1 // SPDX-License-Identifier: GPL-2.0
3 * file.c - part of debugfs, a tiny little debug file system
5 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
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>
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 if (kernel_is_locked_down("debugfs"))
149 r
= debugfs_file_get(dentry
);
151 return r
== -EIO
? -ENOENT
: r
;
153 real_fops
= debugfs_real_fops(filp
);
154 real_fops
= fops_get(real_fops
);
156 /* Huh? Module did not clean up after itself at exit? */
157 WARN(1, "debugfs file owner did not clean up at exit: %pd",
162 replace_fops(filp
, real_fops
);
165 r
= real_fops
->open(inode
, filp
);
168 debugfs_file_put(dentry
);
172 const struct file_operations debugfs_open_proxy_file_operations
= {
173 .open
= open_proxy_open
,
176 #define PROTO(args...) args
177 #define ARGS(args...) args
179 #define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
180 static ret_type full_proxy_ ## name(proto) \
182 struct dentry *dentry = F_DENTRY(filp); \
183 const struct file_operations *real_fops; \
186 r = debugfs_file_get(dentry); \
189 real_fops = debugfs_real_fops(filp); \
190 r = real_fops->name(args); \
191 debugfs_file_put(dentry); \
195 FULL_PROXY_FUNC(llseek
, loff_t
, filp
,
196 PROTO(struct file
*filp
, loff_t offset
, int whence
),
197 ARGS(filp
, offset
, whence
));
199 FULL_PROXY_FUNC(read
, ssize_t
, filp
,
200 PROTO(struct file
*filp
, char __user
*buf
, size_t size
,
202 ARGS(filp
, buf
, size
, ppos
));
204 FULL_PROXY_FUNC(write
, ssize_t
, filp
,
205 PROTO(struct file
*filp
, const char __user
*buf
, size_t size
,
207 ARGS(filp
, buf
, size
, ppos
));
209 FULL_PROXY_FUNC(unlocked_ioctl
, long, filp
,
210 PROTO(struct file
*filp
, unsigned int cmd
, unsigned long arg
),
211 ARGS(filp
, cmd
, arg
));
213 static unsigned int full_proxy_poll(struct file
*filp
,
214 struct poll_table_struct
*wait
)
216 struct dentry
*dentry
= F_DENTRY(filp
);
218 const struct file_operations
*real_fops
;
220 if (debugfs_file_get(dentry
))
223 real_fops
= debugfs_real_fops(filp
);
224 r
= real_fops
->poll(filp
, wait
);
225 debugfs_file_put(dentry
);
229 static int full_proxy_release(struct inode
*inode
, struct file
*filp
)
231 const struct dentry
*dentry
= F_DENTRY(filp
);
232 const struct file_operations
*real_fops
= debugfs_real_fops(filp
);
233 const struct file_operations
*proxy_fops
= filp
->f_op
;
237 * We must not protect this against removal races here: the
238 * original releaser should be called unconditionally in order
239 * not to leak any resources. Releasers must not assume that
240 * ->i_private is still being meaningful here.
