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);
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 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
382 size_t len, loff_t *ppos)
384 struct dentry *dentry = F_DENTRY(file);
387 ret = debugfs_file_get(dentry);
390 ret = simple_attr_write(file, buf, len, ppos);
391 debugfs_file_put(dentry);
394 EXPORT_SYMBOL_GPL(debugfs_attr_write);
396 static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
397 struct dentry *parent, void *value,
398 const struct file_operations *fops,
399 const struct file_operations *fops_ro,
400 const struct file_operations *fops_wo)
402 /* if there are no write bits set, make read only */
403 if (!(mode & S_IWUGO))
404 return debugfs_create_file_unsafe(name, mode, parent, value,
406 /* if there are no read bits set, make write only */
407 if (!(mode & S_IRUGO))
408 return debugfs_create_file_unsafe(name, mode, parent, value,
411 return debugfs_create_file_unsafe(name, mode, parent, value, fops);
414 static int debugfs_u8_set(void *data, u64 val)
419 static int debugfs_u8_get(void *data, u64 *val)
424 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
425 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
426 DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
429 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
430 * @name: a pointer to a string containing the name of the file to create.
431 * @mode: the permission that the file should have
432 * @parent: a pointer to the parent dentry for this file. This should be a
433 * directory dentry if set. If this parameter is %NULL, then the
434 * file will be created in the root of the debugfs filesystem.
435 * @value: a pointer to the variable that the file should read to and write
438 * This function creates a file in debugfs with the given name that
439 * contains the value of the variable @value. If the @mode variable is so
440 * set, it can be read from, and written to.
442 void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
445 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
446 &fops_u8_ro, &fops_u8_wo);
448 EXPORT_SYMBOL_GPL(debugfs_create_u8);
450 static int debugfs_u16_set(void *data, u64 val)
455 static int debugfs_u16_get(void *data, u64 *val)
460 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
461 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
462 DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
465 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
466 * @name: a pointer to a string containing the name of the file to create.
467 * @mode: the permission that the file should have
468 * @parent: a pointer to the parent dentry for this file. This should be a
469 * directory dentry if set. If this parameter is %NULL, then the
470 * file will be created in the root of the debugfs filesystem.
471 * @value: a pointer to the variable that the file should read to and write
474 * This function creates a file in debugfs with the given name that
475 * contains the value of the variable @value. If the @mode variable is so
476 * set, it can be read from, and written to.
478 void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
481 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
482 &fops_u16_ro, &fops_u16_wo);
484 EXPORT_SYMBOL_GPL(debugfs_create_u16);
486 static int debugfs_u32_set(void *data, u64 val)
491 static int debugfs_u32_get(void *data, u64 *val)
496 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
497 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
498 DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
501 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
502 * @name: a pointer to a string containing the name of the file to create.
503 * @mode: the permission that the file should have
504 * @parent: a pointer to the parent dentry for this file. This should be a
505 * directory dentry if set. If this parameter is %NULL, then the
506 * file will be created in the root of the debugfs filesystem.
507 * @value: a pointer to the variable that the file should read to and write
510 * This function creates a file in debugfs with the given name that
511 * contains the value of the variable @value. If the @mode variable is so
512 * set, it can be read from, and written to.
514 void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
517 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
518 &fops_u32_ro, &fops_u32_wo);
520 EXPORT_SYMBOL_GPL(debugfs_create_u32);
522 static int debugfs_u64_set(void *data, u64 val)
528 static int debugfs_u64_get(void *data, u64 *val)
533 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
534 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
535 DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
538 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
539 * @name: a pointer to a string containing the name of the file to create.
540 * @mode: the permission that the file should have
541 * @parent: a pointer to the parent dentry for this file. This should be a
542 * directory dentry if set. If this parameter is %NULL, then the
543 * file will be created in the root of the debugfs filesystem.
544 * @value: a pointer to the variable that the file should read to and write
547 * This function creates a file in debugfs with the given name that
548 * contains the value of the variable @value. If the @mode variable is so
549 * set, it can be read from, and written to.
