcded GKH |
346 | static ssize_t hwrng_attr_current_show(struct device *dev, |
347 | struct device_attribute *attr, | |
844dd05f MB |
348 | char *buf) |
349 | { | |
844dd05f | 350 | ssize_t ret; |
3a2c0ba5 | 351 | struct hwrng *rng; |
844dd05f | 352 | |
3a2c0ba5 RR |
353 | rng = get_current_rng(); |
354 | if (IS_ERR(rng)) | |
355 | return PTR_ERR(rng); | |
356 | ||
357 | ret = snprintf(buf, PAGE_SIZE, "%s\n", rng ? rng->name : "none"); | |
358 | put_rng(rng); | |
844dd05f MB |
359 | |
360 | return ret; | |
361 | } | |
362 | ||
94fbcded GKH |
363 | static ssize_t hwrng_attr_available_show(struct device *dev, |
364 | struct device_attribute *attr, | |
844dd05f MB |
365 | char *buf) |
366 | { | |
367 | int err; | |
844dd05f MB |
368 | struct hwrng *rng; |
369 | ||
370 | err = mutex_lock_interruptible(&rng_mutex); | |
371 | if (err) | |
372 | return -ERESTARTSYS; | |
373 | buf[0] = '\0'; | |
374 | list_for_each_entry(rng, &rng_list, list) { | |
61daf055 RS |
375 | strlcat(buf, rng->name, PAGE_SIZE); |
376 | strlcat(buf, " ", PAGE_SIZE); | |
844dd05f | 377 | } |
61daf055 | 378 | strlcat(buf, "\n", PAGE_SIZE); |
844dd05f MB |
379 | mutex_unlock(&rng_mutex); |
380 | ||
61daf055 | 381 | return strlen(buf); |
844dd05f MB |
382 | } |
383 | ||
10a515dd HF |
384 | static ssize_t hwrng_attr_selected_show(struct device *dev, |
385 | struct device_attribute *attr, | |
386 | char *buf) | |
387 | { | |
388 | return snprintf(buf, PAGE_SIZE, "%d\n", cur_rng_set_by_user); | |
389 | } | |
390 | ||
94fbcded GKH |
391 | static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR, |
392 | hwrng_attr_current_show, | |
393 | hwrng_attr_current_store); | |
394 | static DEVICE_ATTR(rng_available, S_IRUGO, | |
395 | hwrng_attr_available_show, | |
396 | NULL); | |
10a515dd HF |
397 | static DEVICE_ATTR(rng_selected, S_IRUGO, |
398 | hwrng_attr_selected_show, | |
399 | NULL); | |
844dd05f | 400 | |
0daa7a0a TI |
401 | static struct attribute *rng_dev_attrs[] = { |
402 | &dev_attr_rng_current.attr, | |
403 | &dev_attr_rng_available.attr, | |
10a515dd | 404 | &dev_attr_rng_selected.attr, |
0daa7a0a TI |
405 | NULL |
406 | }; | |
407 | ||
408 | ATTRIBUTE_GROUPS(rng_dev); | |
844dd05f | 409 | |
ac3a497f | 410 | static void __exit unregister_miscdev(void) |
844dd05f | 411 | { |
b844eba2 | 412 | misc_deregister(&rng_miscdev); |
844dd05f MB |
413 | } |
414 | ||
ac3a497f | 415 | static int __init register_miscdev(void) |
844dd05f | 416 | { |
0daa7a0a | 417 | return misc_register(&rng_miscdev); |
844dd05f MB |
418 | } |
419 | ||
be4000bc TD |
420 | static int hwrng_fillfn(void *unused) |
421 | { | |
422 | long rc; | |
423 | ||
424 | while (!kthread_should_stop()) { | |
3a2c0ba5 RR |
425 | struct hwrng *rng; |
426 | ||
427 | rng = get_current_rng(); | |
428 | if (IS_ERR(rng) || !rng) | |
be4000bc | 429 | break; |
9372b35e | 430 | mutex_lock(&reading_mutex); |
3a2c0ba5 | 431 | rc = rng_get_data(rng, rng_fillbuf, |
be4000bc | 432 | rng_buffer_size(), 1); |
9372b35e | 433 | mutex_unlock(&reading_mutex); |
3a2c0ba5 | 434 | put_rng(rng); |
be4000bc TD |
435 | if (rc <= 0) { |
