include/linux/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
  21 struct device;
  22 struct file_operations;
  23
  24 struct debugfs_blob_wrapper {
  25         void *data;
  26         unsigned long size;
  27 };
  28
  29 struct debugfs_reg32 {
  30         char *name;
  31         unsigned long offset;
  32 };
  33
  34 struct 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
  41 struct debugfs_u32_array {
  42         u32 *array;
  43         u32 n_elements;
  44 };
  45
  46 extern struct dentry *arch_debugfs_dir;
  47
  48 #define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)           \
  49 static 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 }                                                                       \
  54 static 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   = debugfs_attr_write,                                  \
  60         .llseek  = no_llseek,                                           \
  61 }
  62
  63 typedef struct vfsmount *(*debugfs_automount_t)(struct dentry *, void *);
  64
  65 #if defined(CONFIG_DEBUG_FS)
  66
  67 struct dentry *debugfs_lookup(const char *name, struct dentry *parent);
  68
  69 struct dentry *debugfs_create_file(const char *name, umode_t mode,
  70                                    struct dentry *parent, void *data,
  71                                    const struct file_operations *fops);
  72 struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
  73                                    struct dentry *parent, void *data,
  74                                    const struct file_operations *fops);
  75
  76 void debugfs_create_file_size(const char *name, umode_t mode,
  77                               struct dentry *parent, void *data,
  78                               const struct file_operations *fops,
  79                               loff_t file_size);
  80
  81 struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);
  82
  83 struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
  84                                       const char *dest);
  85
  86 struct dentry *debugfs_create_automount(const char *name,
  87                                         struct dentry *parent,
  88                                         debugfs_automount_t f,
  89                                         void *data);
  90
  91 void debugfs_remove(struct dentry *dentry);
  92 #define debugfs_remove_recursive debugfs_remove
  93
  94 const struct file_operations *debugfs_real_fops(const struct file *filp);
  95
  96 int debugfs_file_get(struct dentry *dentry);
  97 void debugfs_file_put(struct dentry *dentry);
  98
  99 ssize_t debugfs_attr_read(struct file *file, char __user *buf,
 100                         size_t len, loff_t *ppos);
 101 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
 102                         size_t len, loff_t *ppos);
 103
 104 struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 105                 struct dentry *new_dir, const char *new_name);
 106
 107 void debugfs_create_u8(const char *name, umode_t mode, struct dentry *parent,
 108                        u8 *value);
 109 void debugfs_create_u16(const char *name, umode_t mode, struct dentry *parent,
 110                         u16 *value);
 111 void debugfs_create_u32(const char *name, umode_t mode, struct dentry *parent,
 112                         u32 *value);
 113 void debugfs_create_u64(const char *name, umode_t mode, struct dentry *parent,
 114                         u64 *value);
 115 void debugfs_create_ulong(const char *name, umode_t mode, struct dentry *parent,
 116                           unsigned long *value);
 117 void debugfs_create_x8(const char *name, umode_t mode, struct dentry *parent,
 118                        u8 *value);
 119 void debugfs_create_x16(const char *name, umode_t mode, struct dentry *parent,
 120                         u16 *value);
 121 void debugfs_create_x32(const char *name, umode_t mode, struct dentry *parent,
 122                         u32 *value);
 123 void debugfs_create_x64(const char *name, umode_t mode, struct dentry *parent,
 124                         u64 *value);
 125 void debugfs_create_size_t(const char *name, umode_t mode,
 126                            struct dentry *parent, size_t *value);
 127 void debugfs_create_atomic_t(const char *name, umode_t mode,
 128                              struct dentry *parent, atomic_t *value);
 129 void debugfs_create_bool(const char *name, umode_t mode, struct dentry *parent,
 130                          bool *value);
 131 void debugfs_create_str(const char *name, umode_t mode,
 132                         struct dentry *parent, char **value);
 133
 134 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 135                                   struct dentry *parent,
 136                                   struct debugfs_blob_wrapper *blob);
 137
 138 void debugfs_create_regset32(const char *name, umode_t mode,
 139                              struct dentry *parent,
 140                              struct debugfs_regset32 *regset);
 141
 142 void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 143                           int nregs, void __iomem *base, char *prefix);
 144
 145 void debugfs_create_u32_array(const char *name, umode_t mode,
 146                               struct dentry *parent,
 147                               struct debugfs_u32_array *array);
 148
 149 void debugfs_create_devm_seqfile(struct device *dev, const char *name,
 150                                  struct dentry *parent,
 151                                  int (*read_fn)(struct seq_file *s, void *data));
 152
 153 bool debugfs_initialized(void);
 154
 155 ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
 156                                size_t count, loff_t *ppos);
 157
 158 ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
 159                                 size_t count, loff_t *ppos);
 160
 161 ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
 162                               size_t count, loff_t *ppos);
 163
 164 #else
 165
 166 #include <linux/err.h>
 167
 168 /*
 169  * We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
 170  * so users have a chance to detect if there was a real error or not.  We don't
 171  * want to duplicate the design decision mistakes of procfs and devfs again.
