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(size: 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(r: &fsd->active_users, n: 1);
98 init_completion(x: &fsd->active_users_drained);
99 if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
100 kfree(objp: 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(r: &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(r: &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) == 0 &&
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(what: 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(objp: 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(size: 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(objp: 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
381static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf,
382 size_t len, loff_t *ppos, bool is_signed)
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 if (is_signed)
391 ret = simple_attr_write_signed(file, buf, len, ppos);
392 else
393 ret = simple_attr_write(file, buf, len, ppos);
394 debugfs_file_put(dentry);
395 return ret;
396}
397
398ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
399 size_t len, loff_t *ppos)
400{
401 return debugfs_attr_write_xsigned(file, buf, len, ppos, is_signed: false);
402}
403EXPORT_SYMBOL_GPL(debugfs_attr_write);
404
405ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf,
406 size_t len, loff_t *ppos)
407{
408 return debugfs_attr_write_xsigned(file, buf, len, ppos, is_signed: true);
409}
410EXPORT_SYMBOL_GPL(debugfs_attr_write_signed);
411
412static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
413 struct dentry *parent, void *value,
414 const struct file_operations *fops,
415 const struct file_operations *fops_ro,
416 const struct file_operations *fops_wo)
417{
418 /* if there are no write bits set, make read only */
419 if (!(mode & S_IWUGO))
420 return debugfs_create_file_unsafe(name, mode, parent, data: value,
421 fops: fops_ro);
422 /* if there are no read bits set, make write only */
423 if (!(mode & S_IRUGO))
424 return debugfs_create_file_unsafe(name, mode, parent, data: value,
425 fops: fops_wo);
426
427 return debugfs_create_file_unsafe(name, mode, parent, data: value, fops);
428}
429
430static int debugfs_u8_set(void *data, u64 val)
431{
432 *(u8 *)data = val;
433 return 0;
434}
435static int debugfs_u8_get(void *data, u64 *val)
436{
437 *val = *(u8 *)data;
438 return 0;
439}
440DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
441DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
442DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
443
444/**
445 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
446 * @name: a pointer to a string containing the name of the file to create.
447 * @mode: the permission that the file should have
448 * @parent: a pointer to the parent dentry for this file. This should be a
449 * directory dentry if set. If this parameter is %NULL, then the
450 * file will be created in the root of the debugfs filesystem.
451 * @value: a pointer to the variable that the file should read to and write
452 * from.
453 *
454 * This function creates a file in debugfs with the given name that
455 * contains the value of the variable @value. If the @mode variable is so
456 * set, it can be read from, and written to.
457 */
458void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
459 u8 *value)
460{
461 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_u8,
462 fops_ro: &fops_u8_ro, fops_wo: &fops_u8_wo);
463}
464EXPORT_SYMBOL_GPL(debugfs_create_u8);
465
466static int debugfs_u16_set(void *data, u64 val)
467{
468 *(u16 *)data = val;
469 return 0;
470}
471static int debugfs_u16_get(void *data, u64 *val)
472{
473 *val = *(u16 *)data;
474 return 0;
475}
476DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
477DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
478DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
479
480/**
481 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
482 * @name: a pointer to a string containing the name of the file to create.
483 * @mode: the permission that the file should have
484 * @parent: a pointer to the parent dentry for this file. This should be a
485 * directory dentry if set. If this parameter is %NULL, then the
486 * file will be created in the root of the debugfs filesystem.
487 * @value: a pointer to the variable that the file should read to and write
488 * from.
489 *
490 * This function creates a file in debugfs with the given name that
491 * contains the value of the variable @value. If the @mode variable is so
492 * set, it can be read from, and written to.
493 */
494void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
495 u16 *value)
496{
497 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_u16,
498 fops_ro: &fops_u16_ro, fops_wo: &fops_u16_wo);
499}
500EXPORT_SYMBOL_GPL(debugfs_create_u16);
501
502static int debugfs_u32_set(void *data, u64 val)
503{
504 *(u32 *)data = val;
505 return 0;
506}
507static int debugfs_u32_get(void *data, u64 *val)
508{
509 *val = *(u32 *)data;
510 return 0;
511}
512DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
513DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
514DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
515
516/**
517 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
518 * @name: a pointer to a string containing the name of the file to create.