436 | pr_warn("hwrng: no data available\n"); | |
437 | msleep_interruptible(10000); | |
438 | continue; | |
439 | } | |
9372b35e | 440 | /* Outside lock, sure, but y'know: randomness. */ |
be4000bc | 441 | add_hwgenerator_randomness((void *)rng_fillbuf, rc, |
e02b8765 | 442 | rc * current_quality * 8 >> 10); |
be4000bc | 443 | } |
9dda727d | 444 | hwrng_fill = NULL; |
be4000bc TD |
445 | return 0; |
446 | } | |
447 | ||
448 | static void start_khwrngd(void) | |
449 | { | |
450 | hwrng_fill = kthread_run(hwrng_fillfn, NULL, "hwrng"); | |
17fb874d | 451 | if (IS_ERR(hwrng_fill)) { |
4d0ec229 | 452 | pr_err("hwrng_fill thread creation failed\n"); |
be4000bc TD |
453 | hwrng_fill = NULL; |
454 | } | |
455 | } | |
456 | ||
844dd05f MB |
457 | int hwrng_register(struct hwrng *rng) |
458 | { | |
844dd05f MB |
459 | int err = -EINVAL; |
460 | struct hwrng *old_rng, *tmp; | |
2bbb6983 | 461 | struct list_head *rng_list_ptr; |
844dd05f | 462 | |
2a971e3b | 463 | if (!rng->name || (!rng->data_read && !rng->read)) |
844dd05f MB |
464 | goto out; |
465 | ||
466 | mutex_lock(&rng_mutex); | |
844dd05f MB |
467 | /* Must not register two RNGs with the same name. */ |
468 | err = -EEXIST; | |
469 | list_for_each_entry(tmp, &rng_list, list) { | |
470 | if (strcmp(tmp->name, rng->name) == 0) | |
471 | goto out_unlock; | |
472 | } | |
473 | ||
15b66cd5 HX |
474 | init_completion(&rng->cleanup_done); |
475 | complete(&rng->cleanup_done); | |
476 | ||
2bbb6983 HF |
477 | /* rng_list is sorted by decreasing quality */ |
478 | list_for_each(rng_list_ptr, &rng_list) { | |
479 | tmp = list_entry(rng_list_ptr, struct hwrng, list); | |
480 | if (tmp->quality < rng->quality) | |
481 | break; | |
482 | } | |
483 | list_add_tail(&rng->list, rng_list_ptr); | |
484 | ||
844dd05f | 485 | old_rng = current_rng; |
ebbbfa24 | 486 | err = 0; |
10a515dd HF |
487 | if (!old_rng || |
488 | (!cur_rng_set_by_user && rng->quality > old_rng->quality)) { | |
2bbb6983 HF |
489 | /* |
490 | * Set new rng as current as the new rng source | |
10a515dd HF |
491 | * provides better entropy quality and was not |
492 | * chosen by userspace. | |
2bbb6983 | 493 | */ |
90ac41bd | 494 | err = set_current_rng(rng); |
844dd05f MB |
495 | if (err) |
496 | goto out_unlock; | |
844dd05f | 497 | } |
d9e79726 | 498 | |
d3cc7996 AS |
499 | if (old_rng && !rng->init) { |
500 | /* | |
501 | * Use a new device's input to add some randomness to | |
502 | * the system. If this rng device isn't going to be | |
503 | * used right away, its init function hasn't been | |
504 | * called yet; so only use the randomness from devices | |
505 | * that don't need an init callback. | |
506 | */ | |
507 | add_early_randomness(rng); | |
508 | } | |
509 | ||
844dd05f MB |
510 | out_unlock: |
511 | mutex_unlock(&rng_mutex); | |
512 | out: | |
513 | return err; | |
514 | } | |
515 | EXPORT_SYMBOL_GPL(hwrng_register); | |
516 | ||
b844eba2 | 517 | void hwrng_unregister(struct hwrng *rng) |
844dd05f | 518 | { |
837bf7cc MB |
519 | int err; |
520 | ||
844dd05f MB |
521 | mutex_lock(&rng_mutex); |
522 | ||
