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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 goto out;
184#endif
185
186 /* Huh? Module did not clean up after itself at exit? */
187 WARN(1, "debugfs file owner did not clean up at exit: %pd",
188 dentry);
189 r = -ENXIO;
190 goto out;
191 }
192 replace_fops(filp, real_fops);
193
194 if (real_fops->open)
195 r = real_fops->open(inode, filp);
196
197out:
198 debugfs_file_put(dentry);
199 return r;
200}
201
202const struct file_operations debugfs_open_proxy_file_operations = {
203 .open = open_proxy_open,
204};
205
206#define PROTO(args...) args
207#define ARGS(args...) args
208
209#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
210static ret_type full_proxy_ ## name(proto) \
211{ \
212 struct dentry *dentry = F_DENTRY(filp); \
213 const struct file_operations *real_fops; \
214 ret_type r; \
215 \
216 r = debugfs_file_get(dentry); \
217 if (unlikely(r)) \
218 return r; \
219 real_fops = debugfs_real_fops(filp); \
220 r = real_fops->name(args); \
221 debugfs_file_put(dentry); \
222 return r; \
223}
224
225FULL_PROXY_FUNC(llseek, loff_t, filp,
226 PROTO(struct file *filp, loff_t offset, int whence),
227 ARGS(filp, offset, whence));
228
229FULL_PROXY_FUNC(read, ssize_t, filp,
230 PROTO(struct file *filp, char __user *buf, size_t size,
231 loff_t *ppos),
232 ARGS(filp, buf, size, ppos));
233
234FULL_PROXY_FUNC(write, ssize_t, filp,
235 PROTO(struct file *filp, const char __user *buf, size_t size,
236 loff_t *ppos),
237 ARGS(filp, buf, size, ppos));
238
239FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
240 PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
241 ARGS(filp, cmd, arg));
242
243static __poll_t full_proxy_poll(struct file *filp,
244 struct poll_table_struct *wait)
245{
246 struct dentry *dentry = F_DENTRY(filp);
247 __poll_t r = 0;
248 const struct file_operations *real_fops;
249
250 if (debugfs_file_get(dentry))
251 return EPOLLHUP;
252
253 real_fops = debugfs_real_fops(filp);
254 r = real_fops->poll(filp, wait);
255 debugfs_file_put(dentry);
256 return r;
257}
258
259static int full_proxy_release(struct inode *inode, struct file *filp)
260{
261 const struct dentry *dentry = F_DENTRY(filp);
262 const struct file_operations *real_fops = debugfs_real_fops(filp);
263 const struct file_operations *proxy_fops = filp->f_op;
264 int r = 0;
265
266 /*
267 * We must not protect this against removal races here: the
268 * original releaser should be called unconditionally in order
269 * not to leak any resources. Releasers must not assume that
270 * ->i_private is still being meaningful here.
271 */
272 if (real_fops->release)
273 r = real_fops->release(inode, filp);
274
275 replace_fops(filp, d_inode(dentry)->i_fop);
276 kfree(proxy_fops);
277 fops_put(real_fops);
278 return r;
279}
280
281static void __full_proxy_fops_init(struct file_operations *proxy_fops,
282 const struct file_operations *real_fops)
283{
284 proxy_fops->release = full_proxy_release;
285 if (real_fops->llseek)
286 proxy_fops->llseek = full_proxy_llseek;
287 if (real_fops->read)
288 proxy_fops->read = full_proxy_read;
289 if (real_fops->write)
290 proxy_fops->write = full_proxy_write;
291 if (real_fops->poll)
292 proxy_fops->poll = full_proxy_poll;
293 if (real_fops->unlocked_ioctl)
294 proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
295}
296
297static int full_proxy_open(struct inode *inode, struct file *filp)
298{
299 struct dentry *dentry = F_DENTRY(filp);
300 const struct file_operations *real_fops = NULL;
301 struct file_operations *proxy_fops = NULL;
302 int r;
303
304 r = debugfs_file_get(dentry);
305 if (r)
306 return r == -EIO ? -ENOENT : r;
307
308 real_fops = debugfs_real_fops(filp);
309
310 r = debugfs_locked_down(inode, filp, real_fops);
311 if (r)
312 goto out;
313
314 if (!fops_get(real_fops)) {
315#ifdef CONFIG_MODULES
316 if (real_fops->owner &&
317 real_fops->owner->state == MODULE_STATE_GOING)
318 goto out;
319#endif
320
321 /* Huh? Module did not cleanup after itself at exit? */
322 WARN(1, "debugfs file owner did not clean up at exit: %pd",
323 dentry);
