1 // SPDX-License-Identifier: GPL-2.0
3 * file.c - part of debugfs, a tiny little debug file system
6 * Copyright (C) 2004 IBM Inc.
8 * debugfs is for people to use instead of /proc or /sys.
9 * See Documentation/filesystems/ for more details.
12 #include <linux/module.h>
14 #include <linux/seq_file.h>
15 #include <linux/pagemap.h>
16 #include <linux/debugfs.h>
18 #include <linux/slab.h>
19 #include <linux/atomic.h>
20 #include <linux/device.h>
21 #include <linux/poll.h>
25 struct poll_table_struct;
27 static ssize_t default_read_file(struct file *file, char __user *buf,
28 size_t count, loff_t *ppos)
33 static ssize_t default_write_file(struct file *file, const char __user *buf,
34 size_t count, loff_t *ppos)
39 const struct file_operations debugfs_noop_file_operations = {
40 .read = default_read_file,
41 .write = default_write_file,
43 .llseek = noop_llseek,
46 #define F_DENTRY(filp) ((filp)->f_path.dentry)
48 const struct file_operations *debugfs_real_fops(const struct file *filp)
50 struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
52 if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
54 * Urgh, we've been called w/o a protecting
61 return fsd->real_fops;
63 EXPORT_SYMBOL_GPL(debugfs_real_fops);
66 * debugfs_file_get - mark the beginning of file data access
67 * @dentry: the dentry object whose data is being accessed.
69 * Up to a matching call to debugfs_file_put(), any successive call
70 * into the file removing functions debugfs_remove() and
71 * debugfs_remove_recursive() will block. Since associated private
72 * file data may only get freed after a successful return of any of
73 * the removal functions, you may safely access it after a successful
74 * call to debugfs_file_get() without worrying about lifetime issues.
76 * If -%EIO is returned, the file has already been removed and thus,
77 * it is not safe to access any of its data. If, on the other hand,
78 * it is allowed to access the file data, zero is returned.
80 int debugfs_file_get(struct dentry *dentry)
82 struct debugfs_fsdata *fsd;
85 d_fsd = READ_ONCE(dentry->d_fsdata);
86 if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
89 fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
93 fsd->real_fops = (void *)((unsigned long)d_fsd &
94 ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
95 refcount_set(&fsd->active_users, 1);
96 init_completion(&fsd->active_users_drained);
97 if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
99 fsd = READ_ONCE(dentry->d_fsdata);
104 * In case of a successful cmpxchg() above, this check is
105 * strictly necessary and must follow it, see the comment in
106 * __debugfs_remove_file().
107 * OTOH, if the cmpxchg() hasn't been executed or wasn't
108 * successful, this serves the purpose of not starving
111 if (d_unlinked(dentry))
114 if (!refcount_inc_not_zero(&fsd->active_users))
119 EXPORT_SYMBOL_GPL(debugfs_file_get);
122 * debugfs_file_put - mark the end of file data access
123 * @dentry: the dentry object formerly passed to
124 * debugfs_file_get().
126 * Allow any ongoing concurrent call into debugfs_remove() or
127 * debugfs_remove_recursive() blocked by a former call to
128 * debugfs_file_get() to proceed and return to its caller.
