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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/poll.h>
22#include <linux/security.h>
23
24#include "internal.h"
25
26struct poll_table_struct;
27
28static ssize_t default_read_file(struct file *file, char __user *buf,
29 size_t count, loff_t *ppos)
30{
31 return 0;
32}
33
34static ssize_t default_write_file(struct file *file, const char __user *buf,
35 size_t count, loff_t *ppos)
36{
37 return count;
38}
39
40const struct file_operations debugfs_noop_file_operations = {
41 .read = default_read_file,
42 .write = default_write_file,
43 .open = simple_open,
44 .llseek = noop_llseek,
45};
46
47#define F_DENTRY(filp) ((filp)->f_path.dentry)
48
49const struct file_operations *debugfs_real_fops(const struct file *filp)
50{
51 struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
52
53 if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
54 /*
55 * Urgh, we've been called w/o a protecting
56 * debugfs_file_get().
57 */
58 WARN_ON(1);
59 return NULL;
60 }
61
62 return fsd->real_fops;
63}
64EXPORT_SYMBOL_GPL(debugfs_real_fops);
65
66/**
67 * debugfs_file_get - mark the beginning of file data access
68 * @dentry: the dentry object whose data is being accessed.
69 *
70 * Up to a matching call to debugfs_file_put(), any successive call
71 * into the file removing functions debugfs_remove() and
72 * debugfs_remove_recursive() will block. Since associated private
73 * file data may only get freed after a successful return of any of
74 * the removal functions, you may safely access it after a successful
75 * call to debugfs_file_get() without worrying about lifetime issues.
76 *
77 * If -%EIO is returned, the file has already been removed and thus,
78 * it is not safe to access any of its data. If, on the other hand,
79 * it is allowed to access the file data, zero is returned.
80 */
81int debugfs_file_get(struct dentry *dentry)
82{
83 struct debugfs_fsdata *fsd;
84 void *d_fsd;
85
86 d_fsd = READ_ONCE(dentry->d_fsdata);
87 if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
88 fsd = d_fsd;
89 } else {
90 fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
91 if (!fsd)
92 return -ENOMEM;
93
94 fsd->real_fops = (void *)((unsigned long)d_fsd &
95 ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
96 refcount_set(&fsd->active_users, 1);
97 init_completion(&fsd->active_users_drained);
98 if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
99 kfree(fsd);
100 fsd = READ_ONCE(dentry->d_fsdata);
101 }
102 }
103
104 /*
105 * In case of a successful cmpxchg() above, this check is
106 * strictly necessary and must follow it, see the comment in
107 * __debugfs_remove_file().
108 * OTOH, if the cmpxchg() hasn't been executed or wasn't
109 * successful, this serves the purpose of not starving
110 * removers.
111 */
112 if (d_unlinked(dentry))
113 return -EIO;
114
115 if (!refcount_inc_not_zero(&fsd->active_users))
116 return -EIO;
117
118 return 0;
119}
120EXPORT_SYMBOL_GPL(debugfs_file_get);
121
122/**
123 * debugfs_file_put - mark the end of file data access
124 * @dentry: the dentry object formerly passed to
125 * debugfs_file_get().
126 *
127 * Allow any ongoing concurrent call into debugfs_remove() or
128 * debugfs_remove_recursive() blocked by a former call to
129 * debugfs_file_get() to proceed and return to its caller.
130 */
131void debugfs_file_put(struct dentry *dentry)
132{
133 struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
134
135 if (refcount_dec_and_test(&fsd->active_users))
136 complete(&fsd->active_users_drained);
137}
138EXPORT_SYMBOL_GPL(debugfs_file_put);
139
140/*
141 * Only permit access to world-readable files when the kernel is locked down.
142 * We also need to exclude any file that has ways to write or alter it as root
143 * can bypass the permissions check.