324 r = -ENXIO;
325 goto out;
326 }
327
328 proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
329 if (!proxy_fops) {
330 r = -ENOMEM;
331 goto free_proxy;
332 }
333 __full_proxy_fops_init(proxy_fops, real_fops);
334 replace_fops(filp, proxy_fops);
335
336 if (real_fops->open) {
337 r = real_fops->open(inode, filp);
338 if (r) {
339 replace_fops(filp, d_inode(dentry)->i_fop);
340 goto free_proxy;
341 } else if (filp->f_op != proxy_fops) {
342 /* No protection against file removal anymore. */
343 WARN(1, "debugfs file owner replaced proxy fops: %pd",
344 dentry);
345 goto free_proxy;
346 }
347 }
348
349 goto out;
350free_proxy:
351 kfree(proxy_fops);
352 fops_put(real_fops);
353out:
354 debugfs_file_put(dentry);
355 return r;
356}
357
358const struct file_operations debugfs_full_proxy_file_operations = {
359 .open = full_proxy_open,
360};
361
362ssize_t debugfs_attr_read(struct file *file, char __user *buf,
363 size_t len, loff_t *ppos)
364{
365 struct dentry *dentry = F_DENTRY(file);
366 ssize_t ret;
367
368 ret = debugfs_file_get(dentry);
369 if (unlikely(ret))
370 return ret;
371 ret = simple_attr_read(file, buf, len, ppos);
372 debugfs_file_put(dentry);
373 return ret;
374}
375EXPORT_SYMBOL_GPL(debugfs_attr_read);
376
377ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
378 size_t len, loff_t *ppos)
379{
380 struct dentry *dentry = F_DENTRY(file);
381 ssize_t ret;
382
383 ret = debugfs_file_get(dentry);
384 if (unlikely(ret))
385 return ret;
386 ret = simple_attr_write(file, buf, len, ppos);
387 debugfs_file_put(dentry);
388 return ret;
389}
390EXPORT_SYMBOL_GPL(debugfs_attr_write);
391
392static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
393 struct dentry *parent, void *value,
394 const struct file_operations *fops,
395 const struct file_operations *fops_ro,
396 const struct file_operations *fops_wo)
397{
398 /* if there are no write bits set, make read only */
399 if (!(mode & S_IWUGO))
400 return debugfs_create_file_unsafe(name, mode, parent, value,
401 fops_ro);
402 /* if there are no read bits set, make write only */
403 if (!(mode & S_IRUGO))
404 return debugfs_create_file_unsafe(name, mode, parent, value,
405 fops_wo);
406
407 return debugfs_create_file_unsafe(name, mode, parent, value, fops);
408}
409
410static int debugfs_u8_set(void *data, u64 val)
411{
412 *(u8 *)data = val;
413 return 0;
414}
415static int debugfs_u8_get(void *data, u64 *val)
416{
417 *val = *(u8 *)data;
418 return 0;
419}
420DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
421DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
422DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
423
424/**
425 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
426 * @name: a pointer to a string containing the name of the file to create.
427 * @mode: the permission that the file should have
428 * @parent: a pointer to the parent dentry for this file. This should be a
429 * directory dentry if set. If this parameter is %NULL, then the
430 * file will be created in the root of the debugfs filesystem.
431 * @value: a pointer to the variable that the file should read to and write
432 * from.
433 *
434 * This function creates a file in debugfs with the given name that
435 * contains the value of the variable @value. If the @mode variable is so
436 * set, it can be read from, and written to.
437 */
438void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
439 u8 *value)
440{
441 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
442 &fops_u8_ro, &fops_u8_wo);
443}
444EXPORT_SYMBOL_GPL(debugfs_create_u8);
445
446static int debugfs_u16_set(void *data, u64 val)
447{
448 *(u16 *)data = val;
449 return 0;
450}
451static int debugfs_u16_get(void *data, u64 *val)
452{
453 *val = *(u16 *)data;
454 return 0;
455}
456DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
457DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
458DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
459
460/**
461 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
462 * @name: a pointer to a string containing the name of the file to create.
