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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
17/*
18 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
19 */
20static struct posix_clock *get_posix_clock(struct file *fp)
21{
22 struct posix_clock *clk = fp->private_data;
23
24 down_read(&clk->rwsem);
25
26 if (!clk->zombie)
27 return clk;
28
29 up_read(&clk->rwsem);
30
31 return NULL;
32}
33
34static void put_posix_clock(struct posix_clock *clk)
35{
36 up_read(&clk->rwsem);
37}
38
39static ssize_t posix_clock_read(struct file *fp, char __user *buf,
40 size_t count, loff_t *ppos)
41{
42 struct posix_clock *clk = get_posix_clock(fp);
43 int err = -EINVAL;
44
45 if (!clk)
46 return -ENODEV;
47
48 if (clk->ops.read)
49 err = clk->ops.read(clk, fp->f_flags, buf, count);
50
51 put_posix_clock(clk);
52
53 return err;
54}
55
56static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
57{
58 struct posix_clock *clk = get_posix_clock(fp);
59 __poll_t result = 0;
60
61 if (!clk)
62 return EPOLLERR;
63
64 if (clk->ops.poll)
65 result = clk->ops.poll(clk, fp, wait);
66
67 put_posix_clock(clk);
68
69 return result;
70}
71
72static long posix_clock_ioctl(struct file *fp,
73 unsigned int cmd, unsigned long arg)
74{
75 struct posix_clock *clk = get_posix_clock(fp);
76 int err = -ENOTTY;
77
78 if (!clk)
79 return -ENODEV;
80
81 if (clk->ops.ioctl)
82 err = clk->ops.ioctl(clk, cmd, arg);
83
84 put_posix_clock(clk);
85
86 return err;
87}
88
89#ifdef CONFIG_COMPAT
90static long posix_clock_compat_ioctl(struct file *fp,
91 unsigned int cmd, unsigned long arg)
92{
93 struct posix_clock *clk = get_posix_clock(fp);
94 int err = -ENOTTY;
95
96 if (!clk)
97 return -ENODEV;
98
99 if (clk->ops.ioctl)
100 err = clk->ops.ioctl(clk, cmd, arg);
101
102 put_posix_clock(clk);
103
104 return err;
105}
106#endif
107
108static int posix_clock_open(struct inode *inode, struct file *fp)
109{
110 int err;
111 struct posix_clock *clk =
112 container_of(inode->i_cdev, struct posix_clock, cdev);
113
114 down_read(&clk->rwsem);
115
116 if (clk->zombie) {
117 err = -ENODEV;
118 goto out;
119 }
120 if (clk->ops.open)
121 err = clk->ops.open(clk, fp->f_mode);
122 else
123 err = 0;
124
125 if (!err) {
126 get_device(clk->dev);
127 fp->private_data = clk;
128 }
129out:
130 up_read(&clk->rwsem);
131 return err;
132}
133
134static int posix_clock_release(struct inode *inode, struct file *fp)
135{
136 struct posix_clock *clk = fp->private_data;
137 int err = 0;
138
139 if (clk->ops.release)
140 err = clk->ops.release(clk);
141
142 put_device(clk->dev);
143
144 fp->private_data = NULL;
145
146 return err;
147}
148
149static const struct file_operations posix_clock_file_operations = {
150 .owner = THIS_MODULE,
151 .llseek = no_llseek,
152 .read = posix_clock_read,
153 .poll = posix_clock_poll,
154 .unlocked_ioctl = posix_clock_ioctl,
155 .open = posix_clock_open,
156 .release = posix_clock_release,
157#ifdef CONFIG_COMPAT
158 .compat_ioctl = posix_clock_compat_ioctl,
159#endif
160};
161
162int posix_clock_register(struct posix_clock *clk, struct device *dev)
163{
164 int err;
165
166 init_rwsem(&clk->rwsem);
167
168 cdev_init(&clk->cdev, &posix_clock_file_operations);
