[deliverable/linux.git] / include / linux / tracepoint.h

#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) */
Commit	Line	Data
97e1c18e MD	1	#ifndef _LINUX_TRACEPOINT_H
	2	#define _LINUX_TRACEPOINT_H
	3
	4	/*
	5	* Kernel Tracepoint API.
	6	*
8cd09a59	7	* See Documentation/trace/tracepoints.txt.
97e1c18e MD	8	*
	9	* (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
	10	*
	11	* Heavily inspired from the Linux Kernel Markers.
	12	*
	13	* This file is released under the GPLv2.
	14	* See the file COPYING for more details.
	15	*/
	16
b70e4f05	17	#include <linux/errno.h>
97e1c18e MD	18	#include <linux/types.h>
97e1c18e MD	19	#include <linux/rcupdate.h>
8f7b50c5	20	#include <linux/jump_label.h>
97e1c18e MD	21
	22	struct module;
	23	struct tracepoint;
	24
38516ab5 SR	25	struct tracepoint_func {
	26	void *func;
	27	void *data;
	28	};
	29
97e1c18e MD	30	struct tracepoint {
97e1c18e MD	31	const char name; / Tracepoint name */
d430d3d7	32	struct jump_label_key key;
97419875 JS	33	void (*regfunc)(void);
97419875 JS	34	void (*unregfunc)(void);
bd1c8b22	35	struct tracepoint_func __rcu *funcs;
65498646	36	};
97e1c18e	37
2e26ca71 SR	38	/*
	39	* Connect a probe to a tracepoint.
	40	* Internal API, should not be used directly.
	41	*/
38516ab5	42	extern int tracepoint_probe_register(const char name, void probe, void *data);
2e26ca71 SR	43
	44	/*
	45	* Disconnect a probe from a tracepoint.
	46	* Internal API, should not be used directly.
	47	*/
38516ab5 SR	48	extern int
38516ab5 SR	49	tracepoint_probe_unregister(const char name, void probe, void *data);
2e26ca71	50
38516ab5 SR	51	extern int tracepoint_probe_register_noupdate(const char name, void probe,
	52	void *data);
	53	extern int tracepoint_probe_unregister_noupdate(const char name, void probe,
	54	void *data);
2e26ca71 SR	55	extern void tracepoint_probe_update_all(void);
2e26ca71 SR	56
b75ef8b4 MD	57	#ifdef CONFIG_MODULES
	58	struct tp_module {
	59	struct list_head list;
	60	unsigned int num_tracepoints;
	61	struct tracepoint * const *tracepoints_ptrs;
	62	};
	63	#endif /* CONFIG_MODULES */
	64
2e26ca71	65	struct tracepoint_iter {
b75ef8b4 MD	66	#ifdef CONFIG_MODULES
	67	struct tp_module *module;
	68	#endif /* CONFIG_MODULES */
65498646	69	struct tracepoint * const *tracepoint;
2e26ca71 SR	70	};
	71
	72	extern void tracepoint_iter_start(struct tracepoint_iter *iter);
	73	extern void tracepoint_iter_next(struct tracepoint_iter *iter);
	74	extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
	75	extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
2e26ca71 SR	76
	77	/*
	78	* tracepoint_synchronize_unregister must be called between the last tracepoint
	79	* probe unregistration and the end of module exit to make sure there is no
	80	* caller executing a probe when it is freed.
	81	*/
	82	static inline void tracepoint_synchronize_unregister(void)
	83	{
	84	synchronize_sched();
	85	}
	86
	87	#define PARAMS(args...) args
	88
2e26ca71 SR	89	#endif /* _LINUX_TRACEPOINT_H */
	90
	91	/*
	92	* Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
	93	* file ifdef protection.
	94	* This is due to the way trace events work. If a file includes two
	95	* trace event headers under one "CREATE_TRACE_POINTS" the first include
	96	* will override the TRACE_EVENT and break the second include.
