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>
21 #include <linux/pm_runtime.h>
22 #include <linux/poll.h>
23 #include <linux/security.h>
27 struct poll_table_struct;
29 static ssize_t default_read_file(struct file *file, char __user *buf,
30 size_t count, loff_t *ppos)
35 static ssize_t default_write_file(struct file *file, const char __user *buf,
36 size_t count, loff_t *ppos)
41 const struct file_operations debugfs_noop_file_operations = {
42 .read = default_read_file,
43 .write = default_write_file,
45 .llseek = noop_llseek,
48 #define F_DENTRY(filp) ((filp)->f_path.dentry)
50 const struct file_operations *debugfs_real_fops(const struct file *filp)
52 struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
54 if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
56 * Urgh, we've been called w/o a protecting
63 return fsd->real_fops;
65 EXPORT_SYMBOL_GPL(debugfs_real_fops);
68 * debugfs_file_get - mark the beginning of file data access
69 * @dentry: the dentry object whose data is being accessed.
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.
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.
82 int debugfs_file_get(struct dentry *dentry)
84 struct debugfs_fsdata *fsd;
87 d_fsd = READ_ONCE(dentry->d_fsdata);
88 if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
91 fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
95 fsd->real_fops = (void *)((unsigned long)d_fsd &
96 ~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
97 refcount_set(&fsd->active_users, 1);
98 init_completion(&fsd->active_users_drained);
99 if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
101 fsd = READ_ONCE(dentry->d_fsdata);
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
113 if (d_unlinked(dentry))
116 if (!refcount_inc_not_zero(&fsd->active_users))
121 EXPORT_SYMBOL_GPL(debugfs_file_get);
124 * debugfs_file_put - mark the end of file data access
125 * @dentry: the dentry object formerly passed to
126 * debugfs_file_get().
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.
132 void debugfs_file_put(struct dentry *dentry)
134 struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
136 if (refcount_dec_and_test(&fsd->active_users))
137 complete(&fsd->active_users_drained);
139 EXPORT_SYMBOL_GPL(debugfs_file_put);
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.
146 static int debugfs_locked_down(struct inode *inode,
148 const struct file_operations *real_fops)
150 if ((inode->i_mode & 07777 & ~0444) == 0 &&
151 !(filp->f_mode & FMODE_WRITE) &&
152 !real_fops->unlocked_ioctl &&
153 !real_fops->compat_ioctl &&
157 if (security_locked_down(LOCKDOWN_DEBUGFS))
163 static int open_proxy_open(struct inode *inode, struct file *filp)
165 struct dentry *dentry = F_DENTRY(filp);
166 const struct file_operations *real_fops = NULL;
169 r = debugfs_file_get(dentry);
171 return r == -EIO ? -ENOENT : r;
173 real_fops = debugfs_real_fops(filp);
175 r = debugfs_locked_down(inode, filp, real_fops);
179 if (!fops_get(real_fops)) {
180 #ifdef CONFIG_MODULES
181 if (real_fops->owner &&
182 real_fops->owner->state == MODULE_STATE_GOING) {
188 /* Huh? Module did not clean up after itself at exit? */
189 WARN(1, "debugfs file owner did not clean up at exit: %pd",
194 replace_fops(filp, real_fops);
197 r = real_fops->open(inode, filp);
200 debugfs_file_put(dentry);
204 const struct file_operations debugfs_open_proxy_file_operations = {
205 .open = open_proxy_open,
208 #define PROTO(args...) args
209 #define ARGS(args...) args
211 #define FULL_PROXY_FUNC(name, ret_type, filp, proto, args) \
212 static ret_type full_proxy_ ## name(proto) \
214 struct dentry *dentry = F_DENTRY(filp); \
215 const struct file_operations *real_fops; \
218 r = debugfs_file_get(dentry); \
221 real_fops = debugfs_real_fops(filp); \
222 r = real_fops->name(args); \
223 debugfs_file_put(dentry); \
227 FULL_PROXY_FUNC(llseek, loff_t, filp,
228 PROTO(struct file *filp, loff_t offset, int whence),
229 ARGS(filp, offset, whence));
231 FULL_PROXY_FUNC(read, ssize_t, filp,
232 PROTO(struct file *filp, char __user *buf, size_t size,
234 ARGS(filp, buf, size, ppos));
236 FULL_PROXY_FUNC(write, ssize_t, filp,
237 PROTO(struct file *filp, const char __user *buf, size_t size,
239 ARGS(filp, buf, size, ppos));
241 FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
242 PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
243 ARGS(filp, cmd, arg));
245 static __poll_t full_proxy_poll(struct file *filp,
246 struct poll_table_struct *wait)
248 struct dentry *dentry = F_DENTRY(filp);
250 const struct file_operations *real_fops;
252 if (debugfs_file_get(dentry))
255 real_fops = debugfs_real_fops(filp);
256 r = real_fops->poll(filp, wait);
257 debugfs_file_put(dentry);
261 static int full_proxy_release(struct inode *inode, struct file *filp)
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;
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.