130 void debugfs_file_put(struct dentry *dentry)
132 struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
134 if (refcount_dec_and_test(&fsd->active_users))
135 complete(&fsd->active_users_drained);
137 EXPORT_SYMBOL_GPL(debugfs_file_put);
139 static int open_proxy_open(struct inode *inode, struct file *filp)
141 struct dentry *dentry = F_DENTRY(filp);
142 const struct file_operations *real_fops = NULL;
145 r = debugfs_file_get(dentry);
147 return r == -EIO ? -ENOENT : r;
149 real_fops = debugfs_real_fops(filp);
150 real_fops = fops_get(real_fops);
152 /* Huh? Module did not clean up after itself at exit? */
153 WARN(1, "debugfs file owner did not clean up at exit: %pd",
158 replace_fops(filp, real_fops);
161 r = real_fops->open(inode, filp);
164 debugfs_file_put(dentry);
168 const struct file_operations debugfs_open_proxy_file_operations = {
169 .open = open_proxy_open,
172 #define PROTO(args...) args
173 #define ARGS(args...) args
175 #define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
176 static ret_type full_proxy_ ## name(proto) \
178 struct dentry *dentry = F_DENTRY(filp); \
179 const struct file_operations *real_fops; \
182 r = debugfs_file_get(dentry); \
185 real_fops = debugfs_real_fops(filp); \
186 r = real_fops->name(args); \
187 debugfs_file_put(dentry); \
191 FULL_PROXY_FUNC(llseek, loff_t, filp,
192 PROTO(struct file *filp, loff_t offset, int whence),
193 ARGS(filp, offset, whence));
195 FULL_PROXY_FUNC(read, ssize_t, filp,
196 PROTO(struct file *filp, char __user *buf, size_t size,
198 ARGS(filp, buf, size, ppos));
200 FULL_PROXY_FUNC(write, ssize_t, filp,
201 PROTO(struct file *filp, const char __user *buf, size_t size,
203 ARGS(filp, buf, size, ppos));
205 FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
206 PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
207 ARGS(filp, cmd, arg));
209 static __poll_t full_proxy_poll(struct file *filp,
210 struct poll_table_struct *wait)
212 struct dentry *dentry = F_DENTRY(filp);
214 const struct file_operations *real_fops;
216 if (debugfs_file_get(dentry))
219 real_fops = debugfs_real_fops(filp);
220 r = real_fops->poll(filp, wait);
221 debugfs_file_put(dentry);
225 static int full_proxy_release(struct inode *inode, struct file *filp)
227 const struct dentry *dentry = F_DENTRY(filp);
228 const struct file_operations *real_fops = debugfs_real_fops(filp);
229 const struct file_operations *proxy_fops = filp->f_op;
233 * We must not protect this against removal races here: the
234 * original releaser should be called unconditionally in order
235 * not to leak any resources. Releasers must not assume that
236 * ->i_private is still being meaningful here.
238 if (real_fops->release)
239 r = real_fops->release(inode, filp);
241 replace_fops(filp, d_inode(dentry)->i_fop);
242 kfree((void *)proxy_fops);
247 static void __full_proxy_fops_init(struct file_operations *proxy_fops,
248 const struct file_operations *real_fops)
250 proxy_fops->release = full_proxy_release;
251 if (real_fops->llseek)
252 proxy_fops->llseek = full_proxy_llseek;
254 proxy_fops->read = full_proxy_read;
255 if (real_fops->write)
256 proxy_fops->write = full_proxy_write;
258 proxy_fops->poll = full_proxy_poll;
259 if (real_fops->unlocked_ioctl)
260 proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
263 static int full_proxy_open(struct inode *inode, struct file *filp)
265 struct dentry *dentry = F_DENTRY(filp);
266 const struct file_operations *real_fops = NULL;
267 struct file_operations *proxy_fops = NULL;
270 r = debugfs_file_get(dentry);
272 return r == -EIO ? -ENOENT : r;
274 real_fops = debugfs_real_fops(filp);
275 real_fops = fops_get(real_fops);
277 /* Huh? Module did not cleanup after itself at exit? */
278 WARN(1, "debugfs file owner did not clean up at exit: %pd",
284 proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
289 __full_proxy_fops_init(proxy_fops, real_fops);
290 replace_fops(filp, proxy_fops);
292 if (real_fops->open) {
293 r = real_fops->open(inode, filp);
295 replace_fops(filp, d_inode(dentry)->i_fop);
297 } else if (filp->f_op != proxy_fops) {
298 /* No protection against file removal anymore. */
299 WARN(1, "debugfs file owner replaced proxy fops: %pd",
310 debugfs_file_put(dentry);
314 const struct file_operations debugfs_full_proxy_file_operations = {
315 .open = full_proxy_open,
318 ssize_t debugfs_attr_read(struct file *file, char __user *buf,
319 size_t len, loff_t *ppos)
321 struct dentry *dentry = F_DENTRY(file);
324 ret = debugfs_file_get(dentry);
327 ret = simple_attr_read(file, buf, len, ppos);
328 debugfs_file_put(dentry);
331 EXPORT_SYMBOL_GPL(debugfs_attr_read);