144 */
145static bool debugfs_is_locked_down(struct inode *inode,
146 struct file *filp,
147 const struct file_operations *real_fops)
148{
149 if ((inode->i_mode & 07777) == 0444 &&
150 !(filp->f_mode & FMODE_WRITE) &&
151 !real_fops->unlocked_ioctl &&
152 !real_fops->compat_ioctl &&
153 !real_fops->mmap)
154 return false;
155
156 return security_locked_down(LOCKDOWN_DEBUGFS);
157}
158
159static int open_proxy_open(struct inode *inode, struct file *filp)
160{
161 struct dentry *dentry = F_DENTRY(filp);
162 const struct file_operations *real_fops = NULL;
163 int r;
164
165 r = debugfs_file_get(dentry);
166 if (r)
167 return r == -EIO ? -ENOENT : r;
168
169 real_fops = debugfs_real_fops(filp);
170
171 r = debugfs_is_locked_down(inode, filp, real_fops);
172 if (r)
173 goto out;
174
175 real_fops = fops_get(real_fops);
176 if (!real_fops) {
177 /* Huh? Module did not clean up after itself at exit? */
178 WARN(1, "debugfs file owner did not clean up at exit: %pd",
179 dentry);
180 r = -ENXIO;
181 goto out;
182 }
183 replace_fops(filp, real_fops);
184
185 if (real_fops->open)
186 r = real_fops->open(inode, filp);
187
188out:
189 debugfs_file_put(dentry);
190 return r;
191}
192
193const struct file_operations debugfs_open_proxy_file_operations = {
194 .open = open_proxy_open,
195};
196
197#define PROTO(args...) args
198#define ARGS(args...) args
199
200#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
201static ret_type full_proxy_ ## name(proto) \
202{ \
203 struct dentry *dentry = F_DENTRY(filp); \
204 const struct file_operations *real_fops; \
205 ret_type r; \
206 \
207 r = debugfs_file_get(dentry); \
208 if (unlikely(r)) \
209 return r; \
210 real_fops = debugfs_real_fops(filp); \
211 r = real_fops->name(args); \
212 debugfs_file_put(dentry); \
213 return r; \
214}
215
216FULL_PROXY_FUNC(llseek, loff_t, filp,
217 PROTO(struct file *filp, loff_t offset, int whence),
218 ARGS(filp, offset, whence));
219
220FULL_PROXY_FUNC(read, ssize_t, filp,
221 PROTO(struct file *filp, char __user *buf, size_t size,
222 loff_t *ppos),
223 ARGS(filp, buf, size, ppos));
224
225FULL_PROXY_FUNC(write, ssize_t, filp,
226 PROTO(struct file *filp, const char __user *buf, size_t size,
227 loff_t *ppos),
228 ARGS(filp, buf, size, ppos));
229
230FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
231 PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
232 ARGS(filp, cmd, arg));
233
234static __poll_t full_proxy_poll(struct file *filp,
235 struct poll_table_struct *wait)
236{
237 struct dentry *dentry = F_DENTRY(filp);
238 __poll_t r = 0;
239 const struct file_operations *real_fops;
240
241 if (debugfs_file_get(dentry))
242 return EPOLLHUP;
243
244 real_fops = debugfs_real_fops(filp);
245 r = real_fops->poll(filp, wait);
246 debugfs_file_put(dentry);
247 return r;
248}
249
250static int full_proxy_release(struct inode *inode, struct file *filp)
251{
252 const struct dentry *dentry = F_DENTRY(filp);
253 const struct file_operations *real_fops = debugfs_real_fops(filp);
254 const struct file_operations *proxy_fops = filp->f_op;
255 int r = 0;
256
257 /*
258 * We must not protect this against removal races here: the
259 * original releaser should be called unconditionally in order
260 * not to leak any resources. Releasers must not assume that
261 * ->i_private is still being meaningful here.
