Loading...
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
50const struct file_operations *debugfs_real_fops(const struct file *filp)
51{
52 struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
53
54 if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
55 /*
56 * Urgh, we've been called w/o a protecting
57 * debugfs_file_get().
58 */
59 WARN_ON(1);
60 return NULL;
61 }
62
63 return fsd->real_fops;
64}
65EXPORT_SYMBOL_GPL(debugfs_real_fops);
66
67/**
68 * debugfs_file_get - mark the beginning of file data access
69 * @dentry: the dentry object whose data is being accessed.
70 *
71 * Up to a matching call to debugfs_file_put(), any successive call
72 * into the file removing functions debugfs_remove() and
73 * debugfs_remove_recursive() will block. Since associated private
74 * file data may only get freed after a successful return of any of
75 * the removal functions, you may safely access it after a successful
76 * call to debugfs_file_get() without worrying about lifetime issues.
77 *
78 * If -%EIO is returned, the file has already been removed and thus,
79 * it is not safe to access any of its data. If, on the other hand,
80 * it is allowed to access the file data, zero is returned.
81 */
82int debugfs_file_get(struct dentry *dentry)
83{
84 struct debugfs_fsdata *fsd;
85 void *d_fsd;
86
87 d_fsd = READ_ONCE(dentry->d_fsdata);
88 if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
89 fsd = d_fsd;
90 } else {
91 fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
92 if (!fsd)
93 return -ENOMEM;
94
95 fsd->real_fops = (void *)((unsigned long)d_fsd &
96 ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
97 refcount_set(&fsd->active_users, 1);
98 init_completion(&fsd->active_users_drained);
99 if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
100 kfree(fsd);
101 fsd = READ_ONCE(dentry->d_fsdata);
102 }
103 }
104
105 /*
106 * In case of a successful cmpxchg() above, this check is
107 * strictly necessary and must follow it, see the comment in
108 * __debugfs_remove_file().
109 * OTOH, if the cmpxchg() hasn't been executed or wasn't
110 * successful, this serves the purpose of not starving
111 * removers.
112 */
113 if (d_unlinked(dentry))
114 return -EIO;
115
116 if (!refcount_inc_not_zero(&fsd->active_users))
117 return -EIO;
118
119 return 0;
120}
121EXPORT_SYMBOL_GPL(debugfs_file_get);
122
123/**
124 * debugfs_file_put - mark the end of file data access
125 * @dentry: the dentry object formerly passed to
126 * debugfs_file_get().
127 *
128 * Allow any ongoing concurrent call into debugfs_remove() or
129 * debugfs_remove_recursive() blocked by a former call to
130 * debugfs_file_get() to proceed and return to its caller.
131 */
132void debugfs_file_put(struct dentry *dentry)
133{
134 struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
135
136 if (refcount_dec_and_test(&fsd->active_users))
137 complete(&fsd->active_users_drained);
138}
139EXPORT_SYMBOL_GPL(debugfs_file_put);
140
141/*
142 * Only permit access to world-readable files when the kernel is locked down.
143 * We also need to exclude any file that has ways to write or alter it as root
144 * can bypass the permissions check.
145 */
146static int debugfs_locked_down(struct inode *inode,
147 struct file *filp,
148 const struct file_operations *real_fops)
149{
150 if ((inode->i_mode & 07777) == 0444 &&
151 !(filp->f_mode & FMODE_WRITE) &&
152 !real_fops->unlocked_ioctl &&
153 !real_fops->compat_ioctl &&
154 !real_fops->mmap)
155 return 0;
156
157 if (security_locked_down(LOCKDOWN_DEBUGFS))
158 return -EPERM;
159
160 return 0;
161}
162
163static int open_proxy_open(struct inode *inode, struct file *filp)
164{
165 struct dentry *dentry = F_DENTRY(filp);
166 const struct file_operations *real_fops = NULL;
167 int r;
168
169 r = debugfs_file_get(dentry);
170 if (r)
171 return r == -EIO ? -ENOENT : r;
172
173 real_fops = debugfs_real_fops(filp);
174
175 r = debugfs_locked_down(inode, filp, real_fops);
176 if (r)
177 goto out;
178
179 if (!fops_get(real_fops)) {
180#ifdef CONFIG_MODULES
181 if (real_fops->owner &&
182 real_fops->owner->state == MODULE_STATE_GOING) {
183 r = -ENXIO;
184 goto out;
185 }
186#endif
187
188 /* Huh? Module did not clean up after itself at exit? */
189 WARN(1, "debugfs file owner did not clean up at exit: %pd",
190 dentry);
191 r = -ENXIO;
192 goto out;
193 }
194 replace_fops(filp, real_fops);
195
196 if (real_fops->open)
197 r = real_fops->open(inode, filp);
198
199out:
200 debugfs_file_put(dentry);
201 return r;
202}
203
204const struct file_operations debugfs_open_proxy_file_operations = {
205 .open = open_proxy_open,
206};
207
208#define PROTO(args...) args
209#define ARGS(args...) args
210
211#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
212static ret_type full_proxy_ ## name(proto) \
213{ \
214 struct dentry *dentry = F_DENTRY(filp); \
215 const struct file_operations *real_fops; \
216 ret_type r; \
217 \
218 r = debugfs_file_get(dentry); \
219 if (unlikely(r)) \
220 return r; \
221 real_fops = debugfs_real_fops(filp); \
222 r = real_fops->name(args); \
223 debugfs_file_put(dentry); \
224 return r; \
225}
226
227FULL_PROXY_FUNC(llseek, loff_t, filp,
228 PROTO(struct file *filp, loff_t offset, int whence),
229 ARGS(filp, offset, whence));
230
231FULL_PROXY_FUNC(read, ssize_t, filp,
232 PROTO(struct file *filp, char __user *buf, size_t size,
233 loff_t *ppos),
234 ARGS(filp, buf, size, ppos));
235
236FULL_PROXY_FUNC(write, ssize_t, filp,
237 PROTO(struct file *filp, const char __user *buf, size_t size,
238 loff_t *ppos),
239 ARGS(filp, buf, size, ppos));
240
241FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
242 PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
243 ARGS(filp, cmd, arg));
244
245static __poll_t full_proxy_poll(struct file *filp,
246 struct poll_table_struct *wait)
247{
248 struct dentry *dentry = F_DENTRY(filp);
249 __poll_t r = 0;
250 const struct file_operations *real_fops;
251
252 if (debugfs_file_get(dentry))
253 return EPOLLHUP;
254
255 real_fops = debugfs_real_fops(filp);
256 r = real_fops->poll(filp, wait);
257 debugfs_file_put(dentry);
258 return r;
259}
260
261static int full_proxy_release(struct inode *inode, struct file *filp)
262{
263 const struct dentry *dentry = F_DENTRY(filp);
264 const struct file_operations *real_fops = debugfs_real_fops(filp);
265 const struct file_operations *proxy_fops = filp->f_op;
266 int r = 0;
267
268 /*
269 * We must not protect this against removal races here: the
270 * original releaser should be called unconditionally in order
271 * not to leak any resources. Releasers must not assume that
272 * ->i_private is still being meaningful here.
273 */
274 if (real_fops->release)
275 r = real_fops->release(inode, filp);
276
277 replace_fops(filp, d_inode(dentry)->i_fop);
278 kfree(proxy_fops);
279 fops_put(real_fops);
280 return r;
281}
282
283static void __full_proxy_fops_init(struct file_operations *proxy_fops,
284 const struct file_operations *real_fops)
285{
286 proxy_fops->release = full_proxy_release;
287 if (real_fops->llseek)
288 proxy_fops->llseek = full_proxy_llseek;
289 if (real_fops->read)
290 proxy_fops->read = full_proxy_read;
291 if (real_fops->write)
292 proxy_fops->write = full_proxy_write;
293 if (real_fops->poll)
294 proxy_fops->poll = full_proxy_poll;
295 if (real_fops->unlocked_ioctl)
296 proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
297}
298
299static int full_proxy_open(struct inode *inode, struct file *filp)
300{
301 struct dentry *dentry = F_DENTRY(filp);
302 const struct file_operations *real_fops = NULL;
303 struct file_operations *proxy_fops = NULL;
304 int r;
305
306 r = debugfs_file_get(dentry);
307 if (r)
308 return r == -EIO ? -ENOENT : r;
309
310 real_fops = debugfs_real_fops(filp);
311
312 r = debugfs_locked_down(inode, filp, real_fops);
313 if (r)
314 goto out;
315
316 if (!fops_get(real_fops)) {
317#ifdef CONFIG_MODULES
318 if (real_fops->owner &&
319 real_fops->owner->state == MODULE_STATE_GOING) {
320 r = -ENXIO;
321 goto out;
322 }
323#endif
324
325 /* Huh? Module did not cleanup after itself at exit? */
326 WARN(1, "debugfs file owner did not clean up at exit: %pd",
327 dentry);
328 r = -ENXIO;
329 goto out;
330 }
331
332 proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
333 if (!proxy_fops) {
334 r = -ENOMEM;
335 goto free_proxy;
336 }
337 __full_proxy_fops_init(proxy_fops, real_fops);
338 replace_fops(filp, proxy_fops);
339
340 if (real_fops->open) {
341 r = real_fops->open(inode, filp);
342 if (r) {
343 replace_fops(filp, d_inode(dentry)->i_fop);
344 goto free_proxy;
345 } else if (filp->f_op != proxy_fops) {
346 /* No protection against file removal anymore. */
347 WARN(1, "debugfs file owner replaced proxy fops: %pd",
348 dentry);
349 goto free_proxy;
350 }
351 }
352
353 goto out;
354free_proxy:
355 kfree(proxy_fops);
356 fops_put(real_fops);
357out:
358 debugfs_file_put(dentry);
359 return r;
360}
361
362const struct file_operations debugfs_full_proxy_file_operations = {
363 .open = full_proxy_open,
364};
365
366ssize_t debugfs_attr_read(struct file *file, char __user *buf,
367 size_t len, loff_t *ppos)
368{
369 struct dentry *dentry = F_DENTRY(file);
370 ssize_t ret;
371
372 ret = debugfs_file_get(dentry);
373 if (unlikely(ret))
374 return ret;
375 ret = simple_attr_read(file, buf, len, ppos);
376 debugfs_file_put(dentry);
377 return ret;
378}
379EXPORT_SYMBOL_GPL(debugfs_attr_read);
380
381ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
382 size_t len, loff_t *ppos)
383{
384 struct dentry *dentry = F_DENTRY(file);
385 ssize_t ret;
386
387 ret = debugfs_file_get(dentry);
388 if (unlikely(ret))
389 return ret;
390 ret = simple_attr_write(file, buf, len, ppos);
391 debugfs_file_put(dentry);
392 return ret;
393}
394EXPORT_SYMBOL_GPL(debugfs_attr_write);
395
396static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
397 struct dentry *parent, void *value,
398 const struct file_operations *fops,
399 const struct file_operations *fops_ro,
400 const struct file_operations *fops_wo)
401{
402 /* if there are no write bits set, make read only */
403 if (!(mode & S_IWUGO))
404 return debugfs_create_file_unsafe(name, mode, parent, value,
405 fops_ro);
406 /* if there are no read bits set, make write only */
407 if (!(mode & S_IRUGO))
408 return debugfs_create_file_unsafe(name, mode, parent, value,
409 fops_wo);
410
411 return debugfs_create_file_unsafe(name, mode, parent, value, fops);
412}
413
414static int debugfs_u8_set(void *data, u64 val)
415{
416 *(u8 *)data = val;
417 return 0;
418}
419static int debugfs_u8_get(void *data, u64 *val)
420{
421 *val = *(u8 *)data;
422 return 0;
423}
424DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
425DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
426DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
427
428/**
429 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
430 * @name: a pointer to a string containing the name of the file to create.
