1// SPDX-License-Identifier: GPL-2.0
2/*
3 * file.c - part of debugfs, a tiny little debug file system
4 *
5 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
6 * Copyright (C) 2004 IBM Inc.
7 *
8 * debugfs is for people to use instead of /proc or /sys.
9 * See Documentation/filesystems/ for more details.
10 */
11
12#include <linux/module.h>
13#include <linux/fs.h>
14#include <linux/seq_file.h>
15#include <linux/pagemap.h>
16#include <linux/debugfs.h>
17#include <linux/io.h>
18#include <linux/slab.h>
19#include <linux/atomic.h>
20#include <linux/device.h>
21#include <linux/pm_runtime.h>
22#include <linux/poll.h>
23#include <linux/security.h>
24
25#include "internal.h"
26
27struct poll_table_struct;
28
29static ssize_t default_read_file(struct file *file, char __user *buf,
30 size_t count, loff_t *ppos)
31{
32 return 0;
33}
34
35static ssize_t default_write_file(struct file *file, const char __user *buf,
36 size_t count, loff_t *ppos)
37{
38 return count;
39}
40
41const struct file_operations debugfs_noop_file_operations = {
42 .read = default_read_file,
43 .write = default_write_file,
44 .open = simple_open,
45 .llseek = noop_llseek,
46};
47
48#define F_DENTRY(filp) ((filp)->f_path.dentry)
49
50void *debugfs_get_aux(const struct file *file)
51{
52 return DEBUGFS_I(inode: file_inode(f: file))->aux;
53}
54EXPORT_SYMBOL_GPL(debugfs_get_aux);
55
56enum dbgfs_get_mode {
57 DBGFS_GET_ALREADY,
58 DBGFS_GET_REGULAR,
59 DBGFS_GET_SHORT,
60};
61
62static int __debugfs_file_get(struct dentry *dentry, enum dbgfs_get_mode mode)
63{
64 struct debugfs_fsdata *fsd;
65 void *d_fsd;
66
67 /*
68 * This could only happen if some debugfs user erroneously calls
69 * debugfs_file_get() on a dentry that isn't even a file, let
70 * them know about it.
71 */
72 if (WARN_ON(!d_is_reg(dentry)))
73 return -EINVAL;
74
75 d_fsd = READ_ONCE(dentry->d_fsdata);
76 if (d_fsd) {
77 fsd = d_fsd;
78 } else {
79 struct inode *inode = dentry->d_inode;
80 unsigned int methods = 0;
81
82 if (WARN_ON(mode == DBGFS_GET_ALREADY))
83 return -EINVAL;
84
85 fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
86 if (!fsd)
87 return -ENOMEM;
88
89 if (mode == DBGFS_GET_SHORT) {
90 const struct debugfs_short_fops *ops;
91 ops = fsd->short_fops = DEBUGFS_I(inode)->short_fops;
92 if (ops->llseek)
93 methods |= HAS_LSEEK;
94 if (ops->read)
95 methods |= HAS_READ;
96 if (ops->write)
97 methods |= HAS_WRITE;
98 fsd->real_fops = NULL;
99 } else {
100 const struct file_operations *ops;
101 ops = fsd->real_fops = DEBUGFS_I(inode)->real_fops;
102 if (ops->llseek)
103 methods |= HAS_LSEEK;
104 if (ops->read)
105 methods |= HAS_READ;
106 if (ops->write)
107 methods |= HAS_WRITE;
108 if (ops->unlocked_ioctl)
109 methods |= HAS_IOCTL;
110 if (ops->poll)
111 methods |= HAS_POLL;
112 fsd->short_fops = NULL;
113 }
114 fsd->methods = methods;
115 refcount_set(r: &fsd->active_users, n: 1);
116 init_completion(x: &fsd->active_users_drained);
117 INIT_LIST_HEAD(list: &fsd->cancellations);
118 mutex_init(&fsd->cancellations_mtx);
119
120 d_fsd = cmpxchg(&dentry->d_fsdata, NULL, fsd);
121 if (d_fsd) {
122 mutex_destroy(lock: &fsd->cancellations_mtx);
123 kfree(objp: fsd);
124 fsd = d_fsd;
125 }
126 }
127
128 /*
129 * In case of a successful cmpxchg() above, this check is
130 * strictly necessary and must follow it, see the comment in
131 * __debugfs_remove_file().
132 * OTOH, if the cmpxchg() hasn't been executed or wasn't
133 * successful, this serves the purpose of not starving
134 * removers.
135 */
136 if (d_unlinked(dentry))
137 return -EIO;
138
139 if (!refcount_inc_not_zero(r: &fsd->active_users))
140 return -EIO;
141
142 return 0;
143}
144
145/**
146 * debugfs_file_get - mark the beginning of file data access
147 * @dentry: the dentry object whose data is being accessed.
148 *
149 * Up to a matching call to debugfs_file_put(), any successive call
150 * into the file removing functions debugfs_remove() and
151 * debugfs_remove_recursive() will block. Since associated private
152 * file data may only get freed after a successful return of any of
153 * the removal functions, you may safely access it after a successful
154 * call to debugfs_file_get() without worrying about lifetime issues.
155 *
156 * If -%EIO is returned, the file has already been removed and thus,
157 * it is not safe to access any of its data. If, on the other hand,
158 * it is allowed to access the file data, zero is returned.
159 */
160int debugfs_file_get(struct dentry *dentry)
161{
162 return __debugfs_file_get(dentry, mode: DBGFS_GET_ALREADY);
163}
164EXPORT_SYMBOL_GPL(debugfs_file_get);
165
166/**
167 * debugfs_file_put - mark the end of file data access
168 * @dentry: the dentry object formerly passed to
169 * debugfs_file_get().
170 *
171 * Allow any ongoing concurrent call into debugfs_remove() or
172 * debugfs_remove_recursive() blocked by a former call to
173 * debugfs_file_get() to proceed and return to its caller.