262 */
263 if (real_fops->release)
264 r = real_fops->release(inode, filp);
265
266 replace_fops(filp, d_inode(dentry)->i_fop);
267 kfree((void *)proxy_fops);
268 fops_put(real_fops);
269 return r;
270}
271
272static void __full_proxy_fops_init(struct file_operations *proxy_fops,
273 const struct file_operations *real_fops)
274{
275 proxy_fops->release = full_proxy_release;
276 if (real_fops->llseek)
277 proxy_fops->llseek = full_proxy_llseek;
278 if (real_fops->read)
279 proxy_fops->read = full_proxy_read;
280 if (real_fops->write)
281 proxy_fops->write = full_proxy_write;
282 if (real_fops->poll)
283 proxy_fops->poll = full_proxy_poll;
284 if (real_fops->unlocked_ioctl)
285 proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
286}
287
288static int full_proxy_open(struct inode *inode, struct file *filp)
289{
290 struct dentry *dentry = F_DENTRY(filp);
291 const struct file_operations *real_fops = NULL;
292 struct file_operations *proxy_fops = NULL;
293 int r;
294
295 r = debugfs_file_get(dentry);
296 if (r)
297 return r == -EIO ? -ENOENT : r;
298
299 real_fops = debugfs_real_fops(filp);
300
301 r = debugfs_is_locked_down(inode, filp, real_fops);
302 if (r)
303 goto out;
304
305 real_fops = fops_get(real_fops);
306 if (!real_fops) {
307 /* Huh? Module did not cleanup after itself at exit? */
308 WARN(1, "debugfs file owner did not clean up at exit: %pd",
309 dentry);
310 r = -ENXIO;
311 goto out;
312 }
313
314 proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
315 if (!proxy_fops) {
316 r = -ENOMEM;
317 goto free_proxy;
318 }
319 __full_proxy_fops_init(proxy_fops, real_fops);
320 replace_fops(filp, proxy_fops);
321
322 if (real_fops->open) {
323 r = real_fops->open(inode, filp);
324 if (r) {
325 replace_fops(filp, d_inode(dentry)->i_fop);
326 goto free_proxy;
327 } else if (filp->f_op != proxy_fops) {
328 /* No protection against file removal anymore. */
329 WARN(1, "debugfs file owner replaced proxy fops: %pd",
330 dentry);
331 goto free_proxy;
332 }
333 }
334
335 goto out;
336free_proxy:
337 kfree(proxy_fops);
338 fops_put(real_fops);
339out:
340 debugfs_file_put(dentry);
341 return r;
342}
343
344const struct file_operations debugfs_full_proxy_file_operations = {
345 .open = full_proxy_open,
346};
347
348ssize_t debugfs_attr_read(struct file *file, char __user *buf,
349 size_t len, loff_t *ppos)
350{
351 struct dentry *dentry = F_DENTRY(file);
352 ssize_t ret;
353
354 ret = debugfs_file_get(dentry);
355 if (unlikely(ret))
356 return ret;
357 ret = simple_attr_read(file, buf, len, ppos);
358 debugfs_file_put(dentry);
359 return ret;
360}
361EXPORT_SYMBOL_GPL(debugfs_attr_read);
362
363ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
364 size_t len, loff_t *ppos)
365{
366 struct dentry *dentry = F_DENTRY(file);
367 ssize_t ret;
368
369 ret = debugfs_file_get(dentry);
370 if (unlikely(ret))
371 return ret;
372 ret = simple_attr_write(file, buf, len, ppos);
373 debugfs_file_put(dentry);
374 return ret;
375}
376EXPORT_SYMBOL_GPL(debugfs_attr_write);
377
378static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
379 struct dentry *parent, void *value,
380 const struct file_operations *fops,
381 const struct file_operations *fops_ro,
382 const struct file_operations *fops_wo)
383{
384 /* if there are no write bits set, make read only */
385 if (!(mode & S_IWUGO))
386 return debugfs_create_file_unsafe(name, mode, parent, value,
387 fops_ro);
388 /* if there are no read bits set, make write only */
389 if (!(mode & S_IRUGO))
390 return debugfs_create_file_unsafe(name, mode, parent, value,
391 fops_wo);
392
393 return debugfs_create_file_unsafe(name, mode, parent, value, fops);
394}
395
396static int debugfs_u8_set(void *data, u64 val)
397{
398 *(u8 *)data = val;
399 return 0;
400}
401static int debugfs_u8_get(void *data, u64 *val)
402{
403 *val = *(u8 *)data;
404 return 0;
405}
406DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
407DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
408DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
409
410/**
411 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
412 * @name: a pointer to a string containing the name of the file to create.
413 * @mode: the permission that the file should have
414 * @parent: a pointer to the parent dentry for this file. This should be a
415 * directory dentry if set. If this parameter is %NULL, then the
416 * file will be created in the root of the debugfs filesystem.
417 * @value: a pointer to the variable that the file should read to and write
418 * from.
419 *
420 * This function creates a file in debugfs with the given name that
421 * contains the value of the variable @value. If the @mode variable is so
422 * set, it can be read from, and written to.
423 *
424 * This function will return a pointer to a dentry if it succeeds. This
425 * pointer must be passed to the debugfs_remove() function when the file is
426 * to be removed (no automatic cleanup happens if your module is unloaded,
427 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
428 * returned.
429 *
430 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
431 * be returned.
432 */
433struct dentry *debugfs_create_u8(const char *name, umode_t mode,
434 struct dentry *parent, u8 *value)
435{
436 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
437 &fops_u8_ro, &fops_u8_wo);
438}
439EXPORT_SYMBOL_GPL(debugfs_create_u8);
440
441static int debugfs_u16_set(void *data, u64 val)
442{
443 *(u16 *)data = val;
444 return 0;
445}
446static int debugfs_u16_get(void *data, u64 *val)
447{
448 *val = *(u16 *)data;
449 return 0;
450}
451DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
452DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
453DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
454
455/**
456 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
457 * @name: a pointer to a string containing the name of the file to create.