274 if (real_fops->release)
275 r = real_fops->release(inode, filp);
277 replace_fops(filp, d_inode(dentry)->i_fop);
278 kfree((void *)proxy_fops);
283 static void __full_proxy_fops_init(struct file_operations *proxy_fops,
284 const struct file_operations *real_fops)
286 proxy_fops->release = full_proxy_release;
287 if (real_fops->llseek)
288 proxy_fops->llseek = full_proxy_llseek;
290 proxy_fops->read = full_proxy_read;
291 if (real_fops->write)
292 proxy_fops->write = full_proxy_write;
294 proxy_fops->poll = full_proxy_poll;
295 if (real_fops->unlocked_ioctl)
296 proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
299 static int full_proxy_open(struct inode *inode, struct file *filp)
301 struct dentry *dentry = F_DENTRY(filp);
302 const struct file_operations *real_fops = NULL;
303 struct file_operations *proxy_fops = NULL;
306 r = debugfs_file_get(dentry);
308 return r == -EIO ? -ENOENT : r;
310 real_fops = debugfs_real_fops(filp);
312 r = debugfs_locked_down(inode, filp, real_fops);
316 if (!fops_get(real_fops)) {
317 #ifdef CONFIG_MODULES
318 if (real_fops->owner &&
319 real_fops->owner->state == MODULE_STATE_GOING) {
325 /* Huh? Module did not cleanup after itself at exit? */
326 WARN(1, "debugfs file owner did not clean up at exit: %pd",
332 proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
337 __full_proxy_fops_init(proxy_fops, real_fops);
338 replace_fops(filp, proxy_fops);
340 if (real_fops->open) {
341 r = real_fops->open(inode, filp);
343 replace_fops(filp, d_inode(dentry)->i_fop);
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",
358 debugfs_file_put(dentry);
362 const struct file_operations debugfs_full_proxy_file_operations = {
363 .open = full_proxy_open,
366 ssize_t debugfs_attr_read(struct file *file, char __user *buf,
367 size_t len, loff_t *ppos)
369 struct dentry *dentry = F_DENTRY(file);
372 ret = debugfs_file_get(dentry);
375 ret = simple_attr_read(file, buf, len, ppos);
376 debugfs_file_put(dentry);
379 EXPORT_SYMBOL_GPL(debugfs_attr_read);
381 static ssize_t debugfs_attr_write_xsigned(struct file *file, const char __user *buf,
382 size_t len, loff_t *ppos, bool is_signed)
384 struct dentry *dentry = F_DENTRY(file);
387 ret = debugfs_file_get(dentry);
391 ret = simple_attr_write_signed(file, buf, len, ppos);
393 ret = simple_attr_write(file, buf, len, ppos);
394 debugfs_file_put(dentry);
398 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
399 size_t len, loff_t *ppos)
401 return debugfs_attr_write_xsigned(file, buf, len, ppos, false);
403 EXPORT_SYMBOL_GPL(debugfs_attr_write);
405 ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf,
406 size_t len, loff_t *ppos)
408 return debugfs_attr_write_xsigned(file, buf, len, ppos, true);
410 EXPORT_SYMBOL_GPL(debugfs_attr_write_signed);
412 static 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)
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, value,
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, value,
427 return debugfs_create_file_unsafe(name, mode, parent, value, fops);
430 static int debugfs_u8_set(void *data, u64 val)
435 static int debugfs_u8_get(void *data, u64 *val)
440 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
441 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
442 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
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
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.