174 */
175void debugfs_file_put(struct dentry *dentry)
176{
177 struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
178
179 if (refcount_dec_and_test(r: &fsd->active_users))
180 complete(&fsd->active_users_drained);
181}
182EXPORT_SYMBOL_GPL(debugfs_file_put);
183
184/**
185 * debugfs_enter_cancellation - enter a debugfs cancellation
186 * @file: the file being accessed
187 * @cancellation: the cancellation object, the cancel callback
188 * inside of it must be initialized
189 *
190 * When a debugfs file is removed it needs to wait for all active
191 * operations to complete. However, the operation itself may need
192 * to wait for hardware or completion of some asynchronous process
193 * or similar. As such, it may need to be cancelled to avoid long
194 * waits or even deadlocks.
195 *
196 * This function can be used inside a debugfs handler that may
197 * need to be cancelled. As soon as this function is called, the
198 * cancellation's 'cancel' callback may be called, at which point
199 * the caller should proceed to call debugfs_leave_cancellation()
200 * and leave the debugfs handler function as soon as possible.
201 * Note that the 'cancel' callback is only ever called in the
202 * context of some kind of debugfs_remove().
203 *
204 * This function must be paired with debugfs_leave_cancellation().
205 */
206void debugfs_enter_cancellation(struct file *file,
207 struct debugfs_cancellation *cancellation)
208{
209 struct debugfs_fsdata *fsd;
210 struct dentry *dentry = F_DENTRY(file);
211
212 INIT_LIST_HEAD(list: &cancellation->list);
213
214 if (WARN_ON(!d_is_reg(dentry)))
215 return;
216
217 if (WARN_ON(!cancellation->cancel))
218 return;
219
220 fsd = READ_ONCE(dentry->d_fsdata);
221 if (WARN_ON(!fsd))
222 return;
223
224 mutex_lock(&fsd->cancellations_mtx);
225 list_add(new: &cancellation->list, head: &fsd->cancellations);
226 mutex_unlock(lock: &fsd->cancellations_mtx);
227
228 /* if we're already removing wake it up to cancel */
229 if (d_unlinked(dentry))
230 complete(&fsd->active_users_drained);
231}
232EXPORT_SYMBOL_GPL(debugfs_enter_cancellation);
233
234/**
235 * debugfs_leave_cancellation - leave cancellation section
236 * @file: the file being accessed
237 * @cancellation: the cancellation previously registered with
238 * debugfs_enter_cancellation()
239 *
240 * See the documentation of debugfs_enter_cancellation().
241 */
242void debugfs_leave_cancellation(struct file *file,
243 struct debugfs_cancellation *cancellation)
244{
245 struct debugfs_fsdata *fsd;
246 struct dentry *dentry = F_DENTRY(file);
247
248 if (WARN_ON(!d_is_reg(dentry)))
249 return;
250
251 fsd = READ_ONCE(dentry->d_fsdata);
252 if (WARN_ON(!fsd))
253 return;
254
255 mutex_lock(&fsd->cancellations_mtx);
256 if (!list_empty(head: &cancellation->list))
257 list_del(entry: &cancellation->list);
258 mutex_unlock(lock: &fsd->cancellations_mtx);
259}
260EXPORT_SYMBOL_GPL(debugfs_leave_cancellation);
261
262/*
263 * Only permit access to world-readable files when the kernel is locked down.
264 * We also need to exclude any file that has ways to write or alter it as root
265 * can bypass the permissions check.
266 */
267static int debugfs_locked_down(struct inode *inode,
268 struct file *filp,
269 const struct file_operations *real_fops)
270{
271 if ((inode->i_mode & 07777 & ~0444) == 0 &&
272 !(filp->f_mode & FMODE_WRITE) &&
273 (!real_fops ||
274 (!real_fops->unlocked_ioctl &&
275 !real_fops->compat_ioctl &&
276 !real_fops->mmap)))
277 return 0;
278
279 if (security_locked_down(what: LOCKDOWN_DEBUGFS))
280 return -EPERM;
281
282 return 0;
283}
284
285static int open_proxy_open(struct inode *inode, struct file *filp)
286{
287 struct dentry *dentry = F_DENTRY(filp);
288 const struct file_operations *real_fops = DEBUGFS_I(inode)->real_fops;
289 int r;
290
291 r = __debugfs_file_get(dentry, mode: DBGFS_GET_REGULAR);
292 if (r)
293 return r == -EIO ? -ENOENT : r;
294
295 r = debugfs_locked_down(inode, filp, real_fops);
296 if (r)
297 goto out;
298
299 if (!fops_get(real_fops)) {
300#ifdef CONFIG_MODULES
301 if (real_fops->owner &&
302 real_fops->owner->state == MODULE_STATE_GOING) {
303 r = -ENXIO;
304 goto out;
305 }
306#endif
307
308 /* Huh? Module did not clean up after itself at exit? */
309 WARN(1, "debugfs file owner did not clean up at exit: %pd",
310 dentry);
311 r = -ENXIO;
312 goto out;
313 }
314 replace_fops(filp, real_fops);
315
316 if (real_fops->open)
317 r = real_fops->open(inode, filp);
318
319out:
320 debugfs_file_put(dentry);
321 return r;
322}
323
324const struct file_operations debugfs_open_proxy_file_operations = {
325 .open = open_proxy_open,
326};
327
328#define PROTO(args...) args
329#define ARGS(args...) args
330
331#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args, bit, ret) \
332static ret_type full_proxy_ ## name(proto) \
333{ \
334 struct dentry *dentry = F_DENTRY(filp); \
335 struct debugfs_fsdata *fsd = dentry->d_fsdata; \
336 ret_type r; \
337 \
338 if (!(fsd->methods & bit)) \
339 return ret; \
340 r = debugfs_file_get(dentry); \
341 if (unlikely(r)) \
342 return r; \
343 r = fsd->real_fops->name(args); \
344 debugfs_file_put(dentry); \
345 return r; \
346}
347
348#define SHORT_PROXY_FUNC(name, ret_type, filp, proto, args, bit, ret) \
349static ret_type short_proxy_ ## name(proto) \
350{ \
351 struct dentry *dentry = F_DENTRY(filp); \
352 struct debugfs_fsdata *fsd = dentry->d_fsdata; \
353 ret_type r; \
354 \
355 if (!(fsd->methods & bit)) \
356 return ret; \
357 r = debugfs_file_get(dentry); \
358 if (unlikely(r)) \
359 return r; \
360 r = fsd->short_fops->name(args); \
361 debugfs_file_put(dentry); \
362 return r; \