551 void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
554 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
555 &fops_u64_ro, &fops_u64_wo);
557 EXPORT_SYMBOL_GPL(debugfs_create_u64);
559 static int debugfs_ulong_set(void *data, u64 val)
561 *(unsigned long *)data = val;
565 static int debugfs_ulong_get(void *data, u64 *val)
567 *val = *(unsigned long *)data;
570 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
572 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
573 DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");
576 * debugfs_create_ulong - create a debugfs file that is used to read and write
577 * an unsigned long value.
578 * @name: a pointer to a string containing the name of the file to create.
579 * @mode: the permission that the file should have
580 * @parent: a pointer to the parent dentry for this file. This should be a
581 * directory dentry if set. If this parameter is %NULL, then the
582 * file will be created in the root of the debugfs filesystem.
583 * @value: a pointer to the variable that the file should read to and write
586 * This function creates a file in debugfs with the given name that
587 * contains the value of the variable @value. If the @mode variable is so
588 * set, it can be read from, and written to.
590 * This function will return a pointer to a dentry if it succeeds. This
591 * pointer must be passed to the debugfs_remove() function when the file is
592 * to be removed (no automatic cleanup happens if your module is unloaded,
593 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
596 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
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 void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
648 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 void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
666 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 void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
684 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 void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
702 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 void debugfs_create_size_t(const char *name, umode_t mode,
734 struct dentry *parent, size_t *value)
736 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_size_t,
737 &fops_size_t_ro, &fops_size_t_wo);
739 EXPORT_SYMBOL_GPL(debugfs_create_size_t);
741 static int debugfs_atomic_t_set(void *data, u64 val)
743 atomic_set((atomic_t *)data, val);
746 static int debugfs_atomic_t_get(void *data, u64 *val)
748 *val = atomic_read((atomic_t *)data);
751 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
752 debugfs_atomic_t_set, "%lld\n");
753 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
755 DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
759 * debugfs_create_atomic_t - create a debugfs file that is used to read and
760 * write an atomic_t value
761 * @name: a pointer to a string containing the name of the file to create.
762 * @mode: the permission that the file should have
763 * @parent: a pointer to the parent dentry for this file. This should be a
764 * directory dentry if set. If this parameter is %NULL, then the
765 * file will be created in the root of the debugfs filesystem.
766 * @value: a pointer to the variable that the file should read to and write
769 void debugfs_create_atomic_t(const char *name, umode_t mode,
770 struct dentry *parent, atomic_t *value)
772 debugfs_create_mode_unsafe(name, mode, parent, value, &fops_atomic_t,
773 &fops_atomic_t_ro, &fops_atomic_t_wo);
775 EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);
777 ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
778 size_t count, loff_t *ppos)
783 struct dentry *dentry = F_DENTRY(file);
785 r = debugfs_file_get(dentry);
788 val = *(bool *)file->private_data;
789 debugfs_file_put(dentry);
797 return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
799 EXPORT_SYMBOL_GPL(debugfs_read_file_bool);
801 ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
802 size_t count, loff_t *ppos)
806 bool *val = file->private_data;
807 struct dentry *dentry = F_DENTRY(file);
809 r = kstrtobool_from_user(user_buf, count, &bv);
811 r = debugfs_file_get(dentry);
815 debugfs_file_put(dentry);
820 EXPORT_SYMBOL_GPL(debugfs_write_file_bool);
822 static const struct file_operations fops_bool = {
823 .read = debugfs_read_file_bool,
824 .write = debugfs_write_file_bool,
826 .llseek = default_llseek,
829 static const struct file_operations fops_bool_ro = {
830 .read = debugfs_read_file_bool,
832 .llseek = default_llseek,
835 static const struct file_operations fops_bool_wo = {
836 .write = debugfs_write_file_bool,
838 .llseek = default_llseek,
842 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
843 * @name: a pointer to a string containing the name of the file to create.
844 * @mode: the permission that the file should have
845 * @parent: a pointer to the parent dentry for this file. This should be a
846 * directory dentry if set. If this parameter is %NULL, then the
847 * file will be created in the root of the debugfs filesystem.
848 * @value: a pointer to the variable that the file should read to and write
851 * This function creates a file in debugfs with the given name that
852 * contains the value of the variable @value. If the @mode variable is so
853 * set, it can be read from, and written to.