519 * @mode: the permission that the file should have
520 * @parent: a pointer to the parent dentry for this file. This should be a
521 * directory dentry if set. If this parameter is %NULL, then the
522 * file will be created in the root of the debugfs filesystem.
523 * @value: a pointer to the variable that the file should read to and write
524 * from.
525 *
526 * This function creates a file in debugfs with the given name that
527 * contains the value of the variable @value. If the @mode variable is so
528 * set, it can be read from, and written to.
529 */
530void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
531 u32 *value)
532{
533 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_u32,
534 fops_ro: &fops_u32_ro, fops_wo: &fops_u32_wo);
535}
536EXPORT_SYMBOL_GPL(debugfs_create_u32);
537
538static int debugfs_u64_set(void *data, u64 val)
539{
540 *(u64 *)data = val;
541 return 0;
542}
543
544static int debugfs_u64_get(void *data, u64 *val)
545{
546 *val = *(u64 *)data;
547 return 0;
548}
549DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
550DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
551DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
552
553/**
554 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
555 * @name: a pointer to a string containing the name of the file to create.
556 * @mode: the permission that the file should have
557 * @parent: a pointer to the parent dentry for this file. This should be a
558 * directory dentry if set. If this parameter is %NULL, then the
559 * file will be created in the root of the debugfs filesystem.
560 * @value: a pointer to the variable that the file should read to and write
561 * from.
562 *
563 * This function creates a file in debugfs with the given name that
564 * contains the value of the variable @value. If the @mode variable is so
565 * set, it can be read from, and written to.
566 */
567void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
568 u64 *value)
569{
570 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_u64,
571 fops_ro: &fops_u64_ro, fops_wo: &fops_u64_wo);
572}
573EXPORT_SYMBOL_GPL(debugfs_create_u64);
574
575static int debugfs_ulong_set(void *data, u64 val)
576{
577 *(unsigned long *)data = val;
578 return 0;
579}
580
581static int debugfs_ulong_get(void *data, u64 *val)
582{
583 *val = *(unsigned long *)data;
584 return 0;
585}
586DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
587 "%llu\n");
588DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
589DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
590
591/**
592 * debugfs_create_ulong - create a debugfs file that is used to read and write
593 * an unsigned long value.
594 * @name: a pointer to a string containing the name of the file to create.
595 * @mode: the permission that the file should have
596 * @parent: a pointer to the parent dentry for this file. This should be a
597 * directory dentry if set. If this parameter is %NULL, then the
598 * file will be created in the root of the debugfs filesystem.
599 * @value: a pointer to the variable that the file should read to and write
600 * from.
601 *
602 * This function creates a file in debugfs with the given name that
603 * contains the value of the variable @value. If the @mode variable is so
604 * set, it can be read from, and written to.
605 */
606void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent,
607 unsigned long *value)
608{
609 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_ulong,
610 fops_ro: &fops_ulong_ro, fops_wo: &fops_ulong_wo);
611}
612EXPORT_SYMBOL_GPL(debugfs_create_ulong);
613
614DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
615DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
616DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
617
618DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
619 "0x%04llx\n");
620DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
621DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
622
623DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
624 "0x%08llx\n");
625DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
626DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
627
628DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
629 "0x%016llx\n");
630DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
631DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
632
633/*
634 * 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
635 *
636 * These functions are exactly the same as the above functions (but use a hex
637 * output for the decimal challenged). For details look at the above unsigned
638 * decimal functions.
639 */
640
641/**
642 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
643 * @name: a pointer to a string containing the name of the file to create.
644 * @mode: the permission that the file should have
645 * @parent: a pointer to the parent dentry for this file. This should be a
646 * directory dentry if set. If this parameter is %NULL, then the
647 * file will be created in the root of the debugfs filesystem.
648 * @value: a pointer to the variable that the file should read to and write
649 * from.
