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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/export.h>
22#include <linux/file.h>
23#include <linux/posix-clock.h>
24#include <linux/slab.h>
25#include <linux/syscalls.h>
26#include <linux/uaccess.h>
27
28static void delete_clock(struct kref *kref);
29
30/*
31 * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
32 */
33static struct posix_clock *get_posix_clock(struct file *fp)
34{
35 struct posix_clock *clk = fp->private_data;
36
37 down_read(&clk->rwsem);
38
39 if (!clk->zombie)
40 return clk;
41
42 up_read(&clk->rwsem);
43
44 return NULL;
45}
46
47static void put_posix_clock(struct posix_clock *clk)
48{
49 up_read(&clk->rwsem);
50}
51
52static ssize_t posix_clock_read(struct file *fp, char __user *buf,
53 size_t count, loff_t *ppos)
54{
55 struct posix_clock *clk = get_posix_clock(fp);
56 int err = -EINVAL;
57
58 if (!clk)
59 return -ENODEV;
60
61 if (clk->ops.read)
62 err = clk->ops.read(clk, fp->f_flags, buf, count);
63
64 put_posix_clock(clk);
65
66 return err;
67}
68
69static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
70{
71 struct posix_clock *clk = get_posix_clock(fp);
72 unsigned int result = 0;
73
74 if (!clk)
75 return POLLERR;
76
77 if (clk->ops.poll)
78 result = clk->ops.poll(clk, fp, wait);
79
80 put_posix_clock(clk);
81
82 return result;
83}
84
85static int posix_clock_fasync(int fd, struct file *fp, int on)
86{
87 struct posix_clock *clk = get_posix_clock(fp);
88 int err = 0;
89
90 if (!clk)
91 return -ENODEV;
92
93 if (clk->ops.fasync)
94 err = clk->ops.fasync(clk, fd, fp, on);
95
96 put_posix_clock(clk);
97
98 return err;
99}
100
101static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
102{
103 struct posix_clock *clk = get_posix_clock(fp);
104 int err = -ENODEV;
105
106 if (!clk)
107 return -ENODEV;
108
109 if (clk->ops.mmap)
110 err = clk->ops.mmap(clk, vma);
111
112 put_posix_clock(clk);
113
114 return err;
115}
116
117static long posix_clock_ioctl(struct file *fp,
118 unsigned int cmd, unsigned long arg)
119{
120 struct posix_clock *clk = get_posix_clock(fp);
121 int err = -ENOTTY;
122
123 if (!clk)
124 return -ENODEV;
125
126 if (clk->ops.ioctl)
127 err = clk->ops.ioctl(clk, cmd, arg);
128
129 put_posix_clock(clk);
130
131 return err;
132}
133
134#ifdef CONFIG_COMPAT
135static long posix_clock_compat_ioctl(struct file *fp,
136 unsigned int cmd, unsigned long arg)
137{
138 struct posix_clock *clk = get_posix_clock(fp);
139 int err = -ENOTTY;
140
141 if (!clk)
142 return -ENODEV;
143
144 if (clk->ops.ioctl)
145 err = clk->ops.ioctl(clk, cmd, arg);
146
147 put_posix_clock(clk);
148
149 return err;
150}
151#endif
152
153static int posix_clock_open(struct inode *inode, struct file *fp)
154{
155 int err;
156 struct posix_clock *clk =
157 container_of(inode->i_cdev, struct posix_clock, cdev);
158
159 down_read(&clk->rwsem);
160
161 if (clk->zombie) {
162 err = -ENODEV;
163 goto out;
164 }
165 if (clk->ops.open)
166 err = clk->ops.open(clk, fp->f_mode);
167 else
168 err = 0;
169
170 if (!err) {
171 kref_get(&clk->kref);
172 fp->private_data = clk;
173 }
174out:
175 up_read(&clk->rwsem);
176 return err;
177}
178
179static int posix_clock_release(struct inode *inode, struct file *fp)
180{
181 struct posix_clock *clk = fp->private_data;
182 int err = 0;
183
184 if (clk->ops.release)
185 err = clk->ops.release(clk);
186
187 kref_put(&clk->kref, delete_clock);
188
189 fp->private_data = NULL;
190
191 return err;
192}
193
194static const struct file_operations posix_clock_file_operations = {
195 .owner = THIS_MODULE,
196 .llseek = no_llseek,
197 .read = posix_clock_read,
198 .poll = posix_clock_poll,
199 .unlocked_ioctl = posix_clock_ioctl,
200 .open = posix_clock_open,
201 .release = posix_clock_release,
202 .fasync = posix_clock_fasync,
203 .mmap = posix_clock_mmap,
204#ifdef CONFIG_COMPAT
205 .compat_ioctl = posix_clock_compat_ioctl,
206#endif
207};
208
209int posix_clock_register(struct posix_clock *clk, dev_t devid)
210{
211 int err;
212
213 kref_init(&clk->kref);
214 init_rwsem(&clk->rwsem);
215
216 cdev_init(&clk->cdev, &posix_clock_file_operations);
217 clk->cdev.owner = clk->ops.owner;
218 err = cdev_add(&clk->cdev, devid, 1);
219
220 return err;
221}
222EXPORT_SYMBOL_GPL(posix_clock_register);
223
224static void delete_clock(struct kref *kref)
225{
226 struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
227
228 if (clk->release)