458 * This function will return a pointer to a dentry if it succeeds. This
459 * pointer must be passed to the debugfs_remove() function when the file is
460 * to be removed (no automatic cleanup happens if your module is unloaded,
461 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
464 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
467 struct dentry *debugfs_create_u8(const char *name, umode_t mode,
468 struct dentry *parent, u8 *value)
470 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
471 &fops_u8_ro, &fops_u8_wo);
473 EXPORT_SYMBOL_GPL(debugfs_create_u8);
475 static int debugfs_u16_set(void *data, u64 val)
480 static int debugfs_u16_get(void *data, u64 *val)
485 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
486 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
487 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
490 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
491 * @name: a pointer to a string containing the name of the file to create.
492 * @mode: the permission that the file should have
493 * @parent: a pointer to the parent dentry for this file. This should be a
494 * directory dentry if set. If this parameter is %NULL, then the
495 * file will be created in the root of the debugfs filesystem.
496 * @value: a pointer to the variable that the file should read to and write
499 * This function creates a file in debugfs with the given name that
500 * contains the value of the variable @value. If the @mode variable is so
501 * set, it can be read from, and written to.
503 * This function will return a pointer to a dentry if it succeeds. This
504 * pointer must be passed to the debugfs_remove() function when the file is
505 * to be removed (no automatic cleanup happens if your module is unloaded,
506 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
509 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
512 struct dentry *debugfs_create_u16(const char *name, umode_t mode,
513 struct dentry *parent, u16 *value)
515 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
516 &fops_u16_ro, &fops_u16_wo);
518 EXPORT_SYMBOL_GPL(debugfs_create_u16);
520 static int debugfs_u32_set(void *data, u64 val)
525 static int debugfs_u32_get(void *data, u64 *val)
530 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
531 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
532 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
535 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
536 * @name: a pointer to a string containing the name of the file to create.
537 * @mode: the permission that the file should have
538 * @parent: a pointer to the parent dentry for this file. This should be a
539 * directory dentry if set. If this parameter is %NULL, then the
540 * file will be created in the root of the debugfs filesystem.
541 * @value: a pointer to the variable that the file should read to and write
544 * This function creates a file in debugfs with the given name that
545 * contains the value of the variable @value. If the @mode variable is so
546 * set, it can be read from, and written to.
548 * This function will return a pointer to a dentry if it succeeds. This
549 * pointer must be passed to the debugfs_remove() function when the file is
550 * to be removed (no automatic cleanup happens if your module is unloaded,
551 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
554 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
557 struct dentry *debugfs_create_u32(const char *name, umode_t mode,
558 struct dentry *parent, u32 *value)
560 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
561 &fops_u32_ro, &fops_u32_wo);
563 EXPORT_SYMBOL_GPL(debugfs_create_u32);
565 static int debugfs_u64_set(void *data, u64 val)
571 static int debugfs_u64_get(void *data, u64 *val)
576 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
577 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
578 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
581 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
582 * @name: a pointer to a string containing the name of the file to create.
583 * @mode: the permission that the file should have
584 * @parent: a pointer to the parent dentry for this file. This should be a
585 * directory dentry if set. If this parameter is %NULL, then the
586 * file will be created in the root of the debugfs filesystem.
587 * @value: a pointer to the variable that the file should read to and write
590 * This function creates a file in debugfs with the given name that
591 * contains the value of the variable @value. If the @mode variable is so
592 * set, it can be read from, and written to.
