[lttng-ust.git] / include / ust / tracepoint.h

#ifndef _UST_TRACEPOINT_H
#define _UST_TRACEPOINT_H

/*
 * Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
 * Copyright (C) 2009 Pierre-Marc Fournier
 * Copyright (C) 2009 Steven Rostedt <rostedt@goodmis.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 *
 * Heavily inspired from the Linux Kernel Markers.
 *
 * Ported to userspace by Pierre-Marc Fournier.
 */

#include <urcu-bp.h>
#include <ust/core.h>
#include <urcu/list.h>

struct tracepoint;

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

struct tracepoint {
	const char *name;		/* Tracepoint name */
	char state;			/* State. */
	struct tracepoint_probe *probes;
};

#define TP_PARAMS(args...)	args
#define TP_PROTO(args...)	args
#define TP_ARGS(args...)	args

/*
 * Tracepoints should be added to the instrumented code using the
 * "tracepoint()" macro.
 */
#define tracepoint(name, args...)	__trace_##name(args)

#define register_tracepoint(name, probe, data)			\
		__register_trace_##name(probe, data)

#define unregister_tracepoint(name, probe, data)		\
		__unregister_trace_##name(probe, data)

#define CONFIG_TRACEPOINTS
#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.
 */
#define __DO_TRACE(tp, proto, args)					\
	do {								\
		struct tracepoint_probe *__tp_it_probe_ptr;		\
		void *__tp_it_func;					\
		void *__tp_cb_data;					\
									\
		rcu_read_lock();					\
		__tp_it_probe_ptr = rcu_dereference((tp)->probes);	\
		if (__tp_it_probe_ptr) {				\
			do {						\
				__tp_it_func = __tp_it_probe_ptr->func;	\
				__tp_cb_data = __tp_it_probe_ptr->data;	\
				((void(*)(proto))__tp_it_func)(args);	\
			} while ((++__tp_it_probe_ptr)->func);		\
		}							\
		rcu_read_unlock();					\
	} while (0)

#define __CHECK_TRACE(name, proto, args)				\
	do {								\
		if (unlikely(__tracepoint_##name.state))		\
			__DO_TRACE(&__tracepoint_##name,		\
				TP_PROTO(proto), TP_ARGS(args));	\
	} 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, data_proto, data_args)	\
	extern struct tracepoint __tracepoint_##name;			\
	static inline void __trace_##name(proto)			\
	{								\
		__CHECK_TRACE(name, TP_PROTO(data_proto),		\
			      TP_ARGS(data_args));			\
	}								\
	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);		\
	}

#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, 0, NULL };				\
	static struct tracepoint * const __tracepoint_ptr_##name	\
	__attribute__((used, section("__tracepoints_ptrs"))) =		\
		&__tracepoint_##name;

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

extern void tracepoint_update_probe_range(struct tracepoint * const *begin,
	struct tracepoint * const *end);

#else /* !CONFIG_TRACEPOINTS */
#define __DECLARE_TRACE(name, proto, args)				\
	static inline void trace_##name(proto)				\
	{ }								\
	static inline void _trace_##name(proto)				\
	{ }								\
	static inline int __register_trace_##name(void (*probe)(proto), void *data)	\
	{								\
		return -ENOSYS;						\
	}								\
	static inline int __unregister_trace_##name(void (*probe)(proto), void *data)	\
	{								\
		return -ENOSYS;						\
	}

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

static inline void tracepoint_update_probe_range(struct tracepoint *begin,
	struct tracepoint *end)
{ }
#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 *__tp_cb_data" as the callback prototype.
 *
 * DECLARE_TRACE() passes "proto" as the tracepoint protoype and
 * "void *__tp_cb_data, proto" as the callback prototype.
 */
#define DECLARE_TRACE_NOARGS(name)					\
		__DECLARE_TRACE(name, void, , void *__tp_cb_data, __tp_cb_data)

#define DECLARE_TRACE(name, proto, args)				\
		__DECLARE_TRACE(name, TP_PARAMS(proto), TP_PARAMS(args),\
				TP_PARAMS(void *__tp_cb_data, proto),	\
				TP_PARAMS(__tp_cb_data, args))

