text: /*
   * Ftrace header.  For implementation details beyond the random comments
   * scattered below, see: Documentation/trace/ftrace-design.txt
   */
  
  #ifndef _LINUX_FTRACE_H
  #define _LINUX_FTRACE_H
  
  #include <linux/trace_clock.h>
  #include <linux/kallsyms.h>
  #include <linux/linkage.h>
  #include <linux/bitops.h>
  #include <linux/ptrace.h>
  #include <linux/ktime.h>
  #include <linux/sched.h>
  #include <linux/types.h>
  #include <linux/init.h>
  #include <linux/fs.h>
  
  #include <asm/ftrace.h>
  
  /*
   * If the arch supports passing the variable contents of
   * function_trace_op as the third parameter back from the
   * mcount call, then the arch should define this as 1.
   */
  #ifndef ARCH_SUPPORTS_FTRACE_OPS
  #define ARCH_SUPPORTS_FTRACE_OPS 0
  #endif
  
  /*
   * If the arch's mcount caller does not support all of ftrace's
   * features, then it must call an indirect function that
   * does. Or at least does enough to prevent any unwelcomed side effects.
   */
  #if !ARCH_SUPPORTS_FTRACE_OPS
  # define FTRACE_FORCE_LIST_FUNC 1
  #else
  # define FTRACE_FORCE_LIST_FUNC 0
  #endif
  
  
  struct module;
  struct ftrace_hash;
  
  #ifdef CONFIG_FUNCTION_TRACER
  
  extern int ftrace_enabled;
  extern int
  ftrace_enable_sysctl(struct ctl_table *table, int write,
  		     void __user *buffer, size_t *lenp,
  		     loff_t *ppos);
  
  struct ftrace_ops;
  
  typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  			      struct ftrace_ops *op, struct pt_regs *regs);
  
  /*
   * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
   * set in the flags member.
   *
   * ENABLED - set/unset when ftrace_ops is registered/unregistered
   * GLOBAL  - set manualy by ftrace_ops user to denote the ftrace_ops
   *           is part of the global tracers sharing the same filter
   *           via set_ftrace_* debugfs files.
   * DYNAMIC - set when ftrace_ops is registered to denote dynamically
   *           allocated ftrace_ops which need special care
   * CONTROL - set manualy by ftrace_ops user to denote the ftrace_ops
   *           could be controled by following calls:
   *             ftrace_function_local_enable
   *             ftrace_function_local_disable
   * SAVE_REGS - The ftrace_ops wants regs saved at each function called
   *            and passed to the callback. If this flag is set, but the
   *            architecture does not support passing regs
   *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
   *            ftrace_ops will fail to register, unless the next flag
   *            is set.
   * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
   *            handler can handle an arch that does not save regs
   *            (the handler tests if regs == NULL), then it can set
   *            this flag instead. It will not fail registering the ftrace_ops
   *            but, the regs field will be NULL if the arch does not support
   *            passing regs to the handler.
   *            Note, if this flag is set, the SAVE_REGS flag will automatically
   *            get set upon registering the ftrace_ops, if the arch supports it.
   * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure
   *            that the call back has its own recursion protection. If it does
   *            not set this, then the ftrace infrastructure will add recursion
   *            protection for the caller.
   * STUB   - The ftrace_ops is just a place holder.
   * INITIALIZED - The ftrace_ops has already been initialized (first use time
   *            register_ftrace_function() is called, it will initialized the ops)
   */
  enum {
  	FTRACE_OPS_FL_ENABLED			= 1 << 0,
  	FTRACE_OPS_FL_GLOBAL			= 1 << 1,
  	FTRACE_OPS_FL_DYNAMIC			= 1 << 2,
  	FTRACE_OPS_FL_CONTROL			= 1 << 3,
  	FTRACE_OPS_FL_SAVE_REGS			= 1 << 4,
  	FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED	= 1 << 5,
  	FTRACE_OPS_FL_RECURSION_SAFE		= 1 << 6,
  	FTRACE_OPS_FL_STUB			= 1 << 7,
  	FTRACE_OPS_FL_INITIALIZED		= 1 << 8,
  };
  
  struct ftrace_ops {
  	ftrace_func_t			func;
  	struct ftrace_ops		*next;
  	unsigned long			flags;
  	int __percpu			*disabled;
  #ifdef CONFIG_DYNAMIC_FTRACE
  	struct ftrace_hash		*notrace_hash;
  	struct ftrace_hash		*filter_hash;
  	struct mutex			regex_lock;
  #endif
  };
  