463 * @mode: the permission that the file should have
464 * @parent: a pointer to the parent dentry for this file. This should be a
465 * directory dentry if set. If this parameter is %NULL, then the
466 * file will be created in the root of the debugfs filesystem.
467 * @value: a pointer to the variable that the file should read to and write
468 * from.
469 *
470 * This function creates a file in debugfs with the given name that
471 * contains the value of the variable @value. If the @mode variable is so
472 * set, it can be read from, and written to.
473 */
474void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
475 u16 *value)
476{
477 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
478 &fops_u16_ro, &fops_u16_wo);
479}
480EXPORT_SYMBOL_GPL(debugfs_create_u16);
481
482static int debugfs_u32_set(void *data, u64 val)
483{
484 *(u32 *)data = val;
485 return 0;
486}
487static int debugfs_u32_get(void *data, u64 *val)
488{
489 *val = *(u32 *)data;
490 return 0;
491}
492DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
493DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
494DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
495
496/**
497 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
498 * @name: a pointer to a string containing the name of the file to create.
499 * @mode: the permission that the file should have
500 * @parent: a pointer to the parent dentry for this file. This should be a
501 * directory dentry if set. If this parameter is %NULL, then the
502 * file will be created in the root of the debugfs filesystem.
503 * @value: a pointer to the variable that the file should read to and write
504 * from.
505 *
506 * This function creates a file in debugfs with the given name that
507 * contains the value of the variable @value. If the @mode variable is so
508 * set, it can be read from, and written to.
509 */
510void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
511 u32 *value)
512{
513 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
514 &fops_u32_ro, &fops_u32_wo);
515}
516EXPORT_SYMBOL_GPL(debugfs_create_u32);
517
518static int debugfs_u64_set(void *data, u64 val)
519{
520 *(u64 *)data = val;
521 return 0;
522}
523
524static int debugfs_u64_get(void *data, u64 *val)
525{
526 *val = *(u64 *)data;
527 return 0;
528}
529DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
530DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
531DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
532
533/**
534 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
535 * @name: a pointer to a string containing the name of the file to create.
536 * @mode: the permission that the file should have
537 * @parent: a pointer to the parent dentry for this file. This should be a
538 * directory dentry if set. If this parameter is %NULL, then the
539 * file will be created in the root of the debugfs filesystem.
540 * @value: a pointer to the variable that the file should read to and write
541 * from.
542 *
543 * This function creates a file in debugfs with the given name that
544 * contains the value of the variable @value. If the @mode variable is so
545 * set, it can be read from, and written to.
546 */
547void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
548 u64 *value)
549{
550 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
551 &fops_u64_ro, &fops_u64_wo);
552}
553EXPORT_SYMBOL_GPL(debugfs_create_u64);
554
555static int debugfs_ulong_set(void *data, u64 val)
556{
557 *(unsigned long *)data = val;
558 return 0;
559}
560
561static int debugfs_ulong_get(void *data, u64 *val)
562{
563 *val = *(unsigned long *)data;
564 return 0;
565}
566DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
567 "%llu\n");
568DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
569DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
570
571/**
572 * debugfs_create_ulong - create a debugfs file that is used to read and write
573 * an unsigned long 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 *
586 * This function will return a pointer to a dentry if it succeeds. This
587 * pointer must be passed to the debugfs_remove() function when the file is
588 * to be removed (no automatic cleanup happens if your module is unloaded,
589 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
590 * returned.
591 *
592 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
593 * be returned.
594 */
595struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
596 struct dentry *parent, unsigned long *value)
597{
598 return debugfs_create_mode_unsafe(name, mode, parent, value,
599 &fops_ulong, &fops_ulong_ro,
600 &fops_ulong_wo);
601}
602EXPORT_SYMBOL_GPL(debugfs_create_ulong);
603
604DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
605DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
606DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
607
608DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
609 "0x%04llx\n");
610DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
611DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
612
613DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
614 "0x%08llx\n");
615DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
616DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
617
618DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
619 "0x%016llx\n");
620DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
621DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
622
623/*
624 * 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
625 *
626 * These functions are exactly the same as the above functions (but use a hex
627 * output for the decimal challenged). For details look at the above unsigned
628 * decimal functions.
