text: /**
   * @file oprofile.h
   *
   * API for machine-specific interrupts to interface
   * to oprofile.
   *
   * @remark Copyright 2002 OProfile authors
   * @remark Read the file COPYING
   *
   * @author John Levon <levon@movementarian.org>
   */
  
  #ifndef OPROFILE_H
  #define OPROFILE_H
  
  #include <linux/types.h>
  #include <linux/spinlock.h>
  #include <asm/atomic.h>
   
  struct super_block;
  struct dentry;
  struct file_operations;
  struct pt_regs;
   
  /* Operations structure to be filled in */
  struct oprofile_operations {
  	/* create any necessary configuration files in the oprofile fs.
  	 * Optional. */
  	int (*create_files)(struct super_block * sb, struct dentry * root);
  	/* Do any necessary interrupt setup. Optional. */
  	int (*setup)(void);
  	/* Do any necessary interrupt shutdown. Optional. */
  	void (*shutdown)(void);
  	/* Start delivering interrupts. */
  	int (*start)(void);
  	/* Stop delivering interrupts. */
  	void (*stop)(void);
  	/* Initiate a stack backtrace. Optional. */
  	void (*backtrace)(struct pt_regs * const regs, unsigned int depth);
  	/* CPU identification string. */
  	char * cpu_type;
  };
  
  /**
   * One-time initialisation. *ops must be set to a filled-in
   * operations structure. This is called even in timer interrupt
   * mode so an arch can set a backtrace callback.
   *
   * If an error occurs, the fields should be left untouched.
   */
  int oprofile_arch_init(struct oprofile_operations * ops);
   
  /**
   * One-time exit/cleanup for the arch.
   */
  void oprofile_arch_exit(void);
  
  /**
   * Add a sample. This may be called from any context. Pass
   * smp_processor_id() as cpu.
   */
  void oprofile_add_sample(struct pt_regs * const regs, unsigned long event);
  
  /**
   * Add an extended sample.  Use this when the PC is not from the regs, and
   * we cannot determine if we're in kernel mode from the regs.
   *
   * This function does perform a backtrace.
   *
   */
  void oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
  				unsigned long event, int is_kernel);
  
  /* Use this instead when the PC value is not from the regs. Doesn't
   * backtrace. */
  void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event);
  
  /* add a backtrace entry, to be called from the ->backtrace callback */
  void oprofile_add_trace(unsigned long eip);
  
  
  /**
   * Create a file of the given name as a child of the given root, with
   * the specified file operations.
   */
  int oprofilefs_create_file(struct super_block * sb, struct dentry * root,
  	char const * name, const struct file_operations * fops);
  
  int oprofilefs_create_file_perm(struct super_block * sb, struct dentry * root,
  	char const * name, const struct file_operations * fops, int perm);
   
  /** Create a file for read/write access to an unsigned long. */
  int oprofilefs_create_ulong(struct super_block * sb, struct dentry * root,
  	char const * name, ulong * val);
   
  /** Create a file for read-only access to an unsigned long. */
  int oprofilefs_create_ro_ulong(struct super_block * sb, struct dentry * root,
  	char const * name, ulong * val);
   
  /** Create a file for read-only access to an atomic_t. */
  int oprofilefs_create_ro_atomic(struct super_block * sb, struct dentry * root,
  	char const * name, atomic_t * val);
   
  /** create a directory */
  struct dentry * oprofilefs_mkdir(struct super_block * sb, struct dentry * root,
  	char const * name);
  
  /**
   * Write the given asciz string to the given user buffer @buf, updating *offset
   * appropriately. Returns bytes written or -EFAULT.
   */
  ssize_t oprofilefs_str_to_user(char const * str, char __user * buf, size_t count, loff_t * offset);
  
  /**
   * Convert an unsigned long value into ASCII and copy it to the user buffer @buf,
   * updating *offset appropriately. Returns bytes written or -EFAULT.
   */
  ssize_t oprofilefs_ulong_to_user(unsigned long val, char __user * buf, size_t count, loff_t * offset);
  
  /**
   * Read an ASCII string for a number from a userspace buffer and fill *val on success.
   * Returns 0 on success, < 0 on error.
   */
  int oprofilefs_ulong_from_user(unsigned long * val, char const __user * buf, size_t count);
  
  /** lock for read/write safety */
  extern spinlock_t oprofilefs_lock;
   
  #endif /* OPROFILE_H */
  