/*
 * 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);

struct tracepoint_iter {
	struct tracepoint_lib *lib;
	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);
extern int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
	struct tracepoint * const *begin, struct tracepoint * const *end);

/*
 * 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)
{
//ust//	synchronize_sched();
}

struct tracepoint_lib {
	struct tracepoint * const *tracepoints_start;
	int tracepoints_count;
	struct cds_list_head list;
};

extern int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
				   int tracepoints_count);
extern int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);

#define TRACEPOINT_LIB							\
	extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
	extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
	static struct tracepoint * const __tracepoint_ptr_dummy		\
	__attribute__((used, section("__tracepoints_ptrs"))) = NULL;	\
	static void __attribute__((constructor)) __tracepoints__init(void)	\
	{									\
		tracepoint_register_lib(__start___tracepoints_ptrs,			\
					__stop___tracepoints_ptrs -			\
					__start___tracepoints_ptrs);			\
	}									\
										\
	static void __attribute__((destructor)) __tracepoints__destroy(void)	\
	{									\
		tracepoint_unregister_lib(__start___tracepoints_ptrs);		\
	}


#ifndef TRACE_EVENT
/*
 * For use with the TRACE_EVENT macro:
 *
 * We define a tracepoint, its arguments, its printf format
 * and its 'fast binary 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 readers.
 *	*
 *	* 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_printf().
 *	* This is how the tracepoint will appear under debugging
 *	* of tracepoints.
 *	*
 *	* (raw-binary tracing wont actually perform this step.)
 *	*
 *
 *	TP_printf("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 printf format
 * tracing setup.
 *
 * A set of (un)registration functions can be passed to the variant
 * TRACE_EVENT_FN to perform any (un)registration work.
 */

struct trace_event {
	const char *name;
	int (*regfunc)(void *data);
	int (*unregfunc)(void *data);
};

struct trace_event_lib {
	struct trace_event * const *trace_events_start;
	int trace_events_count;
	struct cds_list_head list;
};

struct trace_event_iter {
	struct trace_event_lib *lib;
	struct trace_event * const *trace_event;
};

extern void lock_trace_events(void);
extern void unlock_trace_events(void);

extern void trace_event_iter_start(struct trace_event_iter *iter);
extern void trace_event_iter_next(struct trace_event_iter *iter);
extern void trace_event_iter_reset(struct trace_event_iter *iter);

extern int trace_event_get_iter_range(struct trace_event * const **trace_event,
				      struct trace_event * const *begin,
				      struct trace_event * const *end);

extern void trace_event_update_process(void);
extern int is_trace_event_enabled(const char *channel, const char *name);

extern int trace_event_register_lib(struct trace_event * const *start_trace_events,
				    int trace_event_count);

extern int trace_event_unregister_lib(struct trace_event * const *start_trace_events);

#define TRACE_EVENT_LIB							\
	extern struct trace_event * const __start___trace_events_ptrs[]	\
	__attribute__((weak, visibility("hidden")));			\
	extern struct trace_event * const __stop___trace_events_ptrs[]	\
	__attribute__((weak, visibility("hidden")));			\
	static struct trace_event * const __event_ptrs_dummy		\
	__attribute__((used, section("__trace_events_ptrs"))) =	NULL;	\
	static void __attribute__((constructor))			\
	__trace_events__init(void)					\
	{								\
		trace_event_register_lib(__start___trace_events_ptrs,	\
					 __stop___trace_events_ptrs -	\
					 __start___trace_events_ptrs);	\
	}								\
									\
	static void __attribute__((destructor))				\
	__trace_event__destroy(void)					\
	{								\
		trace_event_unregister_lib(__start___trace_events_ptrs);\
	}

#define DECLARE_TRACE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
#define DEFINE_TRACE_EVENT(template, name, proto, args)		\
	DECLARE_TRACE(name, TP_PARAMS(proto), TP_PARAMS(args))
#define DEFINE_TRACE_EVENT_PRINT(template, name, proto, args, print)	\
	DECLARE_TRACE(name, TP_PARAMS(proto), TP_PARAMS(args))