629 */
630
631/**
632 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
633 * @name: a pointer to a string containing the name of the file to create.
634 * @mode: the permission that the file should have
635 * @parent: a pointer to the parent dentry for this file. This should be a
636 * directory dentry if set. If this parameter is %NULL, then the
637 * file will be created in the root of the debugfs filesystem.
638 * @value: a pointer to the variable that the file should read to and write
639 * from.
640 */
641void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
642 u8 *value)
643{
644 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
645 &fops_x8_ro, &fops_x8_wo);
646}
647EXPORT_SYMBOL_GPL(debugfs_create_x8);
648
649/**
650 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
651 * @name: a pointer to a string containing the name of the file to create.
652 * @mode: the permission that the file should have
653 * @parent: a pointer to the parent dentry for this file. This should be a
654 * directory dentry if set. If this parameter is %NULL, then the
655 * file will be created in the root of the debugfs filesystem.
656 * @value: a pointer to the variable that the file should read to and write
657 * from.
658 */
659void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
660 u16 *value)
661{
662 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
663 &fops_x16_ro, &fops_x16_wo);
664}
665EXPORT_SYMBOL_GPL(debugfs_create_x16);
666
667/**
668 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
669 * @name: a pointer to a string containing the name of the file to create.
670 * @mode: the permission that the file should have
671 * @parent: a pointer to the parent dentry for this file. This should be a
672 * directory dentry if set. If this parameter is %NULL, then the
673 * file will be created in the root of the debugfs filesystem.
674 * @value: a pointer to the variable that the file should read to and write
675 * from.
676 */
677void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
678 u32 *value)
679{
680 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
681 &fops_x32_ro, &fops_x32_wo);
682}
683EXPORT_SYMBOL_GPL(debugfs_create_x32);
684
685/**
686 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
687 * @name: a pointer to a string containing the name of the file to create.
688 * @mode: the permission that the file should have
689 * @parent: a pointer to the parent dentry for this file. This should be a
690 * directory dentry if set. If this parameter is %NULL, then the
691 * file will be created in the root of the debugfs filesystem.
692 * @value: a pointer to the variable that the file should read to and write
693 * from.
694 */
695void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
696 u64 *value)
697{
698 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
699 &fops_x64_ro, &fops_x64_wo);
700}
701EXPORT_SYMBOL_GPL(debugfs_create_x64);
702
703
704static int debugfs_size_t_set(void *data, u64 val)
705{
706 *(size_t *)data = val;
707 return 0;
708}
709static int debugfs_size_t_get(void *data, u64 *val)
710{
711 *val = *(size_t *)data;
712 return 0;
713}
714DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
715 "%llu\n"); /* %llu and %zu are more or less the same */
716DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
717DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
718
719/**
720 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
721 * @name: a pointer to a string containing the name of the file to create.
722 * @mode: the permission that the file should have
723 * @parent: a pointer to the parent dentry for this file. This should be a
724 * directory dentry if set. If this parameter is %NULL, then the
725 * file will be created in the root of the debugfs filesystem.
726 * @value: a pointer to the variable that the file should read to and write
727 * from.
728 */
729void debugfs_create_size_t(const char *name, umode_t mode,
730 struct dentry *parent, size_t *value)
731{
732 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t,
733 &fops_size_t_ro, &fops_size_t_wo);
734}
735EXPORT_SYMBOL_GPL(debugfs_create_size_t);
736
737static int debugfs_atomic_t_set(void *data, u64 val)
738{
739 atomic_set((atomic_t *)data, val);
740 return 0;
741}
742static int debugfs_atomic_t_get(void *data, u64 *val)
743{
744 *val = atomic_read((atomic_t *)data);
745 return 0;
746}
747DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
748 debugfs_atomic_t_set, "%lld\n");
749DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
750 "%lld\n");
751DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
752 "%lld\n");
753
754/**
755 * debugfs_create_atomic_t - create a debugfs file that is used to read and
756 * write an atomic_t value
757 * @name: a pointer to a string containing the name of the file to create.