594 * This function will return a pointer to a dentry if it succeeds. This
595 * pointer must be passed to the debugfs_remove() function when the file is
596 * to be removed (no automatic cleanup happens if your module is unloaded,
597 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
600 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
603 struct dentry *debugfs_create_u64(const char *name, umode_t mode,
604 struct dentry *parent, u64 *value)
606 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
607 &fops_u64_ro, &fops_u64_wo);
609 EXPORT_SYMBOL_GPL(debugfs_create_u64);
611 static int debugfs_ulong_set(void *data, u64 val)
613 *(unsigned long *)data = val;
617 static int debugfs_ulong_get(void *data, u64 *val)
619 *val = *(unsigned long *)data;
622 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
624 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
625 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
628 * debugfs_create_ulong - create a debugfs file that is used to read and write
629 * an unsigned long value.
630 * @name: a pointer to a string containing the name of the file to create.
631 * @mode: the permission that the file should have
632 * @parent: a pointer to the parent dentry for this file. This should be a
633 * directory dentry if set. If this parameter is %NULL, then the
634 * file will be created in the root of the debugfs filesystem.
635 * @value: a pointer to the variable that the file should read to and write
638 * This function creates a file in debugfs with the given name that
639 * contains the value of the variable @value. If the @mode variable is so
640 * set, it can be read from, and written to.
642 * This function will return a pointer to a dentry if it succeeds. This
643 * pointer must be passed to the debugfs_remove() function when the file is
644 * to be removed (no automatic cleanup happens if your module is unloaded,
645 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
648 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
651 struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
652 struct dentry *parent, unsigned long *value)
654 return debugfs_create_mode_unsafe(name, mode, parent, value,
655 &fops_ulong, &fops_ulong_ro,
658 EXPORT_SYMBOL_GPL(debugfs_create_ulong);
660 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
661 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
662 DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
664 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
666 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
667 DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
669 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
671 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
672 DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
674 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
676 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
677 DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");
680 * 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
682 * These functions are exactly the same as the above functions (but use a hex
683 * output for the decimal challenged). For details look at the above unsigned
688 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
689 * @name: a pointer to a string containing the name of the file to create.
690 * @mode: the permission that the file should have
691 * @parent: a pointer to the parent dentry for this file. This should be a
692 * directory dentry if set. If this parameter is %NULL, then the
693 * file will be created in the root of the debugfs filesystem.
694 * @value: a pointer to the variable that the file should read to and write
697 struct dentry *debugfs_create_x8(const char *name, umode_t mode,
698 struct dentry *parent, u8 *value)
700 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
701 &fops_x8_ro, &fops_x8_wo);
703 EXPORT_SYMBOL_GPL(debugfs_create_x8);
706 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
707 * @name: a pointer to a string containing the name of the file to create.
708 * @mode: the permission that the file should have
709 * @parent: a pointer to the parent dentry for this file. This should be a
710 * directory dentry if set. If this parameter is %NULL, then the
711 * file will be created in the root of the debugfs filesystem.
712 * @value: a pointer to the variable that the file should read to and write
715 struct dentry *debugfs_create_x16(const char *name, umode_t mode,
716 struct dentry *parent, u16 *value)
718 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
719 &fops_x16_ro, &fops_x16_wo);
721 EXPORT_SYMBOL_GPL(debugfs_create_x16);
724 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit 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_x32(const char *name, umode_t mode,
734 struct dentry *parent, u32 *value)
736 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
737 &fops_x32_ro, &fops_x32_wo);
739 EXPORT_SYMBOL_GPL(debugfs_create_x32);
742 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
743 * @name: a pointer to a string containing the name of the file to create.
744 * @mode: the permission that the file should have
745 * @parent: a pointer to the parent dentry for this file. This should be a
746 * directory dentry if set. If this parameter is %NULL, then the
747 * file will be created in the root of the debugfs filesystem.