242 if (real_fops
->release
)
243 r
= real_fops
->release(inode
, filp
);
245 replace_fops(filp
, d_inode(dentry
)->i_fop
);
246 kfree((void *)proxy_fops
);
251 static void __full_proxy_fops_init(struct file_operations
*proxy_fops
,
252 const struct file_operations
*real_fops
)
254 proxy_fops
->release
= full_proxy_release
;
255 if (real_fops
->llseek
)
256 proxy_fops
->llseek
= full_proxy_llseek
;
258 proxy_fops
->read
= full_proxy_read
;
259 if (real_fops
->write
)
260 proxy_fops
->write
= full_proxy_write
;
262 proxy_fops
->poll
= full_proxy_poll
;
263 if (real_fops
->unlocked_ioctl
)
264 proxy_fops
->unlocked_ioctl
= full_proxy_unlocked_ioctl
;
267 static int full_proxy_open(struct inode
*inode
, struct file
*filp
)
269 struct dentry
*dentry
= F_DENTRY(filp
);
270 const struct file_operations
*real_fops
= NULL
;
271 struct file_operations
*proxy_fops
= NULL
;
274 if (kernel_is_locked_down("debugfs"))
277 r
= debugfs_file_get(dentry
);
279 return r
== -EIO
? -ENOENT
: r
;
281 real_fops
= debugfs_real_fops(filp
);
282 real_fops
= fops_get(real_fops
);
284 /* Huh? Module did not cleanup after itself at exit? */
285 WARN(1, "debugfs file owner did not clean up at exit: %pd",
291 proxy_fops
= kzalloc(sizeof(*proxy_fops
), GFP_KERNEL
);
296 __full_proxy_fops_init(proxy_fops
, real_fops
);
297 replace_fops(filp
, proxy_fops
);
299 if (real_fops
->open
) {
300 r
= real_fops
->open(inode
, filp
);
302 replace_fops(filp
, d_inode(dentry
)->i_fop
);
304 } else if (filp
->f_op
!= proxy_fops
) {
305 /* No protection against file removal anymore. */
306 WARN(1, "debugfs file owner replaced proxy fops: %pd",
317 debugfs_file_put(dentry
);
321 const struct file_operations debugfs_full_proxy_file_operations
= {
322 .open
= full_proxy_open
,
325 ssize_t
debugfs_attr_read(struct file
*file
, char __user
*buf
,
326 size_t len
, loff_t
*ppos
)
328 struct dentry
*dentry
= F_DENTRY(file
);
331 ret
= debugfs_file_get(dentry
);
334 ret
= simple_attr_read(file
, buf
, len
, ppos
);
335 debugfs_file_put(dentry
);
338 EXPORT_SYMBOL_GPL(debugfs_attr_read
);
340 ssize_t
debugfs_attr_write(struct file
*file
, const char __user
*buf
,
341 size_t len
, loff_t
*ppos
)
343 struct dentry
*dentry
= F_DENTRY(file
);
346 ret
= debugfs_file_get(dentry
);
349 ret
= simple_attr_write(file
, buf
, len
, ppos
);
350 debugfs_file_put(dentry
);
353 EXPORT_SYMBOL_GPL(debugfs_attr_write
);
355 static struct dentry
*debugfs_create_mode_unsafe(const char *name
, umode_t mode
,
356 struct dentry
*parent
, void *value
,
357 const struct file_operations
*fops
,
358 const struct file_operations
*fops_ro
,
359 const struct file_operations
*fops_wo
)
361 /* if there are no write bits set, make read only */
362 if (!(mode
& S_IWUGO
))
363 return debugfs_create_file_unsafe(name
, mode
, parent
, value
,
365 /* if there are no read bits set, make write only */
366 if (!(mode
& S_IRUGO
))
367 return debugfs_create_file_unsafe(name
, mode
, parent
, value
,
370 return debugfs_create_file_unsafe(name
, mode
, parent
, value
, fops
);
373 static int debugfs_u8_set(void *data
, u64 val
)
378 static int debugfs_u8_get(void *data
, u64
*val
)
383 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8
, debugfs_u8_get
, debugfs_u8_set
, "%llu\n");
384 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro
, debugfs_u8_get
, NULL
, "%llu\n");
385 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo
, NULL
, debugfs_u8_set
, "%llu\n");
388 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
389 * @name: a pointer to a string containing the name of the file to create.
390 * @mode: the permission that the file should have
391 * @parent: a pointer to the parent dentry for this file. This should be a
392 * directory dentry if set. If this parameter is %NULL, then the
393 * file will be created in the root of the debugfs filesystem.
394 * @value: a pointer to the variable that the file should read to and write
397 * This function creates a file in debugfs with the given name that
398 * contains the value of the variable @value. If the @mode variable is so
399 * set, it can be read from, and written to.
401 * This function will return a pointer to a dentry if it succeeds. This
402 * pointer must be passed to the debugfs_remove() function when the file is
403 * to be removed (no automatic cleanup happens if your module is unloaded,
404 * you are responsible here.) If an error occurs, %NULL will be returned.