 172  */
 173
 174 static inline struct dentry *debugfs_lookup(const char *name,
 175                                             struct dentry *parent)
 176 {
 177         return ERR_PTR(-ENODEV);
 178 }
 179
 180 static inline struct dentry *debugfs_create_file(const char *name, umode_t mode,
 181                                         struct dentry *parent, void *data,
 182                                         const struct file_operations *fops)
 183 {
 184         return ERR_PTR(-ENODEV);
 185 }
 186
 187 static inline struct dentry *debugfs_create_file_unsafe(const char *name,
 188                                         umode_t mode, struct dentry *parent,
 189                                         void *data,
 190                                         const struct file_operations *fops)
 191 {
 192         return ERR_PTR(-ENODEV);
 193 }
 194
 195 static inline void debugfs_create_file_size(const char *name, umode_t mode,
 196                                             struct dentry *parent, void *data,
 197                                             const struct file_operations *fops,
 198                                             loff_t file_size)
 199 { }
 200
 201 static inline struct dentry *debugfs_create_dir(const char *name,
 202                                                 struct dentry *parent)
 203 {
 204         return ERR_PTR(-ENODEV);
 205 }
 206
 207 static inline struct dentry *debugfs_create_symlink(const char *name,
 208                                                     struct dentry *parent,
 209                                                     const char *dest)
 210 {
 211         return ERR_PTR(-ENODEV);
 212 }
 213
 214 static inline struct dentry *debugfs_create_automount(const char *name,
 215                                         struct dentry *parent,
 216                                         debugfs_automount_t f,
 217                                         void *data)
 218 {
 219         return ERR_PTR(-ENODEV);
 220 }
 221
 222 static inline void debugfs_remove(struct dentry *dentry)
 223 { }
 224
 225 static inline void debugfs_remove_recursive(struct dentry *dentry)
 226 { }
 227
 228 const struct file_operations *debugfs_real_fops(const struct file *filp);
 229
 230 static inline int debugfs_file_get(struct dentry *dentry)
 231 {
 232         return 0;
 233 }
 234
 235 static inline void debugfs_file_put(struct dentry *dentry)
 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 void debugfs_create_u8(const char *name, umode_t mode,
 258                                      struct dentry *parent, u8 *value) { }
 259
 260 static inline void debugfs_create_u16(const char *name, umode_t mode,
 261                                       struct dentry *parent, u16 *value) { }
 262
 263 static inline void debugfs_create_u32(const char *name, umode_t mode,
 264                                       struct dentry *parent, u32 *value) { }
 265
 266 static inline void debugfs_create_u64(const char *name, umode_t mode,
 267                                       struct dentry *parent, u64 *value) { }
 268
 269 static inline void debugfs_create_ulong(const char *name, umode_t mode,
 270                                         struct dentry *parent,
 271                                         unsigned long *value) { }
 272
 273 static inline void debugfs_create_x8(const char *name, umode_t mode,
 274                                      struct dentry *parent, u8 *value) { }
 275
 276 static inline void debugfs_create_x16(const char *name, umode_t mode,
 277                                       struct dentry *parent, u16 *value) { }
 278
 279 static inline void debugfs_create_x32(const char *name, umode_t mode,
 280                                       struct dentry *parent, u32 *value) { }
 281
 282 static inline void debugfs_create_x64(const char *name, umode_t mode,
 283                                       struct dentry *parent, u64 *value) { }
 284
 285 static inline void debugfs_create_size_t(const char *name, umode_t mode,