650 */
651void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
652 u8 *value)
653{
654 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_x8,
655 fops_ro: &fops_x8_ro, fops_wo: &fops_x8_wo);
656}
657EXPORT_SYMBOL_GPL(debugfs_create_x8);
658
659/**
660 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
661 * @name: a pointer to a string containing the name of the file to create.
662 * @mode: the permission that the file should have
663 * @parent: a pointer to the parent dentry for this file. This should be a
664 * directory dentry if set. If this parameter is %NULL, then the
665 * file will be created in the root of the debugfs filesystem.
666 * @value: a pointer to the variable that the file should read to and write
667 * from.
668 */
669void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
670 u16 *value)
671{
672 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_x16,
673 fops_ro: &fops_x16_ro, fops_wo: &fops_x16_wo);
674}
675EXPORT_SYMBOL_GPL(debugfs_create_x16);
676
677/**
678 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
679 * @name: a pointer to a string containing the name of the file to create.
680 * @mode: the permission that the file should have
681 * @parent: a pointer to the parent dentry for this file. This should be a
682 * directory dentry if set. If this parameter is %NULL, then the
683 * file will be created in the root of the debugfs filesystem.
684 * @value: a pointer to the variable that the file should read to and write
685 * from.
686 */
687void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
688 u32 *value)
689{
690 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_x32,
691 fops_ro: &fops_x32_ro, fops_wo: &fops_x32_wo);
692}
693EXPORT_SYMBOL_GPL(debugfs_create_x32);
694
695/**
696 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
697 * @name: a pointer to a string containing the name of the file to create.
698 * @mode: the permission that the file should have
699 * @parent: a pointer to the parent dentry for this file. This should be a
700 * directory dentry if set. If this parameter is %NULL, then the
701 * file will be created in the root of the debugfs filesystem.
702 * @value: a pointer to the variable that the file should read to and write
703 * from.
704 */
705void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
706 u64 *value)
707{
708 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_x64,
709 fops_ro: &fops_x64_ro, fops_wo: &fops_x64_wo);
710}
711EXPORT_SYMBOL_GPL(debugfs_create_x64);
712
713
714static int debugfs_size_t_set(void *data, u64 val)
715{
716 *(size_t *)data = val;
717 return 0;
718}
719static int debugfs_size_t_get(void *data, u64 *val)
720{
721 *val = *(size_t *)data;
722 return 0;
723}
724DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
725 "%llu\n"); /* %llu and %zu are more or less the same */
726DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
727DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
728
729/**
730 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
731 * @name: a pointer to a string containing the name of the file to create.
732 * @mode: the permission that the file should have
733 * @parent: a pointer to the parent dentry for this file. This should be a
734 * directory dentry if set. If this parameter is %NULL, then the
735 * file will be created in the root of the debugfs filesystem.
736 * @value: a pointer to the variable that the file should read to and write
737 * from.
738 */
739void debugfs_create_size_t(const char *name, umode_t mode,
740 struct dentry *parent, size_t *value)
741{
742 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_size_t,
743 fops_ro: &fops_size_t_ro, fops_wo: &fops_size_t_wo);
744}
745EXPORT_SYMBOL_GPL(debugfs_create_size_t);
746
747static int debugfs_atomic_t_set(void *data, u64 val)
748{
749 atomic_set(v: (atomic_t *)data, i: val);
750 return 0;
751}
752static int debugfs_atomic_t_get(void *data, u64 *val)
753{
754 *val = atomic_read(v: (atomic_t *)data);
755 return 0;
756}
757DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t, debugfs_atomic_t_get,
758 debugfs_atomic_t_set, "%lld\n");
759DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
760 "%lld\n");
761DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
762 "%lld\n");
763
764/**
765 * debugfs_create_atomic_t - create a debugfs file that is used to read and
766 * write an atomic_t value
767 * @name: a pointer to a string containing the name of the file to create.
768 * @mode: the permission that the file should have
769 * @parent: a pointer to the parent dentry for this file. This should be a
770 * directory dentry if set. If this parameter is %NULL, then the
771 * file will be created in the root of the debugfs filesystem.
772 * @value: a pointer to the variable that the file should read to and write
773 * from.
