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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Support for dynamic clock devices
4 *
5 * Copyright (C) 2010 OMICRON electronics GmbH
6 */
7#include <linux/device.h>
8#include <linux/export.h>
9#include <linux/file.h>
10#include <linux/posix-clock.h>
11#include <linux/slab.h>
12#include <linux/syscalls.h>
13#include <linux/uaccess.h>
14
15#include "posix-timers.h"
16
17static void delete_clock(struct kref *kref);
18
19/*
20 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
21 */
22static struct posix_clock *get_posix_clock(struct file *fp)
23{
24 struct posix_clock *clk = fp->private_data;
25
26 down_read(&clk->rwsem);
27
28 if (!clk->zombie)
29 return clk;
30
31 up_read(&clk->rwsem);
32
33 return NULL;
34}
35
36static void put_posix_clock(struct posix_clock *clk)
37{
38 up_read(&clk->rwsem);
39}
40
41static ssize_t posix_clock_read(struct file *fp, char __user *buf,
42 size_t count, loff_t *ppos)
43{
44 struct posix_clock *clk = get_posix_clock(fp);
45 int err = -EINVAL;
46
47 if (!clk)
48 return -ENODEV;
49
50 if (clk->ops.read)
51 err = clk->ops.read(clk, fp->f_flags, buf, count);
52
53 put_posix_clock(clk);
54
55 return err;
56}
57
58static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
59{
60 struct posix_clock *clk = get_posix_clock(fp);
61 __poll_t result = 0;
62
63 if (!clk)
64 return EPOLLERR;
65
66 if (clk->ops.poll)
67 result = clk->ops.poll(clk, fp, wait);
68
69 put_posix_clock(clk);
70
71 return result;
72}
73
74static long posix_clock_ioctl(struct file *fp,
75 unsigned int cmd, unsigned long arg)
76{
77 struct posix_clock *clk = get_posix_clock(fp);
78 int err = -ENOTTY;
79
80 if (!clk)
81 return -ENODEV;
82
83 if (clk->ops.ioctl)
84 err = clk->ops.ioctl(clk, cmd, arg);
85
86 put_posix_clock(clk);
87
88 return err;
89}
90
91#ifdef CONFIG_COMPAT
92static long posix_clock_compat_ioctl(struct file *fp,
93 unsigned int cmd, unsigned long arg)
94{
95 struct posix_clock *clk = get_posix_clock(fp);
96 int err = -ENOTTY;
97
98 if (!clk)
99 return -ENODEV;
100
101 if (clk->ops.ioctl)
102 err = clk->ops.ioctl(clk, cmd, arg);
103
104 put_posix_clock(clk);
105
106 return err;
107}
108#endif
109
110static int posix_clock_open(struct inode *inode, struct file *fp)
111{
112 int err;
113 struct posix_clock *clk =
114 container_of(inode->i_cdev, struct posix_clock, cdev);
115
116 down_read(&clk->rwsem);
117
118 if (clk->zombie) {
119 err = -ENODEV;
120 goto out;
121 }
122 if (clk->ops.open)
123 err = clk->ops.open(clk, fp->f_mode);
124 else
125 err = 0;
126
127 if (!err) {
128 kref_get(&clk->kref);
129 fp->private_data = clk;
130 }
131out:
132 up_read(&clk->rwsem);
133 return err;
134}
135
136static int posix_clock_release(struct inode *inode, struct file *fp)
137{
138 struct posix_clock *clk = fp->private_data;
139 int err = 0;
140
141 if (clk->ops.release)
142 err = clk->ops.release(clk);
143
144 kref_put(&clk->kref, delete_clock);
145
146 fp->private_data = NULL;
147
148 return err;
149}
150
151static const struct file_operations posix_clock_file_operations = {
152 .owner = THIS_MODULE,
153 .llseek = no_llseek,
154 .read = posix_clock_read,
155 .poll = posix_clock_poll,
156 .unlocked_ioctl = posix_clock_ioctl,
157 .open = posix_clock_open,
158 .release = posix_clock_release,
159#ifdef CONFIG_COMPAT
160 .compat_ioctl = posix_clock_compat_ioctl,
161#endif
162};
163
164int posix_clock_register(struct posix_clock *clk, dev_t devid)
165{
166 int err;
167
168 kref_init(&clk->kref);
169 init_rwsem(&clk->rwsem);
170
171 cdev_init(&clk->cdev, &posix_clock_file_operations);
172 clk->cdev.owner = clk->ops.owner;
173 err = cdev_add(&clk->cdev, devid, 1);
174
175 return err;
176}
177EXPORT_SYMBOL_GPL(posix_clock_register);
178
179static void delete_clock(struct kref *kref)
180{
181 struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
182
183 if (clk->release)
