debugfs.h

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *  debugfs.h - a tiny little debug file system
  4 *
  5 *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
  6 *  Copyright (C) 2004 IBM Inc.
  7 *
  8 *  debugfs is for people to use instead of /proc or /sys.
  9 *  See Documentation/filesystems/ for more details.
 10 */
 11
 12#ifndef _DEBUGFS_H_
 13#define _DEBUGFS_H_
 14
 15#include <linux/fs.h>
 16#include <linux/seq_file.h>
 17
 18#include <linux/types.h>
 19#include <linux/compiler.h>
 20
 21struct device;
 22struct file_operations;
 23
 24struct debugfs_blob_wrapper {
 25	void *data;
 26	unsigned long size;
 27};
 28
 29struct debugfs_reg32 {
 30	char *name;
 31	unsigned long offset;
 32};
 33
 34struct debugfs_regset32 {
 35	const struct debugfs_reg32 *regs;
 36	int nregs;
 37	void __iomem *base;
 38	struct device *dev;	/* Optional device for Runtime PM */
 39};
 40
 41struct debugfs_u32_array {
 42	u32 *array;
 43	u32 n_elements;
 44};
 45
 46extern struct dentry *arch_debugfs_dir;
 47
 48#define DEFINE_DEBUGFS_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, __is_signed)	\
 49static int __fops ## _open(struct inode *inode, struct file *file)	\
 50{									\
 51	__simple_attr_check_format(__fmt, 0ull);			\
 52	return simple_attr_open(inode, file, __get, __set, __fmt);	\
 53}									\
 54static const struct file_operations __fops = {				\
 55	.owner	 = THIS_MODULE,						\
 56	.open	 = __fops ## _open,					\
 57	.release = simple_attr_release,					\
 58	.read	 = debugfs_attr_read,					\
 59	.write	 = (__is_signed) ? debugfs_attr_write_signed : debugfs_attr_write,	\
 60}
 61
 62#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)		\
 63	DEFINE_DEBUGFS_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, false)
 64
 65#define DEFINE_DEBUGFS_ATTRIBUTE_SIGNED(__fops, __get, __set, __fmt)	\
 66	DEFINE_DEBUGFS_ATTRIBUTE_XSIGNED(__fops, __get, __set, __fmt, true)
 67
 68typedef struct vfsmount *(*debugfs_automount_t)(struct dentry *, void *);
 69
 70struct debugfs_short_fops {
 71	ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
 72	ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
 73	loff_t (*llseek) (struct file *, loff_t, int);
 74};
 75
 76#if defined(CONFIG_DEBUG_FS)
 77
 78struct dentry *debugfs_lookup(const char *name, struct dentry *parent);
 79
 80struct dentry *debugfs_create_file_full(const char *name, umode_t mode,
 81					struct dentry *parent, void *data,
 82					const void *aux,
 83					const struct file_operations *fops);
 84struct dentry *debugfs_create_file_short(const char *name, umode_t mode,
 85					 struct dentry *parent, void *data,
 86					 const void *aux,
 87					 const struct debugfs_short_fops *fops);
 88
 89/**
 90 * debugfs_create_file - create a file in the debugfs filesystem
 91 * @name: a pointer to a string containing the name of the file to create.
 92 * @mode: the permission that the file should have.
 93 * @parent: a pointer to the parent dentry for this file.  This should be a
 94 *          directory dentry if set.  If this parameter is NULL, then the
 95 *          file will be created in the root of the debugfs filesystem.
 96 * @data: a pointer to something that the caller will want to get to later
 97 *        on.  The inode.i_private pointer will point to this value on
 98 *        the open() call.
 99 * @fops: a pointer to a struct file_operations or struct debugfs_short_fops that
100 *        should be used for this file.
101 *
102 * This is the basic "create a file" function for debugfs.  It allows for a
103 * wide range of flexibility in creating a file, or a directory (if you want
104 * to create a directory, the debugfs_create_dir() function is
105 * recommended to be used instead.)
106 *
107 * This function will return a pointer to a dentry if it succeeds.  This
108 * pointer must be passed to the debugfs_remove() function when the file is
109 * to be removed (no automatic cleanup happens if your module is unloaded,
110 * you are responsible here.)  If an error occurs, ERR_PTR(-ERROR) will be
111 * returned.