431 * @mode: the permission that the file should have
432 * @parent: a pointer to the parent dentry for this file. This should be a
433 * directory dentry if set. If this parameter is %NULL, then the
434 * file will be created in the root of the debugfs filesystem.
435 * @value: a pointer to the variable that the file should read to and write
436 * from.
437 *
438 * This function creates a file in debugfs with the given name that
439 * contains the value of the variable @value. If the @mode variable is so
440 * set, it can be read from, and written to.
441 */
442void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
443 u8 *value)
444{
445 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
446 &fops_u8_ro, &fops_u8_wo);
447}
448EXPORT_SYMBOL_GPL(debugfs_create_u8);
449
450static int debugfs_u16_set(void *data, u64 val)
451{
452 *(u16 *)data = val;
453 return 0;
454}
455static int debugfs_u16_get(void *data, u64 *val)
456{
457 *val = *(u16 *)data;
458 return 0;
459}
460DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
461DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
462DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
463
464/**
465 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
466 * @name: a pointer to a string containing the name of the file to create.
467 * @mode: the permission that the file should have
468 * @parent: a pointer to the parent dentry for this file. This should be a
469 * directory dentry if set. If this parameter is %NULL, then the
470 * file will be created in the root of the debugfs filesystem.
471 * @value: a pointer to the variable that the file should read to and write
472 * from.
473 *
474 * This function creates a file in debugfs with the given name that
475 * contains the value of the variable @value. If the @mode variable is so
476 * set, it can be read from, and written to.
477 */
478void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
479 u16 *value)
480{
481 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
482 &fops_u16_ro, &fops_u16_wo);
483}
484EXPORT_SYMBOL_GPL(debugfs_create_u16);
485
486static int debugfs_u32_set(void *data, u64 val)
487{
488 *(u32 *)data = val;
489 return 0;
490}
491static int debugfs_u32_get(void *data, u64 *val)
492{
493 *val = *(u32 *)data;
494 return 0;
495}
496DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
497DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
498DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
499
500/**
501 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
502 * @name: a pointer to a string containing the name of the file to create.
503 * @mode: the permission that the file should have
504 * @parent: a pointer to the parent dentry for this file. This should be a
505 * directory dentry if set. If this parameter is %NULL, then the
506 * file will be created in the root of the debugfs filesystem.
507 * @value: a pointer to the variable that the file should read to and write
508 * from.
509 *
510 * This function creates a file in debugfs with the given name that
511 * contains the value of the variable @value. If the @mode variable is so
512 * set, it can be read from, and written to.
513 */
514void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
515 u32 *value)
516{
517 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
518 &fops_u32_ro, &fops_u32_wo);
519}
520EXPORT_SYMBOL_GPL(debugfs_create_u32);
521
522static int debugfs_u64_set(void *data, u64 val)
523{
524 *(u64 *)data = val;
525 return 0;
526}
527
528static int debugfs_u64_get(void *data, u64 *val)
529{
530 *val = *(u64 *)data;
531 return 0;
532}
533DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
534DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
535DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
536
537/**
538 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
539 * @name: a pointer to a string containing the name of the file to create.
540 * @mode: the permission that the file should have
541 * @parent: a pointer to the parent dentry for this file. This should be a
542 * directory dentry if set. If this parameter is %NULL, then the
543 * file will be created in the root of the debugfs filesystem.
544 * @value: a pointer to the variable that the file should read to and write
545 * from.
546 *
547 * This function creates a file in debugfs with the given name that
548 * contains the value of the variable @value. If the @mode variable is so
549 * set, it can be read from, and written to.
550 */
551void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
552 u64 *value)
553{
554 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
555 &fops_u64_ro, &fops_u64_wo);
556}
557EXPORT_SYMBOL_GPL(debugfs_create_u64);
558
559static int debugfs_ulong_set(void *data, u64 val)
560{
561 *(unsigned long *)data = val;
562 return 0;
563}
564
565static int debugfs_ulong_get(void *data, u64 *val)
566{
567 *val = *(unsigned long *)data;
568 return 0;
569}
570DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
571 "%llu\n");
572DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
573DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
574
575/**
576 * debugfs_create_ulong - create a debugfs file that is used to read and write
577 * an unsigned long value.
578 * @name: a pointer to a string containing the name of the file to create.
579 * @mode: the permission that the file should have
580 * @parent: a pointer to the parent dentry for this file. This should be a
581 * directory dentry if set. If this parameter is %NULL, then the
582 * file will be created in the root of the debugfs filesystem.
583 * @value: a pointer to the variable that the file should read to and write
584 * from.
585 *
586 * This function creates a file in debugfs with the given name that
587 * contains the value of the variable @value. If the @mode variable is so
588 * set, it can be read from, and written to.
589 */
590void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent,
591 unsigned long *value)
592{
593 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_ulong,
594 &fops_ulong_ro, &fops_ulong_wo);
595}
596EXPORT_SYMBOL_GPL(debugfs_create_ulong);
597
598DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
599DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
600DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
601
602DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
603 "0x%04llx\n");
604DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
605DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
606
607DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
608 "0x%08llx\n");
609DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
610DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
611
612DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
613 "0x%016llx\n");
614DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
615DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
616
617/*
618 * 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
619 *
620 * These functions are exactly the same as the above functions (but use a hex
621 * output for the decimal challenged). For details look at the above unsigned
622 * decimal functions.
623 */
624
625/**
626 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
627 * @name: a pointer to a string containing the name of the file to create.
628 * @mode: the permission that the file should have
629 * @parent: a pointer to the parent dentry for this file. This should be a
630 * directory dentry if set. If this parameter is %NULL, then the
631 * file will be created in the root of the debugfs filesystem.
632 * @value: a pointer to the variable that the file should read to and write
633 * from.
634 */
635void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
636 u8 *value)
637{
638 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
639 &fops_x8_ro, &fops_x8_wo);
640}
641EXPORT_SYMBOL_GPL(debugfs_create_x8);
642
643/**
644 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
645 * @name: a pointer to a string containing the name of the file to create.
646 * @mode: the permission that the file should have
647 * @parent: a pointer to the parent dentry for this file. This should be a
648 * directory dentry if set. If this parameter is %NULL, then the
649 * file will be created in the root of the debugfs filesystem.
650 * @value: a pointer to the variable that the file should read to and write
651 * from.
652 */
653void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
654 u16 *value)
655{
656 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
657 &fops_x16_ro, &fops_x16_wo);
658}
659EXPORT_SYMBOL_GPL(debugfs_create_x16);
660
661/**
662 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
663 * @name: a pointer to a string containing the name of the file to create.
664 * @mode: the permission that the file should have
665 * @parent: a pointer to the parent dentry for this file. This should be a
666 * directory dentry if set. If this parameter is %NULL, then the
667 * file will be created in the root of the debugfs filesystem.
668 * @value: a pointer to the variable that the file should read to and write
669 * from.
670 */
671void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
672 u32 *value)
673{
674 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
675 &fops_x32_ro, &fops_x32_wo);
676}
677EXPORT_SYMBOL_GPL(debugfs_create_x32);
678
679/**
680 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
681 * @name: a pointer to a string containing the name of the file to create.
682 * @mode: the permission that the file should have
683 * @parent: a pointer to the parent dentry for this file. This should be a
684 * directory dentry if set. If this parameter is %NULL, then the
685 * file will be created in the root of the debugfs filesystem.