748 * @value: a pointer to the variable that the file should read to and write
751 struct dentry *debugfs_create_x64(const char *name, umode_t mode,
752 struct dentry *parent, u64 *value)
754 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
755 &fops_x64_ro, &fops_x64_wo);
757 EXPORT_SYMBOL_GPL(debugfs_create_x64);
760 static int debugfs_size_t_set(void *data, u64 val)
762 *(size_t *)data = val;
765 static int debugfs_size_t_get(void *data, u64 *val)
767 *val = *(size_t *)data;
770 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
771 "%llu\n"); /* %llu and %zu are more or less the same */
772 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
773 DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");
776 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
777 * @name: a pointer to a string containing the name of the file to create.
778 * @mode: the permission that the file should have
779 * @parent: a pointer to the parent dentry for this file. This should be a
780 * directory dentry if set. If this parameter is %NULL, then the
781 * file will be created in the root of the debugfs filesystem.
782 * @value: a pointer to the variable that the file should read to and write
785 struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
786 struct dentry *parent, size_t *value)
788 return debugfs_create_mode_unsafe(name, mode, parent, value,
789 &fops_size_t, &fops_size_t_ro,
792 EXPORT_SYMBOL_GPL(debugfs_create_size_t);
794 static int debugfs_atomic_t_set(void *data, u64 val)
796 atomic_set((atomic_t *)data, val);
799 static int debugfs_atomic_t_get(void *data, u64 *val)
801 *val = atomic_read((atomic_t *)data);
804 DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t, debugfs_atomic_t_get,
805 debugfs_atomic_t_set, "%lld\n");
806 DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
808 DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
812 * debugfs_create_atomic_t - create a debugfs file that is used to read and
813 * write an atomic_t value
814 * @name: a pointer to a string containing the name of the file to create.
815 * @mode: the permission that the file should have
816 * @parent: a pointer to the parent dentry for this file. This should be a
817 * directory dentry if set. If this parameter is %NULL, then the
818 * file will be created in the root of the debugfs filesystem.
819 * @value: a pointer to the variable that the file should read to and write
822 struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
823 struct dentry *parent, atomic_t *value)
825 return debugfs_create_mode_unsafe(name, mode, parent, value,
826 &fops_atomic_t, &fops_atomic_t_ro,
829 EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
831 ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
832 size_t count, loff_t *ppos)
837 struct dentry *dentry = F_DENTRY(file);
839 r = debugfs_file_get(dentry);
842 val = *(bool *)file->private_data;
843 debugfs_file_put(dentry);
851 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
853 EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
855 ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
856 size_t count, loff_t *ppos)
860 bool *val = file->private_data;
861 struct dentry *dentry = F_DENTRY(file);
863 r = kstrtobool_from_user(user_buf, count, &bv);
865 r = debugfs_file_get(dentry);
869 debugfs_file_put(dentry);
874 EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
876 static const struct file_operations fops_bool = {
877 .read = debugfs_read_file_bool,
878 .write = debugfs_write_file_bool,
880 .llseek = default_llseek,
883 static const struct file_operations fops_bool_ro = {
884 .read = debugfs_read_file_bool,
886 .llseek = default_llseek,
889 static const struct file_operations fops_bool_wo = {
890 .write = debugfs_write_file_bool,
892 .llseek = default_llseek,
896 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
897 * @name: a pointer to a string containing the name of the file to create.
898 * @mode: the permission that the file should have
899 * @parent: a pointer to the parent dentry for this file. This should be a
900 * directory dentry if set. If this parameter is %NULL, then the
901 * file will be created in the root of the debugfs filesystem.
902 * @value: a pointer to the variable that the file should read to and write
905 * This function creates a file in debugfs with the given name that
906 * contains the value of the variable @value. If the @mode variable is so
907 * set, it can be read from, and written to.