 286                                          struct dentry *parent, size_t *value)
 287 { }
 288
 289 static inline void debugfs_create_atomic_t(const char *name, umode_t mode,
 290                                            struct dentry *parent,
 291                                            atomic_t *value)
 292 { }
 293
 294 static inline void debugfs_create_bool(const char *name, umode_t mode,
 295                                        struct dentry *parent, bool *value) { }
 296
 297 static inline void debugfs_create_str(const char *name, umode_t mode,
 298                                       struct dentry *parent,
 299                                       char **value)
 300 { }
 301
 302 static inline struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 303                                   struct dentry *parent,
 304                                   struct debugfs_blob_wrapper *blob)
 305 {
 306         return ERR_PTR(-ENODEV);
 307 }
 308
 309 static inline void debugfs_create_regset32(const char *name, umode_t mode,
 310                                            struct dentry *parent,
 311                                            struct debugfs_regset32 *regset)
 312 {
 313 }
 314
 315 static inline void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 316                          int nregs, void __iomem *base, char *prefix)
 317 {
 318 }
 319
 320 static inline bool debugfs_initialized(void)
 321 {
 322         return false;
 323 }
 324
 325 static inline void debugfs_create_u32_array(const char *name, umode_t mode,
 326                                             struct dentry *parent,
 327                                             struct debugfs_u32_array *array)
 328 {
 329 }
 330
 331 static inline void debugfs_create_devm_seqfile(struct device *dev,
 332                                                const char *name,
 333                                                struct dentry *parent,
 334                                                int (*read_fn)(struct seq_file *s,
 335                                                               void *data))
 336 {
 337 }
 338
 339 static inline ssize_t debugfs_read_file_bool(struct file *file,
 340                                              char __user *user_buf,
 341                                              size_t count, loff_t *ppos)
 342 {
 343         return -ENODEV;
 344 }
 345
 346 static inline ssize_t debugfs_write_file_bool(struct file *file,
 347                                               const char __user *user_buf,
 348                                               size_t count, loff_t *ppos)
 349 {
 350         return -ENODEV;
 351 }
 352
 353 static inline ssize_t debugfs_read_file_str(struct file *file,
 354                                             char __user *user_buf,
 355                                             size_t count, loff_t *ppos)
 356 {
 357         return -ENODEV;
 358 }
 359
 360 #endif
 361
 362 /**
 363  * debugfs_create_xul - create a debugfs file that is used to read and write an
 364  * unsigned long value, formatted in hexadecimal
 365  * @name: a pointer to a string containing the name of the file to create.
 366  * @mode: the permission that the file should have
 367  * @parent: a pointer to the parent dentry for this file.  This should be a
 368  *          directory dentry if set.  If this parameter is %NULL, then the
 369  *          file will be created in the root of the debugfs filesystem.
 370  * @value: a pointer to the variable that the file should read to and write
 371  *         from.
 372  */
 373 static inline void debugfs_create_xul(const char *name, umode_t mode,
 374                                       struct dentry *parent,
 375                                       unsigned long *value)
 376 {
 377         if (sizeof(*value) == sizeof(u32))
 378                 debugfs_create_x32(name, mode, parent, (u32 *)value);
 379         else
 380                 debugfs_create_x64(name, mode, parent, (u64 *)value);
 381 }
 382
 383 #endif