333 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
334 size_t len, loff_t *ppos)
336 struct dentry *dentry = F_DENTRY(file);
339 ret = debugfs_file_get(dentry);
342 ret = simple_attr_write(file, buf, len, ppos);
343 debugfs_file_put(dentry);
346 EXPORT_SYMBOL_GPL(debugfs_attr_write);
348 static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
349 struct dentry *parent, void *value,
350 const struct file_operations *fops,
351 const struct file_operations *fops_ro,
352 const struct file_operations *fops_wo)
354 /* if there are no write bits set, make read only */
355 if (!(mode & S_IWUGO))
356 return debugfs_create_file_unsafe(name, mode, parent, value,
358 /* if there are no read bits set, make write only */
359 if (!(mode & S_IRUGO))
360 return debugfs_create_file_unsafe(name, mode, parent, value,
363 return debugfs_create_file_unsafe(name, mode, parent, value, fops);
366 static int debugfs_u8_set(void *data, u64 val)
371 static int debugfs_u8_get(void *data, u64 *val)
376 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
377 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
378 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
381 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
382 * @name: a pointer to a string containing the name of the file to create.
383 * @mode: the permission that the file should have
384 * @parent: a pointer to the parent dentry for this file. This should be a
385 * directory dentry if set. If this parameter is %NULL, then the
386 * file will be created in the root of the debugfs filesystem.
387 * @value: a pointer to the variable that the file should read to and write
390 * This function creates a file in debugfs with the given name that
391 * contains the value of the variable @value. If the @mode variable is so
392 * set, it can be read from, and written to.
394 * This function will return a pointer to a dentry if it succeeds. This
395 * pointer must be passed to the debugfs_remove() function when the file is
396 * to be removed (no automatic cleanup happens if your module is unloaded,
397 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
400 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
403 struct dentry *debugfs_create_u8(const char *name, umode_t mode,
404 struct dentry *parent, u8 *value)
406 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
407 &fops_u8_ro, &fops_u8_wo);
409 EXPORT_SYMBOL_GPL(debugfs_create_u8);
411 static int debugfs_u16_set(void *data, u64 val)
416 static int debugfs_u16_get(void *data, u64 *val)
421 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
422 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
423 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
426 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
427 * @name: a pointer to a string containing the name of the file to create.
428 * @mode: the permission that the file should have
429 * @parent: a pointer to the parent dentry for this file. This should be a
430 * directory dentry if set. If this parameter is %NULL, then the
431 * file will be created in the root of the debugfs filesystem.
432 * @value: a pointer to the variable that the file should read to and write
435 * This function creates a file in debugfs with the given name that
436 * contains the value of the variable @value. If the @mode variable is so
437 * set, it can be read from, and written to.
439 * This function will return a pointer to a dentry if it succeeds. This
440 * pointer must be passed to the debugfs_remove() function when the file is
441 * to be removed (no automatic cleanup happens if your module is unloaded,
442 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
445 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
448 struct dentry *debugfs_create_u16(const char *name, umode_t mode,
449 struct dentry *parent, u16 *value)
451 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
452 &fops_u16_ro, &fops_u16_wo);
454 EXPORT_SYMBOL_GPL(debugfs_create_u16);
456 static int debugfs_u32_set(void *data, u64 val)
461 static int debugfs_u32_get(void *data, u64 *val)
466 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
467 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
468 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
471 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
472 * @name: a pointer to a string containing the name of the file to create.
473 * @mode: the permission that the file should have
474 * @parent: a pointer to the parent dentry for this file. This should be a
475 * directory dentry if set. If this parameter is %NULL, then the
476 * file will be created in the root of the debugfs filesystem.