406 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
407 * returned. It is not wise to check for this value, but rather, check for
408 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
411 struct dentry
*debugfs_create_u8(const char *name
, umode_t mode
,
412 struct dentry
*parent
, u8
*value
)
414 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_u8
,
415 &fops_u8_ro
, &fops_u8_wo
);
417 EXPORT_SYMBOL_GPL(debugfs_create_u8
);
419 static int debugfs_u16_set(void *data
, u64 val
)
424 static int debugfs_u16_get(void *data
, u64
*val
)
429 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16
, debugfs_u16_get
, debugfs_u16_set
, "%llu\n");
430 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro
, debugfs_u16_get
, NULL
, "%llu\n");
431 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo
, NULL
, debugfs_u16_set
, "%llu\n");
434 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
435 * @name: a pointer to a string containing the name of the file to create.
436 * @mode: the permission that the file should have
437 * @parent: a pointer to the parent dentry for this file. This should be a
438 * directory dentry if set. If this parameter is %NULL, then the
439 * file will be created in the root of the debugfs filesystem.
440 * @value: a pointer to the variable that the file should read to and write
443 * This function creates a file in debugfs with the given name that
444 * contains the value of the variable @value. If the @mode variable is so
445 * set, it can be read from, and written to.
447 * This function will return a pointer to a dentry if it succeeds. This
448 * pointer must be passed to the debugfs_remove() function when the file is
449 * to be removed (no automatic cleanup happens if your module is unloaded,
450 * you are responsible here.) If an error occurs, %NULL will be returned.
452 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
453 * returned. It is not wise to check for this value, but rather, check for
454 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
457 struct dentry
*debugfs_create_u16(const char *name
, umode_t mode
,
458 struct dentry
*parent
, u16
*value
)
460 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_u16
,
461 &fops_u16_ro
, &fops_u16_wo
);
463 EXPORT_SYMBOL_GPL(debugfs_create_u16
);
465 static int debugfs_u32_set(void *data
, u64 val
)
470 static int debugfs_u32_get(void *data
, u64
*val
)
475 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32
, debugfs_u32_get
, debugfs_u32_set
, "%llu\n");
476 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro
, debugfs_u32_get
, NULL
, "%llu\n");
477 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo
, NULL
, debugfs_u32_set
, "%llu\n");
480 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
481 * @name: a pointer to a string containing the name of the file to create.
482 * @mode: the permission that the file should have
483 * @parent: a pointer to the parent dentry for this file. This should be a
484 * directory dentry if set. If this parameter is %NULL, then the
485 * file will be created in the root of the debugfs filesystem.
486 * @value: a pointer to the variable that the file should read to and write
489 * This function creates a file in debugfs with the given name that
490 * contains the value of the variable @value. If the @mode variable is so
491 * set, it can be read from, and written to.
493 * This function will return a pointer to a dentry if it succeeds. This
494 * pointer must be passed to the debugfs_remove() function when the file is
495 * to be removed (no automatic cleanup happens if your module is unloaded,
496 * you are responsible here.) If an error occurs, %NULL will be returned.
498 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
499 * returned. It is not wise to check for this value, but rather, check for
500 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
503 struct dentry
*debugfs_create_u32(const char *name
, umode_t mode
,
504 struct dentry
*parent
, u32
*value
)
506 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_u32
,
507 &fops_u32_ro
, &fops_u32_wo
);
509 EXPORT_SYMBOL_GPL(debugfs_create_u32
);
511 static int debugfs_u64_set(void *data
, u64 val
)
517 static int debugfs_u64_get(void *data
, u64
*val
)
522 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64
, debugfs_u64_get
, debugfs_u64_set
, "%llu\n");
523 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro
, debugfs_u64_get
, NULL
, "%llu\n");
524 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo
, NULL
, debugfs_u64_set
, "%llu\n");
527 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
528 * @name: a pointer to a string containing the name of the file to create.
529 * @mode: the permission that the file should have
530 * @parent: a pointer to the parent dentry for this file. This should be a
531 * directory dentry if set. If this parameter is %NULL, then the
532 * file will be created in the root of the debugfs filesystem.
533 * @value: a pointer to the variable that the file should read to and write
536 * This function creates a file in debugfs with the given name that
537 * contains the value of the variable @value. If the @mode variable is so
538 * set, it can be read from, and written to.
540 * This function will return a pointer to a dentry if it succeeds. This
541 * pointer must be passed to the debugfs_remove() function when the file is
542 * to be removed (no automatic cleanup happens if your module is unloaded,
543 * you are responsible here.) If an error occurs, %NULL will be returned.
