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 <[email protected]> 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 477