include/linux/debugfs.h

   1 /*
   2  *  debugfs.h - a tiny little debug file system
   3  *
   4  *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
   5  *  Copyright (C) 2004 IBM Inc.
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License version
   9  *      2 as published by the Free Software Foundation.
  10  *
  11  *  debugfs is for people to use instead of /proc or /sys.
  12  *  See Documentation/DocBook/filesystems for more details.
  13  */
  14
  15 #ifndef _DEBUGFS_H_
  16 #define _DEBUGFS_H_
  17
  18 #include <linux/fs.h>
  19 #include <linux/seq_file.h>
  20
  21 #include <linux/types.h>
  22 #include <linux/compiler.h>
  23
  24 struct device;
  25 struct file_operations;
  26 struct srcu_struct;
  27
  28 struct debugfs_blob_wrapper {
  29         void *data;
  30         unsigned long size;
  31 };
  32
  33 struct debugfs_reg32 {
  34         char *name;
  35         unsigned long offset;
  36 };
  37
  38 struct debugfs_regset32 {
  39         const struct debugfs_reg32 *regs;
  40         int nregs;
  41         void __iomem *base;
  42 };
  43
  44 extern struct dentry *arch_debugfs_dir;
  45
  46 extern struct srcu_struct debugfs_srcu;
  47
  48 /**
  49  * debugfs_real_fops - getter for the real file operation
  50  * @filp: a pointer to a struct file
  51  *
  52  * Must only be called under the protection established by
  53  * debugfs_use_file_start().
  54  */
  55 static inline const struct file_operations *debugfs_real_fops(struct file *filp)
  56         __must_hold(&debugfs_srcu)
  57 {
  58         /*
  59          * Neither the pointer to the struct file_operations, nor its
  60          * contents ever change -- srcu_dereference() is not needed here.
  61          */
  62         return filp->f_path.dentry->d_fsdata;
  63 }
  64
  65 #if defined(CONFIG_DEBUG_FS)
  66
  67 struct dentry *debugfs_create_file(const char *name, umode_t mode,
  68                                    struct dentry *parent, void *data,
  69                                    const struct file_operations *fops);
  70 struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
  71                                    struct dentry *parent, void *data,
  72                                    const struct file_operations *fops);
  73
  74 struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
  75                                         struct dentry *parent, void *data,
  76                                         const struct file_operations *fops,
  77                                         loff_t file_size);
  78
  79 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);
  80
  81 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
  82                                       const char *dest);
  83
  84 struct dentry *debugfs_create_automount(const char *name,
  85                                         struct dentry *parent,
  86                                         struct vfsmount *(*f)(void *),
  87                                         void *data);
  88
  89 void debugfs_remove(struct dentry *dentry);
  90 void debugfs_remove_recursive(struct dentry *dentry);
  91
  92 int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx)
  93         __acquires(&debugfs_srcu);
  94
  95 void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu);
  96
  97 ssize_t debugfs_attr_read(struct file *file, char __user *buf,
  98                         size_t len, loff_t *ppos);
  99 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
 100                         size_t len, loff_t *ppos);
 101
 102 #define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)           \
 103 static int __fops ## _open(struct inode *inode, struct file *file)      \
 104 {                                                                       \
 105         __simple_attr_check_format(__fmt, 0ull);                        \
 106         return simple_attr_open(inode, file, __get, __set, __fmt);      \
 107 }                                                                       \
 108 static const struct file_operations __fops = {                          \
 109         .owner   = THIS_MODULE,                                 \
 110         .open    = __fops ## _open,                                     \
 111         .release = simple_attr_release,                         \
 112         .read    = debugfs_attr_read,                                   \
 113         .write   = debugfs_attr_write,                                  \
 114         .llseek  = generic_file_llseek,                         \
 115 }
 116
 117 struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 118                 struct dentry *new_dir, const char *new_name);
 119
 120 struct dentry *debugfs_create_u8(const char *name, umode_t mode,
 121                                  struct dentry *parent, u8 *value);
 122 struct dentry *debugfs_create_u16(const char *name, umode_t mode,
 123                                   struct dentry *parent, u16 *value);
 124 struct dentry *debugfs_create_u32(const char *name, umode_t mode,
 125                                   struct dentry *parent, u32 *value);
