linux_kernel/include/linux/debugfs.h

/*
 *  debugfs.h - a tiny little debug file system
 *
 *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
 *  Copyright (C) 2004 IBM Inc.
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License version
 *	2 as published by the Free Software Foundation.
 *
 *  debugfs is for people to use instead of /proc or /sys.
 *  See Documentation/DocBook/filesystems for more details.
 */

#ifndef _DEBUGFS_H_
#define _DEBUGFS_H_

#include <linux/fs.h>
#include <linux/seq_file.h>

#include <linux/types.h>
#include <linux/compiler.h>

struct device;
struct file_operations;
struct srcu_struct;

struct debugfs_blob_wrapper {
	void *data;
	unsigned long size;
};

struct debugfs_reg32 {
	char *name;
	unsigned long offset;
};

struct debugfs_regset32 {
	const struct debugfs_reg32 *regs;
	int nregs;
	void __iomem *base;
};

extern struct dentry *arch_debugfs_dir;

extern struct srcu_struct debugfs_srcu;

/**
 * debugfs_real_fops - getter for the real file operation
 * @filp: a pointer to a struct file
 *
 * Must only be called under the protection established by
 * debugfs_use_file_start().
 */
static inline const struct file_operations *debugfs_real_fops(const struct file *filp)
	__must_hold(&debugfs_srcu)
{
	/*
	 * Neither the pointer to the struct file_operations, nor its
	 * contents ever change -- srcu_dereference() is not needed here.
	 */
	return filp->f_path.dentry->d_fsdata;
}

#define DEFINE_DEBUGFS_ATTRIBUTE(__fops, __get, __set, __fmt)		\
static int __fops ## _open(struct inode *inode, struct file *file)	\
{									\
	__simple_attr_check_format(__fmt, 0ull);			\
	return simple_attr_open(inode, file, __get, __set, __fmt);	\
}									\
static const struct file_operations __fops = {				\
	.owner	 = THIS_MODULE,						\
	.open	 = __fops ## _open,					\
	.release = simple_attr_release,					\
	.read	 = debugfs_attr_read,					\
	.write	 = debugfs_attr_write,					\
	.llseek  = generic_file_llseek,					\
}

#if defined(CONFIG_DEBUG_FS)

struct dentry *debugfs_lookup(const char *name, struct dentry *parent);

struct dentry *debugfs_create_file(const char *name, umode_t mode,
				   struct dentry *parent, void *data,
				   const struct file_operations *fops);
struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
				   struct dentry *parent, void *data,
				   const struct file_operations *fops);

struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
					struct dentry *parent, void *data,
					const struct file_operations *fops,
					loff_t file_size);

struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);

struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
				      const char *dest);

typedef struct vfsmount *(*debugfs_automount_t)(struct dentry *, void *);
struct dentry *debugfs_create_automount(const char *name,
					struct dentry *parent,
					debugfs_automount_t f,
					void *data);

void debugfs_remove(struct dentry *dentry);
void debugfs_remove_recursive(struct dentry *dentry);

int debugfs_use_file_start(const struct dentry *dentry, int *srcu_idx)
	__acquires(&debugfs_srcu);

void debugfs_use_file_finish(int srcu_idx) __releases(&debugfs_srcu);

ssize_t debugfs_attr_read(struct file *file, char __user *buf,
			size_t len, loff_t *ppos);
ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
			size_t len, loff_t *ppos);

struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
                struct dentry *new_dir, const char *new_name);

struct dentry *debugfs_create_u8(const char *name, umode_t mode,
				 struct dentry *parent, u8 *value);
struct dentry *debugfs_create_u16(const char *name, umode_t mode,
				  struct dentry *parent, u16 *value);
struct dentry *debugfs_create_u32(const char *name, umode_t mode,
				  struct dentry *parent, u32 *value);
struct dentry *debugfs_create_u64(const char *name, umode_t mode,
				  struct dentry *parent, u64 *value);
struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
				    struct dentry *parent, unsigned long *value);
struct dentry *debugfs_create_x8(const char *name, umode_t mode,
				 struct dentry *parent, u8 *value);
struct dentry *debugfs_create_x16(const char *name, umode_t mode,
				  struct dentry *parent, u16 *value);
struct dentry *debugfs_create_x32(const char *name, umode_t mode,
				  struct dentry *parent, u32 *value);
struct dentry *debugfs_create_x64(const char *name, umode_t mode,
				  struct dentry *parent, u64 *value);
struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
				     struct dentry *parent, size_t *value);
struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
				     struct dentry *parent, atomic_t *value);
struct dentry *debugfs_create_bool(const char *name, umode_t mode,
				  struct dentry *parent, bool *value);