184 clk->release(clk);
185}
186
187void posix_clock_unregister(struct posix_clock *clk)
188{
189 cdev_del(&clk->cdev);
190
191 down_write(&clk->rwsem);
192 clk->zombie = true;
193 up_write(&clk->rwsem);
194
195 kref_put(&clk->kref, delete_clock);
196}
197EXPORT_SYMBOL_GPL(posix_clock_unregister);
198
199struct posix_clock_desc {
200 struct file *fp;
201 struct posix_clock *clk;
202};
203
204static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
205{
206 struct file *fp = fget(clockid_to_fd(id));
207 int err = -EINVAL;
208
209 if (!fp)
210 return err;
211
212 if (fp->f_op->open != posix_clock_open || !fp->private_data)
213 goto out;
214
215 cd->fp = fp;
216 cd->clk = get_posix_clock(fp);
217
218 err = cd->clk ? 0 : -ENODEV;
219out:
220 if (err)
221 fput(fp);
222 return err;
223}
224
225static void put_clock_desc(struct posix_clock_desc *cd)
226{
227 put_posix_clock(cd->clk);
228 fput(cd->fp);
229}
230
231static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx)
232{
233 struct posix_clock_desc cd;
234 int err;
235
236 err = get_clock_desc(id, &cd);
237 if (err)
238 return err;
239
240 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
241 err = -EACCES;
242 goto out;
243 }
244
245 if (cd.clk->ops.clock_adjtime)
246 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
247 else
248 err = -EOPNOTSUPP;
249out:
250 put_clock_desc(&cd);
251
252 return err;
253}
254
255static int pc_clock_gettime(clockid_t id, struct timespec64 *ts)
256{
257 struct posix_clock_desc cd;
258 int err;
259
260 err = get_clock_desc(id, &cd);
261 if (err)
262 return err;
263
264 if (cd.clk->ops.clock_gettime)
265 err = cd.clk->ops.clock_gettime(cd.clk, ts);
266 else
267 err = -EOPNOTSUPP;
268
269 put_clock_desc(&cd);
270
271 return err;
272}
273
274static int pc_clock_getres(clockid_t id, struct timespec64 *ts)
275{
276 struct posix_clock_desc cd;
277 int err;
278
279 err = get_clock_desc(id, &cd);
280 if (err)
281 return err;
282
283 if (cd.clk->ops.clock_getres)
284 err = cd.clk->ops.clock_getres(cd.clk, ts);
285 else
286 err = -EOPNOTSUPP;
287
288 put_clock_desc(&cd);
289
290 return err;
291}
292
293static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
294{
295 struct posix_clock_desc cd;
296 int err;
297
298 err = get_clock_desc(id, &cd);
299 if (err)
300 return err;
301
302 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
303 err = -EACCES;
304 goto out;
305 }
306
307 if (cd.clk->ops.clock_settime)
308 err = cd.clk->ops.clock_settime(cd.clk, ts);
309 else
310 err = -EOPNOTSUPP;
311out:
312 put_clock_desc(&cd);
313
314 return err;
315}
316
317const struct k_clock clock_posix_dynamic = {
318 .clock_getres = pc_clock_getres,
319 .clock_set = pc_clock_settime,
320 .clock_get = pc_clock_gettime,
321 .clock_adj = pc_clock_adjtime,
322};
1/*
2 * posix-clock.c - support for dynamic clock devices
3 *
4 * Copyright (C) 2010 OMICRON electronics GmbH
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20#include <linux/device.h>
21#include <linux/file.h>
22#include <linux/posix-clock.h>
23#include <linux/slab.h>
24#include <linux/syscalls.h>
25#include <linux/uaccess.h>
26
27static void delete_clock(struct kref *kref);
28
29/*
30 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
31 */
32static struct posix_clock *get_posix_clock(struct file *fp)
33{
34 struct posix_clock *clk = fp->private_data;
35
36 down_read(&clk->rwsem);
37
38 if (!clk->zombie)
39 return clk;
40
41 up_read(&clk->rwsem);
42
43 return NULL;
44}
45
46static void put_posix_clock(struct posix_clock *clk)
47{
48 up_read(&clk->rwsem);
49}
50
51static ssize_t posix_clock_read(struct file *fp, char __user *buf,
52 size_t count, loff_t *ppos)
53{
54 struct posix_clock *clk = get_posix_clock(fp);
55 int err = -EINVAL;
56
57 if (!clk)
58 return -ENODEV;
59
60 if (clk->ops.read)
61 err = clk->ops.read(clk, fp->f_flags, buf, count);
62
63 put_posix_clock(clk);
64
65 return err;
66}
67