458 * @mode: the permission that the file should have
459 * @parent: a pointer to the parent dentry for this file. This should be a
460 * directory dentry if set. If this parameter is %NULL, then the
461 * file will be created in the root of the debugfs filesystem.
462 * @value: a pointer to the variable that the file should read to and write
463 * from.
464 *
465 * This function creates a file in debugfs with the given name that
466 * contains the value of the variable @value. If the @mode variable is so
467 * set, it can be read from, and written to.
468 *
469 * This function will return a pointer to a dentry if it succeeds. This
470 * pointer must be passed to the debugfs_remove() function when the file is
471 * to be removed (no automatic cleanup happens if your module is unloaded,
472 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
473 * returned.
474 *
475 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
476 * be returned.
477 */
478struct dentry *debugfs_create_u16(const char *name, umode_t mode,
479 struct dentry *parent, u16 *value)
480{
481 return 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 *
514 * This function will return a pointer to a dentry if it succeeds. This
515 * pointer must be passed to the debugfs_remove() function when the file is
516 * to be removed (no automatic cleanup happens if your module is unloaded,
517 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
518 * returned.
519 *
520 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
521 * be returned.
522 */
523struct dentry *debugfs_create_u32(const char *name, umode_t mode,
524 struct dentry *parent, u32 *value)
525{
526 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
527 &fops_u32_ro, &fops_u32_wo);
528}
529EXPORT_SYMBOL_GPL(debugfs_create_u32);
530
531static int debugfs_u64_set(void *data, u64 val)
532{
533 *(u64 *)data = val;
534 return 0;
535}
536
537static int debugfs_u64_get(void *data, u64 *val)
538{
539 *val = *(u64 *)data;
540 return 0;
541}
542DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
543DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
544DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
545
546/**
547 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
548 * @name: a pointer to a string containing the name of the file to create.
549 * @mode: the permission that the file should have
550 * @parent: a pointer to the parent dentry for this file. This should be a
551 * directory dentry if set. If this parameter is %NULL, then the
552 * file will be created in the root of the debugfs filesystem.
553 * @value: a pointer to the variable that the file should read to and write
554 * from.
555 *
556 * This function creates a file in debugfs with the given name that
557 * contains the value of the variable @value. If the @mode variable is so
558 * set, it can be read from, and written to.
559 *
560 * This function will return a pointer to a dentry if it succeeds. This
561 * pointer must be passed to the debugfs_remove() function when the file is
562 * to be removed (no automatic cleanup happens if your module is unloaded,
563 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
564 * returned.
565 *
566 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
567 * be returned.
568 */
569struct dentry *debugfs_create_u64(const char *name, umode_t mode,
570 struct dentry *parent, u64 *value)
571{
572 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
573 &fops_u64_ro, &fops_u64_wo);
574}
575EXPORT_SYMBOL_GPL(debugfs_create_u64);
576
577static int debugfs_ulong_set(void *data, u64 val)
578{
579 *(unsigned long *)data = val;
580 return 0;
581}
582
583static int debugfs_ulong_get(void *data, u64 *val)
584{
585 *val = *(unsigned long *)data;
586 return 0;
587}
588DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
589 "%llu\n");
590DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
591DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
592
593/**
594 * debugfs_create_ulong - create a debugfs file that is used to read and write
595 * an unsigned long value.
596 * @name: a pointer to a string containing the name of the file to create.
597 * @mode: the permission that the file should have
598 * @parent: a pointer to the parent dentry for this file. This should be a
599 * directory dentry if set. If this parameter is %NULL, then the
600 * file will be created in the root of the debugfs filesystem.
601 * @value: a pointer to the variable that the file should read to and write
602 * from.
603 *
604 * This function creates a file in debugfs with the given name that
605 * contains the value of the variable @value. If the @mode variable is so
606 * set, it can be read from, and written to.
607 *
608 * This function will return a pointer to a dentry if it succeeds. This
609 * pointer must be passed to the debugfs_remove() function when the file is
610 * to be removed (no automatic cleanup happens if your module is unloaded,
611 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
612 * returned.
613 *
614 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
615 * be returned.