545 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
546 * returned. It is not wise to check for this value, but rather, check for
547 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
550 struct dentry
*debugfs_create_u64(const char *name
, umode_t mode
,
551 struct dentry
*parent
, u64
*value
)
553 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_u64
,
554 &fops_u64_ro
, &fops_u64_wo
);
556 EXPORT_SYMBOL_GPL(debugfs_create_u64
);
558 static int debugfs_ulong_set(void *data
, u64 val
)
560 *(unsigned long *)data
= val
;
564 static int debugfs_ulong_get(void *data
, u64
*val
)
566 *val
= *(unsigned long *)data
;
569 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong
, debugfs_ulong_get
, debugfs_ulong_set
,
571 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro
, debugfs_ulong_get
, NULL
, "%llu\n");
572 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo
, NULL
, debugfs_ulong_set
, "%llu\n");
575 * debugfs_create_ulong - create a debugfs file that is used to read and write
576 * an unsigned long value.
577 * @name: a pointer to a string containing the name of the file to create.
578 * @mode: the permission that the file should have
579 * @parent: a pointer to the parent dentry for this file. This should be a
580 * directory dentry if set. If this parameter is %NULL, then the
581 * file will be created in the root of the debugfs filesystem.
582 * @value: a pointer to the variable that the file should read to and write
585 * This function creates a file in debugfs with the given name that
586 * contains the value of the variable @value. If the @mode variable is so
587 * set, it can be read from, and written to.
589 * This function will return a pointer to a dentry if it succeeds. This
590 * pointer must be passed to the debugfs_remove() function when the file is
591 * to be removed (no automatic cleanup happens if your module is unloaded,
592 * you are responsible here.) If an error occurs, %NULL will be returned.
594 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
595 * returned. It is not wise to check for this value, but rather, check for
596 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
599 struct dentry
*debugfs_create_ulong(const char *name
, umode_t mode
,
600 struct dentry
*parent
, unsigned long *value
)
602 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
,
603 &fops_ulong
, &fops_ulong_ro
,
606 EXPORT_SYMBOL_GPL(debugfs_create_ulong
);
608 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8
, debugfs_u8_get
, debugfs_u8_set
, "0x%02llx\n");
609 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro
, debugfs_u8_get
, NULL
, "0x%02llx\n");
610 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo
, NULL
, debugfs_u8_set
, "0x%02llx\n");
612 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16
, debugfs_u16_get
, debugfs_u16_set
,
614 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro
, debugfs_u16_get
, NULL
, "0x%04llx\n");
615 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo
, NULL
, debugfs_u16_set
, "0x%04llx\n");
617 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32
, debugfs_u32_get
, debugfs_u32_set
,
619 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro
, debugfs_u32_get
, NULL
, "0x%08llx\n");
620 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo
, NULL
, debugfs_u32_set
, "0x%08llx\n");
622 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64
, debugfs_u64_get
, debugfs_u64_set
,
624 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro
, debugfs_u64_get
, NULL
, "0x%016llx\n");
625 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo
, NULL
, debugfs_u64_set
, "0x%016llx\n");
628 * 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
630 * These functions are exactly the same as the above functions (but use a hex
631 * output for the decimal challenged). For details look at the above unsigned
636 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
637 * @name: a pointer to a string containing the name of the file to create.
638 * @mode: the permission that the file should have
639 * @parent: a pointer to the parent dentry for this file. This should be a
640 * directory dentry if set. If this parameter is %NULL, then the
641 * file will be created in the root of the debugfs filesystem.
642 * @value: a pointer to the variable that the file should read to and write
645 struct dentry
*debugfs_create_x8(const char *name
, umode_t mode
,
646 struct dentry
*parent
, u8
*value
)
648 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_x8
,
649 &fops_x8_ro
, &fops_x8_wo
);
651 EXPORT_SYMBOL_GPL(debugfs_create_x8
);
654 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
655 * @name: a pointer to a string containing the name of the file to create.
656 * @mode: the permission that the file should have
657 * @parent: a pointer to the parent dentry for this file. This should be a
658 * directory dentry if set. If this parameter is %NULL, then the
659 * file will be created in the root of the debugfs filesystem.