363}
364
365SHORT_PROXY_FUNC(llseek, loff_t, filp,
366 PROTO(struct file *filp, loff_t offset, int whence),
367 ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE);
368
369FULL_PROXY_FUNC(llseek, loff_t, filp,
370 PROTO(struct file *filp, loff_t offset, int whence),
371 ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE);
372
373SHORT_PROXY_FUNC(read, ssize_t, filp,
374 PROTO(struct file *filp, char __user *buf, size_t size,
375 loff_t *ppos),
376 ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL);
377
378FULL_PROXY_FUNC(read, ssize_t, filp,
379 PROTO(struct file *filp, char __user *buf, size_t size,
380 loff_t *ppos),
381 ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL);
382
383SHORT_PROXY_FUNC(write, ssize_t, filp,
384 PROTO(struct file *filp, const char __user *buf,
385 size_t size, loff_t *ppos),
386 ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL);
387
388FULL_PROXY_FUNC(write, ssize_t, filp,
389 PROTO(struct file *filp, const char __user *buf,
390 size_t size, loff_t *ppos),
391 ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL);
392
393FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
394 PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
395 ARGS(filp, cmd, arg), HAS_IOCTL, -ENOTTY);
396
397static __poll_t full_proxy_poll(struct file *filp,
398 struct poll_table_struct *wait)
399{
400 struct dentry *dentry = F_DENTRY(filp);
401 struct debugfs_fsdata *fsd = dentry->d_fsdata;
402 __poll_t r = 0;
403
404 if (!(fsd->methods & HAS_POLL))
405 return DEFAULT_POLLMASK;
406 if (debugfs_file_get(dentry))
407 return EPOLLHUP;
408
409 r = fsd->real_fops->poll(filp, wait);
410 debugfs_file_put(dentry);
411 return r;
412}
413
414static int full_proxy_release(struct inode *inode, struct file *file)
415{
416 struct debugfs_fsdata *fsd = F_DENTRY(file)->d_fsdata;
417 const struct file_operations *real_fops = fsd->real_fops;
418 int r = 0;
419
420 /*
421 * We must not protect this against removal races here: the
422 * original releaser should be called unconditionally in order
423 * not to leak any resources. Releasers must not assume that
424 * ->i_private is still being meaningful here.
425 */
426 if (real_fops->release)
427 r = real_fops->release(inode, file);
428
429 fops_put(real_fops);
430 return r;
431}
432
433static int full_proxy_open_regular(struct inode *inode, struct file *filp)
434{
435 struct dentry *dentry = F_DENTRY(filp);
436 const struct file_operations *real_fops;
437 struct debugfs_fsdata *fsd;
438 int r;
439
440 r = __debugfs_file_get(dentry, mode: DBGFS_GET_REGULAR);
441 if (r)
442 return r == -EIO ? -ENOENT : r;
443
444 fsd = dentry->d_fsdata;
445 real_fops = fsd->real_fops;
446 r = debugfs_locked_down(inode, filp, real_fops);
447 if (r)
448 goto out;
449
450 if (!fops_get(real_fops)) {
451#ifdef CONFIG_MODULES
452 if (real_fops->owner &&
453 real_fops->owner->state == MODULE_STATE_GOING) {
454 r = -ENXIO;
455 goto out;
456 }
457#endif
458
459 /* Huh? Module did not cleanup after itself at exit? */
460 WARN(1, "debugfs file owner did not clean up at exit: %pd",
461 dentry);
462 r = -ENXIO;
463 goto out;
464 }
465
466 if (real_fops->open) {
467 r = real_fops->open(inode, filp);
468 if (r) {
469 fops_put(real_fops);
470 } else if (filp->f_op != &debugfs_full_proxy_file_operations) {
471 /* No protection against file removal anymore. */
472 WARN(1, "debugfs file owner replaced proxy fops: %pd",
473 dentry);
474 fops_put(real_fops);
475 }
476 }
477out:
478 debugfs_file_put(dentry);
479 return r;
480}
481
482const struct file_operations debugfs_full_proxy_file_operations = {
483 .open = full_proxy_open_regular,
484 .release = full_proxy_release,
485 .llseek = full_proxy_llseek,
486 .read = full_proxy_read,
487 .write = full_proxy_write,
488 .poll = full_proxy_poll,
489 .unlocked_ioctl = full_proxy_unlocked_ioctl
490};
491
492static int full_proxy_open_short(struct inode *inode, struct file *filp)
493{
494 struct dentry *dentry = F_DENTRY(filp);
495 int r;
496
497 r = __debugfs_file_get(dentry, mode: DBGFS_GET_SHORT);
498 if (r)
499 return r == -EIO ? -ENOENT : r;
500 r = debugfs_locked_down(inode, filp, NULL);
501 if (!r)
502 r = simple_open(inode, file: filp);
503 debugfs_file_put(dentry);
504 return r;
505}
506
507const struct file_operations debugfs_full_short_proxy_file_operations = {
508 .open = full_proxy_open_short,
509 .llseek = short_proxy_llseek,
510 .read = short_proxy_read,
511 .write = short_proxy_write,
512};
513
514ssize_t debugfs_attr_read(struct file *file, char __user *buf,
515 size_t len, loff_t *ppos)
516{
517 struct dentry *dentry = F_DENTRY(file);
518 ssize_t ret;
519
520 ret = debugfs_file_get(dentry);
521 if (unlikely(ret))
522 return ret;
523 ret = simple_attr_read(file, buf, len, ppos);
524 debugfs_file_put(dentry);
525 return ret;
526}
527EXPORT_SYMBOL_GPL(debugfs_attr_read);
528
529static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf,
530 size_t len, loff_t *ppos, bool is_signed)
531{
532 struct dentry *dentry = F_DENTRY(file);
533 ssize_t ret;
534
535 ret = debugfs_file_get(dentry);
536 if (unlikely(ret))
537 return ret;
538 if (is_signed)
539 ret = simple_attr_write_signed(file, buf, len, ppos);
540 else
541 ret = simple_attr_write(file, buf, len, ppos);
542 debugfs_file_put(dentry);
543 return ret;
544}
545
546ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
547 size_t len, loff_t *ppos)
548{
549 return debugfs_attr_write_xsigned(file, buf, len, ppos, is_signed: false);
550}
551EXPORT_SYMBOL_GPL(debugfs_attr_write);
552
553ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf,
554 size_t len, loff_t *ppos)
555{