 126 struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 127                                   struct dentry *parent, u64 *value);
 128 struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
 129                                     struct dentry *parent, unsigned long *value);
 130 struct dentry *debugfs_create_x8(const char *name, umode_t mode,
 131                                  struct dentry *parent, u8 *value);
 132 struct dentry *debugfs_create_x16(const char *name, umode_t mode,
 133                                   struct dentry *parent, u16 *value);
 134 struct dentry *debugfs_create_x32(const char *name, umode_t mode,
 135                                   struct dentry *parent, u32 *value);
 136 struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 137                                   struct dentry *parent, u64 *value);
 138 struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 139                                      struct dentry *parent, size_t *value);
 140 struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
 141                                      struct dentry *parent, atomic_t *value);
 142 struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 143                                   struct dentry *parent, bool *value);
 144
 145 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 146                                   struct dentry *parent,
 147                                   struct debugfs_blob_wrapper *blob);
 148
 149 struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
 150                                      struct dentry *parent,
 151                                      struct debugfs_regset32 *regset);
 152
 153 void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 154                           int nregs, void __iomem *base, char *prefix);
 155
 156 struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
 157                                         struct dentry *parent,
 158                                         u32 *array, u32 elements);
 159
 160 struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
 161                                            struct dentry *parent,
 162                                            int (*read_fn)(struct seq_file *s,
 163                                                           void *data));
 164
 165 bool debugfs_initialized(void);
 166
 167 ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
 168                                size_t count, loff_t *ppos);
 169
 170 ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
 171                                 size_t count, loff_t *ppos);
 172
 173 #else
 174
 175 #include <linux/err.h>
 176
 177 /*
 178  * We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
 179  * so users have a chance to detect if there was a real error or not.  We don't
 180  * want to duplicate the design decision mistakes of procfs and devfs again.
 181  */
 182
 183 static inline struct dentry *debugfs_create_file(const char *name, umode_t mode,
 184                                         struct dentry *parent, void *data,
 185                                         const struct file_operations *fops)
 186 {
 187         return ERR_PTR(-ENODEV);
 188 }
 189
 190 static inline struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
 191                                         struct dentry *parent, void *data,
 192                                         const struct file_operations *fops,
 193                                         loff_t file_size)
 194 {
 195         return ERR_PTR(-ENODEV);
 196 }
 197
 198 static inline struct dentry *debugfs_create_dir(const char *name,
 199                                                 struct dentry *parent)
 200 {
 201         return ERR_PTR(-ENODEV);
 202 }
 203
 204 static inline struct dentry *debugfs_create_symlink(const char *name,
 205                                                     struct dentry *parent,
 206                                                     const char *dest)
 207 {
 208         return ERR_PTR(-ENODEV);
 209 }
 210
 211 static inline struct dentry *debugfs_create_automount(const char *name,
 212                                         struct dentry *parent,
 213                                         struct vfsmount *(*f)(void *),
 214                                         void *data)
 215 {
 216         return ERR_PTR(-ENODEV);
 217 }
 218
 219 static inline void debugfs_remove(struct dentry *dentry)
 220 { }
 221
 222 static inline void debugfs_remove_recursive(struct dentry *dentry)
 223 { }
 224
 225 static inline int debugfs_use_file_start(const struct dentry *dentry,
 226                                         int *srcu_idx)
 227         __acquires(&debugfs_srcu)
 228 {
 229         return 0;
 230 }
 231
 232 static inline void debugfs_use_file_finish(int srcu_idx)
 233         __releases(&debugfs_srcu)
 234 { }
 235
 236 #define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)   \
 237         static const struct file_operations __fops = { 0 }
 238
 239 static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 240                 struct dentry *new_dir, char *new_name)