616 */
617struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
618 struct dentry *parent, unsigned long *value)
619{
620 return debugfs_create_mode_unsafe(name, mode, parent, value,
621 &fops_ulong, &fops_ulong_ro,
622 &fops_ulong_wo);
623}
624EXPORT_SYMBOL_GPL(debugfs_create_ulong);
625
626DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
627DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
628DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
629
630DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
631 "0x%04llx\n");
632DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
633DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
634
635DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
636 "0x%08llx\n");
637DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
638DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
639
640DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
641 "0x%016llx\n");
642DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
643DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
644
645/*
646 * 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
647 *
648 * These functions are exactly the same as the above functions (but use a hex
649 * output for the decimal challenged). For details look at the above unsigned
650 * decimal functions.
651 */
652
653/**
654 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
655 * @name: a pointer to a string containing the name of the file to create.
656 * @mode: the permission that the file should have
657 * @parent: a pointer to the parent dentry for this file. This should be a
658 * directory dentry if set. If this parameter is %NULL, then the
659 * file will be created in the root of the debugfs filesystem.
660 * @value: a pointer to the variable that the file should read to and write
661 * from.
662 */
663struct dentry *debugfs_create_x8(const char *name, umode_t mode,
664 struct dentry *parent, u8 *value)
665{
666 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
667 &fops_x8_ro, &fops_x8_wo);
668}
669EXPORT_SYMBOL_GPL(debugfs_create_x8);
670
671/**
672 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
673 * @name: a pointer to a string containing the name of the file to create.
674 * @mode: the permission that the file should have
675 * @parent: a pointer to the parent dentry for this file. This should be a
676 * directory dentry if set. If this parameter is %NULL, then the
677 * file will be created in the root of the debugfs filesystem.
678 * @value: a pointer to the variable that the file should read to and write
679 * from.
680 */
681struct dentry *debugfs_create_x16(const char *name, umode_t mode,
682 struct dentry *parent, u16 *value)
683{
684 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
685 &fops_x16_ro, &fops_x16_wo);
686}
687EXPORT_SYMBOL_GPL(debugfs_create_x16);
688
689/**
690 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
691 * @name: a pointer to a string containing the name of the file to create.
692 * @mode: the permission that the file should have
693 * @parent: a pointer to the parent dentry for this file. This should be a
694 * directory dentry if set. If this parameter is %NULL, then the
695 * file will be created in the root of the debugfs filesystem.
696 * @value: a pointer to the variable that the file should read to and write
697 * from.
698 */
699struct dentry *debugfs_create_x32(const char *name, umode_t mode,
700 struct dentry *parent, u32 *value)
701{
702 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
703 &fops_x32_ro, &fops_x32_wo);
704}
705EXPORT_SYMBOL_GPL(debugfs_create_x32);
706
707/**
708 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
709 * @name: a pointer to a string containing the name of the file to create.
710 * @mode: the permission that the file should have
711 * @parent: a pointer to the parent dentry for this file. This should be a
712 * directory dentry if set. If this parameter is %NULL, then the
713 * file will be created in the root of the debugfs filesystem.
714 * @value: a pointer to the variable that the file should read to and write
715 * from.
716 */
717struct dentry *debugfs_create_x64(const char *name, umode_t mode,
718 struct dentry *parent, u64 *value)
719{
720 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
721 &fops_x64_ro, &fops_x64_wo);
722}
723EXPORT_SYMBOL_GPL(debugfs_create_x64);
724
725
726static int debugfs_size_t_set(void *data, u64 val)
727{
728 *(size_t *)data = val;
729 return 0;
730}
731static int debugfs_size_t_get(void *data, u64 *val)
732{
733 *val = *(size_t *)data;
734 return 0;
735}
736DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
737 "%llu\n"); /* %llu and %zu are more or less the same */
738DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
739DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
740
741/**
742 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
743 * @name: a pointer to a string containing the name of the file to create.
744 * @mode: the permission that the file should have
745 * @parent: a pointer to the parent dentry for this file. This should be a
746 * directory dentry if set. If this parameter is %NULL, then the
747 * file will be created in the root of the debugfs filesystem.
748 * @value: a pointer to the variable that the file should read to and write
749 * from.