477 * @value: a pointer to the variable that the file should read to and write
480 * This function creates a file in debugfs with the given name that
481 * contains the value of the variable @value. If the @mode variable is so
482 * set, it can be read from, and written to.
484 * This function will return a pointer to a dentry if it succeeds. This
485 * pointer must be passed to the debugfs_remove() function when the file is
486 * to be removed (no automatic cleanup happens if your module is unloaded,
487 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
490 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
493 struct dentry *debugfs_create_u32(const char *name, umode_t mode,
494 struct dentry *parent, u32 *value)
496 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
497 &fops_u32_ro, &fops_u32_wo);
499 EXPORT_SYMBOL_GPL(debugfs_create_u32);
501 static int debugfs_u64_set(void *data, u64 val)
507 static int debugfs_u64_get(void *data, u64 *val)
512 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
513 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
514 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
517 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-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
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.
530 * This function will return a pointer to a dentry if it succeeds. This
531 * pointer must be passed to the debugfs_remove() function when the file is
532 * to be removed (no automatic cleanup happens if your module is unloaded,
533 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
536 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
539 struct dentry *debugfs_create_u64(const char *name, umode_t mode,
540 struct dentry *parent, u64 *value)
542 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
543 &fops_u64_ro, &fops_u64_wo);
545 EXPORT_SYMBOL_GPL(debugfs_create_u64);
547 static int debugfs_ulong_set(void *data, u64 val)
549 *(unsigned long *)data = val;
553 static int debugfs_ulong_get(void *data, u64 *val)
555 *val = *(unsigned long *)data;
558 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
560 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
561 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
564 * debugfs_create_ulong - create a debugfs file that is used to read and write
565 * an unsigned long value.
566 * @name: a pointer to a string containing the name of the file to create.
567 * @mode: the permission that the file should have
568 * @parent: a pointer to the parent dentry for this file. This should be a
569 * directory dentry if set. If this parameter is %NULL, then the
570 * file will be created in the root of the debugfs filesystem.
571 * @value: a pointer to the variable that the file should read to and write
574 * This function creates a file in debugfs with the given name that
575 * contains the value of the variable @value. If the @mode variable is so
576 * set, it can be read from, and written to.
578 * This function will return a pointer to a dentry if it succeeds. This
579 * pointer must be passed to the debugfs_remove() function when the file is
580 * to be removed (no automatic cleanup happens if your module is unloaded,
581 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
584 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
587 struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
588 struct dentry *parent, unsigned long *value)
590 return debugfs_create_mode_unsafe(name, mode, parent, value,
591 &fops_ulong, &fops_ulong_ro,
594 EXPORT_SYMBOL_GPL(debugfs_create_ulong);
596 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
597 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
598 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
600 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
602 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
603 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
605 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
607 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
608 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
610 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
612 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
613 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
616 * 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
618 * These functions are exactly the same as the above functions (but use a hex
619 * output for the decimal challenged). For details look at the above unsigned
624 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
625 * @name: a pointer to a string containing the name of the file to create.
626 * @mode: the permission that the file should have
627 * @parent: a pointer to the parent dentry for this file. This should be a
628 * directory dentry if set. If this parameter is %NULL, then the
629 * file will be created in the root of the debugfs filesystem.