758 * @mode: the permission that the file should have
759 * @parent: a pointer to the parent dentry for this file. This should be a
760 * directory dentry if set. If this parameter is %NULL, then the
761 * file will be created in the root of the debugfs filesystem.
762 * @value: a pointer to the variable that the file should read to and write
763 * from.
764 */
765void debugfs_create_atomic_t(const char *name, umode_t mode,
766 struct dentry *parent, atomic_t *value)
767{
768 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t,
769 &fops_atomic_t_ro, &fops_atomic_t_wo);
770}
771EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
772
773ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
774 size_t count, loff_t *ppos)
775{
776 char buf[3];
777 bool val;
778 int r;
779 struct dentry *dentry = F_DENTRY(file);
780
781 r = debugfs_file_get(dentry);
782 if (unlikely(r))
783 return r;
784 val = *(bool *)file->private_data;
785 debugfs_file_put(dentry);
786
787 if (val)
788 buf[0] = 'Y';
789 else
790 buf[0] = 'N';
791 buf[1] = '\n';
792 buf[2] = 0x00;
793 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
794}
795EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
796
797ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
798 size_t count, loff_t *ppos)
799{
800 bool bv;
801 int r;
802 bool *val = file->private_data;
803 struct dentry *dentry = F_DENTRY(file);
804
805 r = kstrtobool_from_user(user_buf, count, &bv);
806 if (!r) {
807 r = debugfs_file_get(dentry);
808 if (unlikely(r))
809 return r;
810 *val = bv;
811 debugfs_file_put(dentry);
812 }
813
814 return count;
815}
816EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
817
818static const struct file_operations fops_bool = {
819 .read = debugfs_read_file_bool,
820 .write = debugfs_write_file_bool,
821 .open = simple_open,
822 .llseek = default_llseek,
823};
824
825static const struct file_operations fops_bool_ro = {
826 .read = debugfs_read_file_bool,
827 .open = simple_open,
828 .llseek = default_llseek,
829};
830
831static const struct file_operations fops_bool_wo = {
832 .write = debugfs_write_file_bool,
833 .open = simple_open,
834 .llseek = default_llseek,
835};
836
837/**
838 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
839 * @name: a pointer to a string containing the name of the file to create.
840 * @mode: the permission that the file should have
841 * @parent: a pointer to the parent dentry for this file. This should be a
842 * directory dentry if set. If this parameter is %NULL, then the
843 * file will be created in the root of the debugfs filesystem.
844 * @value: a pointer to the variable that the file should read to and write
845 * from.
846 *
847 * This function creates a file in debugfs with the given name that
848 * contains the value of the variable @value. If the @mode variable is so
849 * set, it can be read from, and written to.
850 *
851 * This function will return a pointer to a dentry if it succeeds. This
852 * pointer must be passed to the debugfs_remove() function when the file is
853 * to be removed (no automatic cleanup happens if your module is unloaded,
854 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
855 * returned.
856 *
857 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
858 * be returned.
859 */
860struct dentry *debugfs_create_bool(const char *name, umode_t mode,
861 struct dentry *parent, bool *value)
862{
863 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
864 &fops_bool_ro, &fops_bool_wo);
865}
866EXPORT_SYMBOL_GPL(debugfs_create_bool);
867
868static ssize_t read_file_blob(struct file *file, char __user *user_buf,
869 size_t count, loff_t *ppos)
870{
871 struct debugfs_blob_wrapper *blob = file->private_data;
872 struct dentry *dentry = F_DENTRY(file);
873 ssize_t r;
874
875 r = debugfs_file_get(dentry);
876 if (unlikely(r))
877 return r;
878 r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
879 blob->size);
880 debugfs_file_put(dentry);
881 return r;
882}
883
884static const struct file_operations fops_blob = {
885 .read = read_file_blob,
886 .open = simple_open,
887 .llseek = default_llseek,
888};
889
890/**
891 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
892 * @name: a pointer to a string containing the name of the file to create.