750 */
751struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
752 struct dentry *parent, size_t *value)
753{
754 return debugfs_create_mode_unsafe(name, mode, parent, value,
755 &fops_size_t, &fops_size_t_ro,
756 &fops_size_t_wo);
757}
758EXPORT_SYMBOL_GPL(debugfs_create_size_t);
759
760static int debugfs_atomic_t_set(void *data, u64 val)
761{
762 atomic_set((atomic_t *)data, val);
763 return 0;
764}
765static int debugfs_atomic_t_get(void *data, u64 *val)
766{
767 *val = atomic_read((atomic_t *)data);
768 return 0;
769}
770DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
771 debugfs_atomic_t_set, "%lld\n");
772DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
773 "%lld\n");
774DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
775 "%lld\n");
776
777/**
778 * debugfs_create_atomic_t - create a debugfs file that is used to read and
779 * write an atomic_t value
780 * @name: a pointer to a string containing the name of the file to create.
781 * @mode: the permission that the file should have
782 * @parent: a pointer to the parent dentry for this file. This should be a
783 * directory dentry if set. If this parameter is %NULL, then the
784 * file will be created in the root of the debugfs filesystem.
785 * @value: a pointer to the variable that the file should read to and write
786 * from.
787 */
788struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
789 struct dentry *parent, atomic_t *value)
790{
791 return debugfs_create_mode_unsafe(name, mode, parent, value,
792 &fops_atomic_t, &fops_atomic_t_ro,
793 &fops_atomic_t_wo);
794}
795EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
796
797ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
798 size_t count, loff_t *ppos)
799{
800 char buf[3];
801 bool val;
802 int r;
803 struct dentry *dentry = F_DENTRY(file);
804
805 r = debugfs_file_get(dentry);
806 if (unlikely(r))
807 return r;
808 val = *(bool *)file->private_data;
809 debugfs_file_put(dentry);
810
811 if (val)
812 buf[0] = 'Y';
813 else
814 buf[0] = 'N';
815 buf[1] = '\n';
816 buf[2] = 0x00;
817 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
818}
819EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
820
821ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
822 size_t count, loff_t *ppos)
823{
824 bool bv;
825 int r;
826 bool *val = file->private_data;
827 struct dentry *dentry = F_DENTRY(file);
828
829 r = kstrtobool_from_user(user_buf, count, &bv);
830 if (!r) {
831 r = debugfs_file_get(dentry);
832 if (unlikely(r))
833 return r;
834 *val = bv;
835 debugfs_file_put(dentry);
836 }
837
838 return count;
839}
840EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
841
842static const struct file_operations fops_bool = {
843 .read = debugfs_read_file_bool,
844 .write = debugfs_write_file_bool,
845 .open = simple_open,
846 .llseek = default_llseek,
847};
848
849static const struct file_operations fops_bool_ro = {
850 .read = debugfs_read_file_bool,
851 .open = simple_open,
852 .llseek = default_llseek,
853};
854
855static const struct file_operations fops_bool_wo = {
856 .write = debugfs_write_file_bool,
857 .open = simple_open,
858 .llseek = default_llseek,
859};
860
861/**
862 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
863 * @name: a pointer to a string containing the name of the file to create.
864 * @mode: the permission that the file should have
865 * @parent: a pointer to the parent dentry for this file. This should be a
866 * directory dentry if set. If this parameter is %NULL, then the
867 * file will be created in the root of the debugfs filesystem.
868 * @value: a pointer to the variable that the file should read to and write
869 * from.
870 *
871 * This function creates a file in debugfs with the given name that
872 * contains the value of the variable @value. If the @mode variable is so
873 * set, it can be read from, and written to.
874 *
875 * This function will return a pointer to a dentry if it succeeds. This
876 * pointer must be passed to the debugfs_remove() function when the file is
877 * to be removed (no automatic cleanup happens if your module is unloaded,
878 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
879 * returned.
880 *
881 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
882 * be returned.
883 */
884struct dentry *debugfs_create_bool(const char *name, umode_t mode,
885 struct dentry *parent, bool *value)
886{
887 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
888 &fops_bool_ro, &fops_bool_wo);
889}
890EXPORT_SYMBOL_GPL(debugfs_create_bool);
891
892static ssize_t read_file_blob(struct file *file, char __user *user_buf,
893 size_t count, loff_t *ppos)
894{
895 struct debugfs_blob_wrapper *blob = file->private_data;
896 struct dentry *dentry = F_DENTRY(file);
897 ssize_t r;
898
899 r = debugfs_file_get(dentry);
900 if (unlikely(r))
901 return r;
902 r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
903 blob->size);
904 debugfs_file_put(dentry);
905 return r;
906}
907
908static const struct file_operations fops_blob = {
909 .read = read_file_blob,
910 .open = simple_open,
911 .llseek = default_llseek,
912};
913
914/**
915 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
916 * @name: a pointer to a string containing the name of the file to create.