169 err = cdev_device_add(&clk->cdev, dev);
170 if (err) {
171 pr_err("%s unable to add device %d:%d\n",
172 dev_name(dev), MAJOR(dev->devt), MINOR(dev->devt));
173 return err;
174 }
175 clk->cdev.owner = clk->ops.owner;
176 clk->dev = dev;
177
178 return 0;
179}
180EXPORT_SYMBOL_GPL(posix_clock_register);
181
182void posix_clock_unregister(struct posix_clock *clk)
183{
184 cdev_device_del(&clk->cdev, clk->dev);
185
186 down_write(&clk->rwsem);
187 clk->zombie = true;
188 up_write(&clk->rwsem);
189
190 put_device(clk->dev);
191}
192EXPORT_SYMBOL_GPL(posix_clock_unregister);
193
194struct posix_clock_desc {
195 struct file *fp;
196 struct posix_clock *clk;
197};
198
199static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
200{
201 struct file *fp = fget(clockid_to_fd(id));
202 int err = -EINVAL;
203
204 if (!fp)
205 return err;
206
207 if (fp->f_op->open != posix_clock_open || !fp->private_data)
208 goto out;
209
210 cd->fp = fp;
211 cd->clk = get_posix_clock(fp);
212
213 err = cd->clk ? 0 : -ENODEV;
214out:
215 if (err)
216 fput(fp);
217 return err;
218}
219
220static void put_clock_desc(struct posix_clock_desc *cd)
221{
222 put_posix_clock(cd->clk);
223 fput(cd->fp);
224}
225
226static int pc_clock_adjtime(clockid_t id, struct __kernel_timex *tx)
227{
228 struct posix_clock_desc cd;
229 int err;
230
231 err = get_clock_desc(id, &cd);
232 if (err)
233 return err;
234
235 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
236 err = -EACCES;
237 goto out;
238 }
239
240 if (cd.clk->ops.clock_adjtime)
241 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
242 else
243 err = -EOPNOTSUPP;
244out:
245 put_clock_desc(&cd);
246
247 return err;
248}
249
250static int pc_clock_gettime(clockid_t id, struct timespec64 *ts)
251{
252 struct posix_clock_desc cd;
253 int err;
254
255 err = get_clock_desc(id, &cd);
256 if (err)
257 return err;
258
259 if (cd.clk->ops.clock_gettime)
260 err = cd.clk->ops.clock_gettime(cd.clk, ts);
261 else
262 err = -EOPNOTSUPP;
263
264 put_clock_desc(&cd);
265
266 return err;
267}
268
269static int pc_clock_getres(clockid_t id, struct timespec64 *ts)
270{
271 struct posix_clock_desc cd;
272 int err;
273
274 err = get_clock_desc(id, &cd);
275 if (err)
276 return err;
277
278 if (cd.clk->ops.clock_getres)
279 err = cd.clk->ops.clock_getres(cd.clk, ts);
280 else
281 err = -EOPNOTSUPP;
282
283 put_clock_desc(&cd);
284
285 return err;
286}
287
288static int pc_clock_settime(clockid_t id, const struct timespec64 *ts)
289{
290 struct posix_clock_desc cd;
291 int err;
292
293 err = get_clock_desc(id, &cd);
294 if (err)
295 return err;
296
297 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
298 err = -EACCES;
299 goto out;
300 }
301
302 if (cd.clk->ops.clock_settime)
303 err = cd.clk->ops.clock_settime(cd.clk, ts);
304 else
305 err = -EOPNOTSUPP;
306out:
307 put_clock_desc(&cd);
308
309 return err;
310}
311
312const struct k_clock clock_posix_dynamic = {
313 .clock_getres = pc_clock_getres,
314 .clock_set = pc_clock_settime,
315 .clock_get_timespec = pc_clock_gettime,
316 .clock_adj = pc_clock_adjtime,
317};
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};