893 * @mode: the permission that the file should have
894 * @parent: a pointer to the parent dentry for this file. This should be a
895 * directory dentry if set. If this parameter is %NULL, then the
896 * file will be created in the root of the debugfs filesystem.
897 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
898 * to the blob data and the size of the data.
899 *
900 * This function creates a file in debugfs with the given name that exports
901 * @blob->data as a binary blob. If the @mode variable is so set it can be
902 * read from. Writing is not supported.
903 *
904 * This function will return a pointer to a dentry if it succeeds. This
905 * pointer must be passed to the debugfs_remove() function when the file is
906 * to be removed (no automatic cleanup happens if your module is unloaded,
907 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
908 * returned.
909 *
910 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
911 * be returned.
912 */
913struct dentry *debugfs_create_blob(const char *name, umode_t mode,
914 struct dentry *parent,
915 struct debugfs_blob_wrapper *blob)
916{
917 return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob);
918}
919EXPORT_SYMBOL_GPL(debugfs_create_blob);
920
921static size_t u32_format_array(char *buf, size_t bufsize,
922 u32 *array, int array_size)
923{
924 size_t ret = 0;
925
926 while (--array_size >= 0) {
927 size_t len;
928 char term = array_size ? ' ' : '\n';
929
930 len = snprintf(buf, bufsize, "%u%c", *array++, term);
931 ret += len;
932
933 buf += len;
934 bufsize -= len;
935 }
936 return ret;
937}
938
939static int u32_array_open(struct inode *inode, struct file *file)
940{
941 struct debugfs_u32_array *data = inode->i_private;
942 int size, elements = data->n_elements;
943 char *buf;
944
945 /*
946 * Max size:
947 * - 10 digits + ' '/'\n' = 11 bytes per number
948 * - terminating NUL character
949 */
950 size = elements*11;
951 buf = kmalloc(size+1, GFP_KERNEL);
952 if (!buf)
953 return -ENOMEM;
954 buf[size] = 0;
955
956 file->private_data = buf;
957 u32_format_array(buf, size, data->array, data->n_elements);
958
959 return nonseekable_open(inode, file);
960}
961
962static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
963 loff_t *ppos)
964{
965 size_t size = strlen(file->private_data);
966
967 return simple_read_from_buffer(buf, len, ppos,
968 file->private_data, size);
969}
970
971static int u32_array_release(struct inode *inode, struct file *file)
972{
973 kfree(file->private_data);
974
975 return 0;
976}
977
978static const struct file_operations u32_array_fops = {
979 .owner = THIS_MODULE,
980 .open = u32_array_open,
981 .release = u32_array_release,
982 .read = u32_array_read,
983 .llseek = no_llseek,
984};
985
986/**
987 * debugfs_create_u32_array - create a debugfs file that is used to read u32
988 * array.
989 * @name: a pointer to a string containing the name of the file to create.
990 * @mode: the permission that the file should have.
991 * @parent: a pointer to the parent dentry for this file. This should be a
992 * directory dentry if set. If this parameter is %NULL, then the
993 * file will be created in the root of the debugfs filesystem.
994 * @array: wrapper struct containing data pointer and size of the array.
995 *
996 * This function creates a file in debugfs with the given name that exports
997 * @array as data. If the @mode variable is so set it can be read from.
998 * Writing is not supported. Seek within the file is also not supported.
999 * Once array is created its size can not be changed.
1000 */
1001void debugfs_create_u32_array(const char *name, umode_t mode,
1002 struct dentry *parent,
1003 struct debugfs_u32_array *array)
1004{
1005 debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_fops);
1006}
1007EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1008
1009#ifdef CONFIG_HAS_IOMEM
1010
1011/*
1012 * The regset32 stuff is used to print 32-bit registers using the
1013 * seq_file utilities. We offer printing a register set in an already-opened
1014 * sequential file or create a debugfs file that only prints a regset32.
