#ifndef _LINUX_TRACEPOINT_H
  #define _LINUX_TRACEPOINT_H
  
  /*
   * Kernel Tracepoint API.
   *

   * See Documentation/trace/tracepoints.txt.

   *
   * (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   *
   * Heavily inspired from the Linux Kernel Markers.
   *
   * This file is released under the GPLv2.
   * See the file COPYING for more details.
   */

  #include <linux/errno.h>

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

  #include <linux/jump_label.h>

  
  struct module;
  struct tracepoint;

  struct tracepoint_func {
  	void *func;
  	void *data;
  };

  struct tracepoint {
  	const char *name;		/* Tracepoint name */

  	struct jump_label_key key;

  	void (*regfunc)(void);
  	void (*unregfunc)(void);

  	struct tracepoint_func __rcu *funcs;

  };

  /*
   * Connect a probe to a tracepoint.
   * Internal API, should not be used directly.
   */

  extern int tracepoint_probe_register(const char *name, void *probe, void *data);

  
  /*
   * Disconnect a probe from a tracepoint.
   * Internal API, should not be used directly.
   */

  extern int
  tracepoint_probe_unregister(const char *name, void *probe, void *data);

  extern int tracepoint_probe_register_noupdate(const char *name, void *probe,
  					      void *data);
  extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
  						void *data);

  extern void tracepoint_probe_update_all(void);

  #ifdef CONFIG_MODULES
  struct tp_module {
  	struct list_head list;
  	unsigned int num_tracepoints;
  	struct tracepoint * const *tracepoints_ptrs;
  };
  #endif /* CONFIG_MODULES */

  struct tracepoint_iter {

  #ifdef CONFIG_MODULES
  	struct tp_module *module;
  #endif /* CONFIG_MODULES */

  	struct tracepoint * const *tracepoint;

  };
  
  extern void tracepoint_iter_start(struct tracepoint_iter *iter);
  extern void tracepoint_iter_next(struct tracepoint_iter *iter);
  extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
  extern void tracepoint_iter_reset(struct tracepoint_iter *iter);

  
  /*
   * tracepoint_synchronize_unregister must be called between the last tracepoint
   * probe unregistration and the end of module exit to make sure there is no
   * caller executing a probe when it is freed.
   */
  static inline void tracepoint_synchronize_unregister(void)
  {
  	synchronize_sched();
  }
  
  #define PARAMS(args...) args

  #endif /* _LINUX_TRACEPOINT_H */
  
  /*
   * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
   *  file ifdef protection.
   *  This is due to the way trace events work. If a file includes two
   *  trace event headers under one "CREATE_TRACE_POINTS" the first include
   *  will override the TRACE_EVENT and break the second include.
   */

  #ifndef DECLARE_TRACE

  #define TP_PROTO(args...)	args

  #define TP_ARGS(args...)	args

  #define TP_CONDITION(args...)	args

  
  #ifdef CONFIG_TRACEPOINTS
  
  /*
   * it_func[0] is never NULL because there is at least one element in the array
   * when the array itself is non NULL.

   *
   * Note, the proto and args passed in includes "__data" as the first parameter.
   * The reason for this is to handle the "void" prototype. If a tracepoint
   * has a "void" prototype, then it is invalid to declare a function
   * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
   * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto".

   */

  #define __DO_TRACE(tp, proto, args, cond)				\

  	do {								\

  		struct tracepoint_func *it_func_ptr;			\
  		void *it_func;						\
  		void *__data;						\

  									\

  		if (!(cond))						\
  			return;						\

  		rcu_read_lock_sched_notrace();				\

  		it_func_ptr = rcu_dereference_sched((tp)->funcs);	\
  		if (it_func_ptr) {					\

  			do {						\

  				it_func = (it_func_ptr)->func;		\
  				__data = (it_func_ptr)->data;		\
  				((void(*)(proto))(it_func))(args);	\
  			} while ((++it_func_ptr)->func);		\

  		}							\

  		rcu_read_unlock_sched_notrace();			\

  	} while (0)
  
  /*
   * Make sure the alignment of the structure in the __tracepoints section will
   * not add unwanted padding between the beginning of the section and the
   * structure. Force alignment to the same alignment as the section start.
   */

