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