660 * @value: a pointer to the variable that the file should read to and write
663 struct dentry
*debugfs_create_x16(const char *name
, umode_t mode
,
664 struct dentry
*parent
, u16
*value
)
666 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_x16
,
667 &fops_x16_ro
, &fops_x16_wo
);
669 EXPORT_SYMBOL_GPL(debugfs_create_x16
);
672 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
673 * @name: a pointer to a string containing the name of the file to create.
674 * @mode: the permission that the file should have
675 * @parent: a pointer to the parent dentry for this file. This should be a
676 * directory dentry if set. If this parameter is %NULL, then the
677 * file will be created in the root of the debugfs filesystem.
678 * @value: a pointer to the variable that the file should read to and write
681 struct dentry
*debugfs_create_x32(const char *name
, umode_t mode
,
682 struct dentry
*parent
, u32
*value
)
684 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_x32
,
685 &fops_x32_ro
, &fops_x32_wo
);
687 EXPORT_SYMBOL_GPL(debugfs_create_x32
);
690 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
691 * @name: a pointer to a string containing the name of the file to create.
692 * @mode: the permission that the file should have
693 * @parent: a pointer to the parent dentry for this file. This should be a
694 * directory dentry if set. If this parameter is %NULL, then the
695 * file will be created in the root of the debugfs filesystem.
696 * @value: a pointer to the variable that the file should read to and write
699 struct dentry
*debugfs_create_x64(const char *name
, umode_t mode
,
700 struct dentry
*parent
, u64
*value
)
702 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_x64
,
703 &fops_x64_ro
, &fops_x64_wo
);
705 EXPORT_SYMBOL_GPL(debugfs_create_x64
);
708 static int debugfs_size_t_set(void *data
, u64 val
)
710 *(size_t *)data
= val
;
713 static int debugfs_size_t_get(void *data
, u64
*val
)
715 *val
= *(size_t *)data
;
718 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t
, debugfs_size_t_get
, debugfs_size_t_set
,
719 "%llu\n"); /* %llu and %zu are more or less the same */
720 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro
, debugfs_size_t_get
, NULL
, "%llu\n");
721 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo
, NULL
, debugfs_size_t_set
, "%llu\n");
724 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
725 * @name: a pointer to a string containing the name of the file to create.
726 * @mode: the permission that the file should have
727 * @parent: a pointer to the parent dentry for this file. This should be a
728 * directory dentry if set. If this parameter is %NULL, then the
729 * file will be created in the root of the debugfs filesystem.
730 * @value: a pointer to the variable that the file should read to and write
733 struct dentry
*debugfs_create_size_t(const char *name
, umode_t mode
,
734 struct dentry
*parent
, size_t *value
)
736 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
,
737 &fops_size_t
, &fops_size_t_ro
,
740 EXPORT_SYMBOL_GPL(debugfs_create_size_t
);
742 static int debugfs_atomic_t_set(void *data
, u64 val
)
744 atomic_set((atomic_t
*)data
, val
);
747 static int debugfs_atomic_t_get(void *data
, u64
*val
)
749 *val
= atomic_read((atomic_t
*)data
);
752 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t
, debugfs_atomic_t_get
,
753 debugfs_atomic_t_set
, "%lld\n");
754 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro
, debugfs_atomic_t_get
, NULL
,
756 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo
, NULL
, debugfs_atomic_t_set
,
760 * debugfs_create_atomic_t - create a debugfs file that is used to read and
761 * write an atomic_t value
762 * @name: a pointer to a string containing the name of the file to create.
763 * @mode: the permission that the file should have
764 * @parent: a pointer to the parent dentry for this file. This should be a
765 * directory dentry if set. If this parameter is %NULL, then the
766 * file will be created in the root of the debugfs filesystem.