  /*
   * Type of the current tracing.
   */
  enum ftrace_tracing_type_t {
  	FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
  	FTRACE_TYPE_RETURN,	/* Hook the return of the function */
  };
  
  /* Current tracing type, default is FTRACE_TYPE_ENTER */
  extern enum ftrace_tracing_type_t ftrace_tracing_type;
  
  /*
   * The ftrace_ops must be a static and should also
   * be read_mostly.  These functions do modify read_mostly variables
   * so use them sparely. Never free an ftrace_op or modify the
   * next pointer after it has been registered. Even after unregistering
   * it, the next pointer may still be used internally.
   */
  int register_ftrace_function(struct ftrace_ops *ops);
  int unregister_ftrace_function(struct ftrace_ops *ops);
  void clear_ftrace_function(void);
  
  /**
   * ftrace_function_local_enable - enable controlled ftrace_ops on current cpu
   *
   * This function enables tracing on current cpu by decreasing
   * the per cpu control variable.
   * It must be called with preemption disabled and only on ftrace_ops
   * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
   * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
   */
  static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
  {
  	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
  		return;
  
  	(*this_cpu_ptr(ops->disabled))--;
  }
  
  /**
   * ftrace_function_local_disable - enable controlled ftrace_ops on current cpu
   *
   * This function enables tracing on current cpu by decreasing
   * the per cpu control variable.
   * It must be called with preemption disabled and only on ftrace_ops
   * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
   * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
   */
  static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
  {
  	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
  		return;
  
  	(*this_cpu_ptr(ops->disabled))++;
  }
  
  /**
   * ftrace_function_local_disabled - returns ftrace_ops disabled value
   *                                  on current cpu
   *
   * This function returns value of ftrace_ops::disabled on current cpu.
   * It must be called with preemption disabled and only on ftrace_ops
   * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
   * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
   */
  static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
  {
  	WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL));
  	return *this_cpu_ptr(ops->disabled);
  }
  
  extern void ftrace_stub(unsigned long a0, unsigned long a1,
  			struct ftrace_ops *op, struct pt_regs *regs);
  
  #else /* !CONFIG_FUNCTION_TRACER */
  /*
   * (un)register_ftrace_function must be a macro since the ops parameter
   * must not be evaluated.
   */
  #define register_ftrace_function(ops) ({ 0; })
  #define unregister_ftrace_function(ops) ({ 0; })
  static inline int ftrace_nr_registered_ops(void)
  {
  	return 0;
  }
  static inline void clear_ftrace_function(void) { }
  static inline void ftrace_kill(void) { }
  #endif /* CONFIG_FUNCTION_TRACER */
  
  #ifdef CONFIG_STACK_TRACER
  extern int stack_tracer_enabled;
  int
  stack_trace_sysctl(struct ctl_table *table, int write,
  		   void __user *buffer, size_t *lenp,
  		   loff_t *ppos);
  #endif
  
  struct ftrace_func_command {
  	struct list_head	list;
  	char			*name;
  	int			(*func)(struct ftrace_hash *hash,
  					char *func, char *cmd,
  					char *params, int enable);
  };
  
  #ifdef CONFIG_DYNAMIC_FTRACE
  
  int ftrace_arch_code_modify_prepare(void);
  int ftrace_arch_code_modify_post_process(void);
  
  void ftrace_bug(int err, unsigned long ip);
  
  struct seq_file;
  
  struct ftrace_probe_ops {
  	void			(*func)(unsigned long ip,
  					unsigned long parent_ip,
  					void **data);
  	int			(*init)(struct ftrace_probe_ops *ops,
  					unsigned long ip, void **data);
  	void			(*free)(struct ftrace_probe_ops *ops,
  					unsigned long ip, void **data);
  	int			(*print)(struct seq_file *m,
  					 unsigned long ip,
  					 struct ftrace_probe_ops *ops,
  					 void *data);
  };
  
  extern int
  register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
  			      void *data);
  extern void
  unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
  				void *data);
  extern void
  unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
  extern void unregister_ftrace_function_probe_all(char *glob);
  
  extern int ftrace_text_reserved(void *start, void *end);
  
  extern int ftrace_nr_registered_ops(void);
  