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

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


#endif /* _UST_TRACEPOINT_H */
Commit	Line	Data
	1	#ifndef _UST_TRACEPOINT_H
	2	#define _UST_TRACEPOINT_H
	3
	4	/*
	5	* Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
	6	* Copyright (C) 2009 Pierre-Marc Fournier
	7	* Copyright (C) 2009 Steven Rostedt <rostedt@goodmis.org>
	8	*
	9	* This library is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU Lesser General Public
	11	* License as published by the Free Software Foundation;
	12	* version 2.1 of the License.
	13	*
	14	* This library is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	17	* Lesser General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU Lesser General Public
	20	* License along with this library; if not, write to the Free Software
	21	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	22	*
	23	* Heavily inspired from the Linux Kernel Markers.
	24	*
	25	* Ported to userspace by Pierre-Marc Fournier.
	26	*/
	27
	28	#include <urcu-bp.h>
	29	#include <ust/core.h>
	30	#include <urcu/list.h>
	31
	32	struct tracepoint;
	33
	34	struct tracepoint_probe {
	35	void *func;
	36	void *data;
	37	};
	38
	39	struct tracepoint {
	40	const char name; / Tracepoint name */
	41	char state; /* State. */
	42	struct tracepoint_probe *probes;
	43	};
	44
	45	#define TP_PARAMS(args...) args
	46	#define TP_PROTO(args...) args
	47	#define TP_ARGS(args...) args
	48
	49	/*
	50	* Tracepoints should be added to the instrumented code using the
	51	* "tracepoint()" macro.
	52	*/
	53	#define tracepoint(name, args...) __trace_##name(args)
	54
	55	#define register_tracepoint(name, probe, data) \
	56	__register_trace_##name(probe, data)
	57
	58	#define unregister_tracepoint(name, probe, data) \
	59	__unregister_trace_##name(probe, data)
	60
	61	#define CONFIG_TRACEPOINTS
	62	#ifdef CONFIG_TRACEPOINTS
	63
	64	/*
	65	* it_func[0] is never NULL because there is at least one element in the array
	66	* when the array itself is non NULL.
	67	*/
	68	#define __DO_TRACE(tp, proto, args) \
	69	do { \
	70	struct tracepoint_probe *__tp_it_probe_ptr; \
	71	void *__tp_it_func; \
	72	void *__tp_cb_data; \
	73	\
	74	rcu_read_lock(); \
	75	__tp_it_probe_ptr = rcu_dereference((tp)->probes); \
	76	if (__tp_it_probe_ptr) { \
	77	do { \
	78	__tp_it_func = __tp_it_probe_ptr->func; \
	79	__tp_cb_data = __tp_it_probe_ptr->data; \
	80	((void(*)(proto))__tp_it_func)(args); \
	81	} while ((++__tp_it_probe_ptr)->func); \
	82	} \
	83	rcu_read_unlock(); \
	84	} while (0)
	85
	86	#define __CHECK_TRACE(name, proto, args) \
	87	do { \
	88	if (unlikely(__tracepoint_##name.state)) \
	89	__DO_TRACE(&__tracepoint_##name, \
	90	TP_PROTO(proto), TP_ARGS(args)); \
	91	} while (0)
	92
	93	/*
	94	* Make sure the alignment of the structure in the __tracepoints section will
	95	* not add unwanted padding between the beginning of the section and the
	96	* structure. Force alignment to the same alignment as the section start.
	97	*/
	98	#define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \
	99	extern struct tracepoint __tracepoint_##name; \
	100	static inline void __trace_##name(proto) \
	101	{ \
	102	__CHECK_TRACE(name, TP_PROTO(data_proto), \
	103	TP_ARGS(data_args)); \
	104	} \
	105	static inline int \
	106	__register_trace_##name(void (probe)(data_proto), void data) \
	107	{ \
	108	return tracepoint_probe_register(#name, (void *)probe, \
	109	data); \
	110	\
	111	} \
	112	static inline int \
	113	__unregister_trace_##name(void (probe)(data_proto), void data)\
	114	{ \
	115	return tracepoint_probe_unregister(#name, (void *)probe, \
	116	data); \
	117	}
	118