909 * This function will return a pointer to a dentry if it succeeds. This
910 * pointer must be passed to the debugfs_remove() function when the file is
911 * to be removed (no automatic cleanup happens if your module is unloaded,
912 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
915 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
918 struct dentry *debugfs_create_bool(const char *name, umode_t mode,
919 struct dentry *parent, bool *value)
921 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
922 &fops_bool_ro, &fops_bool_wo);
924 EXPORT_SYMBOL_GPL(debugfs_create_bool);
926 static ssize_t read_file_blob(struct file *file, char __user *user_buf,
927 size_t count, loff_t *ppos)
929 struct debugfs_blob_wrapper *blob = file->private_data;
930 struct dentry *dentry = F_DENTRY(file);
933 r = debugfs_file_get(dentry);
936 r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
938 debugfs_file_put(dentry);
942 static const struct file_operations fops_blob = {
943 .read = read_file_blob,
945 .llseek = default_llseek,
949 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
950 * @name: a pointer to a string containing the name of the file to create.
951 * @mode: the permission that the file should have
952 * @parent: a pointer to the parent dentry for this file. This should be a
953 * directory dentry if set. If this parameter is %NULL, then the
954 * file will be created in the root of the debugfs filesystem.
955 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
956 * to the blob data and the size of the data.
958 * This function creates a file in debugfs with the given name that exports
959 * @blob->data as a binary blob. If the @mode variable is so set it can be
960 * read from. Writing is not supported.
962 * This function will return a pointer to a dentry if it succeeds. This
963 * pointer must be passed to the debugfs_remove() function when the file is
964 * to be removed (no automatic cleanup happens if your module is unloaded,
965 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
968 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
971 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
972 struct dentry *parent,
973 struct debugfs_blob_wrapper *blob)
975 return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob);
977 EXPORT_SYMBOL_GPL(debugfs_create_blob);
984 static size_t u32_format_array(char *buf, size_t bufsize,
985 u32 *array, int array_size)
989 while (--array_size >= 0) {
991 char term = array_size ? ' ' : '\n';
993 len = snprintf(buf, bufsize, "%u%c", *array++, term);
1002 static int u32_array_open(struct inode *inode, struct file *file)
1004 struct array_data *data = inode->i_private;
1005 int size, elements = data->elements;
1010 * - 10 digits + ' '/'\n' = 11 bytes per number
1011 * - terminating NUL character
1014 buf = kmalloc(size+1, GFP_KERNEL);
1019 file->private_data = buf;
1020 u32_format_array(buf, size, data->array, data->elements);
1022 return nonseekable_open(inode, file);
1025 static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
1028 size_t size = strlen(file->private_data);
1030 return simple_read_from_buffer(buf, len, ppos,
1031 file->private_data, size);
1034 static int u32_array_release(struct inode *inode, struct file *file)
1036 kfree(file->private_data);
1041 static const struct file_operations u32_array_fops = {
1042 .owner = THIS_MODULE,
1043 .open = u32_array_open,
1044 .release = u32_array_release,
1045 .read = u32_array_read,
1046 .llseek = no_llseek,
1050 * debugfs_create_u32_array - create a debugfs file that is used to read u32
1052 * @name: a pointer to a string containing the name of the file to create.
1053 * @mode: the permission that the file should have.
1054 * @parent: a pointer to the parent dentry for this file. This should be a
1055 * directory dentry if set. If this parameter is %NULL, then the
1056 * file will be created in the root of the debugfs filesystem.
1057 * @array: u32 array that provides data.
1058 * @elements: total number of elements in the array.
1060 * This function creates a file in debugfs with the given name that exports
1061 * @array as data. If the @mode variable is so set it can be read from.
1062 * Writing is not supported. Seek within the file is also not supported.
1063 * Once array is created its size can not be changed.
1065 void debugfs_create_u32_array(const char *name, umode_t mode,
1066 struct dentry *parent, u32 *array, u32 elements)
1068 struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
1073 data->array = array;
1074 data->elements = elements;
1076 debugfs_create_file_unsafe(name, mode, parent, data, &u32_array_fops);
1078 EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1080 #ifdef CONFIG_HAS_IOMEM
1083 * The regset32 stuff is used to print 32-bit registers using the
1084 * seq_file utilities. We offer printing a register set in an already-opened
1085 * sequential file or create a debugfs file that only prints a regset32.