556 return debugfs_attr_write_xsigned(file, buf, len, ppos, is_signed: true);
557}
558EXPORT_SYMBOL_GPL(debugfs_attr_write_signed);
559
560static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
561 struct dentry *parent, void *value,
562 const struct file_operations *fops,
563 const struct file_operations *fops_ro,
564 const struct file_operations *fops_wo)
565{
566 /* if there are no write bits set, make read only */
567 if (!(mode & S_IWUGO))
568 return debugfs_create_file_unsafe(name, mode, parent, data: value,
569 fops: fops_ro);
570 /* if there are no read bits set, make write only */
571 if (!(mode & S_IRUGO))
572 return debugfs_create_file_unsafe(name, mode, parent, data: value,
573 fops: fops_wo);
574
575 return debugfs_create_file_unsafe(name, mode, parent, data: value, fops);
576}
577
578static int debugfs_u8_set(void *data, u64 val)
579{
580 *(u8 *)data = val;
581 return 0;
582}
583static int debugfs_u8_get(void *data, u64 *val)
584{
585 *val = *(u8 *)data;
586 return 0;
587}
588DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
589DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
590DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
591
592/**
593 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
594 * @name: a pointer to a string containing the name of the file to create.
595 * @mode: the permission that the file should have
596 * @parent: a pointer to the parent dentry for this file. This should be a
597 * directory dentry if set. If this parameter is %NULL, then the
598 * file will be created in the root of the debugfs filesystem.
599 * @value: a pointer to the variable that the file should read to and write
600 * from.
601 *
602 * This function creates a file in debugfs with the given name that
603 * contains the value of the variable @value. If the @mode variable is so
604 * set, it can be read from, and written to.
605 */
606void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
607 u8 *value)
608{
609 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_u8,
610 fops_ro: &fops_u8_ro, fops_wo: &fops_u8_wo);
611}
612EXPORT_SYMBOL_GPL(debugfs_create_u8);
613
614static int debugfs_u16_set(void *data, u64 val)
615{
616 *(u16 *)data = val;
617 return 0;
618}
619static int debugfs_u16_get(void *data, u64 *val)
620{
621 *val = *(u16 *)data;
622 return 0;
623}
624DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
625DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
626DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
627
628/**
629 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
630 * @name: a pointer to a string containing the name of the file to create.
631 * @mode: the permission that the file should have
632 * @parent: a pointer to the parent dentry for this file. This should be a
633 * directory dentry if set. If this parameter is %NULL, then the
634 * file will be created in the root of the debugfs filesystem.
635 * @value: a pointer to the variable that the file should read to and write
636 * from.
637 *
638 * This function creates a file in debugfs with the given name that
639 * contains the value of the variable @value. If the @mode variable is so
640 * set, it can be read from, and written to.
641 */
642void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
643 u16 *value)
644{
645 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_u16,
646 fops_ro: &fops_u16_ro, fops_wo: &fops_u16_wo);
647}
648EXPORT_SYMBOL_GPL(debugfs_create_u16);
649
650static int debugfs_u32_set(void *data, u64 val)
651{
652 *(u32 *)data = val;
653 return 0;
654}
655static int debugfs_u32_get(void *data, u64 *val)
656{
657 *val = *(u32 *)data;
658 return 0;
659}
660DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
661DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
662DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
663
664/**
665 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
666 * @name: a pointer to a string containing the name of the file to create.
667 * @mode: the permission that the file should have
668 * @parent: a pointer to the parent dentry for this file. This should be a
669 * directory dentry if set. If this parameter is %NULL, then the
670 * file will be created in the root of the debugfs filesystem.
671 * @value: a pointer to the variable that the file should read to and write
672 * from.
673 *
674 * This function creates a file in debugfs with the given name that
675 * contains the value of the variable @value. If the @mode variable is so
676 * set, it can be read from, and written to.
677 */
678void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
679 u32 *value)
680{
681 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_u32,
682 fops_ro: &fops_u32_ro, fops_wo: &fops_u32_wo);
683}
684EXPORT_SYMBOL_GPL(debugfs_create_u32);
685
686static int debugfs_u64_set(void *data, u64 val)
687{
688 *(u64 *)data = val;
689 return 0;
690}
691
692static int debugfs_u64_get(void *data, u64 *val)
693{
694 *val = *(u64 *)data;
695 return 0;
696}
697DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
698DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
699DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
700
701/**
702 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
703 * @name: a pointer to a string containing the name of the file to create.
704 * @mode: the permission that the file should have
705 * @parent: a pointer to the parent dentry for this file. This should be a
706 * directory dentry if set. If this parameter is %NULL, then the
707 * file will be created in the root of the debugfs filesystem.
708 * @value: a pointer to the variable that the file should read to and write
709 * from.