	119	#define DEFINE_TRACE_FN(name, reg, unreg) \
	120	static const char __tpstrtab_##name[] \
	121	__attribute__((section("__tracepoints_strings"))) = #name; \
	122	struct tracepoint __tracepoint_##name \
	123	__attribute__((section("__tracepoints"))) = \
	124	{ __tpstrtab_##name, 0, NULL }; \
	125	static struct tracepoint * const __tracepoint_ptr_##name \
	126	__attribute__((used, section("__tracepoints_ptrs"))) = \
	127	&__tracepoint_##name;
	128
	129	#define DEFINE_TRACE(name) \
	130	DEFINE_TRACE_FN(name, NULL, NULL)
	131
	132	extern void tracepoint_update_probe_range(struct tracepoint * const *begin,
	133	struct tracepoint * const *end);
	134
	135	#else /* !CONFIG_TRACEPOINTS */
	136	#define __DECLARE_TRACE(name, proto, args) \
	137	static inline void trace_##name(proto) \
	138	{ } \
	139	static inline void _trace_##name(proto) \
	140	{ } \
	141	static inline int __register_trace_##name(void (probe)(proto), void data) \
	142	{ \
	143	return -ENOSYS; \
	144	} \
	145	static inline int __unregister_trace_##name(void (probe)(proto), void data) \
	146	{ \
	147	return -ENOSYS; \
	148	}
	149
	150	#define DEFINE_TRACE(name)
	151	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
	152	#define EXPORT_TRACEPOINT_SYMBOL(name)
	153
	154	static inline void tracepoint_update_probe_range(struct tracepoint *begin,
	155	struct tracepoint *end)
	156	{ }
	157	#endif /* CONFIG_TRACEPOINTS */
	158
	159	/*
	160	* The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
	161	* (void). "void" is a special value in a function prototype and can
	162	* not be combined with other arguments. Since the DECLARE_TRACE()
	163	* macro adds a data element at the beginning of the prototype,
	164	* we need a way to differentiate "(void *data, proto)" from
	165	* "(void *data, void)". The second prototype is invalid.
	166	*
	167	* DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
	168	* and "void *__tp_cb_data" as the callback prototype.
	169	*
	170	* DECLARE_TRACE() passes "proto" as the tracepoint protoype and
	171	* "void *__tp_cb_data, proto" as the callback prototype.
	172	*/
	173	#define DECLARE_TRACE_NOARGS(name) \
	174	__DECLARE_TRACE(name, void, , void *__tp_cb_data, __tp_cb_data)
	175
	176	#define DECLARE_TRACE(name, proto, args) \
	177	__DECLARE_TRACE(name, TP_PARAMS(proto), TP_PARAMS(args),\
	178	TP_PARAMS(void *__tp_cb_data, proto), \
	179	TP_PARAMS(__tp_cb_data, args))
	180
	181	/*
	182	* Connect a probe to a tracepoint.
	183	* Internal API, should not be used directly.
	184	*/
	185	extern int tracepoint_probe_register(const char name, void probe, void *data);
	186
	187	/*
	188	* Disconnect a probe from a tracepoint.
	189	* Internal API, should not be used directly.
	190	*/
	191	extern int tracepoint_probe_unregister(const char name, void probe, void *data);
	192
	193	extern int tracepoint_probe_register_noupdate(const char name, void probe,
	194	void *data);
	195	extern int tracepoint_probe_unregister_noupdate(const char name, void probe,
	196	void *data);
	197	extern void tracepoint_probe_update_all(void);
	198
	199	struct tracepoint_iter {
	200	struct tracepoint_lib *lib;
	201	struct tracepoint * const *tracepoint;
	202	};
	203
	204	extern void tracepoint_iter_start(struct tracepoint_iter *iter);
	205	extern void tracepoint_iter_next(struct tracepoint_iter *iter);
	206	extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
	207	extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
	208	extern int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
	209	struct tracepoint * const begin, struct tracepoint const *end);
	210
	211	/*
	212	* tracepoint_synchronize_unregister must be called between the last tracepoint