630 * @value: a pointer to the variable that the file should read to and write
633 struct dentry *debugfs_create_x8(const char *name, umode_t mode,
634 struct dentry *parent, u8 *value)
636 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
637 &fops_x8_ro, &fops_x8_wo);
639 EXPORT_SYMBOL_GPL(debugfs_create_x8);
642 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-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
651 struct dentry *debugfs_create_x16(const char *name, umode_t mode,
652 struct dentry *parent, u16 *value)
654 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
655 &fops_x16_ro, &fops_x16_wo);
657 EXPORT_SYMBOL_GPL(debugfs_create_x16);
660 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-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
669 struct dentry *debugfs_create_x32(const char *name, umode_t mode,
670 struct dentry *parent, u32 *value)
672 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
673 &fops_x32_ro, &fops_x32_wo);
675 EXPORT_SYMBOL_GPL(debugfs_create_x32);
678 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-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
687 struct dentry *debugfs_create_x64(const char *name, umode_t mode,
688 struct dentry *parent, u64 *value)
690 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
691 &fops_x64_ro, &fops_x64_wo);
693 EXPORT_SYMBOL_GPL(debugfs_create_x64);
696 static int debugfs_size_t_set(void *data, u64 val)
698 *(size_t *)data = val;
701 static int debugfs_size_t_get(void *data, u64 *val)
703 *val = *(size_t *)data;
706 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
707 "%llu\n"); /* %llu and %zu are more or less the same */
708 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
709 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
712 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
713 * @name: a pointer to a string containing the name of the file to create.
714 * @mode: the permission that the file should have
715 * @parent: a pointer to the parent dentry for this file. This should be a
716 * directory dentry if set. If this parameter is %NULL, then the
717 * file will be created in the root of the debugfs filesystem.
718 * @value: a pointer to the variable that the file should read to and write
721 struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
722 struct dentry *parent, size_t *value)
724 return debugfs_create_mode_unsafe(name, mode, parent, value,
725 &fops_size_t, &fops_size_t_ro,
728 EXPORT_SYMBOL_GPL(debugfs_create_size_t);
730 static int debugfs_atomic_t_set(void *data, u64 val)
732 atomic_set((atomic_t *)data, val);
735 static int debugfs_atomic_t_get(void *data, u64 *val)
737 *val = atomic_read((atomic_t *)data);
740 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
741 debugfs_atomic_t_set, "%lld\n");
742 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
744 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
748 * debugfs_create_atomic_t - create a debugfs file that is used to read and
749 * write an atomic_t value
750 * @name: a pointer to a string containing the name of the file to create.
751 * @mode: the permission that the file should have
752 * @parent: a pointer to the parent dentry for this file. This should be a
753 * directory dentry if set. If this parameter is %NULL, then the
754 * file will be created in the root of the debugfs filesystem.
755 * @value: a pointer to the variable that the file should read to and write
758 struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
759 struct dentry *parent, atomic_t *value)
761 return debugfs_create_mode_unsafe(name, mode, parent, value,
762 &fops_atomic_t, &fops_atomic_t_ro,
765 EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
767 ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
768 size_t count, loff_t *ppos)
773 struct dentry *dentry = F_DENTRY(file);
775 r = debugfs_file_get(dentry);
778 val = *(bool *)file->private_data;
779 debugfs_file_put(dentry);
787 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
789 EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
791 ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
792 size_t count, loff_t *ppos)
796 bool *val = file->private_data;
797 struct dentry *dentry = F_DENTRY(file);
799 r = kstrtobool_from_user(user_buf, count, &bv);
801 r = debugfs_file_get(dentry);
805 debugfs_file_put(dentry);
810 EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
812 static const struct file_operations fops_bool = {
813 .read = debugfs_read_file_bool,
814 .write = debugfs_write_file_bool,
816 .llseek = default_llseek,
819 static const struct file_operations fops_bool_ro = {
820 .read = debugfs_read_file_bool,
822 .llseek = default_llseek,
825 static const struct file_operations fops_bool_wo = {
826 .write = debugfs_write_file_bool,
828 .llseek = default_llseek,
832 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
833 * @name: a pointer to a string containing the name of the file to create.
834 * @mode: the permission that the file should have
835 * @parent: a pointer to the parent dentry for this file. This should be a
836 * directory dentry if set. If this parameter is %NULL, then the
837 * file will be created in the root of the debugfs filesystem.
838 * @value: a pointer to the variable that the file should read to and write
841 * This function creates a file in debugfs with the given name that
842 * contains the value of the variable @value. If the @mode variable is so
843 * set, it can be read from, and written to.