  /*
   * The dyn_ftrace record's flags field is split into two parts.
   * the first part which is '0-FTRACE_REF_MAX' is a counter of
   * the number of callbacks that have registered the function that
   * the dyn_ftrace descriptor represents.
   *
   * The second part is a mask:
   *  ENABLED - the function is being traced
   *  REGS    - the record wants the function to save regs
   *  REGS_EN - the function is set up to save regs.
   *
   * When a new ftrace_ops is registered and wants a function to save
   * pt_regs, the rec->flag REGS is set. When the function has been
   * set up to save regs, the REG_EN flag is set. Once a function
   * starts saving regs it will do so until all ftrace_ops are removed
   * from tracing that function.
   */
  enum {
  	FTRACE_FL_ENABLED	= (1UL << 29),
  	FTRACE_FL_REGS		= (1UL << 30),
  	FTRACE_FL_REGS_EN	= (1UL << 31)
  };
  
  #define FTRACE_FL_MASK		(0x7UL << 29)
  #define FTRACE_REF_MAX		((1UL << 29) - 1)
  
  struct dyn_ftrace {
  	union {
  		unsigned long		ip; /* address of mcount call-site */
  		struct dyn_ftrace	*freelist;
  	};
  	unsigned long		flags;
  	struct dyn_arch_ftrace		arch;
  };
  
  int ftrace_force_update(void);
  int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
  			 int remove, int reset);
  int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
  		       int len, int reset);
  int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
  			int len, int reset);
  void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
  void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
  void ftrace_free_filter(struct ftrace_ops *ops);
  
  int register_ftrace_command(struct ftrace_func_command *cmd);
  int unregister_ftrace_command(struct ftrace_func_command *cmd);
  
  enum {
  	FTRACE_UPDATE_CALLS		= (1 << 0),
  	FTRACE_DISABLE_CALLS		= (1 << 1),
  	FTRACE_UPDATE_TRACE_FUNC	= (1 << 2),
  	FTRACE_START_FUNC_RET		= (1 << 3),
  	FTRACE_STOP_FUNC_RET		= (1 << 4),
  };
  
  /*
   * The FTRACE_UPDATE_* enum is used to pass information back
   * from the ftrace_update_record() and ftrace_test_record()
   * functions. These are called by the code update routines
   * to find out what is to be done for a given function.
   *
   *  IGNORE           - The function is already what we want it to be
   *  MAKE_CALL        - Start tracing the function
   *  MODIFY_CALL      - Stop saving regs for the function
   *  MODIFY_CALL_REGS - Start saving regs for the function
   *  MAKE_NOP         - Stop tracing the function
   */
  enum {
  	FTRACE_UPDATE_IGNORE,
  	FTRACE_UPDATE_MAKE_CALL,
  	FTRACE_UPDATE_MODIFY_CALL,
  	FTRACE_UPDATE_MODIFY_CALL_REGS,
  	FTRACE_UPDATE_MAKE_NOP,
  };
  
  enum {
  	FTRACE_ITER_FILTER	= (1 << 0),
  	FTRACE_ITER_NOTRACE	= (1 << 1),
  	FTRACE_ITER_PRINTALL	= (1 << 2),
  	FTRACE_ITER_DO_HASH	= (1 << 3),
  	FTRACE_ITER_HASH	= (1 << 4),
  	FTRACE_ITER_ENABLED	= (1 << 5),
  };
  
  void arch_ftrace_update_code(int command);
  
  struct ftrace_rec_iter;
  
  struct ftrace_rec_iter *ftrace_rec_iter_start(void);
  struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
  struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
  
  #define for_ftrace_rec_iter(iter)		\
  	for (iter = ftrace_rec_iter_start();	\
  	     iter;				\
  	     iter = ftrace_rec_iter_next(iter))
  
  
  int ftrace_update_record(struct dyn_ftrace *rec, int enable);
  int ftrace_test_record(struct dyn_ftrace *rec, int enable);
  void ftrace_run_stop_machine(int command);
  unsigned long ftrace_location(unsigned long ip);
  
  extern ftrace_func_t ftrace_trace_function;
  
  int ftrace_regex_open(struct ftrace_ops *ops, int flag,
  		  struct inode *inode, struct file *file);
  ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
  			    size_t cnt, loff_t *ppos);
  ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
  			     size_t cnt, loff_t *ppos);
  int ftrace_regex_release(struct inode *inode, struct file *file);
  
  void __init
  ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
  
  /* defined in arch */
  extern int ftrace_ip_converted(unsigned long ip);
  extern int ftrace_dyn_arch_init(void *data);
  extern void ftrace_replace_code(int enable);
  extern int ftrace_update_ftrace_func(ftrace_func_t func);
  extern void ftrace_caller(void);
  extern void ftrace_regs_caller(void);
  extern void ftrace_call(void);
  extern void ftrace_regs_call(void);
  extern void mcount_call(void);
  
  void ftrace_modify_all_code(int command);
  