855 * This function will return a pointer to a dentry if it succeeds. This
856 * pointer must be passed to the debugfs_remove() function when the file is
857 * to be removed (no automatic cleanup happens if your module is unloaded,
858 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
861 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
864 struct dentry *debugfs_create_bool(const char *name, umode_t mode,
865 struct dentry *parent, bool *value)
867 return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
868 &fops_bool_ro, &fops_bool_wo);
870 EXPORT_SYMBOL_GPL(debugfs_create_bool);
872 static ssize_t read_file_blob(struct file *file, char __user *user_buf,
873 size_t count, loff_t *ppos)
875 struct debugfs_blob_wrapper *blob = file->private_data;
876 struct dentry *dentry = F_DENTRY(file);
879 r = debugfs_file_get(dentry);
882 r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
884 debugfs_file_put(dentry);
888 static const struct file_operations fops_blob = {
889 .read = read_file_blob,
891 .llseek = default_llseek,
895 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
896 * @name: a pointer to a string containing the name of the file to create.
897 * @mode: the permission that the file should have
898 * @parent: a pointer to the parent dentry for this file. This should be a
899 * directory dentry if set. If this parameter is %NULL, then the
900 * file will be created in the root of the debugfs filesystem.
901 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
902 * to the blob data and the size of the data.
904 * This function creates a file in debugfs with the given name that exports
905 * @blob->data as a binary blob. If the @mode variable is so set it can be
906 * read from. Writing is not supported.
908 * This function will return a pointer to a dentry if it succeeds. This
909 * pointer must be passed to the debugfs_remove() function when the file is
910 * to be removed (no automatic cleanup happens if your module is unloaded,
911 * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
914 * If debugfs is not enabled in the kernel, the value ERR_PTR(-ENODEV) will
917 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
918 struct dentry *parent,
919 struct debugfs_blob_wrapper *blob)
921 return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob);
923 EXPORT_SYMBOL_GPL(debugfs_create_blob);
925 static size_t u32_format_array(char *buf, size_t bufsize,
926 u32 *array, int array_size)
930 while (--array_size >= 0) {
932 char term = array_size ? ' ' : '\n';
934 len = snprintf(buf, bufsize, "%u%c", *array++, term);
943 static int u32_array_open(struct inode *inode, struct file *file)
945 struct debugfs_u32_array *data = inode->i_private;
946 int size, elements = data->n_elements;
951 * - 10 digits + ' '/'\n' = 11 bytes per number
952 * - terminating NUL character
955 buf = kmalloc(size+1, GFP_KERNEL);
960 file->private_data = buf;
961 u32_format_array(buf, size, data->array, data->n_elements);
963 return nonseekable_open(inode, file);
966 static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
969 size_t size = strlen(file->private_data);
971 return simple_read_from_buffer(buf, len, ppos,
972 file->private_data, size);
975 static int u32_array_release(struct inode *inode, struct file *file)
977 kfree(file->private_data);
982 static const struct file_operations u32_array_fops = {
983 .owner = THIS_MODULE,
984 .open = u32_array_open,
985 .release = u32_array_release,
986 .read = u32_array_read,
991 * debugfs_create_u32_array - create a debugfs file that is used to read u32
993 * @name: a pointer to a string containing the name of the file to create.
994 * @mode: the permission that the file should have.
995 * @parent: a pointer to the parent dentry for this file. This should be a
996 * directory dentry if set. If this parameter is %NULL, then the
997 * file will be created in the root of the debugfs filesystem.
998 * @array: wrapper struct containing data pointer and size of the array.
1000 * This function creates a file in debugfs with the given name that exports
1001 * @array as data. If the @mode variable is so set it can be read from.
1002 * Writing is not supported. Seek within the file is also not supported.
1003 * Once array is created its size can not be changed.
1005 void debugfs_create_u32_array(const char *name, umode_t mode,
1006 struct dentry *parent,
1007 struct debugfs_u32_array *array)
1009 debugfs_create_file_unsafe(name, mode, parent, array, &u32_array_fops);
1011 EXPORT_SYMBOL_GPL(debugfs_create_u32_array);
1013 #ifdef CONFIG_HAS_IOMEM
1016 * The regset32 stuff is used to print 32-bit registers using the
1017 * seq_file utilities. We offer printing a register set in an already-opened
1018 * sequential file or create a debugfs file that only prints a regset32.