686 * @value: a pointer to the variable that the file should read to and write
687 * from.
688 */
689void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
690 u64 *value)
691{
692 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
693 &fops_x64_ro, &fops_x64_wo);
694}
695EXPORT_SYMBOL_GPL(debugfs_create_x64);
696
697
698static int debugfs_size_t_set(void *data, u64 val)
699{
700 *(size_t *)data = val;
701 return 0;
702}
703static int debugfs_size_t_get(void *data, u64 *val)
704{
705 *val = *(size_t *)data;
706 return 0;
707}
708DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
709 "%llu\n"); /* %llu and %zu are more or less the same */
710DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
711DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
712
713/**
714 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
715 * @name: a pointer to a string containing the name of the file to create.
716 * @mode: the permission that the file should have
717 * @parent: a pointer to the parent dentry for this file. This should be a
718 * directory dentry if set. If this parameter is %NULL, then the
719 * file will be created in the root of the debugfs filesystem.
720 * @value: a pointer to the variable that the file should read to and write
721 * from.
722 */
723void debugfs_create_size_t(const char *name, umode_t mode,
724 struct dentry *parent, size_t *value)
725{
726 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t,
727 &fops_size_t_ro, &fops_size_t_wo);
728}
729EXPORT_SYMBOL_GPL(debugfs_create_size_t);
730
731static int debugfs_atomic_t_set(void *data, u64 val)
732{
733 atomic_set((atomic_t *)data, val);
734 return 0;
735}
736static int debugfs_atomic_t_get(void *data, u64 *val)
737{
738 *val = atomic_read((atomic_t *)data);
739 return 0;
740}
741DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
742 debugfs_atomic_t_set, "%lld\n");
743DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
744 "%lld\n");
745DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
746 "%lld\n");
747
748/**
749 * debugfs_create_atomic_t - create a debugfs file that is used to read and
750 * write an atomic_t value
751 * @name: a pointer to a string containing the name of the file to create.
752 * @mode: the permission that the file should have
753 * @parent: a pointer to the parent dentry for this file. This should be a
754 * directory dentry if set. If this parameter is %NULL, then the
755 * file will be created in the root of the debugfs filesystem.
756 * @value: a pointer to the variable that the file should read to and write
757 * from.
758 */
759void debugfs_create_atomic_t(const char *name, umode_t mode,
760 struct dentry *parent, atomic_t *value)
761{
762 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t,
763 &fops_atomic_t_ro, &fops_atomic_t_wo);
764}
765EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
766
767ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
768 size_t count, loff_t *ppos)
769{
770 char buf[2];
771 bool val;
772 int r;
773 struct dentry *dentry = F_DENTRY(file);
774
775 r = debugfs_file_get(dentry);
776 if (unlikely(r))
777 return r;
778 val = *(bool *)file->private_data;
779 debugfs_file_put(dentry);
780
781 if (val)
782 buf[0] = 'Y';
783 else
784 buf[0] = 'N';
785 buf[1] = '\n';
786 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
787}
788EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
789
790ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
791 size_t count, loff_t *ppos)
792{
793 bool bv;
794 int r;
795 bool *val = file->private_data;
796 struct dentry *dentry = F_DENTRY(file);
797
798 r = kstrtobool_from_user(user_buf, count, &bv);
799 if (!r) {
800 r = debugfs_file_get(dentry);
801 if (unlikely(r))
802 return r;
803 *val = bv;
804 debugfs_file_put(dentry);
805 }
806
807 return count;
808}
809EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
810
811static const struct file_operations fops_bool = {
812 .read = debugfs_read_file_bool,
813 .write = debugfs_write_file_bool,
814 .open = simple_open,
815 .llseek = default_llseek,
816};
817
818static const struct file_operations fops_bool_ro = {
819 .read = debugfs_read_file_bool,
820 .open = simple_open,
821 .llseek = default_llseek,
822};
823
824static const struct file_operations fops_bool_wo = {
825 .write = debugfs_write_file_bool,
826 .open = simple_open,
827 .llseek = default_llseek,
828};
829
830/**
831 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
832 * @name: a pointer to a string containing the name of the file to create.
833 * @mode: the permission that the file should have
834 * @parent: a pointer to the parent dentry for this file. This should be a
835 * directory dentry if set. If this parameter is %NULL, then the
836 * file will be created in the root of the debugfs filesystem.
837 * @value: a pointer to the variable that the file should read to and write
838 * from.
839 *
840 * This function creates a file in debugfs with the given name that
841 * contains the value of the variable @value. If the @mode variable is so
842 * set, it can be read from, and written to.
843 */
844void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent,
845 bool *value)
846{
847 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
848 &fops_bool_ro, &fops_bool_wo);
849}
850EXPORT_SYMBOL_GPL(debugfs_create_bool);
851
852ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
853 size_t count, loff_t *ppos)
854{
855 struct dentry *dentry = F_DENTRY(file);
856 char *str, *copy = NULL;
857 int copy_len, len;
858 ssize_t ret;
859
860 ret = debugfs_file_get(dentry);
861 if (unlikely(ret))
862 return ret;
863
864 str = *(char **)file->private_data;
865 len = strlen(str) + 1;
866 copy = kmalloc(len, GFP_KERNEL);
867 if (!copy) {
868 debugfs_file_put(dentry);
869 return -ENOMEM;
870 }
871
872 copy_len = strscpy(copy, str, len);
873 debugfs_file_put(dentry);
874 if (copy_len < 0) {
875 kfree(copy);
876 return copy_len;
877 }
878
879 copy[copy_len] = '\n';
880
881 ret = simple_read_from_buffer(user_buf, count, ppos, copy, len);
882 kfree(copy);
883
884 return ret;
885}
886
887static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
888 size_t count, loff_t *ppos)
889{
890 /* This is really only for read-only strings */
891 return -EINVAL;
892}
893
894static const struct file_operations fops_str = {
895 .read = debugfs_read_file_str,
896 .write = debugfs_write_file_str,
897 .open = simple_open,
898 .llseek = default_llseek,
899};
900
901static const struct file_operations fops_str_ro = {
902 .read = debugfs_read_file_str,
903 .open = simple_open,
904 .llseek = default_llseek,
905};
906
907static const struct file_operations fops_str_wo = {
908 .write = debugfs_write_file_str,
909 .open = simple_open,
910 .llseek = default_llseek,
911};
912
913/**
914 * debugfs_create_str - create a debugfs file that is used to read and write a string 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 *
923 * This function creates a file in debugfs with the given name that
924 * contains the value of the variable @value. If the @mode variable is so
925 * set, it can be read from, and written to.
926 *
927 * This function will return a pointer to a dentry if it succeeds. This
928 * pointer must be passed to the debugfs_remove() function when the file is
929 * to be removed (no automatic cleanup happens if your module is unloaded,
930 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
931 * returned.
932 *
933 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
934 * be returned.
935 */
936void debugfs_create_str(const char *name, umode_t mode,
937 struct dentry *parent, char **value)
938{
939 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_str,
940 &fops_str_ro, &fops_str_wo);
941}
942
943static ssize_t read_file_blob(struct file *file, char __user *user_buf,
944 size_t count, loff_t *ppos)
945{
946 struct debugfs_blob_wrapper *blob = file->private_data;
947 struct dentry *dentry = F_DENTRY(file);
948 ssize_t r;
949
950 r = debugfs_file_get(dentry);
951 if (unlikely(r))
952 return r;
953 r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
954 blob->size);
955 debugfs_file_put(dentry);
956 return r;
957}
958
959static const struct file_operations fops_blob = {
960 .read = read_file_blob,
961 .open = simple_open,
962 .llseek = default_llseek,
963};
964
965/**
966 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
967 * @name: a pointer to a string containing the name of the file to create.
968 * @mode: the read permission that the file should have (other permissions are
969 * masked out)
970 * @parent: a pointer to the parent dentry for this file. This should be a
971 * directory dentry if set. If this parameter is %NULL, then the
972 * file will be created in the root of the debugfs filesystem.
973 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
974 * to the blob data and the size of the data.
975 *
976 * This function creates a file in debugfs with the given name that exports
977 * @blob->data as a binary blob. If the @mode variable is so set it can be
978 * read from. Writing is not supported.
979 *
980 * This function will return a pointer to a dentry if it succeeds. This
981 * pointer must be passed to the debugfs_remove() function when the file is
982 * to be removed (no automatic cleanup happens if your module is unloaded,
983 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
984 * returned.
985 *
986 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
987 * be returned.
988 */
989struct dentry *debugfs_create_blob(const char *name, umode_t mode,
990 struct dentry *parent,
991 struct debugfs_blob_wrapper *blob)
992{
993 return debugfs_create_file_unsafe(name, mode & 0444, parent, blob, &fops_blob);
994}
995EXPORT_SYMBOL_GPL(debugfs_create_blob);
996
997static size_t u32_format_array(char *buf, size_t bufsize,
998 u32 *array, int array_size)
999{
1000 size_t ret = 0;
1001
1002 while (--array_size >= 0) {
1003 size_t len;
1004 char term = array_size ? ' ' : '\n';
1005
1006 len = snprintf(buf, bufsize, "%u%c", *array++, term);
1007 ret += len;
1008
1009 buf += len;
1010 bufsize -= len;
1011 }
1012 return ret;
1013}
1014
1015static int u32_array_open(struct inode *inode, struct file *file)
1016{
1017 struct debugfs_u32_array *data = inode->i_private;
1018 int size, elements = data->n_elements;
1019 char *buf;
1020
1021 /*
1022 * Max size:
1023 * - 10 digits + ' '/'\n' = 11 bytes per number
1024 * - terminating NUL character
1025 */
1026 size = elements*11;
1027 buf = kmalloc(size+1, GFP_KERNEL);
1028 if (!buf)
1029 return -ENOMEM;
1030 buf[size] = 0;
1031
1032 file->private_data = buf;
1033 u32_format_array(buf, size, data->array, data->n_elements);
1034
1035 return nonseekable_open(inode, file);
1036}
1037
1038static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
1039 loff_t *ppos)
1040{
1041 size_t size = strlen(file->private_data);
1042
1043 return simple_read_from_buffer(buf, len, ppos,
1044 file->private_data, size);
1045}
1046
1047static int u32_array_release(struct inode *inode, struct file *file)
1048{
1049 kfree(file->private_data);
1050
1051 return 0;
1052}
1053
1054static const struct file_operations u32_array_fops = {
1055 .owner = THIS_MODULE,
1056 .open = u32_array_open,
1057 .release = u32_array_release,
1058 .read = u32_array_read,
1059 .llseek = no_llseek,
1060};
1061
1062/**
1063 * debugfs_create_u32_array - create a debugfs file that is used to read u32
1064 * array.