68static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
69{
70 struct posix_clock *clk = get_posix_clock(fp);
71 int result = 0;
72
73 if (!clk)
74 return -ENODEV;
75
76 if (clk->ops.poll)
77 result = clk->ops.poll(clk, fp, wait);
78
79 put_posix_clock(clk);
80
81 return result;
82}
83
84static int posix_clock_fasync(int fd, struct file *fp, int on)
85{
86 struct posix_clock *clk = get_posix_clock(fp);
87 int err = 0;
88
89 if (!clk)
90 return -ENODEV;
91
92 if (clk->ops.fasync)
93 err = clk->ops.fasync(clk, fd, fp, on);
94
95 put_posix_clock(clk);
96
97 return err;
98}
99
100static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
101{
102 struct posix_clock *clk = get_posix_clock(fp);
103 int err = -ENODEV;
104
105 if (!clk)
106 return -ENODEV;
107
108 if (clk->ops.mmap)
109 err = clk->ops.mmap(clk, vma);
110
111 put_posix_clock(clk);
112
113 return err;
114}
115
116static long posix_clock_ioctl(struct file *fp,
117 unsigned int cmd, unsigned long arg)
118{
119 struct posix_clock *clk = get_posix_clock(fp);
120 int err = -ENOTTY;
121
122 if (!clk)
123 return -ENODEV;
124
125 if (clk->ops.ioctl)
126 err = clk->ops.ioctl(clk, cmd, arg);
127
128 put_posix_clock(clk);
129
130 return err;
131}
132
133#ifdef CONFIG_COMPAT
134static long posix_clock_compat_ioctl(struct file *fp,
135 unsigned int cmd, unsigned long arg)
136{
137 struct posix_clock *clk = get_posix_clock(fp);
138 int err = -ENOTTY;
139
140 if (!clk)
141 return -ENODEV;
142
143 if (clk->ops.ioctl)
144 err = clk->ops.ioctl(clk, cmd, arg);
145
146 put_posix_clock(clk);
147
148 return err;
149}
150#endif
151
152static int posix_clock_open(struct inode *inode, struct file *fp)
153{
154 int err;
155 struct posix_clock *clk =
156 container_of(inode->i_cdev, struct posix_clock, cdev);
157
158 down_read(&clk->rwsem);
159
160 if (clk->zombie) {
161 err = -ENODEV;
162 goto out;
163 }
164 if (clk->ops.open)
165 err = clk->ops.open(clk, fp->f_mode);
166 else
167 err = 0;
168
169 if (!err) {
170 kref_get(&clk->kref);
171 fp->private_data = clk;
172 }
173out:
174 up_read(&clk->rwsem);
175 return err;
176}
177
178static int posix_clock_release(struct inode *inode, struct file *fp)
179{
180 struct posix_clock *clk = fp->private_data;
181 int err = 0;
182
183 if (clk->ops.release)
184 err = clk->ops.release(clk);
185
186 kref_put(&clk->kref, delete_clock);
187
188 fp->private_data = NULL;
189
190 return err;
191}
192
193static const struct file_operations posix_clock_file_operations = {
194 .owner = THIS_MODULE,
195 .llseek = no_llseek,
196 .read = posix_clock_read,
197 .poll = posix_clock_poll,
198 .unlocked_ioctl = posix_clock_ioctl,
199 .open = posix_clock_open,
200 .release = posix_clock_release,
201 .fasync = posix_clock_fasync,
202 .mmap = posix_clock_mmap,
203#ifdef CONFIG_COMPAT
204 .compat_ioctl = posix_clock_compat_ioctl,
205#endif
206};
207
208int posix_clock_register(struct posix_clock *clk, dev_t devid)
209{
210 int err;
211
212 kref_init(&clk->kref);
213 init_rwsem(&clk->rwsem);
214
215 cdev_init(&clk->cdev, &posix_clock_file_operations);
216 clk->cdev.owner = clk->ops.owner;
217 err = cdev_add(&clk->cdev, devid, 1);
218
219 return err;
220}
221EXPORT_SYMBOL_GPL(posix_clock_register);
222
223static void delete_clock(struct kref *kref)
224{
225 struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
226
227 if (clk->release)
228 clk->release(clk);
229}
230
231void posix_clock_unregister(struct posix_clock *clk)
232{
233 cdev_del(&clk->cdev);
234
235 down_write(&clk->rwsem);
236 clk->zombie = true;
237 up_write(&clk->rwsem);
238
239 kref_put(&clk->kref, delete_clock);
240}
241EXPORT_SYMBOL_GPL(posix_clock_unregister);
242
243struct posix_clock_desc {
244 struct file *fp;
245 struct posix_clock *clk;
246};
247
248static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
249{
250 struct file *fp = fget(CLOCKID_TO_FD(id));
251 int err = -EINVAL;
252
253 if (!fp)