  #ifndef FTRACE_ADDR
  #define FTRACE_ADDR ((unsigned long)ftrace_caller)
  #endif
  
  #ifndef FTRACE_REGS_ADDR
  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
  # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
  #else
  # define FTRACE_REGS_ADDR FTRACE_ADDR
  #endif
  #endif
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  extern void ftrace_graph_caller(void);
  extern int ftrace_enable_ftrace_graph_caller(void);
  extern int ftrace_disable_ftrace_graph_caller(void);
  #else
  static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
  static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
  #endif
  
  /**
   * ftrace_make_nop - convert code into nop
   * @mod: module structure if called by module load initialization
   * @rec: the mcount call site record
   * @addr: the address that the call site should be calling
   *
   * This is a very sensitive operation and great care needs
   * to be taken by the arch.  The operation should carefully
   * read the location, check to see if what is read is indeed
   * what we expect it to be, and then on success of the compare,
   * it should write to the location.
   *
   * The code segment at @rec->ip should be a caller to @addr
   *
   * Return must be:
   *  0 on success
   *  -EFAULT on error reading the location
   *  -EINVAL on a failed compare of the contents
   *  -EPERM  on error writing to the location
   * Any other value will be considered a failure.
   */
  extern int ftrace_make_nop(struct module *mod,
  			   struct dyn_ftrace *rec, unsigned long addr);
  
  /**
   * ftrace_make_call - convert a nop call site into a call to addr
   * @rec: the mcount call site record
   * @addr: the address that the call site should call
   *
   * This is a very sensitive operation and great care needs
   * to be taken by the arch.  The operation should carefully
   * read the location, check to see if what is read is indeed
   * what we expect it to be, and then on success of the compare,
   * it should write to the location.
   *
   * The code segment at @rec->ip should be a nop
   *
   * Return must be:
   *  0 on success
   *  -EFAULT on error reading the location
   *  -EINVAL on a failed compare of the contents
   *  -EPERM  on error writing to the location
   * Any other value will be considered a failure.
   */
  extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
  
  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
  /**
   * ftrace_modify_call - convert from one addr to another (no nop)
   * @rec: the mcount call site record
   * @old_addr: the address expected to be currently called to
   * @addr: the address to change to
   *
   * This is a very sensitive operation and great care needs
   * to be taken by the arch.  The operation should carefully
   * read the location, check to see if what is read is indeed
   * what we expect it to be, and then on success of the compare,
   * it should write to the location.
   *
   * The code segment at @rec->ip should be a caller to @old_addr
   *
   * Return must be:
   *  0 on success
   *  -EFAULT on error reading the location
   *  -EINVAL on a failed compare of the contents
   *  -EPERM  on error writing to the location
   * Any other value will be considered a failure.
   */
  extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
  			      unsigned long addr);
  #else
  /* Should never be called */
  static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
  				     unsigned long addr)
  {
  	return -EINVAL;
  }
  #endif
  
  /* May be defined in arch */
  extern int ftrace_arch_read_dyn_info(char *buf, int size);
  
  extern int skip_trace(unsigned long ip);
  extern void ftrace_module_init(struct module *mod);
  
  extern void ftrace_disable_daemon(void);
  extern void ftrace_enable_daemon(void);
  #else /* CONFIG_DYNAMIC_FTRACE */
  static inline int skip_trace(unsigned long ip) { return 0; }
  static inline int ftrace_force_update(void) { return 0; }
  static inline void ftrace_disable_daemon(void) { }
  static inline void ftrace_enable_daemon(void) { }
  static inline void ftrace_release_mod(struct module *mod) {}
  static inline void ftrace_module_init(struct module *mod) {}
  static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
  {
  	return -EINVAL;
  }
  static inline __init int unregister_ftrace_command(char *cmd_name)
  {
  	return -EINVAL;
  }
  static inline int ftrace_text_reserved(void *start, void *end)
  {
  	return 0;
  }
  static inline unsigned long ftrace_location(unsigned long ip)
  {
  	return 0;
  }
  