523 | list_del(&rng->list); | |
837bf7cc MB |
524 | if (current_rng == rng) { |
525 | err = enable_best_rng(); | |
526 | if (err) { | |
527 | drop_current_rng(); | |
528 | cur_rng_set_by_user = 0; | |
529 | } | |
530 | } | |
3a2c0ba5 | 531 | |
be4000bc | 532 | if (list_empty(&rng_list)) { |
1dacb395 | 533 | mutex_unlock(&rng_mutex); |
be4000bc TD |
534 | if (hwrng_fill) |
535 | kthread_stop(hwrng_fill); | |
1dacb395 AK |
536 | } else |
537 | mutex_unlock(&rng_mutex); | |
a027f30d | 538 | |
77584ee5 | 539 | wait_for_completion(&rng->cleanup_done); |
844dd05f | 540 | } |
b844eba2 | 541 | EXPORT_SYMBOL_GPL(hwrng_unregister); |
844dd05f | 542 | |
4d9b519c DT |
543 | static void devm_hwrng_release(struct device *dev, void *res) |
544 | { | |
545 | hwrng_unregister(*(struct hwrng **)res); | |
546 | } | |
547 | ||
548 | static int devm_hwrng_match(struct device *dev, void *res, void *data) | |
549 | { | |
550 | struct hwrng **r = res; | |
551 | ||
552 | if (WARN_ON(!r || !*r)) | |
553 | return 0; | |
554 | ||
555 | return *r == data; | |
556 | } | |
557 | ||
558 | int devm_hwrng_register(struct device *dev, struct hwrng *rng) | |
559 | { | |
560 | struct hwrng **ptr; | |
561 | int error; | |
562 | ||
563 | ptr = devres_alloc(devm_hwrng_release, sizeof(*ptr), GFP_KERNEL); | |
564 | if (!ptr) | |
565 | return -ENOMEM; | |
566 | ||
567 | error = hwrng_register(rng); | |
568 | if (error) { | |
569 | devres_free(ptr); | |
570 | return error; | |
571 | } | |
572 | ||
573 | *ptr = rng; | |
574 | devres_add(dev, ptr); | |
575 | return 0; | |
576 | } | |
577 | EXPORT_SYMBOL_GPL(devm_hwrng_register); | |
578 | ||
579 | void devm_hwrng_unregister(struct device *dev, struct hwrng *rng) | |
580 | { | |
581 | devres_release(dev, devm_hwrng_release, devm_hwrng_match, rng); | |
582 | } | |
583 | EXPORT_SYMBOL_GPL(devm_hwrng_unregister); | |
584 | ||
ac3a497f HX |
585 | static int __init hwrng_modinit(void) |
586 | { | |
58b022ac PM |
587 | int ret = -ENOMEM; |
588 | ||
589 | /* kmalloc makes this safe for virt_to_page() in virtio_rng.c */ | |
590 | rng_buffer = kmalloc(rng_buffer_size(), GFP_KERNEL); | |
591 | if (!rng_buffer) | |
592 | return -ENOMEM; | |
593 | ||
594 | rng_fillbuf = kmalloc(rng_buffer_size(), GFP_KERNEL); | |
595 | if (!rng_fillbuf) { | |
596 | kfree(rng_buffer); | |
597 | return -ENOMEM; | |
598 | } | |
599 | ||
600 | ret = register_miscdev(); | |
601 | if (ret) { | |
602 | kfree(rng_fillbuf); | |
603 | kfree(rng_buffer); | |
604 | } | |
605 | ||
606 | return ret; | |
ac3a497f HX |
607 | } |
608 | ||
609 | static void __exit hwrng_modexit(void) | |
b7d44d94 ST |
610 | { |
611 | mutex_lock(&rng_mutex); | |
612 | BUG_ON(current_rng); | |
613 | kfree(rng_buffer); | |
be4000bc | 614 | kfree(rng_fillbuf); |
b7d44d94 | 615 | mutex_unlock(&rng_mutex); |
ac3a497f HX |
616 | |
617 | unregister_miscdev(); | |
b7d44d94 ST |
618 | } |
619 | ||
ac3a497f HX |
620 | module_init(hwrng_modinit); |
621 | module_exit(hwrng_modexit); | |
844dd05f MB |
622 | |
623 | MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver"); | |
624 | MODULE_LICENSE("GPL"); |