1065 * @name: a pointer to a string containing the name of the file to create.
1066 * @mode: the permission that the file should have.
1067 * @parent: a pointer to the parent dentry for this file. This should be a
1068 * directory dentry if set. If this parameter is %NULL, then the
1069 * file will be created in the root of the debugfs filesystem.
1070 * @array: wrapper struct containing data pointer and size of the array.
1071 *
1072 * This function creates a file in debugfs with the given name that exports
1073 * @array as data. If the @mode variable is so set it can be read from.
1074 * Writing is not supported. Seek within the file is also not supported.
1075 * Once array is created its size can not be changed.
1076 */
1077void debugfs_create_u32_array(const char *name, umode_t mode,
1078 struct dentry *parent,
1079 struct debugfs_u32_array *array)
1080{
1081 debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_fops);
1082}
1083EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1084
1085#ifdef CONFIG_HAS_IOMEM
1086
1087/*
1088 * The regset32 stuff is used to print 32-bit registers using the
1089 * seq_file utilities. We offer printing a register set in an already-opened
1090 * sequential file or create a debugfs file that only prints a regset32.
1091 */
1092
1093/**
1094 * debugfs_print_regs32 - use seq_print to describe a set of registers
1095 * @s: the seq_file structure being used to generate output
1096 * @regs: an array if struct debugfs_reg32 structures
1097 * @nregs: the length of the above array
1098 * @base: the base address to be used in reading the registers
1099 * @prefix: a string to be prefixed to every output line
1100 *
1101 * This function outputs a text block describing the current values of
1102 * some 32-bit hardware registers. It is meant to be used within debugfs
1103 * files based on seq_file that need to show registers, intermixed with other
1104 * information. The prefix argument may be used to specify a leading string,
1105 * because some peripherals have several blocks of identical registers,
1106 * for example configuration of dma channels
1107 */
1108void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1109 int nregs, void __iomem *base, char *prefix)
1110{
1111 int i;
1112
1113 for (i = 0; i < nregs; i++, regs++) {
1114 if (prefix)
1115 seq_printf(s, "%s", prefix);
1116 seq_printf(s, "%s = 0x%08x\n", regs->name,
1117 readl(base + regs->offset));
1118 if (seq_has_overflowed(s))
1119 break;
1120 }
1121}
1122EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1123
1124static int debugfs_show_regset32(struct seq_file *s, void *data)
1125{
1126 struct debugfs_regset32 *regset = s->private;
1127
1128 if (regset->dev)
1129 pm_runtime_get_sync(regset->dev);
1130
1131 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1132
1133 if (regset->dev)
1134 pm_runtime_put(regset->dev);
1135
1136 return 0;
1137}
1138
1139static int debugfs_open_regset32(struct inode *inode, struct file *file)
1140{
1141 return single_open(file, debugfs_show_regset32, inode->i_private);
1142}
1143
1144static const struct file_operations fops_regset32 = {
1145 .open = debugfs_open_regset32,
1146 .read = seq_read,
1147 .llseek = seq_lseek,
1148 .release = single_release,
1149};
1150
1151/**
1152 * debugfs_create_regset32 - create a debugfs file that returns register values
1153 * @name: a pointer to a string containing the name of the file to create.
1154 * @mode: the permission that the file should have
1155 * @parent: a pointer to the parent dentry for this file. This should be a
1156 * directory dentry if set. If this parameter is %NULL, then the
1157 * file will be created in the root of the debugfs filesystem.
1158 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1159 * to an array of register definitions, the array size and the base
1160 * address where the register bank is to be found.
1161 *
1162 * This function creates a file in debugfs with the given name that reports
1163 * the names and values of a set of 32-bit registers. If the @mode variable
1164 * is so set it can be read from. Writing is not supported.
1165 */
1166void debugfs_create_regset32(const char *name, umode_t mode,
1167 struct dentry *parent,
1168 struct debugfs_regset32 *regset)
1169{
1170 debugfs_create_file(name, mode, parent, regset, &fops_regset32);
1171}
1172EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1173
1174#endif /* CONFIG_HAS_IOMEM */
1175
1176struct debugfs_devm_entry {
1177 int (*read)(struct seq_file *seq, void *data);
1178 struct device *dev;
1179};
1180
1181static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1182{
1183 struct debugfs_devm_entry *entry = inode->i_private;
1184
1185 return single_open(f, entry->read, entry->dev);
1186}
1187
1188static const struct file_operations debugfs_devm_entry_ops = {
1189 .owner = THIS_MODULE,
1190 .open = debugfs_devm_entry_open,
1191 .release = single_release,
1192 .read = seq_read,
1193 .llseek = seq_lseek
1194};
1195
1196/**
1197 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1198 *
1199 * @dev: device related to this debugfs file.
1200 * @name: name of the debugfs file.
1201 * @parent: a pointer to the parent dentry for this file. This should be a
1202 * directory dentry if set. If this parameter is %NULL, then the
1203 * file will be created in the root of the debugfs filesystem.
1204 * @read_fn: function pointer called to print the seq_file content.
1205 */
1206void debugfs_create_devm_seqfile(struct device *dev, const char *name,
1207 struct dentry *parent,
1208 int (*read_fn)(struct seq_file *s, void *data))
1209{
1210 struct debugfs_devm_entry *entry;
1211
1212 if (IS_ERR(parent))
1213 return;
1214
1215 entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
1216 if (!entry)
1217 return;
1218
1219 entry->read = read_fn;
1220 entry->dev = dev;
1221
1222 debugfs_create_file(name, S_IRUGO, parent, entry,
1223 &debugfs_devm_entry_ops);
1224}
1225EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);
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
50const struct file_operations *debugfs_real_fops(const struct file *filp)
51{
52 struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
53
54 if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
55 /*
56 * Urgh, we've been called w/o a protecting
57 * debugfs_file_get().
58 */
59 WARN_ON(1);
60 return NULL;
61 }
62
63 return fsd->real_fops;
64}
65EXPORT_SYMBOL_GPL(debugfs_real_fops);
66
67/**
68 * debugfs_file_get - mark the beginning of file data access
69 * @dentry: the dentry object whose data is being accessed.
70 *
71 * Up to a matching call to debugfs_file_put(), any successive call
72 * into the file removing functions debugfs_remove() and
73 * debugfs_remove_recursive() will block. Since associated private
74 * file data may only get freed after a successful return of any of
75 * the removal functions, you may safely access it after a successful
76 * call to debugfs_file_get() without worrying about lifetime issues.
77 *
78 * If -%EIO is returned, the file has already been removed and thus,
79 * it is not safe to access any of its data. If, on the other hand,
80 * it is allowed to access the file data, zero is returned.
81 */
82int debugfs_file_get(struct dentry *dentry)
83{
84 struct debugfs_fsdata *fsd;
85 void *d_fsd;
86
87 /*
88 * This could only happen if some debugfs user erroneously calls
89 * debugfs_file_get() on a dentry that isn't even a file, let
90 * them know about it.
91 */
92 if (WARN_ON(!d_is_reg(dentry)))
93 return -EINVAL;
94
95 d_fsd = READ_ONCE(dentry->d_fsdata);
96 if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
97 fsd = d_fsd;
98 } else {
99 fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
100 if (!fsd)
101 return -ENOMEM;
102
103 fsd->real_fops = (void *)((unsigned long)d_fsd &
104 ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
105 refcount_set(&fsd->active_users, 1);
106 init_completion(&fsd->active_users_drained);
107 INIT_LIST_HEAD(&fsd->cancellations);
108 mutex_init(&fsd->cancellations_mtx);
109
110 if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
111 mutex_destroy(&fsd->cancellations_mtx);
112 kfree(fsd);
113 fsd = READ_ONCE(dentry->d_fsdata);
114 }
115 }
116
117 /*
118 * In case of a successful cmpxchg() above, this check is
119 * strictly necessary and must follow it, see the comment in
120 * __debugfs_remove_file().
121 * OTOH, if the cmpxchg() hasn't been executed or wasn't
122 * successful, this serves the purpose of not starving
123 * removers.
124 */
125 if (d_unlinked(dentry))
126 return -EIO;
127
128 if (!refcount_inc_not_zero(&fsd->active_users))
129 return -EIO;
130
131 return 0;
132}
133EXPORT_SYMBOL_GPL(debugfs_file_get);
134
135/**
136 * debugfs_file_put - mark the end of file data access
137 * @dentry: the dentry object formerly passed to
138 * debugfs_file_get().