774 */
775void debugfs_create_atomic_t(const char *name, umode_t mode,
776 struct dentry *parent, atomic_t *value)
777{
778 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_atomic_t,
779 fops_ro: &fops_atomic_t_ro, fops_wo: &fops_atomic_t_wo);
780}
781EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
782
783ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
784 size_t count, loff_t *ppos)
785{
786 char buf[2];
787 bool val;
788 int r;
789 struct dentry *dentry = F_DENTRY(file);
790
791 r = debugfs_file_get(dentry);
792 if (unlikely(r))
793 return r;
794 val = *(bool *)file->private_data;
795 debugfs_file_put(dentry);
796
797 if (val)
798 buf[0] = 'Y';
799 else
800 buf[0] = 'N';
801 buf[1] = '\n';
802 return simple_read_from_buffer(to: user_buf, count, ppos, from: buf, available: 2);
803}
804EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
805
806ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
807 size_t count, loff_t *ppos)
808{
809 bool bv;
810 int r;
811 bool *val = file->private_data;
812 struct dentry *dentry = F_DENTRY(file);
813
814 r = kstrtobool_from_user(s: user_buf, count, res: &bv);
815 if (!r) {
816 r = debugfs_file_get(dentry);
817 if (unlikely(r))
818 return r;
819 *val = bv;
820 debugfs_file_put(dentry);
821 }
822
823 return count;
824}
825EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
826
827static const struct file_operations fops_bool = {
828 .read = debugfs_read_file_bool,
829 .write = debugfs_write_file_bool,
830 .open = simple_open,
831 .llseek = default_llseek,
832};
833
834static const struct file_operations fops_bool_ro = {
835 .read = debugfs_read_file_bool,
836 .open = simple_open,
837 .llseek = default_llseek,
838};
839
840static const struct file_operations fops_bool_wo = {
841 .write = debugfs_write_file_bool,
842 .open = simple_open,
843 .llseek = default_llseek,
844};
845
846/**
847 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
848 * @name: a pointer to a string containing the name of the file to create.
849 * @mode: the permission that the file should have
850 * @parent: a pointer to the parent dentry for this file. This should be a
851 * directory dentry if set. If this parameter is %NULL, then the
852 * file will be created in the root of the debugfs filesystem.
853 * @value: a pointer to the variable that the file should read to and write
854 * from.
855 *
856 * This function creates a file in debugfs with the given name that
857 * contains the value of the variable @value. If the @mode variable is so
858 * set, it can be read from, and written to.
859 */
860void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent,
861 bool *value)
862{
863 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_bool,
864 fops_ro: &fops_bool_ro, fops_wo: &fops_bool_wo);
865}
866EXPORT_SYMBOL_GPL(debugfs_create_bool);
867
868ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
869 size_t count, loff_t *ppos)
870{
871 struct dentry *dentry = F_DENTRY(file);
872 char *str, *copy = NULL;
873 int copy_len, len;
874 ssize_t ret;
875
876 ret = debugfs_file_get(dentry);
877 if (unlikely(ret))
878 return ret;
879
880 str = *(char **)file->private_data;
881 len = strlen(str) + 1;
882 copy = kmalloc(size: len, GFP_KERNEL);
883 if (!copy) {
884 debugfs_file_put(dentry);
885 return -ENOMEM;
886 }
887
888 copy_len = strscpy(p: copy, q: str, size: len);
889 debugfs_file_put(dentry);
890 if (copy_len < 0) {
891 kfree(objp: copy);
892 return copy_len;
893 }
894
895 copy[copy_len] = '\n';
896
897 ret = simple_read_from_buffer(to: user_buf, count, ppos, from: copy, available: len);
898 kfree(objp: copy);
899
900 return ret;
901}
902EXPORT_SYMBOL_GPL(debugfs_create_str);
903
904static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
905 size_t count, loff_t *ppos)
906{
907 struct dentry *dentry = F_DENTRY(file);
908 char *old, *new = NULL;
909 int pos = *ppos;
910 int r;
911
912 r = debugfs_file_get(dentry);
913 if (unlikely(r))
914 return r;
915