767 * @value: a pointer to the variable that the file should read to and write
770 struct dentry
*debugfs_create_atomic_t(const char *name
, umode_t mode
,
771 struct dentry
*parent
, atomic_t
*value
)
773 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
,
774 &fops_atomic_t
, &fops_atomic_t_ro
,
777 EXPORT_SYMBOL_GPL(debugfs_create_atomic_t
);
779 ssize_t
debugfs_read_file_bool(struct file
*file
, char __user
*user_buf
,
780 size_t count
, loff_t
*ppos
)
785 struct dentry
*dentry
= F_DENTRY(file
);
787 r
= debugfs_file_get(dentry
);
790 val
= *(bool *)file
->private_data
;
791 debugfs_file_put(dentry
);
799 return simple_read_from_buffer(user_buf
, count
, ppos
, buf
, 2);
801 EXPORT_SYMBOL_GPL(debugfs_read_file_bool
);
803 ssize_t
debugfs_write_file_bool(struct file
*file
, const char __user
*user_buf
,
804 size_t count
, loff_t
*ppos
)
810 bool *val
= file
->private_data
;
811 struct dentry
*dentry
= F_DENTRY(file
);
813 buf_size
= min(count
, (sizeof(buf
)-1));
814 if (copy_from_user(buf
, user_buf
, buf_size
))
817 buf
[buf_size
] = '\0';
818 if (strtobool(buf
, &bv
) == 0) {
819 r
= debugfs_file_get(dentry
);
823 debugfs_file_put(dentry
);
828 EXPORT_SYMBOL_GPL(debugfs_write_file_bool
);
830 static const struct file_operations fops_bool
= {
831 .read
= debugfs_read_file_bool
,
832 .write
= debugfs_write_file_bool
,
834 .llseek
= default_llseek
,
837 static const struct file_operations fops_bool_ro
= {
838 .read
= debugfs_read_file_bool
,
840 .llseek
= default_llseek
,
843 static const struct file_operations fops_bool_wo
= {
844 .write
= debugfs_write_file_bool
,
846 .llseek
= default_llseek
,
850 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
851 * @name: a pointer to a string containing the name of the file to create.
852 * @mode: the permission that the file should have
853 * @parent: a pointer to the parent dentry for this file. This should be a
854 * directory dentry if set. If this parameter is %NULL, then the
855 * file will be created in the root of the debugfs filesystem.
856 * @value: a pointer to the variable that the file should read to and write
859 * This function creates a file in debugfs with the given name that
860 * contains the value of the variable @value. If the @mode variable is so
861 * set, it can be read from, and written to.
863 * This function will return a pointer to a dentry if it succeeds. This
864 * pointer must be passed to the debugfs_remove() function when the file is
865 * to be removed (no automatic cleanup happens if your module is unloaded,
866 * you are responsible here.) If an error occurs, %NULL will be returned.
868 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
869 * returned. It is not wise to check for this value, but rather, check for
870 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
873 struct dentry
*debugfs_create_bool(const char *name
, umode_t mode
,
874 struct dentry
*parent
, bool *value
)
876 return debugfs_create_mode_unsafe(name
, mode
, parent
, value
, &fops_bool
,
877 &fops_bool_ro
, &fops_bool_wo
);
879 EXPORT_SYMBOL_GPL(debugfs_create_bool
);
881 static ssize_t
read_file_blob(struct file
*file
, char __user
*user_buf
,
882 size_t count
, loff_t
*ppos
)
884 struct debugfs_blob_wrapper
*blob
= file
->private_data
;
885 struct dentry
*dentry
= F_DENTRY(file
);
888 r
= debugfs_file_get(dentry
);
891 r
= simple_read_from_buffer(user_buf
, count
, ppos
, blob
->data
,
893 debugfs_file_put(dentry
);
897 static const struct file_operations fops_blob
= {
898 .read
= read_file_blob
,
900 .llseek
= default_llseek
,
904 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
905 * @name: a pointer to a string containing the name of the file to create.
906 * @mode: the permission that the file should have
907 * @parent: a pointer to the parent dentry for this file. This should be a
908 * directory dentry if set. If this parameter is %NULL, then the
909 * file will be created in the root of the debugfs filesystem.
910 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
911 * to the blob data and the size of the data.
913 * This function creates a file in debugfs with the given name that exports
914 * @blob->data as a binary blob. If the @mode variable is so set it can be
915 * read from. Writing is not supported.
917 * This function will return a pointer to a dentry if it succeeds. This
918 * pointer must be passed to the debugfs_remove() function when the file is
919 * to be removed (no automatic cleanup happens if your module is unloaded,
920 * you are responsible here.) If an error occurs, %NULL will be returned.