	97	*/
	98
ea20d929 SR	99	#ifndef DECLARE_TRACE
ea20d929 SR	100
2939b046	101	#define TP_PROTO(args...) args
8cd09a59	102	#define TP_ARGS(args...) args
287050d3	103	#define TP_CONDITION(args...) args
97e1c18e MD	104
	105	#ifdef CONFIG_TRACEPOINTS
	106
	107	/*
	108	* it_func[0] is never NULL because there is at least one element in the array
	109	* when the array itself is non NULL.
38516ab5 SR	110	*
	111	* Note, the proto and args passed in includes "__data" as the first parameter.
	112	* The reason for this is to handle the "void" prototype. If a tracepoint
	113	* has a "void" prototype, then it is invalid to declare a function
	114	* as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
	115	* "void data", where as the DECLARE_TRACE() will pass in "void data, proto".
97e1c18e	116	*/
287050d3	117	#define __DO_TRACE(tp, proto, args, cond) \
97e1c18e	118	do { \
38516ab5 SR	119	struct tracepoint_func *it_func_ptr; \
	120	void *it_func; \
	121	void *__data; \
97e1c18e	122	\
287050d3 SR	123	if (!(cond)) \
287050d3 SR	124	return; \
da7b3eab	125	rcu_read_lock_sched_notrace(); \
38516ab5 SR	126	it_func_ptr = rcu_dereference_sched((tp)->funcs); \
38516ab5 SR	127	if (it_func_ptr) { \
97e1c18e	128	do { \
38516ab5 SR	129	it_func = (it_func_ptr)->func; \
	130	__data = (it_func_ptr)->data; \
	131	((void(*)(proto))(it_func))(args); \
	132	} while ((++it_func_ptr)->func); \
97e1c18e	133	} \
da7b3eab	134	rcu_read_unlock_sched_notrace(); \
97e1c18e MD	135	} while (0)
	136
	137	/*
	138	* Make sure the alignment of the structure in the __tracepoints section will
	139	* not add unwanted padding between the beginning of the section and the
	140	* structure. Force alignment to the same alignment as the section start.
	141	*/
287050d3	142	#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
7e066fb8	143	extern struct tracepoint __tracepoint_##name; \
97e1c18e MD	144	static inline void trace_##name(proto) \
97e1c18e MD	145	{ \
d430d3d7	146	if (static_branch(&__tracepoint_##name.key)) \
97e1c18e	147	__DO_TRACE(&__tracepoint_##name, \
38516ab5	148	TP_PROTO(data_proto), \
287050d3 SR	149	TP_ARGS(data_args), \
287050d3 SR	150	TP_CONDITION(cond)); \
97e1c18e	151	} \
38516ab5 SR	152	static inline int \
38516ab5 SR	153	register_trace_##name(void (probe)(data_proto), void data) \
97e1c18e	154	{ \
38516ab5 SR	155	return tracepoint_probe_register(#name, (void *)probe, \
38516ab5 SR	156	data); \
97e1c18e	157	} \
38516ab5 SR	158	static inline int \
38516ab5 SR	159	unregister_trace_##name(void (probe)(data_proto), void data) \
97e1c18e	160	{ \
38516ab5 SR	161	return tracepoint_probe_unregister(#name, (void *)probe, \
38516ab5 SR	162	data); \
53da59aa	163	} \
38516ab5 SR	164	static inline void \
38516ab5 SR	165	check_trace_callback_type_##name(void (*cb)(data_proto)) \
53da59aa	166	{ \
97e1c18e MD	167	}
97e1c18e MD	168
65498646 MD	169	/*
	170	* We have no guarantee that gcc and the linker won't up-align the tracepoint
	171	* structures, so we create an array of pointers that will be used for iteration
	172	* on the tracepoints.