845 * This function will return a pointer to a dentry if it succeeds. This
846 * pointer must be passed to the debugfs_remove() function when the file is
847 * to be removed (no automatic cleanup happens if your module is unloaded,
848 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
851 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
854 struct dentry *debugfs_create_bool(const char *name, umode_t mode,
855 struct dentry *parent, bool *value)
857 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
858 &fops_bool_ro, &fops_bool_wo);
860 EXPORT_SYMBOL_GPL(debugfs_create_bool);
862 static ssize_t read_file_blob(struct file *file, char __user *user_buf,
863 size_t count, loff_t *ppos)
865 struct debugfs_blob_wrapper *blob = file->private_data;
866 struct dentry *dentry = F_DENTRY(file);
869 r = debugfs_file_get(dentry);
872 r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
874 debugfs_file_put(dentry);
878 static const struct file_operations fops_blob = {
879 .read = read_file_blob,
881 .llseek = default_llseek,
885 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
886 * @name: a pointer to a string containing the name of the file to create.
887 * @mode: the permission that the file should have
888 * @parent: a pointer to the parent dentry for this file. This should be a
889 * directory dentry if set. If this parameter is %NULL, then the
890 * file will be created in the root of the debugfs filesystem.
891 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
892 * to the blob data and the size of the data.
894 * This function creates a file in debugfs with the given name that exports
895 * @blob->data as a binary blob. If the @mode variable is so set it can be
896 * read from. Writing is not supported.
898 * This function will return a pointer to a dentry if it succeeds. This
899 * pointer must be passed to the debugfs_remove() function when the file is
900 * to be removed (no automatic cleanup happens if your module is unloaded,
901 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
904 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
907 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
908 struct dentry *parent,
909 struct debugfs_blob_wrapper *blob)
911 return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob);
913 EXPORT_SYMBOL_GPL(debugfs_create_blob);
920 static size_t u32_format_array(char *buf, size_t bufsize,
921 u32 *array, int array_size)
925 while (--array_size >= 0) {
927 char term = array_size ? ' ' : '\n';
929 len = snprintf(buf, bufsize, "%u%c", *array++, term);
938 static int u32_array_open(struct inode *inode, struct file *file)
940 struct array_data *data = inode->i_private;
941 int size, elements = data->elements;
946 * - 10 digits + ' '/'\n' = 11 bytes per number
947 * - terminating NUL character
950 buf = kmalloc(size+1, GFP_KERNEL);
955 file->private_data = buf;
956 u32_format_array(buf, size, data->array, data->elements);
958 return nonseekable_open(inode, file);
961 static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
964 size_t size = strlen(file->private_data);
966 return simple_read_from_buffer(buf, len, ppos,
967 file->private_data, size);
970 static int u32_array_release(struct inode *inode, struct file *file)
972 kfree(file->private_data);
977 static const struct file_operations u32_array_fops = {
978 .owner = THIS_MODULE,
979 .open = u32_array_open,
980 .release = u32_array_release,
981 .read = u32_array_read,
986 * debugfs_create_u32_array - create a debugfs file that is used to read u32
988 * @name: a pointer to a string containing the name of the file to create.
989 * @mode: the permission that the file should have.
990 * @parent: a pointer to the parent dentry for this file. This should be a
991 * directory dentry if set. If this parameter is %NULL, then the
992 * file will be created in the root of the debugfs filesystem.
993 * @array: u32 array that provides data.
994 * @elements: total number of elements in the array.
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.
1001 * The function returns a pointer to dentry on success. If an error occurs,
1002 * %ERR_PTR(-ERROR) or NULL will be returned. If debugfs is not enabled in
1003 * the kernel, the value %ERR_PTR(-ENODEV) will be returned.
1005 struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
1006 struct dentry *parent,
1007 u32 *array, u32 elements)
1009 struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
1014 data->array = array;
1015 data->elements = elements;
1017 return debugfs_create_file_unsafe(name, mode, parent, data,
1020 EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1022 #ifdef CONFIG_HAS_IOMEM
1025 * The regset32 stuff is used to print 32-bit registers using the
1026 * seq_file utilities. We offer printing a register set in an already-opened
1027 * sequential file or create a debugfs file that only prints a regset32.