112 *
113 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
114 * returned.
115 *
116 * If fops points to a struct debugfs_short_fops, then simple_open() will be
117 * used for the open, and only read/write/llseek are supported and are proxied,
118 * so no module reference or release are needed.
119 *
120 * NOTE: it's expected that most callers should _ignore_ the errors returned
121 * by this function. Other debugfs functions handle the fact that the "dentry"
122 * passed to them could be an error and they don't crash in that case.
123 * Drivers should generally work fine even if debugfs fails to init anyway.
124 */
125#define debugfs_create_file(name, mode, parent, data, fops)			\
126	_Generic(fops,								\
127		 const struct file_operations *: debugfs_create_file_full,	\
128		 const struct debugfs_short_fops *: debugfs_create_file_short,	\
129		 struct file_operations *: debugfs_create_file_full,		\
130		 struct debugfs_short_fops *: debugfs_create_file_short)	\
131		(name, mode, parent, data, NULL, fops)
132
133#define debugfs_create_file_aux(name, mode, parent, data, aux, fops)		\
134	_Generic(fops,								\
135		 const struct file_operations *: debugfs_create_file_full,	\
136		 const struct debugfs_short_fops *: debugfs_create_file_short,	\
137		 struct file_operations *: debugfs_create_file_full,		\
138		 struct debugfs_short_fops *: debugfs_create_file_short)	\
139		(name, mode, parent, data, aux, fops)
140
141struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
142				   struct dentry *parent, void *data,
143				   const struct file_operations *fops);
144
145void debugfs_create_file_size(const char *name, umode_t mode,
146			      struct dentry *parent, void *data,
147			      const struct file_operations *fops,
148			      loff_t file_size);
149
150struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);
151
152struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
153				      const char *dest);
154
155struct dentry *debugfs_create_automount(const char *name,
156					struct dentry *parent,
157					debugfs_automount_t f,
158					void *data);
159
160void debugfs_remove(struct dentry *dentry);
161#define debugfs_remove_recursive debugfs_remove
162
163void debugfs_lookup_and_remove(const char *name, struct dentry *parent);
164
165void *debugfs_get_aux(const struct file *file);
166
167int debugfs_file_get(struct dentry *dentry);
168void debugfs_file_put(struct dentry *dentry);
169
170ssize_t debugfs_attr_read(struct file *file, char __user *buf,
171			size_t len, loff_t *ppos);
172ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
173			size_t len, loff_t *ppos);
174ssize_t debugfs_attr_write_signed(struct file *file, const char __user *buf,
175			size_t len, loff_t *ppos);
176
177int debugfs_change_name(struct dentry *dentry, const char *fmt, ...) __printf(2, 3);
178
179void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
180		       u8 *value);
181void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
182			u16 *value);
183void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
184			u32 *value);
185void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
186			u64 *value);
187void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent,
188			  unsigned long *value);
189void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
190		       u8 *value);
191void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
192			u16 *value);
193void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
194			u32 *value);
195void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
196			u64 *value);
197void debugfs_create_size_t(const char *name, umode_t mode,
198			   struct dentry *parent, size_t *value);
199void debugfs_create_atomic_t(const char *name, umode_t mode,
200			     struct dentry *parent, atomic_t *value);
201void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent,
202			 bool *value);
203void debugfs_create_str(const char *name, umode_t mode,
204			struct dentry *parent, char **value);
205
206struct dentry *debugfs_create_blob(const char *name, umode_t mode,
207				  struct dentry *parent,
208				  struct debugfs_blob_wrapper *blob);
209
210void debugfs_create_regset32(const char *name, umode_t mode,
211			     struct dentry *parent,
212			     struct debugfs_regset32 *regset);
213
214void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
215			  int nregs, void __iomem *base, char *prefix);
216
217void debugfs_create_u32_array(const char *name, umode_t mode,
218			      struct dentry *parent,
219			      struct debugfs_u32_array *array);
220
221void debugfs_create_devm_seqfile(struct device *dev, const char *name,
222				 struct dentry *parent,
223				 int (*read_fn)(struct seq_file *s, void *data));
224
225bool debugfs_initialized(void);
226
227ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
228			       size_t count, loff_t *ppos);
229
230ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
231				size_t count, loff_t *ppos);
232
233ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
234			      size_t count, loff_t *ppos);
235
236/**
237 * struct debugfs_cancellation - cancellation data
238 * @list: internal, for keeping track
239 * @cancel: callback to call
240 * @cancel_data: extra data for the callback to call
241 */
242struct debugfs_cancellation {
243	struct list_head list;
244	void (*cancel)(struct dentry *, void *);
245	void *cancel_data;
246};
247
248void __acquires(cancellation)
249debugfs_enter_cancellation(struct file *file,
250			   struct debugfs_cancellation *cancellation);
251void __releases(cancellation)
252debugfs_leave_cancellation(struct file *file,
253			   struct debugfs_cancellation *cancellation);
254
255#else
256
257#include <linux/err.h>
258
259/*
260 * We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
261 * so users have a chance to detect if there was a real error or not.  We don't
262 * want to duplicate the design decision mistakes of procfs and devfs again.