  #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args)	\

  	extern struct tracepoint __tracepoint_##name;			\

  	static inline void trace_##name(proto)				\
  	{								\

  		if (static_branch(&__tracepoint_##name.key))		\

  			__DO_TRACE(&__tracepoint_##name,		\

  				TP_PROTO(data_proto),			\

  				TP_ARGS(data_args),			\
  				TP_CONDITION(cond));			\

  	}								\

  	static inline int						\
  	register_trace_##name(void (*probe)(data_proto), void *data)	\

  	{								\

  		return tracepoint_probe_register(#name, (void *)probe,	\
  						 data);			\

  	}								\

  	static inline int						\
  	unregister_trace_##name(void (*probe)(data_proto), void *data)	\

  	{								\

  		return tracepoint_probe_unregister(#name, (void *)probe, \
  						   data);		\

  	}								\

  	static inline void						\
  	check_trace_callback_type_##name(void (*cb)(data_proto))	\

  	{								\

  	}

  /*
   * We have no guarantee that gcc and the linker won't up-align the tracepoint
   * structures, so we create an array of pointers that will be used for iteration
   * on the tracepoints.
   */

  #define DEFINE_TRACE_FN(name, reg, unreg)				 \
  	static const char __tpstrtab_##name[]				 \
  	__attribute__((section("__tracepoints_strings"))) = #name;	 \
  	struct tracepoint __tracepoint_##name				 \
  	__attribute__((section("__tracepoints"))) =			 \
  		{ __tpstrtab_##name, JUMP_LABEL_INIT, reg, unreg, NULL };\
  	static struct tracepoint * const __tracepoint_ptr_##name __used	 \
  	__attribute__((section("__tracepoints_ptrs"))) =		 \

  		&__tracepoint_##name;

  
  #define DEFINE_TRACE(name)						\
  	DEFINE_TRACE_FN(name, NULL, NULL);

  
  #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)				\
  	EXPORT_SYMBOL_GPL(__tracepoint_##name)
  #define EXPORT_TRACEPOINT_SYMBOL(name)					\
  	EXPORT_SYMBOL(__tracepoint_##name)

  #else /* !CONFIG_TRACEPOINTS */

  #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args)	\

  	static inline void trace_##name(proto)				\
  	{ }								\

  	static inline int						\
  	register_trace_##name(void (*probe)(data_proto),		\
  			      void *data)				\

  	{								\
  		return -ENOSYS;						\
  	}								\

  	static inline int						\
  	unregister_trace_##name(void (*probe)(data_proto),		\
  				void *data)				\

  	{								\
  		return -ENOSYS;						\

  	}								\

  	static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \

  	{								\

  	}

  #define DEFINE_TRACE_FN(name, reg, unreg)

  #define DEFINE_TRACE(name)
  #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
  #define EXPORT_TRACEPOINT_SYMBOL(name)

  #endif /* CONFIG_TRACEPOINTS */

  
  /*
   * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
   * (void). "void" is a special value in a function prototype and can
   * not be combined with other arguments. Since the DECLARE_TRACE()
   * macro adds a data element at the beginning of the prototype,
   * we need a way to differentiate "(void *data, proto)" from
   * "(void *data, void)". The second prototype is invalid.
   *
   * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
   * and "void *__data" as the callback prototype.
   *
   * DECLARE_TRACE() passes "proto" as the tracepoint protoype and
   * "void *__data, proto" as the callback prototype.
   */
  #define DECLARE_TRACE_NOARGS(name)					\

  		__DECLARE_TRACE(name, void, , 1, void *__data, __data)

  
  #define DECLARE_TRACE(name, proto, args)				\

  		__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), 1,	\

  				PARAMS(void *__data, proto),		\
  				PARAMS(__data, args))

  #define DECLARE_TRACE_CONDITION(name, proto, args, cond)		\
  	__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), PARAMS(cond), \
  			PARAMS(void *__data, proto),			\
  			PARAMS(__data, args))

  #define TRACE_EVENT_FLAGS(event, flag)