  /*
   * Again users of functions that have ftrace_ops may not
   * have them defined when ftrace is not enabled, but these
   * functions may still be called. Use a macro instead of inline.
   */
  #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
  #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
  #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
  #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
  #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
  #define ftrace_free_filter(ops) do { } while (0)
  
  static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
  			    size_t cnt, loff_t *ppos) { return -ENODEV; }
  static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
  			     size_t cnt, loff_t *ppos) { return -ENODEV; }
  static inline loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int whence)
  {
  	return -ENODEV;
  }
  static inline int
  ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
  #endif /* CONFIG_DYNAMIC_FTRACE */
  
  loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence);
  
  /* totally disable ftrace - can not re-enable after this */
  void ftrace_kill(void);
  
  static inline void tracer_disable(void)
  {
  #ifdef CONFIG_FUNCTION_TRACER
  	ftrace_enabled = 0;
  #endif
  }
  
  /*
   * Ftrace disable/restore without lock. Some synchronization mechanism
   * must be used to prevent ftrace_enabled to be changed between
   * disable/restore.
   */
  static inline int __ftrace_enabled_save(void)
  {
  #ifdef CONFIG_FUNCTION_TRACER
  	int saved_ftrace_enabled = ftrace_enabled;
  	ftrace_enabled = 0;
  	return saved_ftrace_enabled;
  #else
  	return 0;
  #endif
  }
  
  static inline void __ftrace_enabled_restore(int enabled)
  {
  #ifdef CONFIG_FUNCTION_TRACER
  	ftrace_enabled = enabled;
  #endif
  }
  
  #ifndef HAVE_ARCH_CALLER_ADDR
  # ifdef CONFIG_FRAME_POINTER
  #  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
  #  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
  #  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
  #  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
  #  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
  #  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
  #  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
  # else
  #  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
  #  define CALLER_ADDR1 0UL
  #  define CALLER_ADDR2 0UL
  #  define CALLER_ADDR3 0UL
  #  define CALLER_ADDR4 0UL
  #  define CALLER_ADDR5 0UL
  #  define CALLER_ADDR6 0UL
  # endif
  #endif /* ifndef HAVE_ARCH_CALLER_ADDR */
  
  #ifdef CONFIG_IRQSOFF_TRACER
    extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
    extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
  #else
    static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
    static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
  #endif
  
  #ifdef CONFIG_PREEMPT_TRACER
    extern void trace_preempt_on(unsigned long a0, unsigned long a1);
    extern void trace_preempt_off(unsigned long a0, unsigned long a1);
  #else
  /*
   * Use defines instead of static inlines because some arches will make code out
   * of the CALLER_ADDR, when we really want these to be a real nop.
   */
  # define trace_preempt_on(a0, a1) do { } while (0)
  # define trace_preempt_off(a0, a1) do { } while (0)
  #endif
  
  #ifdef CONFIG_FTRACE_MCOUNT_RECORD
  extern void ftrace_init(void);
  #else
  static inline void ftrace_init(void) { }
  #endif
  
  /*
   * Structure that defines an entry function trace.
   */
  struct ftrace_graph_ent {
  	unsigned long func; /* Current function */
  	int depth;
  };
  
  /*
   * Structure that defines a return function trace.
   */
  struct ftrace_graph_ret {
  	unsigned long func; /* Current function */
  	unsigned long long calltime;
  	unsigned long long rettime;
  	/* Number of functions that overran the depth limit for current task */
  	unsigned long overrun;
  	int depth;
  };
  
  /* Type of the callback handlers for tracing function graph*/
  typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
  typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
  
  #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  
  /* for init task */
  #define INIT_FTRACE_GRAPH		.ret_stack = NULL,
  
  /*
   * Stack of return addresses for functions
   * of a thread.
   * Used in struct thread_info
   */
  struct ftrace_ret_stack {
  	unsigned long ret;
  	unsigned long func;
  	unsigned long long calltime;
  	unsigned long long subtime;
  	unsigned long fp;
  };
  
  /*
   * Primary handler of a function return.
   * It relays on ftrace_return_to_handler.
   * Defined in entry_32/64.S
   */
  extern void return_to_handler(void);
  
  extern int
  ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
  			 unsigned long frame_pointer);
  