1015 */
1016
1017/**
1018 * debugfs_print_regs32 - use seq_print to describe a set of registers
1019 * @s: the seq_file structure being used to generate output
1020 * @regs: an array if struct debugfs_reg32 structures
1021 * @nregs: the length of the above array
1022 * @base: the base address to be used in reading the registers
1023 * @prefix: a string to be prefixed to every output line
1024 *
1025 * This function outputs a text block describing the current values of
1026 * some 32-bit hardware registers. It is meant to be used within debugfs
1027 * files based on seq_file that need to show registers, intermixed with other
1028 * information. The prefix argument may be used to specify a leading string,
1029 * because some peripherals have several blocks of identical registers,
1030 * for example configuration of dma channels
1031 */
1032void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1033 int nregs, void __iomem *base, char *prefix)
1034{
1035 int i;
1036
1037 for (i = 0; i < nregs; i++, regs++) {
1038 if (prefix)
1039 seq_printf(s, "%s", prefix);
1040 seq_printf(s, "%s = 0x%08x\n", regs->name,
1041 readl(base + regs->offset));
1042 if (seq_has_overflowed(s))
1043 break;
1044 }
1045}
1046EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1047
1048static int debugfs_show_regset32(struct seq_file *s, void *data)
1049{
1050 struct debugfs_regset32 *regset = s->private;
1051
1052 if (regset->dev)
1053 pm_runtime_get_sync(regset->dev);
1054
1055 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1056
1057 if (regset->dev)
1058 pm_runtime_put(regset->dev);
1059
1060 return 0;
1061}
1062
1063static int debugfs_open_regset32(struct inode *inode, struct file *file)
1064{
1065 return single_open(file, debugfs_show_regset32, inode->i_private);
1066}
1067
1068static const struct file_operations fops_regset32 = {
1069 .open = debugfs_open_regset32,
1070 .read = seq_read,
1071 .llseek = seq_lseek,
1072 .release = single_release,
1073};
1074
1075/**
1076 * debugfs_create_regset32 - create a debugfs file that returns register values
1077 * @name: a pointer to a string containing the name of the file to create.
1078 * @mode: the permission that the file should have
1079 * @parent: a pointer to the parent dentry for this file. This should be a
1080 * directory dentry if set. If this parameter is %NULL, then the
1081 * file will be created in the root of the debugfs filesystem.
1082 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1083 * to an array of register definitions, the array size and the base
1084 * address where the register bank is to be found.
1085 *
1086 * This function creates a file in debugfs with the given name that reports
1087 * the names and values of a set of 32-bit registers. If the @mode variable
1088 * is so set it can be read from. Writing is not supported.
1089 */
1090void debugfs_create_regset32(const char *name, umode_t mode,
1091 struct dentry *parent,
1092 struct debugfs_regset32 *regset)
1093{
1094 debugfs_create_file(name, mode, parent, regset, &fops_regset32);
1095}
1096EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1097
1098#endif /* CONFIG_HAS_IOMEM */
1099
1100struct debugfs_devm_entry {
1101 int (*read)(struct seq_file *seq, void *data);
1102 struct device *dev;
1103};
1104
1105static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1106{
1107 struct debugfs_devm_entry *entry = inode->i_private;
1108
1109 return single_open(f, entry->read, entry->dev);
1110}
1111
1112static const struct file_operations debugfs_devm_entry_ops = {
1113 .owner = THIS_MODULE,
1114 .open = debugfs_devm_entry_open,
1115 .release = single_release,
1116 .read = seq_read,
1117 .llseek = seq_lseek
1118};
1119
1120/**
1121 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1122 *
1123 * @dev: device related to this debugfs file.
1124 * @name: name of the debugfs file.
1125 * @parent: a pointer to the parent dentry for this file. This should be a
1126 * directory dentry if set. If this parameter is %NULL, then the
1127 * file will be created in the root of the debugfs filesystem.
1128 * @read_fn: function pointer called to print the seq_file content.
1129 */
1130struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
1131 struct dentry *parent,
1132 int (*read_fn)(struct seq_file *s,
1133 void *data))
1134{
1135 struct debugfs_devm_entry *entry;
1136
1137 if (IS_ERR(parent))
1138 return ERR_PTR(-ENOENT);
1139
1140 entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
1141 if (!entry)
1142 return ERR_PTR(-ENOMEM);
1143
1144 entry->read = read_fn;
1145 entry->dev = dev;
1146
1147 return debugfs_create_file(name, S_IRUGO, parent, entry,
1148 &debugfs_devm_entry_ops);
1149}
1150EXPORT_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);