struct dentry *debugfs_create_blob(const char *name, umode_t mode,
				  struct dentry *parent,
				  struct debugfs_blob_wrapper *blob);

struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
				     struct dentry *parent,
				     struct debugfs_regset32 *regset);

void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
			  int nregs, void __iomem *base, char *prefix);

struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
					struct dentry *parent,
					u32 *array, u32 elements);

struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
					   struct dentry *parent,
					   int (*read_fn)(struct seq_file *s,
							  void *data));

bool debugfs_initialized(void);

ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
			       size_t count, loff_t *ppos);

ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
				size_t count, loff_t *ppos);

#else

#include <linux/err.h>

/*
 * We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
 * so users have a chance to detect if there was a real error or not.  We don't
 * want to duplicate the design decision mistakes of procfs and devfs again.
 */

static inline struct dentry *debugfs_lookup(const char *name,
					    struct dentry *parent)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_file(const char *name, umode_t mode,
					struct dentry *parent, void *data,
					const struct file_operations *fops)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
					struct dentry *parent, void *data,
					const struct file_operations *fops,
					loff_t file_size)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_dir(const char *name,
						struct dentry *parent)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_symlink(const char *name,
						    struct dentry *parent,
						    const char *dest)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_automount(const char *name,
					struct dentry *parent,
					struct vfsmount *(*f)(void *),
					void *data)
{
	return ERR_PTR(-ENODEV);
}

static inline void debugfs_remove(struct dentry *dentry)
{ }

static inline void debugfs_remove_recursive(struct dentry *dentry)
{ }

static inline int debugfs_use_file_start(const struct dentry *dentry,
					int *srcu_idx)
	__acquires(&debugfs_srcu)
{
	return 0;
}

static inline void debugfs_use_file_finish(int srcu_idx)
	__releases(&debugfs_srcu)
{ }

static inline ssize_t debugfs_attr_read(struct file *file, char __user *buf,
					size_t len, loff_t *ppos)
{
	return -ENODEV;
}

static inline ssize_t debugfs_attr_write(struct file *file,
					const char __user *buf,
					size_t len, loff_t *ppos)
{
	return -ENODEV;
}

static inline struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
                struct dentry *new_dir, char *new_name)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_u8(const char *name, umode_t mode,
					       struct dentry *parent,
					       u8 *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_u16(const char *name, umode_t mode,
						struct dentry *parent,
						u16 *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_u32(const char *name, umode_t mode,
						struct dentry *parent,
						u32 *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_u64(const char *name, umode_t mode,
						struct dentry *parent,
						u64 *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_x8(const char *name, umode_t mode,
					       struct dentry *parent,
					       u8 *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_x16(const char *name, umode_t mode,
						struct dentry *parent,
						u16 *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_x32(const char *name, umode_t mode,
						struct dentry *parent,
						u32 *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_x64(const char *name, umode_t mode,
						struct dentry *parent,
						u64 *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
				     struct dentry *parent,
				     size_t *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
				     struct dentry *parent, atomic_t *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_bool(const char *name, umode_t mode,
						 struct dentry *parent,
						 bool *value)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_blob(const char *name, umode_t mode,
				  struct dentry *parent,
				  struct debugfs_blob_wrapper *blob)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_regset32(const char *name,
				   umode_t mode, struct dentry *parent,
				   struct debugfs_regset32 *regset)
{
	return ERR_PTR(-ENODEV);
}

static inline void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
			 int nregs, void __iomem *base, char *prefix)
{
}

static inline bool debugfs_initialized(void)
{
	return false;
}

static inline struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
					struct dentry *parent,
					u32 *array, u32 elements)
{
	return ERR_PTR(-ENODEV);
}

static inline struct dentry *debugfs_create_devm_seqfile(struct device *dev,
							 const char *name,
							 struct dentry *parent,
					   int (*read_fn)(struct seq_file *s,
							  void *data))
{
	return ERR_PTR(-ENODEV);
}

static inline ssize_t debugfs_read_file_bool(struct file *file,
					     char __user *user_buf,
					     size_t count, loff_t *ppos)
{
	return -ENODEV;
}

static inline ssize_t debugfs_write_file_bool(struct file *file,
					      const char __user *user_buf,
					      size_t count, loff_t *ppos)
{
	return -ENODEV;
}

#endif

#endif