710 *
711 * This function creates a file in debugfs with the given name that
712 * contains the value of the variable @value. If the @mode variable is so
713 * set, it can be read from, and written to.
714 */
715void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
716 u64 *value)
717{
718 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_u64,
719 fops_ro: &fops_u64_ro, fops_wo: &fops_u64_wo);
720}
721EXPORT_SYMBOL_GPL(debugfs_create_u64);
722
723static int debugfs_ulong_set(void *data, u64 val)
724{
725 *(unsigned long *)data = val;
726 return 0;
727}
728
729static int debugfs_ulong_get(void *data, u64 *val)
730{
731 *val = *(unsigned long *)data;
732 return 0;
733}
734DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
735 "%llu\n");
736DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
737DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
738
739/**
740 * debugfs_create_ulong - create a debugfs file that is used to read and write
741 * an unsigned long value.
742 * @name: a pointer to a string containing the name of the file to create.
743 * @mode: the permission that the file should have
744 * @parent: a pointer to the parent dentry for this file. This should be a
745 * directory dentry if set. If this parameter is %NULL, then the
746 * file will be created in the root of the debugfs filesystem.
747 * @value: a pointer to the variable that the file should read to and write
748 * from.
749 *
750 * This function creates a file in debugfs with the given name that
751 * contains the value of the variable @value. If the @mode variable is so
752 * set, it can be read from, and written to.
753 */
754void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent,
755 unsigned long *value)
756{
757 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_ulong,
758 fops_ro: &fops_ulong_ro, fops_wo: &fops_ulong_wo);
759}
760EXPORT_SYMBOL_GPL(debugfs_create_ulong);
761
762DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
763DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
764DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
765
766DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
767 "0x%04llx\n");
768DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
769DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
770
771DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
772 "0x%08llx\n");
773DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
774DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
775
776DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
777 "0x%016llx\n");
778DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
779DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
780
781/*
782 * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
783 *
784 * These functions are exactly the same as the above functions (but use a hex
785 * output for the decimal challenged). For details look at the above unsigned
786 * decimal functions.
787 */
788
789/**
790 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
791 * @name: a pointer to a string containing the name of the file to create.
792 * @mode: the permission that the file should have
793 * @parent: a pointer to the parent dentry for this file. This should be a
794 * directory dentry if set. If this parameter is %NULL, then the
795 * file will be created in the root of the debugfs filesystem.
796 * @value: a pointer to the variable that the file should read to and write
797 * from.
798 */
799void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
800 u8 *value)
801{
802 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_x8,
803 fops_ro: &fops_x8_ro, fops_wo: &fops_x8_wo);
804}
805EXPORT_SYMBOL_GPL(debugfs_create_x8);
806
807/**
808 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
809 * @name: a pointer to a string containing the name of the file to create.
810 * @mode: the permission that the file should have
811 * @parent: a pointer to the parent dentry for this file. This should be a
812 * directory dentry if set. If this parameter is %NULL, then the
813 * file will be created in the root of the debugfs filesystem.
814 * @value: a pointer to the variable that the file should read to and write
815 * from.
816 */
817void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
818 u16 *value)
819{
820 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_x16,
821 fops_ro: &fops_x16_ro, fops_wo: &fops_x16_wo);
822}
823EXPORT_SYMBOL_GPL(debugfs_create_x16);
824
825/**
826 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
827 * @name: a pointer to a string containing the name of the file to create.
828 * @mode: the permission that the file should have
829 * @parent: a pointer to the parent dentry for this file. This should be a
830 * directory dentry if set. If this parameter is %NULL, then the
831 * file will be created in the root of the debugfs filesystem.
832 * @value: a pointer to the variable that the file should read to and write
833 * from.
834 */
835void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
836 u32 *value)
837{
838 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_x32,
839 fops_ro: &fops_x32_ro, fops_wo: &fops_x32_wo);
840}
841EXPORT_SYMBOL_GPL(debugfs_create_x32);
842
843/**
844 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
845 * @name: a pointer to a string containing the name of the file to create.
846 * @mode: the permission that the file should have
847 * @parent: a pointer to the parent dentry for this file. This should be a
848 * directory dentry if set. If this parameter is %NULL, then the
849 * file will be created in the root of the debugfs filesystem.
850 * @value: a pointer to the variable that the file should read to and write
851 * from.
852 */
853void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
854 u64 *value)
855{
856 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_x64,
857 fops_ro: &fops_x64_ro, fops_wo: &fops_x64_wo);
858}
859EXPORT_SYMBOL_GPL(debugfs_create_x64);
860
861
862static int debugfs_size_t_set(void *data, u64 val)
863{
864 *(size_t *)data = val;
865 return 0;
866}
867static int debugfs_size_t_get(void *data, u64 *val)
868{
869 *val = *(size_t *)data;
870 return 0;
871}
872DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
873 "%llu\n"); /* %llu and %zu are more or less the same */
874DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
875DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
876
877/**
878 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
879 * @name: a pointer to a string containing the name of the file to create.
880 * @mode: the permission that the file should have
881 * @parent: a pointer to the parent dentry for this file. This should be a
882 * directory dentry if set. If this parameter is %NULL, then the
883 * file will be created in the root of the debugfs filesystem.
884 * @value: a pointer to the variable that the file should read to and write
885 * from.
886 */
887void debugfs_create_size_t(const char *name, umode_t mode,
888 struct dentry *parent, size_t *value)
889{
890 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_size_t,
891 fops_ro: &fops_size_t_ro, fops_wo: &fops_size_t_wo);
892}
893EXPORT_SYMBOL_GPL(debugfs_create_size_t);
894
895static int debugfs_atomic_t_set(void *data, u64 val)
896{
897 atomic_set(v: (atomic_t *)data, i: val);
898 return 0;
899}
900static int debugfs_atomic_t_get(void *data, u64 *val)
901{
902 *val = atomic_read(v: (atomic_t *)data);
903 return 0;
904}
905DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t, debugfs_atomic_t_get,
906 debugfs_atomic_t_set, "%lld\n");
907DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
908 "%lld\n");
909DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
910 "%lld\n");
911
912/**
913 * debugfs_create_atomic_t - create a debugfs file that is used to read and
914 * write an atomic_t value
915 * @name: a pointer to a string containing the name of the file to create.