916 old = *(char **)file->private_data;
917
918 /* only allow strict concatenation */
919 r = -EINVAL;
920 if (pos && pos != strlen(old))
921 goto error;
922
923 r = -E2BIG;
924 if (pos + count + 1 > PAGE_SIZE)
925 goto error;
926
927 r = -ENOMEM;
928 new = kmalloc(size: pos + count + 1, GFP_KERNEL);
929 if (!new)
930 goto error;
931
932 if (pos)
933 memcpy(new, old, pos);
934
935 r = -EFAULT;
936 if (copy_from_user(to: new + pos, from: user_buf, n: count))
937 goto error;
938
939 new[pos + count] = '\0';
940 strim(new);
941
942 rcu_assign_pointer(*(char __rcu **)file->private_data, new);
943 synchronize_rcu();
944 kfree(objp: old);
945
946 debugfs_file_put(dentry);
947 return count;
948
949error:
950 kfree(objp: new);
951 debugfs_file_put(dentry);
952 return r;
953}
954
955static const struct file_operations fops_str = {
956 .read = debugfs_read_file_str,
957 .write = debugfs_write_file_str,
958 .open = simple_open,
959 .llseek = default_llseek,
960};
961
962static const struct file_operations fops_str_ro = {
963 .read = debugfs_read_file_str,
964 .open = simple_open,
965 .llseek = default_llseek,
966};
967
968static const struct file_operations fops_str_wo = {
969 .write = debugfs_write_file_str,
970 .open = simple_open,
971 .llseek = default_llseek,
972};
973
974/**
975 * debugfs_create_str - create a debugfs file that is used to read and write a string value
976 * @name: a pointer to a string containing the name of the file to create.
977 * @mode: the permission that the file should have
978 * @parent: a pointer to the parent dentry for this file. This should be a
979 * directory dentry if set. If this parameter is %NULL, then the
980 * file will be created in the root of the debugfs filesystem.
981 * @value: a pointer to the variable that the file should read to and write
982 * from.
983 *
984 * This function creates a file in debugfs with the given name that
985 * contains the value of the variable @value. If the @mode variable is so
986 * set, it can be read from, and written to.
987 */
988void debugfs_create_str(const char *name, umode_t mode,
989 struct dentry *parent, char **value)
990{
991 debugfs_create_mode_unsafe(name, mode, parent, value, fops: &fops_str,
992 fops_ro: &fops_str_ro, fops_wo: &fops_str_wo);
993}
994
995static ssize_t read_file_blob(struct file *file, char __user *user_buf,
996 size_t count, loff_t *ppos)
997{
998 struct debugfs_blob_wrapper *blob = file->private_data;
999 struct dentry *dentry = F_DENTRY(file);
1000 ssize_t r;
1001
1002 r = debugfs_file_get(dentry);
1003 if (unlikely(r))
1004 return r;
1005 r = simple_read_from_buffer(to: user_buf, count, ppos, from: blob->data,
1006 available: blob->size);
1007 debugfs_file_put(dentry);
1008 return r;
1009}
1010
1011static const struct file_operations fops_blob = {
1012 .read = read_file_blob,
1013 .open = simple_open,
1014 .llseek = default_llseek,
1015};
1016
1017/**
1018 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
1019 * @name: a pointer to a string containing the name of the file to create.
1020 * @mode: the read permission that the file should have (other permissions are
1021 * masked out)
1022 * @parent: a pointer to the parent dentry for this file. This should be a
1023 * directory dentry if set. If this parameter is %NULL, then the
1024 * file will be created in the root of the debugfs filesystem.
1025 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
1026 * to the blob data and the size of the data.
1027 *
1028 * This function creates a file in debugfs with the given name that exports
1029 * @blob->data as a binary blob. If the @mode variable is so set it can be
1030 * read from. Writing is not supported.
1031 *
1032 * This function will return a pointer to a dentry if it succeeds. This
1033 * pointer must be passed to the debugfs_remove() function when the file is
1034 * to be removed (no automatic cleanup happens if your module is unloaded,
1035 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
1036 * returned.