	173	*/
d430d3d7 JB	174	#define DEFINE_TRACE_FN(name, reg, unreg) \
	175	static const char __tpstrtab_##name[] \
	176	__attribute__((section("__tracepoints_strings"))) = #name; \
	177	struct tracepoint __tracepoint_##name \
	178	__attribute__((section("__tracepoints"))) = \
	179	{ __tpstrtab_##name, JUMP_LABEL_INIT, reg, unreg, NULL };\
	180	static struct tracepoint * const __tracepoint_ptr_##name __used \
	181	__attribute__((section("__tracepoints_ptrs"))) = \
65498646	182	&__tracepoint_##name;
97419875 JS	183
	184	#define DEFINE_TRACE(name) \
	185	DEFINE_TRACE_FN(name, NULL, NULL);
7e066fb8 MD	186
	187	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
	188	EXPORT_SYMBOL_GPL(__tracepoint_##name)
	189	#define EXPORT_TRACEPOINT_SYMBOL(name) \
	190	EXPORT_SYMBOL(__tracepoint_##name)
	191
97e1c18e	192	#else /* !CONFIG_TRACEPOINTS */
287050d3	193	#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
97e1c18e MD	194	static inline void trace_##name(proto) \
97e1c18e MD	195	{ } \
38516ab5 SR	196	static inline int \
	197	register_trace_##name(void (*probe)(data_proto), \
	198	void *data) \
97e1c18e MD	199	{ \
	200	return -ENOSYS; \
	201	} \
38516ab5 SR	202	static inline int \
	203	unregister_trace_##name(void (*probe)(data_proto), \
	204	void *data) \
c420970e MD	205	{ \
c420970e MD	206	return -ENOSYS; \
53da59aa	207	} \
38516ab5	208	static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
53da59aa	209	{ \
c420970e	210	}
97e1c18e	211
97419875	212	#define DEFINE_TRACE_FN(name, reg, unreg)
7e066fb8 MD	213	#define DEFINE_TRACE(name)
	214	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
	215	#define EXPORT_TRACEPOINT_SYMBOL(name)
	216
97e1c18e	217	#endif /* CONFIG_TRACEPOINTS */
38516ab5 SR	218
	219	/*
	220	* The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
	221	* (void). "void" is a special value in a function prototype and can
	222	* not be combined with other arguments. Since the DECLARE_TRACE()
	223	* macro adds a data element at the beginning of the prototype,
	224	* we need a way to differentiate "(void *data, proto)" from
	225	* "(void *data, void)". The second prototype is invalid.
	226	*
	227	* DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
	228	* and "void *__data" as the callback prototype.
	229	*
	230	* DECLARE_TRACE() passes "proto" as the tracepoint protoype and
	231	* "void *__data, proto" as the callback prototype.
	232	*/
	233	#define DECLARE_TRACE_NOARGS(name) \
287050d3	234	__DECLARE_TRACE(name, void, , 1, void *__data, __data)
38516ab5 SR	235
38516ab5 SR	236	#define DECLARE_TRACE(name, proto, args) \
287050d3	237	__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), 1, \
38516ab5 SR	238	PARAMS(void *__data, proto), \
	239	PARAMS(__data, args))
	240
287050d3 SR	241	#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
	242	__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), PARAMS(cond), \
	243	PARAMS(void *__data, proto), \
	244	PARAMS(__data, args))
	245
1ed0c597 FW	246	#define TRACE_EVENT_FLAGS(event, flag)
1ed0c597 FW	247
ea20d929	248	#endif /* DECLARE_TRACE */
97e1c18e	249
ea20d929	250	#ifndef TRACE_EVENT
823f9124 SR	251	/*
	252	* For use with the TRACE_EVENT macro:
	253	*
	254	* We define a tracepoint, its arguments, its printk format
	255	* and its 'fast binay record' layout.
	256	*
	257	* Firstly, name your tracepoint via TRACE_EVENT(name : the
	258	* 'subsystem_event' notation is fine.
	259	*
	260	* Think about this whole construct as the
	261	* 'trace_sched_switch() function' from now on.
	262	*
	263	*
	264	* TRACE_EVENT(sched_switch,
	265	*
	266	* *
	267	* * A function has a regular function arguments
	268	* * prototype, declare it via TP_PROTO():
	269	* *
	270	*
ef18012b SR	271	* TP_PROTO(struct rq rq, struct task_struct prev,
ef18012b SR	272	* struct task_struct *next),
823f9124 SR	273	*
	274	* *
	275	* * Define the call signature of the 'function'.