916 * @mode: the permission that the file should have
917 * @parent: a pointer to the parent dentry for this file. This should be a
918 * directory dentry if set. If this parameter is %NULL, then the
919 * file will be created in the root of the debugfs filesystem.
920 * @value: a pointer to the variable that the file should read to and write
921 * from.
922 */
923void debugfs_create_atomic_t(const char *name, umode_t mode,
924 struct dentry *parent, atomic_t *value)
925{
926 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_atomic_t,
927 fops_ro: &fops_atomic_t_ro, fops_wo: &fops_atomic_t_wo);
928}
929EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
930
931ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
932 size_t count, loff_t *ppos)
933{
934 char buf[2];
935 bool val;
936 int r;
937 struct dentry *dentry = F_DENTRY(file);
938
939 r = debugfs_file_get(dentry);
940 if (unlikely(r))
941 return r;
942 val = *(bool *)file->private_data;
943 debugfs_file_put(dentry);
944
945 if (val)
946 buf[0] = 'Y';
947 else
948 buf[0] = 'N';
949 buf[1] = '\n';
950 return simple_read_from_buffer(to: user_buf, count, ppos, from: buf, available: 2);
951}
952EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
953
954ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
955 size_t count, loff_t *ppos)
956{
957 bool bv;
958 int r;
959 bool *val = file->private_data;
960 struct dentry *dentry = F_DENTRY(file);
961
962 r = kstrtobool_from_user(s: user_buf, count, res: &bv);
963 if (!r) {
964 r = debugfs_file_get(dentry);
965 if (unlikely(r))
966 return r;
967 *val = bv;
968 debugfs_file_put(dentry);
969 }
970
971 return count;
972}
973EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
974
975static const struct file_operations fops_bool = {
976 .read = debugfs_read_file_bool,
977 .write = debugfs_write_file_bool,
978 .open = simple_open,
979 .llseek = default_llseek,
980};
981
982static const struct file_operations fops_bool_ro = {
983 .read = debugfs_read_file_bool,
984 .open = simple_open,
985 .llseek = default_llseek,
986};
987
988static const struct file_operations fops_bool_wo = {
989 .write = debugfs_write_file_bool,
990 .open = simple_open,
991 .llseek = default_llseek,
992};
993
994/**
995 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
996 * @name: a pointer to a string containing the name of the file to create.
997 * @mode: the permission that the file should have
998 * @parent: a pointer to the parent dentry for this file. This should be a
999 * directory dentry if set. If this parameter is %NULL, then the
1000 * file will be created in the root of the debugfs filesystem.
1001 * @value: a pointer to the variable that the file should read to and write
1002 * from.
1003 *
1004 * This function creates a file in debugfs with the given name that
1005 * contains the value of the variable @value. If the @mode variable is so
1006 * set, it can be read from, and written to.
1007 */
1008void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent,
1009 bool *value)
1010{
1011 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_bool,
1012 fops_ro: &fops_bool_ro, fops_wo: &fops_bool_wo);
1013}
1014EXPORT_SYMBOL_GPL(debugfs_create_bool);
1015
1016ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
1017 size_t count, loff_t *ppos)
1018{
1019 struct dentry *dentry = F_DENTRY(file);
1020 char *str, *copy = NULL;
1021 int copy_len, len;
1022 ssize_t ret;
1023
1024 ret = debugfs_file_get(dentry);
1025 if (unlikely(ret))
1026 return ret;
1027
1028 str = *(char **)file->private_data;
1029 len = strlen(str) + 1;
1030 copy = kmalloc(len, GFP_KERNEL);
1031 if (!copy) {
1032 debugfs_file_put(dentry);
1033 return -ENOMEM;
1034 }
1035
1036 copy_len = strscpy(copy, str, len);
1037 debugfs_file_put(dentry);
1038 if (copy_len < 0) {
1039 kfree(objp: copy);
1040 return copy_len;
1041 }
1042
1043 copy[copy_len] = '\n';
1044
1045 ret = simple_read_from_buffer(to: user_buf, count, ppos, from: copy, available: len);
1046 kfree(objp: copy);
1047
1048 return ret;
1049}
1050EXPORT_SYMBOL_GPL(debugfs_create_str);
1051
1052static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
1053 size_t count, loff_t *ppos)
1054{
1055 struct dentry *dentry = F_DENTRY(file);
1056 char *old, *new = NULL;
1057 int pos = *ppos;
1058 int r;
1059
1060 r = debugfs_file_get(dentry);
1061 if (unlikely(r))
1062 return r;
1063
1064 old = *(char **)file->private_data;
1065
1066 /* only allow strict concatenation */
1067 r = -EINVAL;
1068 if (pos && pos != strlen(old))
1069 goto error;
1070
1071 r = -E2BIG;
1072 if (pos + count + 1 > PAGE_SIZE)
1073 goto error;
1074
1075 r = -ENOMEM;
1076 new = kmalloc(pos + count + 1, GFP_KERNEL);
1077 if (!new)
1078 goto error;
1079
1080 if (pos)
1081 memcpy(new, old, pos);
1082
1083 r = -EFAULT;
1084 if (copy_from_user(to: new + pos, from: user_buf, n: count))
1085 goto error;
1086
1087 new[pos + count] = '\0';
1088 strim(new);
1089
1090 rcu_assign_pointer(*(char __rcu **)file->private_data, new);
1091 synchronize_rcu();
1092 kfree(objp: old);
1093
1094 debugfs_file_put(dentry);
1095 return count;
1096
1097error:
1098 kfree(objp: new);
1099 debugfs_file_put(dentry);
1100 return r;
1101}
1102
1103static const struct file_operations fops_str = {
1104 .read = debugfs_read_file_str,
1105 .write = debugfs_write_file_str,
1106 .open = simple_open,
1107 .llseek = default_llseek,
1108};
1109
1110static const struct file_operations fops_str_ro = {
1111 .read = debugfs_read_file_str,
1112 .open = simple_open,
1113 .llseek = default_llseek,
1114};
1115
1116static const struct file_operations fops_str_wo = {
1117 .write = debugfs_write_file_str,
1118 .open = simple_open,
1119 .llseek = default_llseek,
1120};
1121
1122/**
1123 * debugfs_create_str - create a debugfs file that is used to read and write a string value
1124 * @name: a pointer to a string containing the name of the file to create.