263 */
264
265static inline struct dentry *debugfs_lookup(const char *name,
266					    struct dentry *parent)
267{
268	return ERR_PTR(-ENODEV);
269}
270
271static inline struct dentry *debugfs_create_file_aux(const char *name,
272					umode_t mode, struct dentry *parent,
273					void *data, void *aux,
274					const void *fops)
275{
276	return ERR_PTR(-ENODEV);
277}
278
279static inline struct dentry *debugfs_create_file(const char *name, umode_t mode,
280					struct dentry *parent, void *data,
281					const void *fops)
282{
283	return ERR_PTR(-ENODEV);
284}
285
286static inline struct dentry *debugfs_create_file_unsafe(const char *name,
287					umode_t mode, struct dentry *parent,
288					void *data,
289					const struct file_operations *fops)
290{
291	return ERR_PTR(-ENODEV);
292}
293
294static inline void debugfs_create_file_size(const char *name, umode_t mode,
295					    struct dentry *parent, void *data,
296					    const struct file_operations *fops,
297					    loff_t file_size)
298{ }
299
300static inline struct dentry *debugfs_create_dir(const char *name,
301						struct dentry *parent)
302{
303	return ERR_PTR(-ENODEV);
304}
305
306static inline struct dentry *debugfs_create_symlink(const char *name,
307						    struct dentry *parent,
308						    const char *dest)
309{
310	return ERR_PTR(-ENODEV);
311}
312
313static inline struct dentry *debugfs_create_automount(const char *name,
314					struct dentry *parent,
315					debugfs_automount_t f,
316					void *data)
317{
318	return ERR_PTR(-ENODEV);
319}
320
321static inline void debugfs_remove(struct dentry *dentry)
322{ }
323
324static inline void debugfs_remove_recursive(struct dentry *dentry)
325{ }
326
327static inline void debugfs_lookup_and_remove(const char *name,
328					     struct dentry *parent)
329{ }
330
331void *debugfs_get_aux(const struct file *file);
332
333static inline int debugfs_file_get(struct dentry *dentry)
334{
335	return 0;
336}
337
338static inline void debugfs_file_put(struct dentry *dentry)
339{ }
340
341static inline ssize_t debugfs_attr_read(struct file *file, char __user *buf,
342					size_t len, loff_t *ppos)
343{
344	return -ENODEV;
345}
346
347static inline ssize_t debugfs_attr_write(struct file *file,
348					const char __user *buf,
349					size_t len, loff_t *ppos)
350{
351	return -ENODEV;
352}
353
354static inline ssize_t debugfs_attr_write_signed(struct file *file,
355					const char __user *buf,
356					size_t len, loff_t *ppos)
357{
358	return -ENODEV;
359}
360
361static inline int __printf(2, 3) debugfs_change_name(struct dentry *dentry,
362					const char *fmt, ...)