922 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
923 * returned. It is not wise to check for this value, but rather, check for
924 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
927 struct dentry
*debugfs_create_blob(const char *name
, umode_t mode
,
928 struct dentry
*parent
,
929 struct debugfs_blob_wrapper
*blob
)
931 return debugfs_create_file_unsafe(name
, mode
, parent
, blob
, &fops_blob
);
933 EXPORT_SYMBOL_GPL(debugfs_create_blob
);
940 static size_t u32_format_array(char *buf
, size_t bufsize
,
941 u32
*array
, int array_size
)
945 while (--array_size
>= 0) {
947 char term
= array_size
? ' ' : '\n';
949 len
= snprintf(buf
, bufsize
, "%u%c", *array
++, term
);
958 static int u32_array_open(struct inode
*inode
, struct file
*file
)
960 struct array_data
*data
= inode
->i_private
;
961 int size
, elements
= data
->elements
;
966 * - 10 digits + ' '/'\n' = 11 bytes per number
967 * - terminating NUL character
970 buf
= kmalloc(size
+1, GFP_KERNEL
);
975 file
->private_data
= buf
;
976 u32_format_array(buf
, size
, data
->array
, data
->elements
);
978 return nonseekable_open(inode
, file
);
981 static ssize_t
u32_array_read(struct file
*file
, char __user
*buf
, size_t len
,
984 size_t size
= strlen(file
->private_data
);
986 return simple_read_from_buffer(buf
, len
, ppos
,
987 file
->private_data
, size
);
990 static int u32_array_release(struct inode
*inode
, struct file
*file
)
992 kfree(file
->private_data
);
997 static const struct file_operations u32_array_fops
= {
998 .owner
= THIS_MODULE
,
999 .open
= u32_array_open
,
1000 .release
= u32_array_release
,
1001 .read
= u32_array_read
,
1002 .llseek
= no_llseek
,
1006 * debugfs_create_u32_array - create a debugfs file that is used to read u32
1008 * @name: a pointer to a string containing the name of the file to create.
1009 * @mode: the permission that the file should have.
1010 * @parent: a pointer to the parent dentry for this file. This should be a
1011 * directory dentry if set. If this parameter is %NULL, then the
1012 * file will be created in the root of the debugfs filesystem.
1013 * @array: u32 array that provides data.
1014 * @elements: total number of elements in the array.
1016 * This function creates a file in debugfs with the given name that exports
1017 * @array as data. If the @mode variable is so set it can be read from.
1018 * Writing is not supported. Seek within the file is also not supported.
1019 * Once array is created its size can not be changed.
1021 * The function returns a pointer to dentry on success. If debugfs is not
1022 * enabled in the kernel, the value -%ENODEV will be returned.
1024 struct dentry
*debugfs_create_u32_array(const char *name
, umode_t mode
,
1025 struct dentry
*parent
,
1026 u32
*array
, u32 elements
)
1028 struct array_data
*data
= kmalloc(sizeof(*data
), GFP_KERNEL
);
1033 data
->array
= array
;
1034 data
->elements
= elements
;
1036 return debugfs_create_file_unsafe(name
, mode
, parent
, data
,
1039 EXPORT_SYMBOL_GPL(debugfs_create_u32_array
);
1041 #ifdef CONFIG_HAS_IOMEM
1044 * The regset32 stuff is used to print 32-bit registers using the
1045 * seq_file utilities. We offer printing a register set in an already-opened
1046 * sequential file or create a debugfs file that only prints a regset32.