139 *
140 * Allow any ongoing concurrent call into debugfs_remove() or
141 * debugfs_remove_recursive() blocked by a former call to
142 * debugfs_file_get() to proceed and return to its caller.
143 */
144void debugfs_file_put(struct dentry *dentry)
145{
146 struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
147
148 if (refcount_dec_and_test(&fsd->active_users))
149 complete(&fsd->active_users_drained);
150}
151EXPORT_SYMBOL_GPL(debugfs_file_put);
152
153/**
154 * debugfs_enter_cancellation - enter a debugfs cancellation
155 * @file: the file being accessed
156 * @cancellation: the cancellation object, the cancel callback
157 * inside of it must be initialized
158 *
159 * When a debugfs file is removed it needs to wait for all active
160 * operations to complete. However, the operation itself may need
161 * to wait for hardware or completion of some asynchronous process
162 * or similar. As such, it may need to be cancelled to avoid long
163 * waits or even deadlocks.
164 *
165 * This function can be used inside a debugfs handler that may
166 * need to be cancelled. As soon as this function is called, the
167 * cancellation's 'cancel' callback may be called, at which point
168 * the caller should proceed to call debugfs_leave_cancellation()
169 * and leave the debugfs handler function as soon as possible.
170 * Note that the 'cancel' callback is only ever called in the
171 * context of some kind of debugfs_remove().
172 *
173 * This function must be paired with debugfs_leave_cancellation().
174 */
175void debugfs_enter_cancellation(struct file *file,
176 struct debugfs_cancellation *cancellation)
177{
178 struct debugfs_fsdata *fsd;
179 struct dentry *dentry = F_DENTRY(file);
180
181 INIT_LIST_HEAD(&cancellation->list);
182
183 if (WARN_ON(!d_is_reg(dentry)))
184 return;
185
186 if (WARN_ON(!cancellation->cancel))
187 return;
188
189 fsd = READ_ONCE(dentry->d_fsdata);
190 if (WARN_ON(!fsd ||
191 ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)))
192 return;
193
194 mutex_lock(&fsd->cancellations_mtx);
195 list_add(&cancellation->list, &fsd->cancellations);
196 mutex_unlock(&fsd->cancellations_mtx);
197
198 /* if we're already removing wake it up to cancel */
199 if (d_unlinked(dentry))
200 complete(&fsd->active_users_drained);
201}
202EXPORT_SYMBOL_GPL(debugfs_enter_cancellation);
203
204/**
205 * debugfs_leave_cancellation - leave cancellation section
206 * @file: the file being accessed
207 * @cancellation: the cancellation previously registered with
208 * debugfs_enter_cancellation()
209 *
210 * See the documentation of debugfs_enter_cancellation().
211 */
212void debugfs_leave_cancellation(struct file *file,
213 struct debugfs_cancellation *cancellation)
214{
215 struct debugfs_fsdata *fsd;
216 struct dentry *dentry = F_DENTRY(file);
217
218 if (WARN_ON(!d_is_reg(dentry)))
219 return;
220
221 fsd = READ_ONCE(dentry->d_fsdata);
222 if (WARN_ON(!fsd ||
223 ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)))
224 return;
225
226 mutex_lock(&fsd->cancellations_mtx);
227 if (!list_empty(&cancellation->list))
228 list_del(&cancellation->list);
229 mutex_unlock(&fsd->cancellations_mtx);
230}
231EXPORT_SYMBOL_GPL(debugfs_leave_cancellation);
232
233/*
234 * Only permit access to world-readable files when the kernel is locked down.
235 * We also need to exclude any file that has ways to write or alter it as root
236 * can bypass the permissions check.
237 */
238static int debugfs_locked_down(struct inode *inode,
239 struct file *filp,
240 const struct file_operations *real_fops)
241{
242 if ((inode->i_mode & 07777 & ~0444) == 0 &&
243 !(filp->f_mode & FMODE_WRITE) &&
244 !real_fops->unlocked_ioctl &&
245 !real_fops->compat_ioctl &&
246 !real_fops->mmap)
247 return 0;
248
249 if (security_locked_down(LOCKDOWN_DEBUGFS))
250 return -EPERM;
251
252 return 0;
253}
254
255static int open_proxy_open(struct inode *inode, struct file *filp)
256{
257 struct dentry *dentry = F_DENTRY(filp);
258 const struct file_operations *real_fops = NULL;
259 int r;
260
261 r = debugfs_file_get(dentry);
262 if (r)
263 return r == -EIO ? -ENOENT : r;
264
265 real_fops = debugfs_real_fops(filp);
266
267 r = debugfs_locked_down(inode, filp, real_fops);
268 if (r)
269 goto out;
270
271 if (!fops_get(real_fops)) {
272#ifdef CONFIG_MODULES
273 if (real_fops->owner &&
274 real_fops->owner->state == MODULE_STATE_GOING) {
275 r = -ENXIO;
276 goto out;
277 }
278#endif
279
280 /* Huh? Module did not clean up after itself at exit? */
281 WARN(1, "debugfs file owner did not clean up at exit: %pd",
282 dentry);
283 r = -ENXIO;
284 goto out;
285 }
286 replace_fops(filp, real_fops);
287
288 if (real_fops->open)
289 r = real_fops->open(inode, filp);
290
291out:
292 debugfs_file_put(dentry);
293 return r;
294}
295
296const struct file_operations debugfs_open_proxy_file_operations = {
297 .open = open_proxy_open,
298};
299
300#define PROTO(args...) args
301#define ARGS(args...) args
302
303#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
304static ret_type full_proxy_ ## name(proto) \
305{ \
306 struct dentry *dentry = F_DENTRY(filp); \
307 const struct file_operations *real_fops; \
308 ret_type r; \
309 \
310 r = debugfs_file_get(dentry); \
311 if (unlikely(r)) \
312 return r; \
313 real_fops = debugfs_real_fops(filp); \
314 r = real_fops->name(args); \
315 debugfs_file_put(dentry); \
316 return r; \
317}
318
319FULL_PROXY_FUNC(llseek, loff_t, filp,
320 PROTO(struct file *filp, loff_t offset, int whence),
321 ARGS(filp, offset, whence));
322
323FULL_PROXY_FUNC(read, ssize_t, filp,
324 PROTO(struct file *filp, char __user *buf, size_t size,
325 loff_t *ppos),
326 ARGS(filp, buf, size, ppos));
327
328FULL_PROXY_FUNC(write, ssize_t, filp,
329 PROTO(struct file *filp, const char __user *buf, size_t size,
330 loff_t *ppos),
331 ARGS(filp, buf, size, ppos));
332
333FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
334 PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
335 ARGS(filp, cmd, arg));
336
337static __poll_t full_proxy_poll(struct file *filp,
338 struct poll_table_struct *wait)
339{
340 struct dentry *dentry = F_DENTRY(filp);
341 __poll_t r = 0;
342 const struct file_operations *real_fops;
343
344 if (debugfs_file_get(dentry))
345 return EPOLLHUP;
346
347 real_fops = debugfs_real_fops(filp);
348 r = real_fops->poll(filp, wait);
349 debugfs_file_put(dentry);
350 return r;
351}
352
353static int full_proxy_release(struct inode *inode, struct file *filp)
354{
355 const struct dentry *dentry = F_DENTRY(filp);
356 const struct file_operations *real_fops = debugfs_real_fops(filp);
357 const struct file_operations *proxy_fops = filp->f_op;
358 int r = 0;
359
360 /*
361 * We must not protect this against removal races here: the
362 * original releaser should be called unconditionally in order
363 * not to leak any resources. Releasers must not assume that
364 * ->i_private is still being meaningful here.