	276	* * (Design sidenote: we use this instead of a
	277	* * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
	278	* *
	279	*
ef18012b	280	* TP_ARGS(rq, prev, next),
823f9124 SR	281	*
	282	* *
	283	* * Fast binary tracing: define the trace record via
	284	* * TP_STRUCT__entry(). You can think about it like a
	285	* * regular C structure local variable definition.
	286	* *
	287	* * This is how the trace record is structured and will
	288	* * be saved into the ring buffer. These are the fields
	289	* * that will be exposed to user-space in
156f5a78	290	* * /sys/kernel/debug/tracing/events/<*>/format.
823f9124 SR	291	* *
	292	* * The declared 'local variable' is called '__entry'
	293	* *
	294	* * __field(pid_t, prev_prid) is equivalent to a standard declariton:
	295	* *
	296	* * pid_t prev_pid;
	297	* *
	298	* * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
	299	* *
	300	* * char prev_comm[TASK_COMM_LEN];
	301	* *
	302	*
	303	* TP_STRUCT__entry(
	304	* __array( char, prev_comm, TASK_COMM_LEN )
	305	* __field( pid_t, prev_pid )
	306	* __field( int, prev_prio )
	307	* __array( char, next_comm, TASK_COMM_LEN )
	308	* __field( pid_t, next_pid )
	309	* __field( int, next_prio )
	310	* ),
	311	*
	312	* *
	313	* * Assign the entry into the trace record, by embedding
	314	* * a full C statement block into TP_fast_assign(). You
	315	* * can refer to the trace record as '__entry' -
	316	* * otherwise you can put arbitrary C code in here.
	317	* *
	318	* * Note: this C code will execute every time a trace event
	319	* * happens, on an active tracepoint.
	320	* *
	321	*
ef18012b SR	322	* TP_fast_assign(
	323	* memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
	324	* __entry->prev_pid = prev->pid;
	325	* __entry->prev_prio = prev->prio;
823f9124 SR	326	* memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
823f9124 SR	327	* __entry->next_pid = next->pid;
ef18012b	328	* __entry->next_prio = next->prio;
ec6e7c3a	329	* ),
823f9124 SR	330	*
	331	* *
	332	* * Formatted output of a trace record via TP_printk().
	333	* * This is how the tracepoint will appear under ftrace
	334	* * plugins that make use of this tracepoint.
	335	* *
	336	* * (raw-binary tracing wont actually perform this step.)
	337	* *
	338	*
	339	* TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
	340	* __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
	341	* __entry->next_comm, __entry->next_pid, __entry->next_prio),
	342	*
	343	* );
	344	*
	345	* This macro construct is thus used for the regular printk format
	346	* tracing setup, it is used to construct a function pointer based
	347	* tracepoint callback (this is used by programmatic plugins and
	348	* can also by used by generic instrumentation like SystemTap), and
	349	* it is also used to expose a structured trace record in
156f5a78	350	* /sys/kernel/debug/tracing/events/.
97419875 JS	351	*
	352	* A set of (un)registration functions can be passed to the variant
	353	* TRACE_EVENT_FN to perform any (un)registration work.
823f9124 SR	354	*/
823f9124 SR	355
091ad365	356	#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
ff038f5c SR	357	#define DEFINE_EVENT(template, name, proto, args) \
ff038f5c SR	358	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
e5bc9721 SR	359	#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
e5bc9721 SR	360	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
287050d3 SR	361	#define DEFINE_EVENT_CONDITION(template, name, proto, \
	362	args, cond) \
	363	DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
	364	PARAMS(args), PARAMS(cond))
ff038f5c	365
30a8fecc	366	#define TRACE_EVENT(name, proto, args, struct, assign, print) \
da4d0302	367	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
97419875 JS	368	#define TRACE_EVENT_FN(name, proto, args, struct, \
	369	assign, print, reg, unreg) \
	370	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
287050d3 SR	371	#define TRACE_EVENT_CONDITION(name, proto, args, cond, \
	372	struct, assign, print) \
	373	DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
	374	PARAMS(args), PARAMS(cond))
7cb2e3ee	375
1ed0c597 FW	376	#define TRACE_EVENT_FLAGS(event, flag)
1ed0c597 FW	377
7cb2e3ee	378	#endif /* ifdef TRACE_EVENT (see note above) */