linux/include/linux/debugfs.h
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   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
  24struct device;
  25struct file_operations;
  26struct srcu_struct;
  27
  28struct debugfs_blob_wrapper {
  29        void *data;
  30        unsigned long size;
  31};
  32
  33struct debugfs_reg32 {
  34        char *name;
  35        unsigned long offset;
  36};
  37
  38struct debugfs_regset32 {
  39        const struct debugfs_reg32 *regs;
  40        int nregs;
  41        void __iomem *base;
  42};
  43
  44extern struct dentry *arch_debugfs_dir;
  45
  46extern 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 */
  55static 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
  67struct dentry *debugfs_create_file(const char *name, umode_t mode,
  68                                   struct dentry *parent, void *data,
  69                                   const struct file_operations *fops);
  70struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
  71                                   struct dentry *parent, void *data,
  72                                   const struct file_operations *fops);
  73
  74struct 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
  79struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);
  80
  81struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
  82                                      const char *dest);
  83
  84struct dentry *debugfs_create_automount(const char *name,
  85                                        struct dentry *parent,
  86                                        struct vfsmount *(*f)(void *),
  87                                        void *data);
  88
  89void debugfs_remove(struct dentry *dentry);
  90void debugfs_remove_recursive(struct dentry *dentry);
  91
  92int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx)
  93        __acquires(&debugfs_srcu);
  94
  95void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu);
  96
  97ssize_t debugfs_attr_read(struct file *file, char __user *buf,
  98                        size_t len, loff_t *ppos);
  99ssize_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)           \
 103static 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}                                                                       \
 108static 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
 117struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 118                struct dentry *new_dir, const char *new_name);
 119
 120struct dentry *debugfs_create_u8(const char *name, umode_t mode,
 121                                 struct dentry *parent, u8 *value);
 122struct dentry *debugfs_create_u16(const char *name, umode_t mode,
 123                                  struct dentry *parent, u16 *value);
 124struct dentry *debugfs_create_u32(const char *name, umode_t mode,
 125                                  struct dentry *parent, u32 *value);
 126struct dentry *debugfs_create_u64(const char *name, umode_t mode,
 127                                  struct dentry *parent, u64 *value);
 128struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
 129                                    struct dentry *parent, unsigned long *value);
 130struct dentry *debugfs_create_x8(const char *name, umode_t mode,
 131                                 struct dentry *parent, u8 *value);
 132struct dentry *debugfs_create_x16(const char *name, umode_t mode,
 133                                  struct dentry *parent, u16 *value);
 134struct dentry *debugfs_create_x32(const char *name, umode_t mode,
 135                                  struct dentry *parent, u32 *value);
 136struct dentry *debugfs_create_x64(const char *name, umode_t mode,
 137                                  struct dentry *parent, u64 *value);
 138struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
 139                                     struct dentry *parent, size_t *value);
 140struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
 141                                     struct dentry *parent, atomic_t *value);
 142struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 143                                  struct dentry *parent, bool *value);
 144
 145struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 146                                  struct dentry *parent,
 147                                  struct debugfs_blob_wrapper *blob);
 148
 149struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
 150                                     struct dentry *parent,
 151                                     struct debugfs_regset32 *regset);
 152
 153void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 154                          int nregs, void __iomem *base, char *prefix);
 155
 156struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
 157                                        struct dentry *parent,
 158                                        u32 *array, u32 elements);
 159
 160struct 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
 165bool debugfs_initialized(void);
 166
 167ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
 168                               size_t count, loff_t *ppos);
 169
 170ssize_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
 183static 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
 190static 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
 198static inline struct dentry *debugfs_create_dir(const char *name,
 199                                                struct dentry *parent)
 200{
 201        return ERR_PTR(-ENODEV);
 202}
 203
 204static 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
 211static 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
 219static inline void debugfs_remove(struct dentry *dentry)
 220{ }
 221
 222static inline void debugfs_remove_recursive(struct dentry *dentry)
 223{ }
 224
 225static inline int debugfs_use_file_start(const struct dentry *dentry,
 226                                        int *srcu_idx)
 227        __acquires(&debugfs_srcu)
 228{
 229        return 0;
 230}
 231
 232static 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
 239static 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
 245static 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
 252static 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
 259static 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
 266static 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
 273static 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
 280static 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
 287static 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
 294static 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
 301static 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
 308static 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
 314static 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
 321static 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
 328static 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
 335static 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
 340static inline bool debugfs_initialized(void)
 341{
 342        return false;
 343}
 344
 345static 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
 352static 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
 361static 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
 368static 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
 378