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 struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
 116                                     struct dentry *parent, 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 struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 130                                   struct dentry *parent, bool *value);
 131
 132 struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 133                                   struct dentry *parent,
 134                                   struct debugfs_blob_wrapper *blob);
 135
 136 void debugfs_create_regset32(const char *name, umode_t mode,
 137                              struct dentry *parent,
 138                              struct debugfs_regset32 *regset);
 139
 140 void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 141                           int nregs, void __iomem *base, char *prefix);
 142
 143 void debugfs_create_u32_array(const char *name, umode_t mode,
 144                               struct dentry *parent,
 145                               struct debugfs_u32_array *array);
 146
 147 void debugfs_create_devm_seqfile(struct device *dev, const char *name,
 148                                  struct dentry *parent,
 149                                  int (*read_fn)(struct seq_file *s, void *data));
 150
 151 bool debugfs_initialized(void);
 152
 153 ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
 154                                size_t count, loff_t *ppos);
 155
 156 ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
 157                                 size_t count, loff_t *ppos);
 158
 159 #else
 160
 161 #include <linux/err.h>
 162
 163 /*
 164  * We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
 165  * so users have a chance to detect if there was a real error or not.  We don't
 166  * want to duplicate the design decision mistakes of procfs and devfs again.
 167  */
 168
 169 static inline struct dentry *debugfs_lookup(const char *name,
 170                                             struct dentry *parent)
 171 {
 172         return ERR_PTR(-ENODEV);
 173 }
 174
 175 static inline struct dentry *debugfs_create_file(const char *name, umode_t mode,
 176                                         struct dentry *parent, void *data,
 177                                         const struct file_operations *fops)
 178 {
 179         return ERR_PTR(-ENODEV);
 180 }
 181
 182 static inline struct dentry *debugfs_create_file_unsafe(const char *name,
 183                                         umode_t mode, struct dentry *parent,
 184                                         void *data,
 185                                         const struct file_operations *fops)
 186 {
 187         return ERR_PTR(-ENODEV);
 188 }
 189
 190 static inline void 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
 196 static inline struct dentry *debugfs_create_dir(const char *name,
 197                                                 struct dentry *parent)
 198 {
 199         return ERR_PTR(-ENODEV);
 200 }
 201
 202 static inline struct dentry *debugfs_create_symlink(const char *name,
 203                                                     struct dentry *parent,
 204                                                     const char *dest)
 205 {
 206         return ERR_PTR(-ENODEV);
 207 }
 208
 209 static inline struct dentry *debugfs_create_automount(const char *name,
 210                                         struct dentry *parent,
 211                                         debugfs_automount_t f,
 212                                         void *data)
 213 {
 214         return ERR_PTR(-ENODEV);
 215 }
 216
 217 static inline void debugfs_remove(struct dentry *dentry)
 218 { }
 219
 220 static inline void debugfs_remove_recursive(struct dentry *dentry)
 221 { }
 222
 223 const struct file_operations *debugfs_real_fops(const struct file *filp);
 224
 225 static inline int debugfs_file_get(struct dentry *dentry)
 226 {
 227         return 0;
 228 }
 229
 230 static inline void debugfs_file_put(struct dentry *dentry)
 231 { }
 232
 233 static inline ssize_t debugfs_attr_read(struct file *file, char __user *buf,
 234                                         size_t len, loff_t *ppos)
 235 {
 236         return -ENODEV;
 237 }
 238
 239 static inline ssize_t debugfs_attr_write(struct file *file,
 240                                         const char __user *buf,
 241                                         size_t len, loff_t *ppos)
 242 {
 243         return -ENODEV;
 244 }
 245
 246 static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
 247                 struct dentry *new_dir, char *new_name)
 248 {
 249         return ERR_PTR(-ENODEV);
 250 }
 251
 252 static inline void debugfs_create_u8(const char *name, umode_t mode,
 253                                      struct dentry *parent, u8 *value) { }
 254
 255 static inline void debugfs_create_u16(const char *name, umode_t mode,
 256                                       struct dentry *parent, u16 *value) { }
 257