1089 * debugfs_print_regs32 - use seq_print to describe a set of registers
1090 * @s: the seq_file structure being used to generate output
1091 * @regs: an array if struct debugfs_reg32 structures
1092 * @nregs: the length of the above array
1093 * @base: the base address to be used in reading the registers
1094 * @prefix: a string to be prefixed to every output line
1096 * This function outputs a text block describing the current values of
1097 * some 32-bit hardware registers. It is meant to be used within debugfs
1098 * files based on seq_file that need to show registers, intermixed with other
1099 * information. The prefix argument may be used to specify a leading string,
1100 * because some peripherals have several blocks of identical registers,
1101 * for example configuration of dma channels
1103 void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1104 int nregs, void __iomem *base, char *prefix)
1108 for (i = 0; i < nregs; i++, regs++) {
1110 seq_printf(s, "%s", prefix);
1111 seq_printf(s, "%s = 0x%08x\n", regs->name,
1112 readl(base + regs->offset));
1113 if (seq_has_overflowed(s))
1117 EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1119 static int debugfs_show_regset32(struct seq_file *s, void *data)
1121 struct debugfs_regset32 *regset = s->private;
1124 pm_runtime_get_sync(regset->dev);
1126 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1129 pm_runtime_put(regset->dev);
1134 static int debugfs_open_regset32(struct inode *inode, struct file *file)
1136 return single_open(file, debugfs_show_regset32, inode->i_private);
1139 static const struct file_operations fops_regset32 = {
1140 .open = debugfs_open_regset32,
1142 .llseek = seq_lseek,
1143 .release = single_release,
1147 * debugfs_create_regset32 - create a debugfs file that returns register values
1148 * @name: a pointer to a string containing the name of the file to create.
1149 * @mode: the permission that the file should have
1150 * @parent: a pointer to the parent dentry for this file. This should be a
1151 * directory dentry if set. If this parameter is %NULL, then the
1152 * file will be created in the root of the debugfs filesystem.
1153 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1154 * to an array of register definitions, the array size and the base
1155 * address where the register bank is to be found.
1157 * This function creates a file in debugfs with the given name that reports
1158 * the names and values of a set of 32-bit registers. If the @mode variable
1159 * is so set it can be read from. Writing is not supported.
1161 * This function will return a pointer to a dentry if it succeeds. This
1162 * pointer must be passed to the debugfs_remove() function when the file is
1163 * to be removed (no automatic cleanup happens if your module is unloaded,
1164 * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be
1167 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
1170 struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
1171 struct dentry *parent,
1172 struct debugfs_regset32 *regset)
1174 return debugfs_create_file(name, mode, parent, regset, &fops_regset32);
1176 EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1178 #endif /* CONFIG_HAS_IOMEM */
1180 struct debugfs_devm_entry {
1181 int (*read)(struct seq_file *seq, void *data);
1185 static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1187 struct debugfs_devm_entry *entry = inode->i_private;
1189 return single_open(f, entry->read, entry->dev);
1192 static const struct file_operations debugfs_devm_entry_ops = {
1193 .owner = THIS_MODULE,
1194 .open = debugfs_devm_entry_open,
1195 .release = single_release,
1201 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1203 * @dev: device related to this debugfs file.
1204 * @name: name of the debugfs file.
1205 * @parent: a pointer to the parent dentry for this file. This should be a
1206 * directory dentry if set. If this parameter is %NULL, then the
1207 * file will be created in the root of the debugfs filesystem.
1208 * @read_fn: function pointer called to print the seq_file content.
1210 struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
1211 struct dentry *parent,
1212 int (*read_fn)(struct seq_file *s,
1215 struct debugfs_devm_entry *entry;
1218 return ERR_PTR(-ENOENT);
1220 entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
1222 return ERR_PTR(-ENOMEM);
1224 entry->read = read_fn;
1227 return debugfs_create_file(name, S_IRUGO, parent, entry,
1228 &debugfs_devm_entry_ops);
1230 EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);