365 */
366 if (real_fops->release)
367 r = real_fops->release(inode, filp);
368
369 replace_fops(filp, d_inode(dentry)->i_fop);
370 kfree(proxy_fops);
371 fops_put(real_fops);
372 return r;
373}
374
375static void __full_proxy_fops_init(struct file_operations *proxy_fops,
376 const struct file_operations *real_fops)
377{
378 proxy_fops->release = full_proxy_release;
379 if (real_fops->llseek)
380 proxy_fops->llseek = full_proxy_llseek;
381 if (real_fops->read)
382 proxy_fops->read = full_proxy_read;
383 if (real_fops->write)
384 proxy_fops->write = full_proxy_write;
385 if (real_fops->poll)
386 proxy_fops->poll = full_proxy_poll;
387 if (real_fops->unlocked_ioctl)
388 proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
389}
390
391static int full_proxy_open(struct inode *inode, struct file *filp)
392{
393 struct dentry *dentry = F_DENTRY(filp);
394 const struct file_operations *real_fops = NULL;
395 struct file_operations *proxy_fops = NULL;
396 int r;
397
398 r = debugfs_file_get(dentry);
399 if (r)
400 return r == -EIO ? -ENOENT : r;
401
402 real_fops = debugfs_real_fops(filp);
403
404 r = debugfs_locked_down(inode, filp, real_fops);
405 if (r)
406 goto out;
407
408 if (!fops_get(real_fops)) {
409#ifdef CONFIG_MODULES
410 if (real_fops->owner &&
411 real_fops->owner->state == MODULE_STATE_GOING) {
412 r = -ENXIO;
413 goto out;
414 }
415#endif
416
417 /* Huh? Module did not cleanup after itself at exit? */
418 WARN(1, "debugfs file owner did not clean up at exit: %pd",
419 dentry);
420 r = -ENXIO;
421 goto out;
422 }
423
424 proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
425 if (!proxy_fops) {
426 r = -ENOMEM;
427 goto free_proxy;
428 }
429 __full_proxy_fops_init(proxy_fops, real_fops);
430 replace_fops(filp, proxy_fops);
431
432 if (real_fops->open) {
433 r = real_fops->open(inode, filp);
434 if (r) {
435 replace_fops(filp, d_inode(dentry)->i_fop);
436 goto free_proxy;
437 } else if (filp->f_op != proxy_fops) {
438 /* No protection against file removal anymore. */
439 WARN(1, "debugfs file owner replaced proxy fops: %pd",
440 dentry);
441 goto free_proxy;
442 }
443 }
444
445 goto out;
446free_proxy:
447 kfree(proxy_fops);
448 fops_put(real_fops);
449out:
450 debugfs_file_put(dentry);
451 return r;
452}
453
454const struct file_operations debugfs_full_proxy_file_operations = {
455 .open = full_proxy_open,
456};
457
458ssize_t debugfs_attr_read(struct file *file, char __user *buf,
459 size_t len, loff_t *ppos)
460{
461 struct dentry *dentry = F_DENTRY(file);
462 ssize_t ret;
463
464 ret = debugfs_file_get(dentry);
465 if (unlikely(ret))
466 return ret;
467 ret = simple_attr_read(file, buf, len, ppos);
468 debugfs_file_put(dentry);
469 return ret;
470}
471EXPORT_SYMBOL_GPL(debugfs_attr_read);
472
473static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf,
474 size_t len, loff_t *ppos, bool is_signed)
475{
476 struct dentry *dentry = F_DENTRY(file);
477 ssize_t ret;
478
479 ret = debugfs_file_get(dentry);
480 if (unlikely(ret))
481 return ret;
482 if (is_signed)
483 ret = simple_attr_write_signed(file, buf, len, ppos);
484 else
485 ret = simple_attr_write(file, buf, len, ppos);
486 debugfs_file_put(dentry);
487 return ret;
488}
489
490ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
491 size_t len, loff_t *ppos)
492{
493 return debugfs_attr_write_xsigned(file, buf, len, ppos, false);
494}
495EXPORT_SYMBOL_GPL(debugfs_attr_write);
496
497ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf,
498 size_t len, loff_t *ppos)
499{
500 return debugfs_attr_write_xsigned(file, buf, len, ppos, true);
501}
502EXPORT_SYMBOL_GPL(debugfs_attr_write_signed);
503
504static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
505 struct dentry *parent, void *value,
506 const struct file_operations *fops,
507 const struct file_operations *fops_ro,
508 const struct file_operations *fops_wo)
509{
510 /* if there are no write bits set, make read only */
511 if (!(mode & S_IWUGO))
512 return debugfs_create_file_unsafe(name, mode, parent, value,
513 fops_ro);
514 /* if there are no read bits set, make write only */
515 if (!(mode & S_IRUGO))
516 return debugfs_create_file_unsafe(name, mode, parent, value,
517 fops_wo);
518
519 return debugfs_create_file_unsafe(name, mode, parent, value, fops);
520}
521
522static int debugfs_u8_set(void *data, u64 val)
523{
524 *(u8 *)data = val;
525 return 0;
526}
527static int debugfs_u8_get(void *data, u64 *val)
528{
529 *val = *(u8 *)data;
530 return 0;
531}
532DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
533DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
534DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
535
536/**
537 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
538 * @name: a pointer to a string containing the name of the file to create.
539 * @mode: the permission that the file should have
540 * @parent: a pointer to the parent dentry for this file. This should be a
541 * directory dentry if set. If this parameter is %NULL, then the
542 * file will be created in the root of the debugfs filesystem.
543 * @value: a pointer to the variable that the file should read to and write
544 * from.
545 *
546 * This function creates a file in debugfs with the given name that
547 * contains the value of the variable @value. If the @mode variable is so
548 * set, it can be read from, and written to.
549 */
550void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
551 u8 *value)
552{
553 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
554 &fops_u8_ro, &fops_u8_wo);
555}
556EXPORT_SYMBOL_GPL(debugfs_create_u8);
557
558static int debugfs_u16_set(void *data, u64 val)
559{
560 *(u16 *)data = val;
561 return 0;
562}
563static int debugfs_u16_get(void *data, u64 *val)
564{
565 *val = *(u16 *)data;
566 return 0;
567}
568DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
569DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
570DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
571
572/**
573 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
574 * @name: a pointer to a string containing the name of the file to create.
575 * @mode: the permission that the file should have
576 * @parent: a pointer to the parent dentry for this file. This should be a
577 * directory dentry if set. If this parameter is %NULL, then the
578 * file will be created in the root of the debugfs filesystem.
579 * @value: a pointer to the variable that the file should read to and write
580 * from.
581 *
582 * This function creates a file in debugfs with the given name that
583 * contains the value of the variable @value. If the @mode variable is so
584 * set, it can be read from, and written to.
585 */
586void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
587 u16 *value)
588{
589 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
590 &fops_u16_ro, &fops_u16_wo);
591}
592EXPORT_SYMBOL_GPL(debugfs_create_u16);
593
594static int debugfs_u32_set(void *data, u64 val)
595{
596 *(u32 *)data = val;
597 return 0;
598}
599static int debugfs_u32_get(void *data, u64 *val)
600{
601 *val = *(u32 *)data;
602 return 0;
603}
604DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
605DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
606DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
607
608/**
609 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
610 * @name: a pointer to a string containing the name of the file to create.
611 * @mode: the permission that the file should have
612 * @parent: a pointer to the parent dentry for this file. This should be a
613 * directory dentry if set. If this parameter is %NULL, then the
614 * file will be created in the root of the debugfs filesystem.
615 * @value: a pointer to the variable that the file should read to and write
616 * from.
617 *
618 * This function creates a file in debugfs with the given name that
619 * contains the value of the variable @value. If the @mode variable is so
620 * set, it can be read from, and written to.
621 */
622void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
623 u32 *value)
624{
625 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
626 &fops_u32_ro, &fops_u32_wo);
627}
628EXPORT_SYMBOL_GPL(debugfs_create_u32);
629
630static int debugfs_u64_set(void *data, u64 val)
631{
632 *(u64 *)data = val;
633 return 0;
634}
635
636static int debugfs_u64_get(void *data, u64 *val)
637{
638 *val = *(u64 *)data;
639 return 0;
640}
641DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
642DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
643DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
644
645/**
646 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
647 * @name: a pointer to a string containing the name of the file to create.
648 * @mode: the permission that the file should have
649 * @parent: a pointer to the parent dentry for this file. This should be a
650 * directory dentry if set. If this parameter is %NULL, then the
651 * file will be created in the root of the debugfs filesystem.
652 * @value: a pointer to the variable that the file should read to and write
653 * from.
654 *
655 * This function creates a file in debugfs with the given name that
656 * contains the value of the variable @value. If the @mode variable is so
657 * set, it can be read from, and written to.
658 */
659void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
660 u64 *value)
661{
662 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
663 &fops_u64_ro, &fops_u64_wo);
664}
665EXPORT_SYMBOL_GPL(debugfs_create_u64);
666
667static int debugfs_ulong_set(void *data, u64 val)
668{
669 *(unsigned long *)data = val;
670 return 0;
671}
672
673static int debugfs_ulong_get(void *data, u64 *val)
674{
675 *val = *(unsigned long *)data;
676 return 0;
677}
678DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
679 "%llu\n");
680DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
681DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
682
683/**
684 * debugfs_create_ulong - create a debugfs file that is used to read and write
685 * an unsigned long value.
686 * @name: a pointer to a string containing the name of the file to create.
687 * @mode: the permission that the file should have
688 * @parent: a pointer to the parent dentry for this file. This should be a
689 * directory dentry if set. If this parameter is %NULL, then the
690 * file will be created in the root of the debugfs filesystem.
691 * @value: a pointer to the variable that the file should read to and write
692 * from.
693 *
694 * This function creates a file in debugfs with the given name that
695 * contains the value of the variable @value. If the @mode variable is so
696 * set, it can be read from, and written to.
697 */
698void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent,
699 unsigned long *value)
700{
701 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_ulong,
702 &fops_ulong_ro, &fops_ulong_wo);
703}
704EXPORT_SYMBOL_GPL(debugfs_create_ulong);
705
706DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
707DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
708DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
709
710DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
711 "0x%04llx\n");
712DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
713DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
714
715DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
716 "0x%08llx\n");
717DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
718DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
719
720DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
721 "0x%016llx\n");
722DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
723DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
724
725/*
726 * 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
727 *
728 * These functions are exactly the same as the above functions (but use a hex
729 * output for the decimal challenged). For details look at the above unsigned
730 * decimal functions.
731 */
732
733/**
734 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
735 * @name: a pointer to a string containing the name of the file to create.
736 * @mode: the permission that the file should have
737 * @parent: a pointer to the parent dentry for this file. This should be a
738 * directory dentry if set. If this parameter is %NULL, then the
739 * file will be created in the root of the debugfs filesystem.
740 * @value: a pointer to the variable that the file should read to and write
741 * from.
742 */
743void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
744 u8 *value)
745{
746 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
747 &fops_x8_ro, &fops_x8_wo);
748}
749EXPORT_SYMBOL_GPL(debugfs_create_x8);
750
751/**
752 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
753 * @name: a pointer to a string containing the name of the file to create.
754 * @mode: the permission that the file should have
755 * @parent: a pointer to the parent dentry for this file. This should be a
756 * directory dentry if set. If this parameter is %NULL, then the
757 * file will be created in the root of the debugfs filesystem.
758 * @value: a pointer to the variable that the file should read to and write
759 * from.
760 */
761void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
762 u16 *value)
763{
764 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
765 &fops_x16_ro, &fops_x16_wo);
766}
767EXPORT_SYMBOL_GPL(debugfs_create_x16);
768
769/**
770 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
771 * @name: a pointer to a string containing the name of the file to create.