 258 static inline void debugfs_create_u32(const char *name, umode_t mode,
 259                                       struct dentry *parent, u32 *value) { }
 260
 261 static inline void debugfs_create_u64(const char *name, umode_t mode,
 262                                       struct dentry *parent, u64 *value) { }
 263
 264 static inline struct dentry *debugfs_create_ulong(const char *name,
 265                                                 umode_t mode,
 266                                                 struct dentry *parent,
 267                                                 unsigned long *value)
 268 {
 269         return ERR_PTR(-ENODEV);
 270 }
 271
 272 static inline void debugfs_create_x8(const char *name, umode_t mode,
 273                                      struct dentry *parent, u8 *value) { }
 274
 275 static inline void debugfs_create_x16(const char *name, umode_t mode,
 276                                       struct dentry *parent, u16 *value) { }
 277
 278 static inline void debugfs_create_x32(const char *name, umode_t mode,
 279                                       struct dentry *parent, u32 *value) { }
 280
 281 static inline void debugfs_create_x64(const char *name, umode_t mode,
 282                                       struct dentry *parent, u64 *value) { }
 283
 284 static inline void debugfs_create_size_t(const char *name, umode_t mode,
 285                                          struct dentry *parent, size_t *value)
 286 { }
 287
 288 static inline void debugfs_create_atomic_t(const char *name, umode_t mode,
 289                                            struct dentry *parent,
 290                                            atomic_t *value)
 291 { }
 292
 293 static inline struct dentry *debugfs_create_bool(const char *name, umode_t mode,
 294                                                  struct dentry *parent,
 295                                                  bool *value)
 296 {
 297         return ERR_PTR(-ENODEV);
 298 }
 299
 300 static inline struct dentry *debugfs_create_blob(const char *name, umode_t mode,
 301                                   struct dentry *parent,
 302                                   struct debugfs_blob_wrapper *blob)
 303 {
 304         return ERR_PTR(-ENODEV);
 305 }
 306
 307 static inline void debugfs_create_regset32(const char *name, umode_t mode,
 308                                            struct dentry *parent,
 309                                            struct debugfs_regset32 *regset)
 310 {
 311 }
 312
 313 static inline void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
 314                          int nregs, void __iomem *base, char *prefix)
 315 {
 316 }
 317
 318 static inline bool debugfs_initialized(void)
 319 {
 320         return false;
 321 }
 322
 323 static inline void debugfs_create_u32_array(const char *name, umode_t mode,
 324                                             struct dentry *parent,
 325                                             struct debugfs_u32_array *array)
 326 {
 327 }
 328
 329 static inline void debugfs_create_devm_seqfile(struct device *dev,
 330                                                const char *name,
 331                                                struct dentry *parent,
 332                                                int (*read_fn)(struct seq_file *s,
 333                                                               void *data))
 334 {
 335 }
 336
 337 static inline ssize_t debugfs_read_file_bool(struct file *file,
 338                                              char __user *user_buf,
 339                                              size_t count, loff_t *ppos)
 340 {
 341         return -ENODEV;
 342 }
 343
 344 static inline ssize_t debugfs_write_file_bool(struct file *file,
 345                                               const char __user *user_buf,
 346                                               size_t count, loff_t *ppos)
 347 {
 348         return -ENODEV;
 349 }
 350
 351 #endif
 352
 353 /**
 354  * debugfs_create_xul - create a debugfs file that is used to read and write an
 355  * unsigned long value, formatted in hexadecimal
 356  * @name: a pointer to a string containing the name of the file to create.
 357  * @mode: the permission that the file should have
 358  * @parent: a pointer to the parent dentry for this file.  This should be a
 359  *          directory dentry if set.  If this parameter is %NULL, then the
 360  *          file will be created in the root of the debugfs filesystem.
 361  * @value: a pointer to the variable that the file should read to and write
 362  *         from.
 363  */
 364 static inline void debugfs_create_xul(const char *name, umode_t mode,
 365                                       struct dentry *parent,
 366                                       unsigned long *value)
 367 {
 368         if (sizeof(*value) == sizeof(u32))
 369                 debugfs_create_x32(name, mode, parent, (u32 *)value);
 370         else
 371                 debugfs_create_x64(name, mode, parent, (u64 *)value);
 372 }
 373
 374 #endif