917 * @mode: the permission that the file should have
918 * @parent: a pointer to the parent dentry for this file. This should be a
919 * directory dentry if set. If this parameter is %NULL, then the
920 * file will be created in the root of the debugfs filesystem.
921 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
922 * to the blob data and the size of the data.
923 *
924 * This function creates a file in debugfs with the given name that exports
925 * @blob->data as a binary blob. If the @mode variable is so set it can be
926 * read from. Writing is not supported.
927 *
928 * This function will return a pointer to a dentry if it succeeds. This
929 * pointer must be passed to the debugfs_remove() function when the file is
930 * to be removed (no automatic cleanup happens if your module is unloaded,
931 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
932 * returned.
933 *
934 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
935 * be returned.
936 */
937struct dentry *debugfs_create_blob(const char *name, umode_t mode,
938 struct dentry *parent,
939 struct debugfs_blob_wrapper *blob)
940{
941 return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob);
942}
943EXPORT_SYMBOL_GPL(debugfs_create_blob);
944
945struct array_data {
946 void *array;
947 u32 elements;
948};
949
950static size_t u32_format_array(char *buf, size_t bufsize,
951 u32 *array, int array_size)
952{
953 size_t ret = 0;
954
955 while (--array_size >= 0) {
956 size_t len;
957 char term = array_size ? ' ' : '\n';
958
959 len = snprintf(buf, bufsize, "%u%c", *array++, term);
960 ret += len;
961
962 buf += len;
963 bufsize -= len;
964 }
965 return ret;
966}
967
968static int u32_array_open(struct inode *inode, struct file *file)
969{
970 struct array_data *data = inode->i_private;
971 int size, elements = data->elements;
972 char *buf;
973
974 /*
975 * Max size:
976 * - 10 digits + ' '/'\n' = 11 bytes per number
977 * - terminating NUL character
978 */
979 size = elements*11;
980 buf = kmalloc(size+1, GFP_KERNEL);
981 if (!buf)
982 return -ENOMEM;
983 buf[size] = 0;
984
985 file->private_data = buf;
986 u32_format_array(buf, size, data->array, data->elements);
987
988 return nonseekable_open(inode, file);
989}
990
991static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
992 loff_t *ppos)
993{
994 size_t size = strlen(file->private_data);
995
996 return simple_read_from_buffer(buf, len, ppos,
997 file->private_data, size);
998}
999
1000static int u32_array_release(struct inode *inode, struct file *file)
1001{
1002 kfree(file->private_data);
1003
1004 return 0;
1005}
1006
1007static const struct file_operations u32_array_fops = {
1008 .owner = THIS_MODULE,
1009 .open = u32_array_open,
1010 .release = u32_array_release,
1011 .read = u32_array_read,
1012 .llseek = no_llseek,
1013};
1014
1015/**
1016 * debugfs_create_u32_array - create a debugfs file that is used to read u32
1017 * array.
1018 * @name: a pointer to a string containing the name of the file to create.
1019 * @mode: the permission that the file should have.
1020 * @parent: a pointer to the parent dentry for this file. This should be a
1021 * directory dentry if set. If this parameter is %NULL, then the
1022 * file will be created in the root of the debugfs filesystem.
1023 * @array: u32 array that provides data.
1024 * @elements: total number of elements in the array.
1025 *
1026 * This function creates a file in debugfs with the given name that exports
1027 * @array as data. If the @mode variable is so set it can be read from.
1028 * Writing is not supported. Seek within the file is also not supported.
1029 * Once array is created its size can not be changed.
1030 */
1031void debugfs_create_u32_array(const char *name, umode_t mode,
1032 struct dentry *parent, u32 *array, u32 elements)
1033{
1034 struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
1035
1036 if (data == NULL)
1037 return;
1038
1039 data->array = array;
1040 data->elements = elements;
1041
1042 debugfs_create_file_unsafe(name, mode, parent, data, &u32_array_fops);
1043}
1044EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1045
1046#ifdef CONFIG_HAS_IOMEM
1047
1048/*
1049 * The regset32 stuff is used to print 32-bit registers using the
1050 * seq_file utilities. We offer printing a register set in an already-opened
1051 * sequential file or create a debugfs file that only prints a regset32.