772 * @mode: the permission that the file should have
773 * @parent: a pointer to the parent dentry for this file. This should be a
774 * directory dentry if set. If this parameter is %NULL, then the
775 * file will be created in the root of the debugfs filesystem.
776 * @value: a pointer to the variable that the file should read to and write
777 * from.
778 */
779void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
780 u32 *value)
781{
782 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
783 &fops_x32_ro, &fops_x32_wo);
784}
785EXPORT_SYMBOL_GPL(debugfs_create_x32);
786
787/**
788 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
789 * @name: a pointer to a string containing the name of the file to create.
790 * @mode: the permission that the file should have
791 * @parent: a pointer to the parent dentry for this file. This should be a
792 * directory dentry if set. If this parameter is %NULL, then the
793 * file will be created in the root of the debugfs filesystem.
794 * @value: a pointer to the variable that the file should read to and write
795 * from.
796 */
797void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
798 u64 *value)
799{
800 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
801 &fops_x64_ro, &fops_x64_wo);
802}
803EXPORT_SYMBOL_GPL(debugfs_create_x64);
804
805
806static int debugfs_size_t_set(void *data, u64 val)
807{
808 *(size_t *)data = val;
809 return 0;
810}
811static int debugfs_size_t_get(void *data, u64 *val)
812{
813 *val = *(size_t *)data;
814 return 0;
815}
816DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
817 "%llu\n"); /* %llu and %zu are more or less the same */
818DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
819DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
820
821/**
822 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
823 * @name: a pointer to a string containing the name of the file to create.
824 * @mode: the permission that the file should have
825 * @parent: a pointer to the parent dentry for this file. This should be a
826 * directory dentry if set. If this parameter is %NULL, then the
827 * file will be created in the root of the debugfs filesystem.
828 * @value: a pointer to the variable that the file should read to and write
829 * from.
830 */
831void debugfs_create_size_t(const char *name, umode_t mode,
832 struct dentry *parent, size_t *value)
833{
834 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t,
835 &fops_size_t_ro, &fops_size_t_wo);
836}
837EXPORT_SYMBOL_GPL(debugfs_create_size_t);
838
839static int debugfs_atomic_t_set(void *data, u64 val)
840{
841 atomic_set((atomic_t *)data, val);
842 return 0;
843}
844static int debugfs_atomic_t_get(void *data, u64 *val)
845{
846 *val = atomic_read((atomic_t *)data);
847 return 0;
848}
849DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t, debugfs_atomic_t_get,
850 debugfs_atomic_t_set, "%lld\n");
851DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
852 "%lld\n");
853DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
854 "%lld\n");
855
856/**
857 * debugfs_create_atomic_t - create a debugfs file that is used to read and
858 * write an atomic_t value
859 * @name: a pointer to a string containing the name of the file to create.
860 * @mode: the permission that the file should have
861 * @parent: a pointer to the parent dentry for this file. This should be a
862 * directory dentry if set. If this parameter is %NULL, then the
863 * file will be created in the root of the debugfs filesystem.
864 * @value: a pointer to the variable that the file should read to and write
865 * from.
866 */
867void debugfs_create_atomic_t(const char *name, umode_t mode,
868 struct dentry *parent, atomic_t *value)
869{
870 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t,
871 &fops_atomic_t_ro, &fops_atomic_t_wo);
872}
873EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
874
875ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
876 size_t count, loff_t *ppos)
877{
878 char buf[2];
879 bool val;
880 int r;
881 struct dentry *dentry = F_DENTRY(file);
882
883 r = debugfs_file_get(dentry);
884 if (unlikely(r))
885 return r;
886 val = *(bool *)file->private_data;
887 debugfs_file_put(dentry);
888
889 if (val)
890 buf[0] = 'Y';
891 else
892 buf[0] = 'N';
893 buf[1] = '\n';
894 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
895}
896EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
897
898ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
899 size_t count, loff_t *ppos)
900{
901 bool bv;
902 int r;
903 bool *val = file->private_data;
904 struct dentry *dentry = F_DENTRY(file);
905
906 r = kstrtobool_from_user(user_buf, count, &bv);
907 if (!r) {
908 r = debugfs_file_get(dentry);
909 if (unlikely(r))
910 return r;
911 *val = bv;
912 debugfs_file_put(dentry);
913 }
914
915 return count;
916}
917EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
918
919static const struct file_operations fops_bool = {
920 .read = debugfs_read_file_bool,
921 .write = debugfs_write_file_bool,
922 .open = simple_open,
923 .llseek = default_llseek,
924};
925
926static const struct file_operations fops_bool_ro = {
927 .read = debugfs_read_file_bool,
928 .open = simple_open,
929 .llseek = default_llseek,
930};
931
932static const struct file_operations fops_bool_wo = {
933 .write = debugfs_write_file_bool,
934 .open = simple_open,
935 .llseek = default_llseek,
936};
937
938/**
939 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
940 * @name: a pointer to a string containing the name of the file to create.
941 * @mode: the permission that the file should have
942 * @parent: a pointer to the parent dentry for this file. This should be a
943 * directory dentry if set. If this parameter is %NULL, then the
944 * file will be created in the root of the debugfs filesystem.
945 * @value: a pointer to the variable that the file should read to and write
946 * from.
947 *
948 * This function creates a file in debugfs with the given name that
949 * contains the value of the variable @value. If the @mode variable is so
950 * set, it can be read from, and written to.
951 */
952void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent,
953 bool *value)
954{
955 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
956 &fops_bool_ro, &fops_bool_wo);
957}
958EXPORT_SYMBOL_GPL(debugfs_create_bool);
959
960ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
961 size_t count, loff_t *ppos)
962{
963 struct dentry *dentry = F_DENTRY(file);
964 char *str, *copy = NULL;
965 int copy_len, len;
966 ssize_t ret;
967
968 ret = debugfs_file_get(dentry);
969 if (unlikely(ret))
970 return ret;
971
972 str = *(char **)file->private_data;
973 len = strlen(str) + 1;
974 copy = kmalloc(len, GFP_KERNEL);
975 if (!copy) {
976 debugfs_file_put(dentry);
977 return -ENOMEM;
978 }
979
980 copy_len = strscpy(copy, str, len);
981 debugfs_file_put(dentry);
982 if (copy_len < 0) {
983 kfree(copy);
984 return copy_len;
985 }
986
987 copy[copy_len] = '\n';
988
989 ret = simple_read_from_buffer(user_buf, count, ppos, copy, len);
990 kfree(copy);
991
992 return ret;
993}
994EXPORT_SYMBOL_GPL(debugfs_create_str);
995
996static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
997 size_t count, loff_t *ppos)
998{
999 struct dentry *dentry = F_DENTRY(file);
1000 char *old, *new = NULL;
1001 int pos = *ppos;
1002 int r;
1003
1004 r = debugfs_file_get(dentry);
1005 if (unlikely(r))
1006 return r;
1007
1008 old = *(char **)file->private_data;
1009
1010 /* only allow strict concatenation */
1011 r = -EINVAL;
1012 if (pos && pos != strlen(old))
1013 goto error;
1014
1015 r = -E2BIG;
1016 if (pos + count + 1 > PAGE_SIZE)
1017 goto error;
1018
1019 r = -ENOMEM;
1020 new = kmalloc(pos + count + 1, GFP_KERNEL);
1021 if (!new)
1022 goto error;
1023
1024 if (pos)
1025 memcpy(new, old, pos);
1026
1027 r = -EFAULT;
1028 if (copy_from_user(new + pos, user_buf, count))
1029 goto error;
1030
1031 new[pos + count] = '\0';
1032 strim(new);
1033
1034 rcu_assign_pointer(*(char __rcu **)file->private_data, new);
1035 synchronize_rcu();
1036 kfree(old);
1037
1038 debugfs_file_put(dentry);
1039 return count;
1040
1041error:
1042 kfree(new);
1043 debugfs_file_put(dentry);
1044 return r;
1045}
1046
1047static const struct file_operations fops_str = {
1048 .read = debugfs_read_file_str,
1049 .write = debugfs_write_file_str,
1050 .open = simple_open,
1051 .llseek = default_llseek,
1052};
1053
1054static const struct file_operations fops_str_ro = {
1055 .read = debugfs_read_file_str,
1056 .open = simple_open,
1057 .llseek = default_llseek,
1058};
1059
1060static const struct file_operations fops_str_wo = {
1061 .write = debugfs_write_file_str,
1062 .open = simple_open,
1063 .llseek = default_llseek,
1064};
1065
1066/**
1067 * debugfs_create_str - create a debugfs file that is used to read and write a string value
1068 * @name: a pointer to a string containing the name of the file to create.
1069 * @mode: the permission that the file should have
1070 * @parent: a pointer to the parent dentry for this file. This should be a
1071 * directory dentry if set. If this parameter is %NULL, then the
1072 * file will be created in the root of the debugfs filesystem.
1073 * @value: a pointer to the variable that the file should read to and write
1074 * from.
1075 *
1076 * This function creates a file in debugfs with the given name that
1077 * contains the value of the variable @value. If the @mode variable is so
1078 * set, it can be read from, and written to.