1125 * @mode: the permission that the file should have
1126 * @parent: a pointer to the parent dentry for this file. This should be a
1127 * directory dentry if set. If this parameter is %NULL, then the
1128 * file will be created in the root of the debugfs filesystem.
1129 * @value: a pointer to the variable that the file should read to and write
1130 * from.
1131 *
1132 * This function creates a file in debugfs with the given name that
1133 * contains the value of the variable @value. If the @mode variable is so
1134 * set, it can be read from, and written to.
1135 */
1136void debugfs_create_str(const char *name, umode_t mode,
1137 struct dentry *parent, char **value)
1138{
1139 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_str,
1140 fops_ro: &fops_str_ro, fops_wo: &fops_str_wo);
1141}
1142
1143static ssize_t read_file_blob(struct file *file, char __user *user_buf,
1144 size_t count, loff_t *ppos)
1145{
1146 struct debugfs_blob_wrapper *blob = file->private_data;
1147 struct dentry *dentry = F_DENTRY(file);
1148 ssize_t r;
1149
1150 r = debugfs_file_get(dentry);
1151 if (unlikely(r))
1152 return r;
1153 r = simple_read_from_buffer(to: user_buf, count, ppos, from: blob->data,
1154 available: blob->size);
1155 debugfs_file_put(dentry);
1156 return r;
1157}
1158
1159static ssize_t write_file_blob(struct file *file, const char __user *user_buf,
1160 size_t count, loff_t *ppos)
1161{
1162 struct debugfs_blob_wrapper *blob = file->private_data;
1163 struct dentry *dentry = F_DENTRY(file);
1164 ssize_t r;
1165
1166 r = debugfs_file_get(dentry);
1167 if (unlikely(r))
1168 return r;
1169 r = simple_write_to_buffer(to: blob->data, available: blob->size, ppos, from: user_buf,
1170 count);
1171
1172 debugfs_file_put(dentry);
1173 return r;
1174}
1175
1176static const struct file_operations fops_blob = {
1177 .read = read_file_blob,
1178 .write = write_file_blob,
1179 .open = simple_open,
1180 .llseek = default_llseek,
1181};
1182
1183/**
1184 * debugfs_create_blob - create a debugfs file that is used to read and write
1185 * a binary blob
1186 * @name: a pointer to a string containing the name of the file to create.
1187 * @mode: the permission that the file should have
1188 * @parent: a pointer to the parent dentry for this file. This should be a
1189 * directory dentry if set. If this parameter is %NULL, then the
1190 * file will be created in the root of the debugfs filesystem.
1191 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
1192 * to the blob data and the size of the data.
1193 *
1194 * This function creates a file in debugfs with the given name that exports
1195 * @blob->data as a binary blob. If the @mode variable is so set it can be
1196 * read from and written to.
1197 *
1198 * This function will return a pointer to a dentry if it succeeds. This
1199 * pointer must be passed to the debugfs_remove() function when the file is
1200 * to be removed (no automatic cleanup happens if your module is unloaded,
1201 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
1202 * returned.
1203 *
1204 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
1205 * be returned.
1206 */
1207struct dentry *debugfs_create_blob(const char *name, umode_t mode,
1208 struct dentry *parent,
1209 struct debugfs_blob_wrapper *blob)
1210{
1211 return debugfs_create_file_unsafe(name, mode: mode & 0644, parent, data: blob, fops: &fops_blob);
1212}
1213EXPORT_SYMBOL_GPL(debugfs_create_blob);
1214
1215static size_t u32_format_array(char *buf, size_t bufsize,
1216 u32 *array, int array_size)
1217{
1218 size_t ret = 0;
1219
1220 while (--array_size >= 0) {
1221 size_t len;
1222 char term = array_size ? ' ' : '\n';
1223
1224 len = snprintf(buf, size: bufsize, fmt: "%u%c", *array++, term);
1225 ret += len;
1226
1227 buf += len;
1228 bufsize -= len;
1229 }
1230 return ret;
1231}
1232
1233static int u32_array_open(struct inode *inode, struct file *file)
1234{
1235 struct debugfs_u32_array *data = inode->i_private;
1236 int size, elements = data->n_elements;
1237 char *buf;
1238
1239 /*
1240 * Max size:
1241 * - 10 digits + ' '/'\n' = 11 bytes per number
1242 * - terminating NUL character
1243 */
1244 size = elements*11;
1245 buf = kmalloc(size+1, GFP_KERNEL);
1246 if (!buf)
1247 return -ENOMEM;
1248 buf[size] = 0;
1249
1250 file->private_data = buf;
1251 u32_format_array(buf, bufsize: size, array: data->array, array_size: data->n_elements);
1252
1253 return nonseekable_open(inode, filp: file);
1254}
1255
1256static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
1257 loff_t *ppos)
1258{
1259 size_t size = strlen(file->private_data);
1260
1261 return simple_read_from_buffer(to: buf, count: len, ppos,
1262 from: file->private_data, available: size);
1263}
1264
1265static int u32_array_release(struct inode *inode, struct file *file)
1266{
1267 kfree(objp: file->private_data);
1268
1269 return 0;
1270}
1271
1272static const struct file_operations u32_array_fops = {
1273 .owner = THIS_MODULE,
1274 .open = u32_array_open,
1275 .release = u32_array_release,
1276 .read = u32_array_read,
1277};
1278
1279/**
1280 * debugfs_create_u32_array - create a debugfs file that is used to read u32
1281 * array.