1052 */
1053
1054/**
1055 * debugfs_print_regs32 - use seq_print to describe a set of registers
1056 * @s: the seq_file structure being used to generate output
1057 * @regs: an array if struct debugfs_reg32 structures
1058 * @nregs: the length of the above array
1059 * @base: the base address to be used in reading the registers
1060 * @prefix: a string to be prefixed to every output line
1061 *
1062 * This function outputs a text block describing the current values of
1063 * some 32-bit hardware registers. It is meant to be used within debugfs
1064 * files based on seq_file that need to show registers, intermixed with other
1065 * information. The prefix argument may be used to specify a leading string,
1066 * because some peripherals have several blocks of identical registers,
1067 * for example configuration of dma channels
1068 */
1069void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1070 int nregs, void __iomem *base, char *prefix)
1071{
1072 int i;
1073
1074 for (i = 0; i < nregs; i++, regs++) {
1075 if (prefix)
1076 seq_printf(s, "%s", prefix);
1077 seq_printf(s, "%s = 0x%08x\n", regs->name,
1078 readl(base + regs->offset));
1079 if (seq_has_overflowed(s))
1080 break;
1081 }
1082}
1083EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1084
1085static int debugfs_show_regset32(struct seq_file *s, void *data)
1086{
1087 struct debugfs_regset32 *regset = s->private;
1088
1089 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1090 return 0;
1091}
1092
1093static int debugfs_open_regset32(struct inode *inode, struct file *file)
1094{
1095 return single_open(file, debugfs_show_regset32, inode->i_private);
1096}
1097
1098static const struct file_operations fops_regset32 = {
1099 .open = debugfs_open_regset32,
1100 .read = seq_read,
1101 .llseek = seq_lseek,
1102 .release = single_release,
1103};
1104
1105/**
1106 * debugfs_create_regset32 - create a debugfs file that returns register values
1107 * @name: a pointer to a string containing the name of the file to create.
1108 * @mode: the permission that the file should have
1109 * @parent: a pointer to the parent dentry for this file. This should be a
1110 * directory dentry if set. If this parameter is %NULL, then the
1111 * file will be created in the root of the debugfs filesystem.
1112 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1113 * to an array of register definitions, the array size and the base
1114 * address where the register bank is to be found.
1115 *
1116 * This function creates a file in debugfs with the given name that reports
1117 * the names and values of a set of 32-bit registers. If the @mode variable
1118 * is so set it can be read from. Writing is not supported.
1119 *
1120 * This function will return a pointer to a dentry if it succeeds. This
1121 * pointer must be passed to the debugfs_remove() function when the file is
1122 * to be removed (no automatic cleanup happens if your module is unloaded,
1123 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
1124 * returned.
1125 *
1126 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
1127 * be returned.
1128 */
1129struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
1130 struct dentry *parent,
1131 struct debugfs_regset32 *regset)
1132{
1133 return debugfs_create_file(name, mode, parent, regset, &fops_regset32);
1134}
1135EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1136
1137#endif /* CONFIG_HAS_IOMEM */
1138
1139struct debugfs_devm_entry {
1140 int (*read)(struct seq_file *seq, void *data);
1141 struct device *dev;
1142};
1143
1144static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1145{
1146 struct debugfs_devm_entry *entry = inode->i_private;
1147
1148 return single_open(f, entry->read, entry->dev);
1149}
1150
1151static const struct file_operations debugfs_devm_entry_ops = {
1152 .owner = THIS_MODULE,
1153 .open = debugfs_devm_entry_open,
1154 .release = single_release,
1155 .read = seq_read,
1156 .llseek = seq_lseek
1157};
1158
1159/**
1160 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1161 *
1162 * @dev: device related to this debugfs file.
1163 * @name: name of the debugfs file.
1164 * @parent: a pointer to the parent dentry for this file. This should be a
1165 * directory dentry if set. If this parameter is %NULL, then the
1166 * file will be created in the root of the debugfs filesystem.
1167 * @read_fn: function pointer called to print the seq_file content.
1168 */
1169struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
1170 struct dentry *parent,
1171 int (*read_fn)(struct seq_file *s,
1172 void *data))
1173{
1174 struct debugfs_devm_entry *entry;
1175
1176 if (IS_ERR(parent))
1177 return ERR_PTR(-ENOENT);
1178
1179 entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
1180 if (!entry)
1181 return ERR_PTR(-ENOMEM);
1182
1183 entry->read = read_fn;
1184 entry->dev = dev;
1185
1186 return debugfs_create_file(name, S_IRUGO, parent, entry,
1187 &debugfs_devm_entry_ops);
1188}
1189EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);
1190