	213	* probe unregistration and the end of module exit to make sure there is no
	214	* caller executing a probe when it is freed.
	215	*/
	216	static inline void tracepoint_synchronize_unregister(void)
	217	{
	218	//ust// synchronize_sched();
	219	}
	220
	221	struct tracepoint_lib {
	222	struct tracepoint * const *tracepoints_start;
	223	int tracepoints_count;
	224	struct cds_list_head list;
	225	};
	226
	227	extern int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
	228	int tracepoints_count);
	229	extern int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
	230
	231	#define TRACEPOINT_LIB \
	232	extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
	233	extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
	234	static struct tracepoint * const __tracepoint_ptr_dummy \
	235	__attribute__((used, section("__tracepoints_ptrs"))) = NULL; \
	236	static void __attribute__((constructor)) __tracepoints__init(void) \
	237	{ \
	238	tracepoint_register_lib(__start___tracepoints_ptrs, \
	239	__stop___tracepoints_ptrs - \
	240	__start___tracepoints_ptrs); \
	241	} \
	242	\
	243	static void __attribute__((destructor)) __tracepoints__destroy(void) \
	244	{ \
	245	tracepoint_unregister_lib(__start___tracepoints_ptrs); \
	246	}
	247
	248
	249	#ifndef TRACE_EVENT
	250	/*
	251	* For use with the TRACE_EVENT macro:
	252	*
	253	* We define a tracepoint, its arguments, its printf format
	254	* and its 'fast binary record' layout.
	255	*
	256	* Firstly, name your tracepoint via TRACE_EVENT(name : the
	257	* 'subsystem_event' notation is fine.
	258	*
	259	* Think about this whole construct as the
	260	* 'trace_sched_switch() function' from now on.
	261	*
	262	*
	263	* TRACE_EVENT(sched_switch,
	264	*
	265	* *
	266	* * A function has a regular function arguments
	267	* * prototype, declare it via TP_PROTO():
	268	* *
	269	*
	270	* TP_PROTO(struct rq rq, struct task_struct prev,
	271	* struct task_struct *next),
	272	*
	273	* *
	274	* * Define the call signature of the 'function'.
	275	* * (Design sidenote: we use this instead of a
	276	* * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
	277	* *
	278	*
	279	* TP_ARGS(rq, prev, next),
	280	*
	281	* *
	282	* * Fast binary tracing: define the trace record via
	283	* * TP_STRUCT__entry(). You can think about it like a
	284	* * regular C structure local variable definition.
	285	* *
	286	* * This is how the trace record is structured and will
	287	* * be saved into the ring buffer. These are the fields
	288	* * that will be exposed to readers.
	289	* *
	290	* * The declared 'local variable' is called '__entry'
	291	* *
	292	* * __field(pid_t, prev_prid) is equivalent to a standard declariton:
	293	* *
	294	* * pid_t prev_pid;
	295	* *
	296	* * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
	297	* *
	298	* * char prev_comm[TASK_COMM_LEN];
	299	* *
	300	*
	301	* TP_STRUCT__entry(
	302	* __array( char, prev_comm, TASK_COMM_LEN )
	303	* __field( pid_t, prev_pid )
	304	* __field( int, prev_prio )
	305	* __array( char, next_comm, TASK_COMM_LEN )
	306	* __field( pid_t, next_pid )
	307	* __field( int, next_prio )
	308	* ),
	309	*
	310	* *
	311	* * Assign the entry into the trace record, by embedding
	312	* * a full C statement block into TP_fast_assign(). You
	313	* * can refer to the trace record as '__entry' -
	314	* * otherwise you can put arbitrary C code in here.
	315	* *
	316	* * Note: this C code will execute every time a trace event
	317	* * happens, on an active tracepoint.
	318	* *
	319	*
	320	* TP_fast_assign(
	321	* memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
	322	* __entry->prev_pid = prev->pid;