1022 * debugfs_print_regs32 - use seq_print to describe a set of registers
1023 * @s: the seq_file structure being used to generate output
1024 * @regs: an array if struct debugfs_reg32 structures
1025 * @nregs: the length of the above array
1026 * @base: the base address to be used in reading the registers
1027 * @prefix: a string to be prefixed to every output line
1029 * This function outputs a text block describing the current values of
1030 * some 32-bit hardware registers. It is meant to be used within debugfs
1031 * files based on seq_file that need to show registers, intermixed with other
1032 * information. The prefix argument may be used to specify a leading string,
1033 * because some peripherals have several blocks of identical registers,
1034 * for example configuration of dma channels
1036 void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
1037 int nregs, void __iomem *base, char *prefix)
1041 for (i = 0; i < nregs; i++, regs++) {
1043 seq_printf(s, "%s", prefix);
1044 seq_printf(s, "%s = 0x%08x\n", regs->name,
1045 readl(base + regs->offset));
1046 if (seq_has_overflowed(s))
1050 EXPORT_SYMBOL_GPL(debugfs_print_regs32);
1052 static int debugfs_show_regset32(struct seq_file *s, void *data)
1054 struct debugfs_regset32 *regset = s->private;
1057 pm_runtime_get_sync(regset->dev);
1059 debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
1062 pm_runtime_put(regset->dev);
1067 static int debugfs_open_regset32(struct inode *inode, struct file *file)
1069 return single_open(file, debugfs_show_regset32, inode->i_private);
1072 static const struct file_operations fops_regset32 = {
1073 .open = debugfs_open_regset32,
1075 .llseek = seq_lseek,
1076 .release = single_release,
1080 * debugfs_create_regset32 - create a debugfs file that returns register values
1081 * @name: a pointer to a string containing the name of the file to create.
1082 * @mode: the permission that the file should have
1083 * @parent: a pointer to the parent dentry for this file. This should be a
1084 * directory dentry if set. If this parameter is %NULL, then the
1085 * file will be created in the root of the debugfs filesystem.
1086 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
1087 * to an array of register definitions, the array size and the base
1088 * address where the register bank is to be found.
1090 * This function creates a file in debugfs with the given name that reports
1091 * the names and values of a set of 32-bit registers. If the @mode variable
1092 * is so set it can be read from. Writing is not supported.
1094 void debugfs_create_regset32(const char *name, umode_t mode,
1095 struct dentry *parent,
1096 struct debugfs_regset32 *regset)
1098 debugfs_create_file(name, mode, parent, regset, &fops_regset32);
1100 EXPORT_SYMBOL_GPL(debugfs_create_regset32);
1102 #endif /* CONFIG_HAS_IOMEM */
1104 struct debugfs_devm_entry {
1105 int (*read)(struct seq_file *seq, void *data);
1109 static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
1111 struct debugfs_devm_entry *entry = inode->i_private;
1113 return single_open(f, entry->read, entry->dev);
1116 static const struct file_operations debugfs_devm_entry_ops = {
1117 .owner = THIS_MODULE,
1118 .open = debugfs_devm_entry_open,
1119 .release = single_release,
1125 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
1127 * @dev: device related to this debugfs file.
1128 * @name: name of the debugfs file.
1129 * @parent: a pointer to the parent dentry for this file. This should be a
1130 * directory dentry if set. If this parameter is %NULL, then the
1131 * file will be created in the root of the debugfs filesystem.
1132 * @read_fn: function pointer called to print the seq_file content.
1134 void debugfs_create_devm_seqfile(struct device *dev, const char *name,
1135 struct dentry *parent,
1136 int (*read_fn)(struct seq_file *s, void *data))
1138 struct debugfs_devm_entry *entry;
1143 entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
1147 entry->read = read_fn;
1150 debugfs_create_file(name, S_IRUGO, parent, entry,
1151 &debugfs_devm_entry_ops);
1153 EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);