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 *
  56 debugfs_real_fops(const struct file *filp)
  57         __must_hold(&debugfs_srcu)
  58 {
  59         /*
  60          * Neither the pointer to the struct file_operations, nor its
  61          * contents ever change -- srcu_dereference() is not needed here.
  62          */
  63         return filp->f_path.dentry->d_fsdata;
  64 }
  65
  66 #define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)           \
  67 static int __fops ## _open(struct inode *inode, struct file *file)      \
  68 {                                                                       \
  69         __simple_attr_check_format(__fmt, 0ull);                        \
  70         return simple_attr_open(inode, file, __get, __set, __fmt);      \
  71 }                                                                       \
  72 static const struct file_operations __fops = {                          \
  73         .owner   = THIS_MODULE,                                         \
  74         .open    = __fops ## _open,                                     \
  75         .release = simple_attr_release,                                 \
  76         .read    = debugfs_attr_read,                                   \
  77         .write   = debugfs_attr_write,                                  \
  78         .llseek  = generic_file_llseek,                                 \
  79 }
  80
  81 #if defined(CONFIG_DEBUG_FS)
  82
  83 struct dentry *debugfs_create_file(const char *name, umode_t mode,
  84                                    struct dentry *parent, void *data,
  85                                    const struct file_operations *fops);
  86 struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
  87                                    struct dentry *parent, void *data,
  88                                    const struct file_operations *fops);
  89
  90 struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
  91                                         struct dentry *parent, void *data,
  92                                         const struct file_operations *fops,
  93                                         loff_t file_size);
  94
  95 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);
  96
  97 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
  98                                       const char *dest);
  99
 100 typedef struct vfsmount *(*debugfs_automount_t)(struct dentry *, void *);
 101 struct dentry *debugfs_create_automount(const char *name,
 102                                         struct dentry *parent,
 103                                         debugfs_automount_t f,
 104                                         void *data);
 105
 106 void debugfs_remove(struct dentry *dentry);
 107 void debugfs_remove_recursive(struct dentry *dentry);
 108
 109 int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx)
 110         __acquires(&debugfs_srcu);
 111
 112 void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu);
 113
 114 ssize_t debugfs_attr_read(struct file *file, char __user *buf,
 115                         size_t len, loff_t *ppos);
 116 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
 117                         size_t len, loff_t *ppos);
 118
 119 struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 120                 struct dentry *new_dir, const char *new_name);
 121
 122 struct dentry *debugfs_create_u8(const char *name, umode_t mode,
 123                                  struct dentry *parent, u8 *value);
 124 struct dentry *debugfs_create_u16(const char *name, umode_t mode,
 125                                   struct dentry *parent, u16 *value);
 126 struct dentry *debugfs_create_u32(const char *name, umode_t mode,
 127                                   struct dentry *parent, u32 *value);
 128 struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 129                                   struct dentry *parent, u64 *value);
 130 struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
 131                                     struct dentry *parent, unsigned long *value);
 132 struct dentry *debugfs_create_x8(const char *name, umode_t mode,
 133                                  struct dentry *parent, u8 *value);
 134 struct dentry *debugfs_create_x16(const char *name, umode_t mode,
 135                                   struct dentry *parent, u16 *value);
 136 struct dentry *debugfs_create_x32(const char *name, umode_t mode,
 137                                   struct dentry *parent, u32 *value);
 138 struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 139                                   struct dentry *parent, u64 *value);
 140 struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 141                                      struct dentry *parent, size_t *value);
 142 struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
 143                                      struct dentry *parent, atomic_t *value);
 144 struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 145                                   struct dentry *parent, bool *value);
 146
 147 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 148                                   struct dentry *parent,
 149                                   struct debugfs_blob_wrapper *blob);
 150
 151 struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
 152                                      struct dentry *parent,
 153                                      struct debugfs_regset32 *regset);
 154
 155 void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 156                           int nregs, void __iomem *base, char *prefix);
 157
 158 struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
 159                                         struct dentry *parent,
 160                                         u32 *array, u32 elements);
 161
 162 struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
 163                                            struct dentry *parent,
 164                                            int (*read_fn)(struct seq_file *s,
 165                                                           void *data));
 166
 167 bool debugfs_initialized(void);
 168
 169 ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
 170                                size_t count, loff_t *ppos);
 171
 172 ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
 173                                 size_t count, loff_t *ppos);
 174
 175 #else
 176
 177 #include <linux/err.h>
 178
 179 /*
 180  * We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
 181  * so users have a chance to detect if there was a real error or not.  We don't
 182  * want to duplicate the design decision mistakes of procfs and devfs again.