	323	* __entry->prev_prio = prev->prio;
	324	* memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
	325	* __entry->next_pid = next->pid;
	326	* __entry->next_prio = next->prio;
	327	* )
	328	*
	329	* *
	330	* * Formatted output of a trace record via TP_printf().
	331	* * This is how the tracepoint will appear under debugging
	332	* * of tracepoints.
	333	* *
	334	* * (raw-binary tracing wont actually perform this step.)
	335	* *
	336	*
	337	* TP_printf("task %s:%d [%d] ==> %s:%d [%d]",
	338	* __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
	339	* __entry->next_comm, __entry->next_pid, __entry->next_prio),
	340	*
	341	* );
	342	*
	343	* This macro construct is thus used for the regular printf format
	344	* tracing setup.
	345	*
	346	* A set of (un)registration functions can be passed to the variant
	347	* TRACE_EVENT_FN to perform any (un)registration work.
	348	*/
	349
	350	struct trace_event {
	351	const char *name;
	352	int (regfunc)(void data);
	353	int (unregfunc)(void data);
	354	};
	355
	356	struct trace_event_lib {
	357	struct trace_event * const *trace_events_start;
	358	int trace_events_count;
	359	struct cds_list_head list;
	360	};
	361
	362	struct trace_event_iter {
	363	struct trace_event_lib *lib;
	364	struct trace_event * const *trace_event;
	365	};
	366
	367	extern void lock_trace_events(void);
	368	extern void unlock_trace_events(void);
	369
	370	extern void trace_event_iter_start(struct trace_event_iter *iter);
	371	extern void trace_event_iter_next(struct trace_event_iter *iter);
	372	extern void trace_event_iter_reset(struct trace_event_iter *iter);
	373
	374	extern int trace_event_get_iter_range(struct trace_event * const **trace_event,
	375	struct trace_event * const *begin,
	376	struct trace_event * const *end);
	377
	378	extern void trace_event_update_process(void);
	379	extern int is_trace_event_enabled(const char channel, const char name);
	380
	381	extern int trace_event_register_lib(struct trace_event * const *start_trace_events,
	382	int trace_event_count);
	383
	384	extern int trace_event_unregister_lib(struct trace_event * const *start_trace_events);
	385
	386	#define TRACE_EVENT_LIB \
	387	extern struct trace_event * const __start___trace_events_ptrs[] \
	388	__attribute__((weak, visibility("hidden"))); \
	389	extern struct trace_event * const __stop___trace_events_ptrs[] \
	390	__attribute__((weak, visibility("hidden"))); \
	391	static struct trace_event * const __event_ptrs_dummy \
	392	__attribute__((used, section("__trace_events_ptrs"))) = NULL; \
	393	static void __attribute__((constructor)) \
	394	__trace_events__init(void) \
	395	{ \
	396	trace_event_register_lib(__start___trace_events_ptrs, \
	397	__stop___trace_events_ptrs - \
	398	__start___trace_events_ptrs); \
	399	} \
	400	\
	401	static void __attribute__((destructor)) \
	402	__trace_event__destroy(void) \
	403	{ \
	404	trace_event_unregister_lib(__start___trace_events_ptrs);\
	405	}
	406
	407	#define DECLARE_TRACE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
	408	#define DEFINE_TRACE_EVENT(template, name, proto, args) \
	409	DECLARE_TRACE(name, TP_PARAMS(proto), TP_PARAMS(args))
	410	#define DEFINE_TRACE_EVENT_PRINT(template, name, proto, args, print) \
	411	DECLARE_TRACE(name, TP_PARAMS(proto), TP_PARAMS(args))
	412
	413	#define TRACE_EVENT(name, proto, args, struct, assign, print) \
	414	DECLARE_TRACE(name, TP_PARAMS(proto), TP_PARAMS(args))
	415	#define TRACE_EVENT_FN(name, proto, args, struct, \
	416	assign, print, reg, unreg) \
	417	DECLARE_TRACE(name, TP_PARAMS(proto), TP_PARAMS(args))
	418
	419	#endif /* ifdef TRACE_EVENT (see note above) */
	420
	421
	422	#endif /* _UST_TRACEPOINT_H */