1282 * @name: a pointer to a string containing the name of the file to create.
1283 * @mode: the permission that the file should have.
1284 * @parent: a pointer to the parent dentry for this file. This should be a
1285 * directory dentry if set. If this parameter is %NULL, then the
1286 * file will be created in the root of the debugfs filesystem.
1287 * @array: wrapper struct containing data pointer and size of the array.
1288 *
1289 * This function creates a file in debugfs with the given name that exports
1290 * @array as data. If the @mode variable is so set it can be read from.
1291 * Writing is not supported. Seek within the file is also not supported.
1292 * Once array is created its size can not be changed.
1293 */
1294void debugfs_create_u32_array(const char *name, umode_t mode,
1295 struct dentry *parent,
1296 struct debugfs_u32_array *array)
1297{
1298 debugfs_create_file_unsafe(name, mode, parent, data: array, fops: &u32_array_fops);
1299}
1300EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1301
1302#ifdef CONFIG_HAS_IOMEM
1303
1304/*
1305 * The regset32 stuff is used to print 32-bit registers using the
1306 * seq_file utilities. We offer printing a register set in an already-opened
1307 * sequential file or create a debugfs file that only prints a regset32.
1308 */
1309
1310/**
1311 * debugfs_print_regs32 - use seq_print to describe a set of registers
1312 * @s: the seq_file structure being used to generate output
1313 * @regs: an array if struct debugfs_reg32 structures
1314 * @nregs: the length of the above array
1315 * @base: the base address to be used in reading the registers
1316 * @prefix: a string to be prefixed to every output line
1317 *
1318 * This function outputs a text block describing the current values of
1319 * some 32-bit hardware registers. It is meant to be used within debugfs
1320 * files based on seq_file that need to show registers, intermixed with other
1321 * information. The prefix argument may be used to specify a leading string,
1322 * because some peripherals have several blocks of identical registers,
1323 * for example configuration of dma channels
1324 */
1325void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1326 int nregs, void __iomem *base, char *prefix)
1327{
1328 int i;
1329
1330 for (i = 0; i < nregs; i++, regs++) {
1331 if (prefix)
1332 seq_printf(m: s, fmt: "%s", prefix);
1333 seq_printf(m: s, fmt: "%s = 0x%08x\n", regs->name,
1334 readl(addr: base + regs->offset));
1335 if (seq_has_overflowed(m: s))
1336 break;
1337 }
1338}
1339EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1340
1341static int debugfs_regset32_show(struct seq_file *s, void *data)
1342{
1343 struct debugfs_regset32 *regset = s->private;
1344
1345 if (regset->dev)
1346 pm_runtime_get_sync(dev: regset->dev);
1347
1348 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1349
1350 if (regset->dev)
1351 pm_runtime_put(dev: regset->dev);
1352
1353 return 0;
1354}
1355
1356DEFINE_SHOW_ATTRIBUTE(debugfs_regset32);
1357
1358/**
1359 * debugfs_create_regset32 - create a debugfs file that returns register values
1360 * @name: a pointer to a string containing the name of the file to create.
1361 * @mode: the permission that the file should have
1362 * @parent: a pointer to the parent dentry for this file. This should be a
1363 * directory dentry if set. If this parameter is %NULL, then the
1364 * file will be created in the root of the debugfs filesystem.
1365 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1366 * to an array of register definitions, the array size and the base
1367 * address where the register bank is to be found.
1368 *
1369 * This function creates a file in debugfs with the given name that reports
1370 * the names and values of a set of 32-bit registers. If the @mode variable
1371 * is so set it can be read from. Writing is not supported.
1372 */
1373void debugfs_create_regset32(const char *name, umode_t mode,
1374 struct dentry *parent,
1375 struct debugfs_regset32 *regset)
1376{
1377 debugfs_create_file(name, mode, parent, regset, &debugfs_regset32_fops);
1378}
1379EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1380
1381#endif /* CONFIG_HAS_IOMEM */
1382
1383struct debugfs_devm_entry {
1384 int (*read)(struct seq_file *seq, void *data);
1385 struct device *dev;
1386};
1387
1388static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1389{
1390 struct debugfs_devm_entry *entry = inode->i_private;
1391
1392 return single_open(f, entry->read, entry->dev);
1393}
1394
1395static const struct file_operations debugfs_devm_entry_ops = {
1396 .owner = THIS_MODULE,
1397 .open = debugfs_devm_entry_open,
1398 .release = single_release,
1399 .read = seq_read,
1400 .llseek = seq_lseek
1401};
1402
1403/**
1404 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1405 *
1406 * @dev: device related to this debugfs file.
1407 * @name: name of the debugfs file.
1408 * @parent: a pointer to the parent dentry for this file. This should be a
1409 * directory dentry if set. If this parameter is %NULL, then the
1410 * file will be created in the root of the debugfs filesystem.
1411 * @read_fn: function pointer called to print the seq_file content.
1412 */
1413void debugfs_create_devm_seqfile(struct device *dev, const char *name,
1414 struct dentry *parent,
1415 int (*read_fn)(struct seq_file *s, void *data))
1416{
1417 struct debugfs_devm_entry *entry;
1418
1419 if (IS_ERR(ptr: parent))
1420 return;
1421
1422 entry = devm_kzalloc(dev, size: sizeof(*entry), GFP_KERNEL);
1423 if (!entry)
1424 return;
1425
1426 entry->read = read_fn;
1427 entry->dev = dev;
1428
1429 debugfs_create_file(name, S_IRUGO, parent, entry,
1430 &debugfs_devm_entry_ops);
1431}
1432EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);
1433

source code of linux/fs/debugfs/file.c