  /*
   * Sometimes we don't want to trace a function with the function
   * graph tracer but we want them to keep traced by the usual function
   * tracer if the function graph tracer is not configured.
   */
  #define __notrace_funcgraph		notrace
  
  /*
   * We want to which function is an entrypoint of a hardirq.
   * That will help us to put a signal on output.
   */
  #define __irq_entry		 __attribute__((__section__(".irqentry.text")))
  
  /* Limits of hardirq entrypoints */
  extern char __irqentry_text_start[];
  extern char __irqentry_text_end[];
  
  #define FTRACE_RETFUNC_DEPTH 50
  #define FTRACE_RETSTACK_ALLOC_SIZE 32
  extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
  				trace_func_graph_ent_t entryfunc);
  
  extern bool ftrace_graph_is_dead(void);
  extern void ftrace_graph_stop(void);
  
  /* The current handlers in use */
  extern trace_func_graph_ret_t ftrace_graph_return;
  extern trace_func_graph_ent_t ftrace_graph_entry;
  
  extern void unregister_ftrace_graph(void);
  
  extern void ftrace_graph_init_task(struct task_struct *t);
  extern void ftrace_graph_exit_task(struct task_struct *t);
  extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
  
  static inline int task_curr_ret_stack(struct task_struct *t)
  {
  	return t->curr_ret_stack;
  }
  
  static inline void pause_graph_tracing(void)
  {
  	atomic_inc(&current->tracing_graph_pause);
  }
  
  static inline void unpause_graph_tracing(void)
  {
  	atomic_dec(&current->tracing_graph_pause);
  }
  #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
  
  #define __notrace_funcgraph
  #define __irq_entry
  #define INIT_FTRACE_GRAPH
  
  static inline void ftrace_graph_init_task(struct task_struct *t) { }
  static inline void ftrace_graph_exit_task(struct task_struct *t) { }
  static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
  
  static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
  			  trace_func_graph_ent_t entryfunc)
  {
  	return -1;
  }
  static inline void unregister_ftrace_graph(void) { }
  
  static inline int task_curr_ret_stack(struct task_struct *tsk)
  {
  	return -1;
  }
  
  static inline void pause_graph_tracing(void) { }
  static inline void unpause_graph_tracing(void) { }
  #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
  
  #ifdef CONFIG_TRACING
  
  /* flags for current->trace */
  enum {
  	TSK_TRACE_FL_TRACE_BIT	= 0,
  	TSK_TRACE_FL_GRAPH_BIT	= 1,
  };
  enum {
  	TSK_TRACE_FL_TRACE	= 1 << TSK_TRACE_FL_TRACE_BIT,
  	TSK_TRACE_FL_GRAPH	= 1 << TSK_TRACE_FL_GRAPH_BIT,
  };
  
  static inline void set_tsk_trace_trace(struct task_struct *tsk)
  {
  	set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
  }
  
  static inline void clear_tsk_trace_trace(struct task_struct *tsk)
  {
  	clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
  }
  
  static inline int test_tsk_trace_trace(struct task_struct *tsk)
  {
  	return tsk->trace & TSK_TRACE_FL_TRACE;
  }
  
  static inline void set_tsk_trace_graph(struct task_struct *tsk)
  {
  	set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
  }
  
  static inline void clear_tsk_trace_graph(struct task_struct *tsk)
  {
  	clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
  }
  
  static inline int test_tsk_trace_graph(struct task_struct *tsk)
  {
  	return tsk->trace & TSK_TRACE_FL_GRAPH;
  }
  
  enum ftrace_dump_mode;
  
  extern enum ftrace_dump_mode ftrace_dump_on_oops;
  
  extern void disable_trace_on_warning(void);
  extern int __disable_trace_on_warning;
  
  #ifdef CONFIG_PREEMPT
  #define INIT_TRACE_RECURSION		.trace_recursion = 0,
  #endif
  
  #else /* CONFIG_TRACING */
  static inline void  disable_trace_on_warning(void) { }
  #endif /* CONFIG_TRACING */
  
  #ifndef INIT_TRACE_RECURSION
  #define INIT_TRACE_RECURSION
  #endif
  
  #ifdef CONFIG_FTRACE_SYSCALLS
  
  unsigned long arch_syscall_addr(int nr);
  
  #endif /* CONFIG_FTRACE_SYSCALLS */
  
  #endif /* _LINUX_FTRACE_H */
  