1037 *
1038 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
1039 * be returned.
1040 */
1041struct dentry *debugfs_create_blob(const char *name, umode_t mode,
1042 struct dentry *parent,
1043 struct debugfs_blob_wrapper *blob)
1044{
1045 return debugfs_create_file_unsafe(name, mode: mode & 0444, parent, data: blob, fops: &fops_blob);
1046}
1047EXPORT_SYMBOL_GPL(debugfs_create_blob);
1048
1049static size_t u32_format_array(char *buf, size_t bufsize,
1050 u32 *array, int array_size)
1051{
1052 size_t ret = 0;
1053
1054 while (--array_size >= 0) {
1055 size_t len;
1056 char term = array_size ? ' ' : '\n';
1057
1058 len = snprintf(buf, size: bufsize, fmt: "%u%c", *array++, term);
1059 ret += len;
1060
1061 buf += len;
1062 bufsize -= len;
1063 }
1064 return ret;
1065}
1066
1067static int u32_array_open(struct inode *inode, struct file *file)
1068{
1069 struct debugfs_u32_array *data = inode->i_private;
1070 int size, elements = data->n_elements;
1071 char *buf;
1072
1073 /*
1074 * Max size:
1075 * - 10 digits + ' '/'\n' = 11 bytes per number
1076 * - terminating NUL character
1077 */
1078 size = elements*11;
1079 buf = kmalloc(size: size+1, GFP_KERNEL);
1080 if (!buf)
1081 return -ENOMEM;
1082 buf[size] = 0;
1083
1084 file->private_data = buf;
1085 u32_format_array(buf, bufsize: size, array: data->array, array_size: data->n_elements);
1086
1087 return nonseekable_open(inode, filp: file);
1088}
1089
1090static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
1091 loff_t *ppos)
1092{
1093 size_t size = strlen(file->private_data);
1094
1095 return simple_read_from_buffer(to: buf, count: len, ppos,
1096 from: file->private_data, available: size);
1097}
1098
1099static int u32_array_release(struct inode *inode, struct file *file)
1100{
1101 kfree(objp: file->private_data);
1102
1103 return 0;
1104}
1105
1106static const struct file_operations u32_array_fops = {
1107 .owner = THIS_MODULE,
1108 .open = u32_array_open,
1109 .release = u32_array_release,
1110 .read = u32_array_read,
1111 .llseek = no_llseek,
1112};
1113
1114/**
1115 * debugfs_create_u32_array - create a debugfs file that is used to read u32
1116 * array.
1117 * @name: a pointer to a string containing the name of the file to create.
1118 * @mode: the permission that the file should have.
1119 * @parent: a pointer to the parent dentry for this file. This should be a
1120 * directory dentry if set. If this parameter is %NULL, then the
1121 * file will be created in the root of the debugfs filesystem.
1122 * @array: wrapper struct containing data pointer and size of the array.
1123 *
1124 * This function creates a file in debugfs with the given name that exports
1125 * @array as data. If the @mode variable is so set it can be read from.
1126 * Writing is not supported. Seek within the file is also not supported.
1127 * Once array is created its size can not be changed.
1128 */
1129void debugfs_create_u32_array(const char *name, umode_t mode,
1130 struct dentry *parent,
1131 struct debugfs_u32_array *array)
1132{
1133 debugfs_create_file_unsafe(name, mode, parent, data: array, fops: &u32_array_fops);
1134}
1135EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1136
1137#ifdef CONFIG_HAS_IOMEM
1138
1139/*
1140 * The regset32 stuff is used to print 32-bit registers using the
1141 * seq_file utilities. We offer printing a register set in an already-opened
1142 * sequential file or create a debugfs file that only prints a regset32.