1050 * debugfs_print_regs32 - use seq_print to describe a set of registers
1051 * @s: the seq_file structure being used to generate output
1052 * @regs: an array if struct debugfs_reg32 structures
1053 * @nregs: the length of the above array
1054 * @base: the base address to be used in reading the registers
1055 * @prefix: a string to be prefixed to every output line
1057 * This function outputs a text block describing the current values of
1058 * some 32-bit hardware registers. It is meant to be used within debugfs
1059 * files based on seq_file that need to show registers, intermixed with other
1060 * information. The prefix argument may be used to specify a leading string,
1061 * because some peripherals have several blocks of identical registers,
1062 * for example configuration of dma channels
1064 void debugfs_print_regs32(struct seq_file
*s
, const struct debugfs_reg32
*regs
,
1065 int nregs
, void __iomem
*base
, char *prefix
)
1069 for (i
= 0; i
< nregs
; i
++, regs
++) {
1071 seq_printf(s
, "%s", prefix
);
1072 seq_printf(s
, "%s = 0x%08x\n", regs
->name
,
1073 readl(base
+ regs
->offset
));
1074 if (seq_has_overflowed(s
))
1078 EXPORT_SYMBOL_GPL(debugfs_print_regs32
);
1080 static int debugfs_show_regset32(struct seq_file
*s
, void *data
)
1082 struct debugfs_regset32
*regset
= s
->private;
1084 debugfs_print_regs32(s
, regset
->regs
, regset
->nregs
, regset
->base
, "");
1088 static int debugfs_open_regset32(struct inode
*inode
, struct file
*file
)
1090 return single_open(file
, debugfs_show_regset32
, inode
->i_private
);
1093 static const struct file_operations fops_regset32
= {
1094 .open
= debugfs_open_regset32
,
1096 .llseek
= seq_lseek
,
1097 .release
= single_release
,
1101 * debugfs_create_regset32 - create a debugfs file that returns register values
1102 * @name: a pointer to a string containing the name of the file to create.
1103 * @mode: the permission that the file should have
1104 * @parent: a pointer to the parent dentry for this file. This should be a
1105 * directory dentry if set. If this parameter is %NULL, then the
1106 * file will be created in the root of the debugfs filesystem.
1107 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1108 * to an array of register definitions, the array size and the base
1109 * address where the register bank is to be found.
1111 * This function creates a file in debugfs with the given name that reports
1112 * the names and values of a set of 32-bit registers. If the @mode variable
1113 * is so set it can be read from. Writing is not supported.
1115 * This function will return a pointer to a dentry if it succeeds. This
1116 * pointer must be passed to the debugfs_remove() function when the file is
1117 * to be removed (no automatic cleanup happens if your module is unloaded,
1118 * you are responsible here.) If an error occurs, %NULL will be returned.
1120 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
1121 * returned. It is not wise to check for this value, but rather, check for
1122 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
1125 struct dentry
*debugfs_create_regset32(const char *name
, umode_t mode
,
1126 struct dentry
*parent
,
1127 struct debugfs_regset32
*regset
)
1129 return debugfs_create_file(name
, mode
, parent
, regset
, &fops_regset32
);
1131 EXPORT_SYMBOL_GPL(debugfs_create_regset32
);
1133 #endif /* CONFIG_HAS_IOMEM */
1135 struct debugfs_devm_entry
{
1136 int (*read
)(struct seq_file
*seq
, void *data
);
1140 static int debugfs_devm_entry_open(struct inode
*inode
, struct file
*f
)
1142 struct debugfs_devm_entry
*entry
= inode
->i_private
;
1144 return single_open(f
, entry
->read
, entry
->dev
);
1147 static const struct file_operations debugfs_devm_entry_ops
= {
1148 .owner
= THIS_MODULE
,
1149 .open
= debugfs_devm_entry_open
,
1150 .release
= single_release
,
1156 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1158 * @dev: device related to this debugfs file.
1159 * @name: name of the debugfs file.
1160 * @parent: a pointer to the parent dentry for this file. This should be a
1161 * directory dentry if set. If this parameter is %NULL, then the
1162 * file will be created in the root of the debugfs filesystem.
1163 * @read_fn: function pointer called to print the seq_file content.
1165 struct dentry
*debugfs_create_devm_seqfile(struct device
*dev
, const char *name
,
1166 struct dentry
*parent
,
1167 int (*read_fn
)(struct seq_file
*s
,
1170 struct debugfs_devm_entry
*entry
;
1173 return ERR_PTR(-ENOENT
);
1175 entry
= devm_kzalloc(dev
, sizeof(*entry
), GFP_KERNEL
);
1177 return ERR_PTR(-ENOMEM
);
1179 entry
->read
= read_fn
;
1182 return debugfs_create_file(name
, S_IRUGO
, parent
, entry
,
1183 &debugfs_devm_entry_ops
);
1185 EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile
);