1031 * debugfs_print_regs32 - use seq_print to describe a set of registers
1032 * @s: the seq_file structure being used to generate output
1033 * @regs: an array if struct debugfs_reg32 structures
1034 * @nregs: the length of the above array
1035 * @base: the base address to be used in reading the registers
1036 * @prefix: a string to be prefixed to every output line
1038 * This function outputs a text block describing the current values of
1039 * some 32-bit hardware registers. It is meant to be used within debugfs
1040 * files based on seq_file that need to show registers, intermixed with other
1041 * information. The prefix argument may be used to specify a leading string,
1042 * because some peripherals have several blocks of identical registers,
1043 * for example configuration of dma channels
1045 void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1046 int nregs, void __iomem *base, char *prefix)
1050 for (i = 0; i < nregs; i++, regs++) {
1052 seq_printf(s, "%s", prefix);
1053 seq_printf(s, "%s = 0x%08x\n", regs->name,
1054 readl(base + regs->offset));
1055 if (seq_has_overflowed(s))
1059 EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1061 static int debugfs_show_regset32(struct seq_file *s, void *data)
1063 struct debugfs_regset32 *regset = s->private;
1065 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1069 static int debugfs_open_regset32(struct inode *inode, struct file *file)
1071 return single_open(file, debugfs_show_regset32, inode->i_private);
1074 static const struct file_operations fops_regset32 = {
1075 .open = debugfs_open_regset32,
1077 .llseek = seq_lseek,
1078 .release = single_release,
1082 * debugfs_create_regset32 - create a debugfs file that returns register values
1083 * @name: a pointer to a string containing the name of the file to create.
1084 * @mode: the permission that the file should have
1085 * @parent: a pointer to the parent dentry for this file. This should be a
1086 * directory dentry if set. If this parameter is %NULL, then the
1087 * file will be created in the root of the debugfs filesystem.
1088 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1089 * to an array of register definitions, the array size and the base
1090 * address where the register bank is to be found.
1092 * This function creates a file in debugfs with the given name that reports
1093 * the names and values of a set of 32-bit registers. If the @mode variable
1094 * is so set it can be read from. Writing is not supported.
1096 * This function will return a pointer to a dentry if it succeeds. This
1097 * pointer must be passed to the debugfs_remove() function when the file is
1098 * to be removed (no automatic cleanup happens if your module is unloaded,
1099 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
1102 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
1105 struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
1106 struct dentry *parent,
1107 struct debugfs_regset32 *regset)
1109 return debugfs_create_file(name, mode, parent, regset, &fops_regset32);
1111 EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1113 #endif /* CONFIG_HAS_IOMEM */
1115 struct debugfs_devm_entry {
1116 int (*read)(struct seq_file *seq, void *data);
1120 static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1122 struct debugfs_devm_entry *entry = inode->i_private;
1124 return single_open(f, entry->read, entry->dev);
1127 static const struct file_operations debugfs_devm_entry_ops = {
1128 .owner = THIS_MODULE,
1129 .open = debugfs_devm_entry_open,
1130 .release = single_release,
1136 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1138 * @dev: device related to this debugfs file.
1139 * @name: name of the debugfs file.
1140 * @parent: a pointer to the parent dentry for this file. This should be a
1141 * directory dentry if set. If this parameter is %NULL, then the
1142 * file will be created in the root of the debugfs filesystem.
1143 * @read_fn: function pointer called to print the seq_file content.
1145 struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
1146 struct dentry *parent,
1147 int (*read_fn)(struct seq_file *s,
1150 struct debugfs_devm_entry *entry;
1153 return ERR_PTR(-ENOENT);
1155 entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
1157 return ERR_PTR(-ENOMEM);
1159 entry->read = read_fn;
1162 return debugfs_create_file(name, S_IRUGO, parent, entry,
1163 &debugfs_devm_entry_ops);
1165 EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);