  #endif /* DECLARE_TRACE */

  #ifndef TRACE_EVENT

  /*
   * For use with the TRACE_EVENT macro:
   *
   * We define a tracepoint, its arguments, its printk format
   * and its 'fast binay record' layout.
   *
   * Firstly, name your tracepoint via TRACE_EVENT(name : the
   * 'subsystem_event' notation is fine.
   *
   * Think about this whole construct as the
   * 'trace_sched_switch() function' from now on.
   *
   *
   *  TRACE_EVENT(sched_switch,
   *
   *	*
   *	* A function has a regular function arguments
   *	* prototype, declare it via TP_PROTO():
   *	*
   *

   *	TP_PROTO(struct rq *rq, struct task_struct *prev,
   *		 struct task_struct *next),

   *
   *	*
   *	* Define the call signature of the 'function'.
   *	* (Design sidenote: we use this instead of a
   *	*  TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
   *	*
   *

   *	TP_ARGS(rq, prev, next),

   *
   *	*
   *	* Fast binary tracing: define the trace record via
   *	* TP_STRUCT__entry(). You can think about it like a
   *	* regular C structure local variable definition.
   *	*
   *	* This is how the trace record is structured and will
   *	* be saved into the ring buffer. These are the fields
   *	* that will be exposed to user-space in

   *	* /sys/kernel/debug/tracing/events/<*>/format.

   *	*
   *	* The declared 'local variable' is called '__entry'
   *	*
   *	* __field(pid_t, prev_prid) is equivalent to a standard declariton:
   *	*
   *	*	pid_t	prev_pid;
   *	*
   *	* __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
   *	*
   *	*	char	prev_comm[TASK_COMM_LEN];
   *	*
   *
   *	TP_STRUCT__entry(
   *		__array(	char,	prev_comm,	TASK_COMM_LEN	)
   *		__field(	pid_t,	prev_pid			)
   *		__field(	int,	prev_prio			)
   *		__array(	char,	next_comm,	TASK_COMM_LEN	)
   *		__field(	pid_t,	next_pid			)
   *		__field(	int,	next_prio			)
   *	),
   *
   *	*
   *	* Assign the entry into the trace record, by embedding
   *	* a full C statement block into TP_fast_assign(). You
   *	* can refer to the trace record as '__entry' -
   *	* otherwise you can put arbitrary C code in here.
   *	*
   *	* Note: this C code will execute every time a trace event
   *	* happens, on an active tracepoint.
   *	*
   *

   *	TP_fast_assign(
   *		memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
   *		__entry->prev_pid	= prev->pid;
   *		__entry->prev_prio	= prev->prio;

   *		memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
   *		__entry->next_pid	= next->pid;

   *		__entry->next_prio	= next->prio;

   *	),

   *
   *	*
   *	* Formatted output of a trace record via TP_printk().
   *	* This is how the tracepoint will appear under ftrace
   *	* plugins that make use of this tracepoint.
   *	*
   *	* (raw-binary tracing wont actually perform this step.)
   *	*
   *
   *	TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
   *		__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
   *		__entry->next_comm, __entry->next_pid, __entry->next_prio),
   *
   * );
   *
   * This macro construct is thus used for the regular printk format
   * tracing setup, it is used to construct a function pointer based
   * tracepoint callback (this is used by programmatic plugins and
   * can also by used by generic instrumentation like SystemTap), and
   * it is also used to expose a structured trace record in

   * /sys/kernel/debug/tracing/events/.

   *
   * A set of (un)registration functions can be passed to the variant
   * TRACE_EVENT_FN to perform any (un)registration work.

   */

  #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)

  #define DEFINE_EVENT(template, name, proto, args)		\
  	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))

  #define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
  	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))

  #define DEFINE_EVENT_CONDITION(template, name, proto,		\
  			       args, cond)			\
  	DECLARE_TRACE_CONDITION(name, PARAMS(proto),		\
  				PARAMS(args), PARAMS(cond))

  #define TRACE_EVENT(name, proto, args, struct, assign, print)	\

  	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))

  #define TRACE_EVENT_FN(name, proto, args, struct,		\
  		assign, print, reg, unreg)			\
  	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))

  #define TRACE_EVENT_CONDITION(name, proto, args, cond,		\
  			      struct, assign, print)		\
  	DECLARE_TRACE_CONDITION(name, PARAMS(proto),		\
  				PARAMS(args), PARAMS(cond))

  #define TRACE_EVENT_FLAGS(event, flag)

  #endif /* ifdef TRACE_EVENT (see note above) */