 241 {
 242         return ERR_PTR(-ENODEV);
 243 }
 244
 245 static inline struct dentry *debugfs_create_u8(const char *name, umode_t mode,
 246                                                struct dentry *parent,
 247                                                u8 *value)
 248 {
 249         return ERR_PTR(-ENODEV);
 250 }
 251
 252 static inline struct dentry *debugfs_create_u16(const char *name, umode_t mode,
 253                                                 struct dentry *parent,
 254                                                 u16 *value)
 255 {
 256         return ERR_PTR(-ENODEV);
 257 }
 258
 259 static inline struct dentry *debugfs_create_u32(const char *name, umode_t mode,
 260                                                 struct dentry *parent,
 261                                                 u32 *value)
 262 {
 263         return ERR_PTR(-ENODEV);
 264 }
 265
 266 static inline struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 267                                                 struct dentry *parent,
 268                                                 u64 *value)
 269 {
 270         return ERR_PTR(-ENODEV);
 271 }
 272
 273 static inline struct dentry *debugfs_create_x8(const char *name, umode_t mode,
 274                                                struct dentry *parent,
 275                                                u8 *value)
 276 {
 277         return ERR_PTR(-ENODEV);
 278 }
 279
 280 static inline struct dentry *debugfs_create_x16(const char *name, umode_t mode,
 281                                                 struct dentry *parent,
 282                                                 u16 *value)
 283 {
 284         return ERR_PTR(-ENODEV);
 285 }
 286
 287 static inline struct dentry *debugfs_create_x32(const char *name, umode_t mode,
 288                                                 struct dentry *parent,
 289                                                 u32 *value)
 290 {
 291         return ERR_PTR(-ENODEV);
 292 }
 293
 294 static inline struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 295                                                 struct dentry *parent,
 296                                                 u64 *value)
 297 {
 298         return ERR_PTR(-ENODEV);
 299 }
 300
 301 static inline struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 302                                      struct dentry *parent,
 303                                      size_t *value)
 304 {
 305         return ERR_PTR(-ENODEV);
 306 }
 307
 308 static inline struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
 309                                      struct dentry *parent, atomic_t *value)
 310 {
 311         return ERR_PTR(-ENODEV);
 312 }
 313
 314 static inline struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 315                                                  struct dentry *parent,
 316                                                  bool *value)
 317 {
 318         return ERR_PTR(-ENODEV);
 319 }
 320
 321 static inline struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 322                                   struct dentry *parent,
 323                                   struct debugfs_blob_wrapper *blob)
 324 {
 325         return ERR_PTR(-ENODEV);
 326 }
 327
 328 static inline struct dentry *debugfs_create_regset32(const char *name,
 329                                    umode_t mode, struct dentry *parent,
 330                                    struct debugfs_regset32 *regset)
 331 {
 332         return ERR_PTR(-ENODEV);
 333 }
 334
 335 static inline void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 336                          int nregs, void __iomem *base, char *prefix)
 337 {
 338 }
 339
 340 static inline bool debugfs_initialized(void)
 341 {
 342         return false;
 343 }
 344
 345 static inline struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
 346                                         struct dentry *parent,
 347                                         u32 *array, u32 elements)
 348 {
 349         return ERR_PTR(-ENODEV);
 350 }
 351
 352 static inline struct dentry *debugfs_create_devm_seqfile(struct device *dev,
 353                                                          const char *name,
 354                                                          struct dentry *parent,
 355                                            int (*read_fn)(struct seq_file *s,
 356                                                           void *data))
 357 {
 358         return ERR_PTR(-ENODEV);
 359 }
 360
 361 static inline ssize_t debugfs_read_file_bool(struct file *file,
 362                                              char __user *user_buf,
 363                                              size_t count, loff_t *ppos)
 364 {
 365         return -ENODEV;
 366 }
 367
 368 static inline ssize_t debugfs_write_file_bool(struct file *file,
 369                                               const char __user *user_buf,
 370                                               size_t count, loff_t *ppos)
 371 {
 372         return -ENODEV;
 373 }
 374
 375 #endif
 376
 377 #endif