 183  */
 184
 185 static inline struct dentry *debugfs_create_file(const char *name, umode_t mode,
 186                                         struct dentry *parent, void *data,
 187                                         const struct file_operations *fops)
 188 {
 189         return ERR_PTR(-ENODEV);
 190 }
 191
 192 static inline struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
 193                                         struct dentry *parent, void *data,
 194                                         const struct file_operations *fops,
 195                                         loff_t file_size)
 196 {
 197         return ERR_PTR(-ENODEV);
 198 }
 199
 200 static inline struct dentry *debugfs_create_dir(const char *name,
 201                                                 struct dentry *parent)
 202 {
 203         return ERR_PTR(-ENODEV);
 204 }
 205
 206 static inline struct dentry *debugfs_create_symlink(const char *name,
 207                                                     struct dentry *parent,
 208                                                     const char *dest)
 209 {
 210         return ERR_PTR(-ENODEV);
 211 }
 212
 213 static inline struct dentry *debugfs_create_automount(const char *name,
 214                                         struct dentry *parent,
 215                                         struct vfsmount *(*f)(void *),
 216                                         void *data)
 217 {
 218         return ERR_PTR(-ENODEV);
 219 }
 220
 221 static inline void debugfs_remove(struct dentry *dentry)
 222 { }
 223
 224 static inline void debugfs_remove_recursive(struct dentry *dentry)
 225 { }
 226
 227 static inline int debugfs_use_file_start(const struct dentry *dentry,
 228                                         int *srcu_idx)
 229         __acquires(&debugfs_srcu)
 230 {
 231         return 0;
 232 }
 233
 234 static inline void debugfs_use_file_finish(int srcu_idx)
 235         __releases(&debugfs_srcu)
 236 { }
 237
 238 static inline ssize_t debugfs_attr_read(struct file *file, char __user *buf,
 239                                         size_t len, loff_t *ppos)
 240 {
 241         return -ENODEV;
 242 }
 243
 244 static inline ssize_t debugfs_attr_write(struct file *file,
 245                                         const char __user *buf,
 246                                         size_t len, loff_t *ppos)
 247 {
 248         return -ENODEV;
 249 }
 250
 251 static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 252                 struct dentry *new_dir, char *new_name)
 253 {
 254         return ERR_PTR(-ENODEV);
 255 }
 256
 257 static inline struct dentry *debugfs_create_u8(const char *name, umode_t mode,
 258                                                struct dentry *parent,
 259                                                u8 *value)
 260 {
 261         return ERR_PTR(-ENODEV);
 262 }
 263
 264 static inline struct dentry *debugfs_create_u16(const char *name, umode_t mode,
 265                                                 struct dentry *parent,
 266                                                 u16 *value)
 267 {
 268         return ERR_PTR(-ENODEV);
 269 }
 270
 271 static inline struct dentry *debugfs_create_u32(const char *name, umode_t mode,
 272                                                 struct dentry *parent,
 273                                                 u32 *value)
 274 {
 275         return ERR_PTR(-ENODEV);
 276 }
 277
 278 static inline struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 279                                                 struct dentry *parent,
 280                                                 u64 *value)
 281 {
 282         return ERR_PTR(-ENODEV);
 283 }
 284
 285 static inline struct dentry *debugfs_create_x8(const char *name, umode_t mode,
 286                                                struct dentry *parent,
 287                                                u8 *value)
 288 {
 289         return ERR_PTR(-ENODEV);
 290 }
 291
 292 static inline struct dentry *debugfs_create_x16(const char *name, umode_t mode,
 293                                                 struct dentry *parent,
 294                                                 u16 *value)
 295 {
 296         return ERR_PTR(-ENODEV);
 297 }
 298
 299 static inline struct dentry *debugfs_create_x32(const char *name, umode_t mode,
 300                                                 struct dentry *parent,
 301                                                 u32 *value)
 302 {
 303         return ERR_PTR(-ENODEV);
 304 }
 305
 306 static inline struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 307                                                 struct dentry *parent,
 308                                                 u64 *value)
 309 {
 310         return ERR_PTR(-ENODEV);
 311 }
 312
 313 static inline struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 314                                      struct dentry *parent,
 315                                      size_t *value)
 316 {
 317         return ERR_PTR(-ENODEV);
 318 }
 319
 320 static inline struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
 321                                      struct dentry *parent, atomic_t *value)
 322 {
 323         return ERR_PTR(-ENODEV);
 324 }
 325
 326 static inline struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 327                                                  struct dentry *parent,
 328                                                  bool *value)
 329 {
 330         return ERR_PTR(-ENODEV);
 331 }
 332
 333 static inline struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 334                                   struct dentry *parent,
 335                                   struct debugfs_blob_wrapper *blob)
 336 {
 337         return ERR_PTR(-ENODEV);
 338 }
 339
 340 static inline struct dentry *debugfs_create_regset32(const char *name,
 341                                    umode_t mode, struct dentry *parent,
 342                                    struct debugfs_regset32 *regset)
 343 {
 344         return ERR_PTR(-ENODEV);
 345 }
 346
 347 static inline void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 348                          int nregs, void __iomem *base, char *prefix)
 349 {
 350 }
 351
 352 static inline bool debugfs_initialized(void)
 353 {
 354         return false;
 355 }
 356
 357 static inline struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
 358                                         struct dentry *parent,
 359                                         u32 *array, u32 elements)
 360 {
 361         return ERR_PTR(-ENODEV);
 362 }
 363
 364 static inline struct dentry *debugfs_create_devm_seqfile(struct device *dev,
 365                                                          const char *name,
 366                                                          struct dentry *parent,
 367                                            int (*read_fn)(struct seq_file *s,
 368                                                           void *data))
 369 {
 370         return ERR_PTR(-ENODEV);
 371 }
 372
 373 static inline ssize_t debugfs_read_file_bool(struct file *file,
 374                                              char __user *user_buf,
 375                                              size_t count, loff_t *ppos)
 376 {
 377         return -ENODEV;
 378 }
 379
 380 static inline ssize_t debugfs_write_file_bool(struct file *file,
 381                                               const char __user *user_buf,
 382                                               size_t count, loff_t *ppos)
 383 {
 384         return -ENODEV;
 385 }
 386
 387 #endif
 388
 389 #endif