254 return err;
255
256 if (fp->f_op->open != posix_clock_open || !fp->private_data)
257 goto out;
258
259 cd->fp = fp;
260 cd->clk = get_posix_clock(fp);
261
262 err = cd->clk ? 0 : -ENODEV;
263out:
264 if (err)
265 fput(fp);
266 return err;
267}
268
269static void put_clock_desc(struct posix_clock_desc *cd)
270{
271 put_posix_clock(cd->clk);
272 fput(cd->fp);
273}
274
275static int pc_clock_adjtime(clockid_t id, struct timex *tx)
276{
277 struct posix_clock_desc cd;
278 int err;
279
280 err = get_clock_desc(id, &cd);
281 if (err)
282 return err;
283
284 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
285 err = -EACCES;
286 goto out;
287 }
288
289 if (cd.clk->ops.clock_adjtime)
290 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
291 else
292 err = -EOPNOTSUPP;
293out:
294 put_clock_desc(&cd);
295
296 return err;
297}
298
299static int pc_clock_gettime(clockid_t id, struct timespec *ts)
300{
301 struct posix_clock_desc cd;
302 int err;
303
304 err = get_clock_desc(id, &cd);
305 if (err)
306 return err;
307
308 if (cd.clk->ops.clock_gettime)
309 err = cd.clk->ops.clock_gettime(cd.clk, ts);
310 else
311 err = -EOPNOTSUPP;
312
313 put_clock_desc(&cd);
314
315 return err;
316}
317
318static int pc_clock_getres(clockid_t id, struct timespec *ts)
319{
320 struct posix_clock_desc cd;
321 int err;
322
323 err = get_clock_desc(id, &cd);
324 if (err)
325 return err;
326
327 if (cd.clk->ops.clock_getres)
328 err = cd.clk->ops.clock_getres(cd.clk, ts);
329 else
330 err = -EOPNOTSUPP;
331
332 put_clock_desc(&cd);
333
334 return err;
335}
336
337static int pc_clock_settime(clockid_t id, const struct timespec *ts)
338{
339 struct posix_clock_desc cd;
340 int err;
341
342 err = get_clock_desc(id, &cd);
343 if (err)
344 return err;
345
346 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
347 err = -EACCES;
348 goto out;
349 }
350
351 if (cd.clk->ops.clock_settime)
352 err = cd.clk->ops.clock_settime(cd.clk, ts);
353 else
354 err = -EOPNOTSUPP;
355out:
356 put_clock_desc(&cd);
357
358 return err;
359}
360
361static int pc_timer_create(struct k_itimer *kit)
362{
363 clockid_t id = kit->it_clock;
364 struct posix_clock_desc cd;
365 int err;
366
367 err = get_clock_desc(id, &cd);
368 if (err)
369 return err;
370
371 if (cd.clk->ops.timer_create)
372 err = cd.clk->ops.timer_create(cd.clk, kit);
373 else
374 err = -EOPNOTSUPP;
375
376 put_clock_desc(&cd);
377
378 return err;
379}
380
381static int pc_timer_delete(struct k_itimer *kit)
382{
383 clockid_t id = kit->it_clock;
384 struct posix_clock_desc cd;
385 int err;
386
387 err = get_clock_desc(id, &cd);
388 if (err)
389 return err;
390
391 if (cd.clk->ops.timer_delete)
392 err = cd.clk->ops.timer_delete(cd.clk, kit);
393 else
394 err = -EOPNOTSUPP;
395
396 put_clock_desc(&cd);
397
398 return err;
399}
400
401static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
402{
403 clockid_t id = kit->it_clock;
404 struct posix_clock_desc cd;
405
406 if (get_clock_desc(id, &cd))
407 return;
408
409 if (cd.clk->ops.timer_gettime)
410 cd.clk->ops.timer_gettime(cd.clk, kit, ts);
411
412 put_clock_desc(&cd);
413}
414
415static int pc_timer_settime(struct k_itimer *kit, int flags,
416 struct itimerspec *ts, struct itimerspec *old)
417{
418 clockid_t id = kit->it_clock;
419 struct posix_clock_desc cd;
420 int err;
421
422 err = get_clock_desc(id, &cd);
423 if (err)
424 return err;
425
426 if (cd.clk->ops.timer_settime)
427 err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
428 else
429 err = -EOPNOTSUPP;
430
431 put_clock_desc(&cd);
432
433 return err;
434}
435
436struct k_clock clock_posix_dynamic = {
437 .clock_getres = pc_clock_getres,
438 .clock_set = pc_clock_settime,
439 .clock_get = pc_clock_gettime,
440 .clock_adj = pc_clock_adjtime,
441 .timer_create = pc_timer_create,
442 .timer_set = pc_timer_settime,
443 .timer_del = pc_timer_delete,
444 .timer_get = pc_timer_gettime,
445};