1143 */
1144
1145/**
1146 * debugfs_print_regs32 - use seq_print to describe a set of registers
1147 * @s: the seq_file structure being used to generate output
1148 * @regs: an array if struct debugfs_reg32 structures
1149 * @nregs: the length of the above array
1150 * @base: the base address to be used in reading the registers
1151 * @prefix: a string to be prefixed to every output line
1152 *
1153 * This function outputs a text block describing the current values of
1154 * some 32-bit hardware registers. It is meant to be used within debugfs
1155 * files based on seq_file that need to show registers, intermixed with other
1156 * information. The prefix argument may be used to specify a leading string,
1157 * because some peripherals have several blocks of identical registers,
1158 * for example configuration of dma channels
1159 */
1160void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1161 int nregs, void __iomem *base, char *prefix)
1162{
1163 int i;
1164
1165 for (i = 0; i < nregs; i++, regs++) {
1166 if (prefix)
1167 seq_printf(m: s, fmt: "%s", prefix);
1168 seq_printf(m: s, fmt: "%s = 0x%08x\n", regs->name,
1169 readl(addr: base + regs->offset));
1170 if (seq_has_overflowed(m: s))
1171 break;
1172 }
1173}
1174EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1175
1176static int debugfs_regset32_show(struct seq_file *s, void *data)
1177{
1178 struct debugfs_regset32 *regset = s->private;
1179
1180 if (regset->dev)
1181 pm_runtime_get_sync(dev: regset->dev);
1182
1183 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1184
1185 if (regset->dev)
1186 pm_runtime_put(dev: regset->dev);
1187
1188 return 0;
1189}
1190
1191DEFINE_SHOW_ATTRIBUTE(debugfs_regset32);
1192
1193/**
1194 * debugfs_create_regset32 - create a debugfs file that returns register values
1195 * @name: a pointer to a string containing the name of the file to create.
1196 * @mode: the permission that the file should have
1197 * @parent: a pointer to the parent dentry for this file. This should be a
1198 * directory dentry if set. If this parameter is %NULL, then the
1199 * file will be created in the root of the debugfs filesystem.
1200 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1201 * to an array of register definitions, the array size and the base
1202 * address where the register bank is to be found.
1203 *
1204 * This function creates a file in debugfs with the given name that reports
1205 * the names and values of a set of 32-bit registers. If the @mode variable
1206 * is so set it can be read from. Writing is not supported.
1207 */
1208void debugfs_create_regset32(const char *name, umode_t mode,
1209 struct dentry *parent,
1210 struct debugfs_regset32 *regset)
1211{
1212 debugfs_create_file(name, mode, parent, data: regset, fops: &debugfs_regset32_fops);
1213}
1214EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1215
1216#endif /* CONFIG_HAS_IOMEM */
1217
1218struct debugfs_devm_entry {
1219 int (*read)(struct seq_file *seq, void *data);
1220 struct device *dev;
1221};
1222
1223static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1224{
1225 struct debugfs_devm_entry *entry = inode->i_private;
1226
1227 return single_open(f, entry->read, entry->dev);
1228}
1229
1230static const struct file_operations debugfs_devm_entry_ops = {
1231 .owner = THIS_MODULE,
1232 .open = debugfs_devm_entry_open,
1233 .release = single_release,
1234 .read = seq_read,
1235 .llseek = seq_lseek
1236};
1237
1238/**
1239 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1240 *
1241 * @dev: device related to this debugfs file.
1242 * @name: name of the debugfs file.
1243 * @parent: a pointer to the parent dentry for this file. This should be a
1244 * directory dentry if set. If this parameter is %NULL, then the
1245 * file will be created in the root of the debugfs filesystem.
1246 * @read_fn: function pointer called to print the seq_file content.
1247 */
1248void debugfs_create_devm_seqfile(struct device *dev, const char *name,
1249 struct dentry *parent,
1250 int (*read_fn)(struct seq_file *s, void *data))
1251{
1252 struct debugfs_devm_entry *entry;
1253
1254 if (IS_ERR(ptr: parent))
1255 return;
1256
1257 entry = devm_kzalloc(dev, size: sizeof(*entry), GFP_KERNEL);
1258 if (!entry)
1259 return;
1260
1261 entry->read = read_fn;
1262 entry->dev = dev;
1263
1264 debugfs_create_file(name, S_IRUGO, parent, data: entry,
1265 fops: &debugfs_devm_entry_ops);
1266}
1267EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);
1268

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