229 clk->release(clk);
230}
231
232void posix_clock_unregister(struct posix_clock *clk)
233{
234 cdev_del(&clk->cdev);
235
236 down_write(&clk->rwsem);
237 clk->zombie = true;
238 up_write(&clk->rwsem);
239
240 kref_put(&clk->kref, delete_clock);
241}
242EXPORT_SYMBOL_GPL(posix_clock_unregister);
243
244struct posix_clock_desc {
245 struct file *fp;
246 struct posix_clock *clk;
247};
248
249static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
250{
251 struct file *fp = fget(CLOCKID_TO_FD(id));
252 int err = -EINVAL;
253
254 if (!fp)
255 return err;
256
257 if (fp->f_op->open != posix_clock_open || !fp->private_data)
258 goto out;
259
260 cd->fp = fp;
261 cd->clk = get_posix_clock(fp);
262
263 err = cd->clk ? 0 : -ENODEV;
264out:
265 if (err)
266 fput(fp);
267 return err;
268}
269
270static void put_clock_desc(struct posix_clock_desc *cd)
271{
272 put_posix_clock(cd->clk);
273 fput(cd->fp);
274}
275
276static int pc_clock_adjtime(clockid_t id, struct timex *tx)
277{
278 struct posix_clock_desc cd;
279 int err;
280
281 err = get_clock_desc(id, &cd);
282 if (err)
283 return err;
284
285 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
286 err = -EACCES;
287 goto out;
288 }
289
290 if (cd.clk->ops.clock_adjtime)
291 err = cd.clk->ops.clock_adjtime(cd.clk, tx);
292 else
293 err = -EOPNOTSUPP;
294out:
295 put_clock_desc(&cd);
296
297 return err;
298}
299
300static int pc_clock_gettime(clockid_t id, struct timespec *ts)
301{
302 struct posix_clock_desc cd;
303 int err;
304
305 err = get_clock_desc(id, &cd);
306 if (err)
307 return err;
308
309 if (cd.clk->ops.clock_gettime)
310 err = cd.clk->ops.clock_gettime(cd.clk, ts);
311 else
312 err = -EOPNOTSUPP;
313
314 put_clock_desc(&cd);
315
316 return err;
317}
318
319static int pc_clock_getres(clockid_t id, struct timespec *ts)
320{
321 struct posix_clock_desc cd;
322 int err;
323
324 err = get_clock_desc(id, &cd);
325 if (err)
326 return err;
327
328 if (cd.clk->ops.clock_getres)
329 err = cd.clk->ops.clock_getres(cd.clk, ts);
330 else
331 err = -EOPNOTSUPP;
332
333 put_clock_desc(&cd);
334
335 return err;
336}
337
338static int pc_clock_settime(clockid_t id, const struct timespec *ts)
339{
340 struct posix_clock_desc cd;
341 int err;
342
343 err = get_clock_desc(id, &cd);
344 if (err)
345 return err;
346
347 if ((cd.fp->f_mode & FMODE_WRITE) == 0) {
348 err = -EACCES;
349 goto out;
350 }
351
352 if (cd.clk->ops.clock_settime)
353 err = cd.clk->ops.clock_settime(cd.clk, ts);
354 else
355 err = -EOPNOTSUPP;
356out:
357 put_clock_desc(&cd);
358
359 return err;
360}
361
362static int pc_timer_create(struct k_itimer *kit)
363{
364 clockid_t id = kit->it_clock;
365 struct posix_clock_desc cd;
366 int err;
367
368 err = get_clock_desc(id, &cd);
369 if (err)
370 return err;
371
372 if (cd.clk->ops.timer_create)
373 err = cd.clk->ops.timer_create(cd.clk, kit);
374 else
375 err = -EOPNOTSUPP;
376
377 put_clock_desc(&cd);
378
379 return err;
380}
381
382static int pc_timer_delete(struct k_itimer *kit)
383{
384 clockid_t id = kit->it_clock;
385 struct posix_clock_desc cd;
386 int err;
387
388 err = get_clock_desc(id, &cd);
389 if (err)
390 return err;
391
392 if (cd.clk->ops.timer_delete)
393 err = cd.clk->ops.timer_delete(cd.clk, kit);
394 else
395 err = -EOPNOTSUPP;
396
397 put_clock_desc(&cd);
398
399 return err;
400}
401
402static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
403{
404 clockid_t id = kit->it_clock;
405 struct posix_clock_desc cd;
406
407 if (get_clock_desc(id, &cd))
408 return;
409
410 if (cd.clk->ops.timer_gettime)
411 cd.clk->ops.timer_gettime(cd.clk, kit, ts);
412
413 put_clock_desc(&cd);
414}
415
416static int pc_timer_settime(struct k_itimer *kit, int flags,
417 struct itimerspec *ts, struct itimerspec *old)
418{
419 clockid_t id = kit->it_clock;
420 struct posix_clock_desc cd;
421 int err;
422
423 err = get_clock_desc(id, &cd);
424 if (err)
425 return err;
426
427 if (cd.clk->ops.timer_settime)
428 err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
429 else
430 err = -EOPNOTSUPP;
431
432 put_clock_desc(&cd);
433
434 return err;
435}
436
437struct k_clock clock_posix_dynamic = {
438 .clock_getres = pc_clock_getres,
439 .clock_set = pc_clock_settime,
440 .clock_get = pc_clock_gettime,
441 .clock_adj = pc_clock_adjtime,
442 .timer_create = pc_timer_create,
443 .timer_set = pc_timer_settime,
444 .timer_del = pc_timer_delete,
445 .timer_get = pc_timer_gettime,
446};