1079 */
1080void debugfs_create_str(const char *name, umode_t mode,
1081 struct dentry *parent, char **value)
1082{
1083 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_str,
1084 &fops_str_ro, &fops_str_wo);
1085}
1086
1087static ssize_t read_file_blob(struct file *file, char __user *user_buf,
1088 size_t count, loff_t *ppos)
1089{
1090 struct debugfs_blob_wrapper *blob = file->private_data;
1091 struct dentry *dentry = F_DENTRY(file);
1092 ssize_t r;
1093
1094 r = debugfs_file_get(dentry);
1095 if (unlikely(r))
1096 return r;
1097 r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
1098 blob->size);
1099 debugfs_file_put(dentry);
1100 return r;
1101}
1102
1103static ssize_t write_file_blob(struct file *file, const char __user *user_buf,
1104 size_t count, loff_t *ppos)
1105{
1106 struct debugfs_blob_wrapper *blob = file->private_data;
1107 struct dentry *dentry = F_DENTRY(file);
1108 ssize_t r;
1109
1110 r = debugfs_file_get(dentry);
1111 if (unlikely(r))
1112 return r;
1113 r = simple_write_to_buffer(blob->data, blob->size, ppos, user_buf,
1114 count);
1115
1116 debugfs_file_put(dentry);
1117 return r;
1118}
1119
1120static const struct file_operations fops_blob = {
1121 .read = read_file_blob,
1122 .write = write_file_blob,
1123 .open = simple_open,
1124 .llseek = default_llseek,
1125};
1126
1127/**
1128 * debugfs_create_blob - create a debugfs file that is used to read and write
1129 * a binary blob
1130 * @name: a pointer to a string containing the name of the file to create.
1131 * @mode: the permission that the file should have
1132 * @parent: a pointer to the parent dentry for this file. This should be a
1133 * directory dentry if set. If this parameter is %NULL, then the
1134 * file will be created in the root of the debugfs filesystem.
1135 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
1136 * to the blob data and the size of the data.
1137 *
1138 * This function creates a file in debugfs with the given name that exports
1139 * @blob->data as a binary blob. If the @mode variable is so set it can be
1140 * read from and written to.
1141 *
1142 * This function will return a pointer to a dentry if it succeeds. This
1143 * pointer must be passed to the debugfs_remove() function when the file is
1144 * to be removed (no automatic cleanup happens if your module is unloaded,
1145 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
1146 * returned.
1147 *
1148 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
1149 * be returned.
1150 */
1151struct dentry *debugfs_create_blob(const char *name, umode_t mode,
1152 struct dentry *parent,
1153 struct debugfs_blob_wrapper *blob)
1154{
1155 return debugfs_create_file_unsafe(name, mode & 0644, parent, blob, &fops_blob);
1156}
1157EXPORT_SYMBOL_GPL(debugfs_create_blob);
1158
1159static size_t u32_format_array(char *buf, size_t bufsize,
1160 u32 *array, int array_size)
1161{
1162 size_t ret = 0;
1163
1164 while (--array_size >= 0) {
1165 size_t len;
1166 char term = array_size ? ' ' : '\n';
1167
1168 len = snprintf(buf, bufsize, "%u%c", *array++, term);
1169 ret += len;
1170
1171 buf += len;
1172 bufsize -= len;
1173 }
1174 return ret;
1175}
1176
1177static int u32_array_open(struct inode *inode, struct file *file)
1178{
1179 struct debugfs_u32_array *data = inode->i_private;
1180 int size, elements = data->n_elements;
1181 char *buf;
1182
1183 /*
1184 * Max size:
1185 * - 10 digits + ' '/'\n' = 11 bytes per number
1186 * - terminating NUL character
1187 */
1188 size = elements*11;
1189 buf = kmalloc(size+1, GFP_KERNEL);
1190 if (!buf)
1191 return -ENOMEM;
1192 buf[size] = 0;
1193
1194 file->private_data = buf;
1195 u32_format_array(buf, size, data->array, data->n_elements);
1196
1197 return nonseekable_open(inode, file);
1198}
1199
1200static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
1201 loff_t *ppos)
1202{
1203 size_t size = strlen(file->private_data);
1204
1205 return simple_read_from_buffer(buf, len, ppos,
1206 file->private_data, size);
1207}
1208
1209static int u32_array_release(struct inode *inode, struct file *file)
1210{
1211 kfree(file->private_data);
1212
1213 return 0;
1214}
1215
1216static const struct file_operations u32_array_fops = {
1217 .owner = THIS_MODULE,
1218 .open = u32_array_open,
1219 .release = u32_array_release,
1220 .read = u32_array_read,
1221 .llseek = no_llseek,
1222};
1223
1224/**
1225 * debugfs_create_u32_array - create a debugfs file that is used to read u32
1226 * array.
1227 * @name: a pointer to a string containing the name of the file to create.
1228 * @mode: the permission that the file should have.
1229 * @parent: a pointer to the parent dentry for this file. This should be a
1230 * directory dentry if set. If this parameter is %NULL, then the
1231 * file will be created in the root of the debugfs filesystem.
1232 * @array: wrapper struct containing data pointer and size of the array.
1233 *
1234 * This function creates a file in debugfs with the given name that exports
1235 * @array as data. If the @mode variable is so set it can be read from.
1236 * Writing is not supported. Seek within the file is also not supported.
1237 * Once array is created its size can not be changed.
1238 */
1239void debugfs_create_u32_array(const char *name, umode_t mode,
1240 struct dentry *parent,
1241 struct debugfs_u32_array *array)
1242{
1243 debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_fops);
1244}
1245EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1246
1247#ifdef CONFIG_HAS_IOMEM
1248
1249/*
1250 * The regset32 stuff is used to print 32-bit registers using the
1251 * seq_file utilities. We offer printing a register set in an already-opened
1252 * sequential file or create a debugfs file that only prints a regset32.
1253 */
1254
1255/**
1256 * debugfs_print_regs32 - use seq_print to describe a set of registers
1257 * @s: the seq_file structure being used to generate output
1258 * @regs: an array if struct debugfs_reg32 structures
1259 * @nregs: the length of the above array
1260 * @base: the base address to be used in reading the registers
1261 * @prefix: a string to be prefixed to every output line
1262 *
1263 * This function outputs a text block describing the current values of
1264 * some 32-bit hardware registers. It is meant to be used within debugfs
1265 * files based on seq_file that need to show registers, intermixed with other
1266 * information. The prefix argument may be used to specify a leading string,
1267 * because some peripherals have several blocks of identical registers,
1268 * for example configuration of dma channels
1269 */
1270void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1271 int nregs, void __iomem *base, char *prefix)
1272{
1273 int i;
1274
1275 for (i = 0; i < nregs; i++, regs++) {
1276 if (prefix)
1277 seq_printf(s, "%s", prefix);
1278 seq_printf(s, "%s = 0x%08x\n", regs->name,
1279 readl(base + regs->offset));
1280 if (seq_has_overflowed(s))
1281 break;
1282 }
1283}
1284EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1285
1286static int debugfs_regset32_show(struct seq_file *s, void *data)
1287{
1288 struct debugfs_regset32 *regset = s->private;
1289
1290 if (regset->dev)
1291 pm_runtime_get_sync(regset->dev);
1292
1293 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1294
1295 if (regset->dev)
1296 pm_runtime_put(regset->dev);
1297
1298 return 0;
1299}
1300
1301DEFINE_SHOW_ATTRIBUTE(debugfs_regset32);
1302
1303/**
1304 * debugfs_create_regset32 - create a debugfs file that returns register values
1305 * @name: a pointer to a string containing the name of the file to create.
1306 * @mode: the permission that the file should have
1307 * @parent: a pointer to the parent dentry for this file. This should be a
1308 * directory dentry if set. If this parameter is %NULL, then the
1309 * file will be created in the root of the debugfs filesystem.
1310 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1311 * to an array of register definitions, the array size and the base
1312 * address where the register bank is to be found.
1313 *
1314 * This function creates a file in debugfs with the given name that reports
1315 * the names and values of a set of 32-bit registers. If the @mode variable
1316 * is so set it can be read from. Writing is not supported.
1317 */
1318void debugfs_create_regset32(const char *name, umode_t mode,
1319 struct dentry *parent,
1320 struct debugfs_regset32 *regset)
1321{
1322 debugfs_create_file(name, mode, parent, regset, &debugfs_regset32_fops);
1323}
1324EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1325
1326#endif /* CONFIG_HAS_IOMEM */
1327
1328struct debugfs_devm_entry {
1329 int (*read)(struct seq_file *seq, void *data);
1330 struct device *dev;
1331};
1332
1333static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1334{
1335 struct debugfs_devm_entry *entry = inode->i_private;
1336
1337 return single_open(f, entry->read, entry->dev);
1338}
1339
1340static const struct file_operations debugfs_devm_entry_ops = {
1341 .owner = THIS_MODULE,
1342 .open = debugfs_devm_entry_open,
1343 .release = single_release,
1344 .read = seq_read,
1345 .llseek = seq_lseek
1346};
1347
1348/**
1349 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1350 *
1351 * @dev: device related to this debugfs file.
1352 * @name: name of the debugfs file.
1353 * @parent: a pointer to the parent dentry for this file. This should be a
1354 * directory dentry if set. If this parameter is %NULL, then the
1355 * file will be created in the root of the debugfs filesystem.
1356 * @read_fn: function pointer called to print the seq_file content.
1357 */
1358void debugfs_create_devm_seqfile(struct device *dev, const char *name,
1359 struct dentry *parent,
1360 int (*read_fn)(struct seq_file *s, void *data))
1361{
1362 struct debugfs_devm_entry *entry;
1363
1364 if (IS_ERR(parent))
1365 return;
1366
1367 entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
1368 if (!entry)
1369 return;
1370
1371 entry->read = read_fn;
1372 entry->dev = dev;
1373
1374 debugfs_create_file(name, S_IRUGO, parent, entry,
1375 &debugfs_devm_entry_ops);
1376}
1377EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);