363{
364	return -ENODEV;
365}
366
367static inline void debugfs_create_u8(const char *name, umode_t mode,
368				     struct dentry *parent, u8 *value) { }
369
370static inline void debugfs_create_u16(const char *name, umode_t mode,
371				      struct dentry *parent, u16 *value) { }
372
373static inline void debugfs_create_u32(const char *name, umode_t mode,
374				      struct dentry *parent, u32 *value) { }
375
376static inline void debugfs_create_u64(const char *name, umode_t mode,
377				      struct dentry *parent, u64 *value) { }
378
379static inline void debugfs_create_ulong(const char *name, umode_t mode,
380					struct dentry *parent,
381					unsigned long *value) { }
382
383static inline void debugfs_create_x8(const char *name, umode_t mode,
384				     struct dentry *parent, u8 *value) { }
385
386static inline void debugfs_create_x16(const char *name, umode_t mode,
387				      struct dentry *parent, u16 *value) { }
388
389static inline void debugfs_create_x32(const char *name, umode_t mode,
390				      struct dentry *parent, u32 *value) { }
391
392static inline void debugfs_create_x64(const char *name, umode_t mode,
393				      struct dentry *parent, u64 *value) { }
394
395static inline void debugfs_create_size_t(const char *name, umode_t mode,
396					 struct dentry *parent, size_t *value)
397{ }
398
399static inline void debugfs_create_atomic_t(const char *name, umode_t mode,
400					   struct dentry *parent,
401					   atomic_t *value)
402{ }
403
404static inline void debugfs_create_bool(const char *name, umode_t mode,
405				       struct dentry *parent, bool *value) { }
406
407static inline void debugfs_create_str(const char *name, umode_t mode,
408				      struct dentry *parent,
409				      char **value)
410{ }
411
412static inline struct dentry *debugfs_create_blob(const char *name, umode_t mode,
413				  struct dentry *parent,
414				  struct debugfs_blob_wrapper *blob)
415{
416	return ERR_PTR(-ENODEV);
417}
418
419static inline void debugfs_create_regset32(const char *name, umode_t mode,
420					   struct dentry *parent,
421					   struct debugfs_regset32 *regset)
422{
423}
424
425static inline void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
426			 int nregs, void __iomem *base, char *prefix)
427{
428}
429
430static inline bool debugfs_initialized(void)
431{
432	return false;
433}
434
435static inline void debugfs_create_u32_array(const char *name, umode_t mode,
436					    struct dentry *parent,
437					    struct debugfs_u32_array *array)
438{
439}
440
441static inline void debugfs_create_devm_seqfile(struct device *dev,
442					       const char *name,
443					       struct dentry *parent,
444					       int (*read_fn)(struct seq_file *s,
445							      void *data))
446{
447}
448
449static inline ssize_t debugfs_read_file_bool(struct file *file,
450					     char __user *user_buf,
451					     size_t count, loff_t *ppos)
452{
453	return -ENODEV;
454}
455
456static inline ssize_t debugfs_write_file_bool(struct file *file,
457					      const char __user *user_buf,
458					      size_t count, loff_t *ppos)
459{
460	return -ENODEV;
461}
462
463static inline ssize_t debugfs_read_file_str(struct file *file,
464					    char __user *user_buf,
465					    size_t count, loff_t *ppos)
466{
467	return -ENODEV;
468}
469
470#endif
471
472#define debugfs_create_file_aux_num(name, mode, parent, data, n, fops) \
473	debugfs_create_file_aux(name, mode, parent, data, \
474				(void *)(unsigned long)n, fops)
475#define debugfs_get_aux_num(f) (unsigned long)debugfs_get_aux(f)
476
477/**
478 * debugfs_create_xul - create a debugfs file that is used to read and write an
479 * unsigned long value, formatted in hexadecimal
480 * @name: a pointer to a string containing the name of the file to create.
481 * @mode: the permission that the file should have
482 * @parent: a pointer to the parent dentry for this file.  This should be a
483 *          directory dentry if set.  If this parameter is %NULL, then the
484 *          file will be created in the root of the debugfs filesystem.
485 * @value: a pointer to the variable that the file should read to and write
486 *         from.
487 */
488static inline void debugfs_create_xul(const char *name, umode_t mode,
489				      struct dentry *parent,
490				      unsigned long *value)
491{
492	if (sizeof(*value) == sizeof(u32))
493		debugfs_create_x32(name, mode, parent, (u32 *)value);
494	else
495		debugfs_create_x64(name, mode, parent, (u64 *)value);
496}
497
498#endif