[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);

struct tracepoint_iter {
	struct module *module;
	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)
{
	synchronize_sched();
}

#define PARAMS(args...) args

#ifdef CONFIG_TRACEPOINTS
extern
void tracepoint_update_probe_range(struct tracepoint * const *begin,
	struct tracepoint * const *end);
#else
static inline
void tracepoint_update_probe_range(struct tracepoint * const *begin,
	struct tracepoint * const *end)
{ }
#endif /* CONFIG_TRACEPOINTS */

#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);
	56
	57	struct tracepoint_iter {
	58	struct module *module;
65498646	59	struct tracepoint * const *tracepoint;
2e26ca71 SR	60	};
	61
	62	extern void tracepoint_iter_start(struct tracepoint_iter *iter);
	63	extern void tracepoint_iter_next(struct tracepoint_iter *iter);
	64	extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
	65	extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
65498646 MD	66	extern int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
65498646 MD	67	struct tracepoint * const begin, struct tracepoint const *end);
2e26ca71 SR	68
	69	/*
	70	* tracepoint_synchronize_unregister must be called between the last tracepoint
	71	* probe unregistration and the end of module exit to make sure there is no
	72	* caller executing a probe when it is freed.
	73	*/
	74	static inline void tracepoint_synchronize_unregister(void)
	75	{
	76	synchronize_sched();
	77	}
	78
	79	#define PARAMS(args...) args
	80
	81	#ifdef CONFIG_TRACEPOINTS
65498646 MD	82	extern
	83	void tracepoint_update_probe_range(struct tracepoint * const *begin,
	84	struct tracepoint * const *end);
2e26ca71	85	#else
65498646 MD	86	static inline
	87	void tracepoint_update_probe_range(struct tracepoint * const *begin,
	88	struct tracepoint * const *end)
2e26ca71 SR	89	{ }
	90	#endif /* CONFIG_TRACEPOINTS */
	91
	92	#endif /* _LINUX_TRACEPOINT_H */
	93
	94	/*
	95	* Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
	96	* file ifdef protection.
	97	* This is due to the way trace events work. If a file includes two
	98	* trace event headers under one "CREATE_TRACE_POINTS" the first include
	99	* will override the TRACE_EVENT and break the second include.
	100	*/
	101
ea20d929 SR	102	#ifndef DECLARE_TRACE
ea20d929 SR	103
2939b046	104	#define TP_PROTO(args...) args
8cd09a59	105	#define TP_ARGS(args...) args
287050d3	106	#define TP_CONDITION(args...) args
97e1c18e MD	107
	108	#ifdef CONFIG_TRACEPOINTS
	109
	110	/*
	111	* it_func[0] is never NULL because there is at least one element in the array
	112	* when the array itself is non NULL.
38516ab5 SR	113	*
	114	* Note, the proto and args passed in includes "__data" as the first parameter.
	115	* The reason for this is to handle the "void" prototype. If a tracepoint
	116	* has a "void" prototype, then it is invalid to declare a function
	117	* as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
	118	* "void data", where as the DECLARE_TRACE() will pass in "void data, proto".
97e1c18e	119	*/
287050d3	120	#define __DO_TRACE(tp, proto, args, cond) \
97e1c18e	121	do { \
38516ab5 SR	122	struct tracepoint_func *it_func_ptr; \
	123	void *it_func; \
	124	void *__data; \
97e1c18e	125	\
287050d3 SR	126	if (!(cond)) \
287050d3 SR	127	return; \
da7b3eab	128	rcu_read_lock_sched_notrace(); \
38516ab5 SR	129	it_func_ptr = rcu_dereference_sched((tp)->funcs); \
38516ab5 SR	130	if (it_func_ptr) { \
97e1c18e	131	do { \
38516ab5 SR	132	it_func = (it_func_ptr)->func; \
	133	__data = (it_func_ptr)->data; \
	134	((void(*)(proto))(it_func))(args); \
	135	} while ((++it_func_ptr)->func); \
97e1c18e	136	} \
da7b3eab	137	rcu_read_unlock_sched_notrace(); \
97e1c18e MD	138	} while (0)
	139
	140	/*
	141	* Make sure the alignment of the structure in the __tracepoints section will
	142	* not add unwanted padding between the beginning of the section and the
	143	* structure. Force alignment to the same alignment as the section start.
	144	*/
287050d3	145	#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
7e066fb8	146	extern struct tracepoint __tracepoint_##name; \
97e1c18e MD	147	static inline void trace_##name(proto) \
97e1c18e MD	148	{ \
d430d3d7	149	if (static_branch(&__tracepoint_##name.key)) \
97e1c18e	150	__DO_TRACE(&__tracepoint_##name, \
38516ab5	151	TP_PROTO(data_proto), \
287050d3 SR	152	TP_ARGS(data_args), \
287050d3 SR	153	TP_CONDITION(cond)); \
97e1c18e	154	} \
38516ab5 SR	155	static inline int \
38516ab5 SR	156	register_trace_##name(void (probe)(data_proto), void data) \
97e1c18e	157	{ \
38516ab5 SR	158	return tracepoint_probe_register(#name, (void *)probe, \
38516ab5 SR	159	data); \
97e1c18e	160	} \
38516ab5 SR	161	static inline int \
38516ab5 SR	162	unregister_trace_##name(void (probe)(data_proto), void data) \
97e1c18e	163	{ \
38516ab5 SR	164	return tracepoint_probe_unregister(#name, (void *)probe, \
38516ab5 SR	165	data); \
53da59aa	166	} \
38516ab5 SR	167	static inline void \
38516ab5 SR	168	check_trace_callback_type_##name(void (*cb)(data_proto)) \
53da59aa	169	{ \
97e1c18e MD	170	}
97e1c18e MD	171
65498646 MD	172	/*
	173	* We have no guarantee that gcc and the linker won't up-align the tracepoint
	174	* structures, so we create an array of pointers that will be used for iteration
	175	* on the tracepoints.
	176	*/
d430d3d7 JB	177	#define DEFINE_TRACE_FN(name, reg, unreg) \
	178	static const char __tpstrtab_##name[] \
	179	__attribute__((section("__tracepoints_strings"))) = #name; \
	180	struct tracepoint __tracepoint_##name \
	181	__attribute__((section("__tracepoints"))) = \
	182	{ __tpstrtab_##name, JUMP_LABEL_INIT, reg, unreg, NULL };\
	183	static struct tracepoint * const __tracepoint_ptr_##name __used \
	184	__attribute__((section("__tracepoints_ptrs"))) = \
65498646	185	&__tracepoint_##name;
97419875 JS	186
	187	#define DEFINE_TRACE(name) \
	188	DEFINE_TRACE_FN(name, NULL, NULL);
7e066fb8 MD	189
	190	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
	191	EXPORT_SYMBOL_GPL(__tracepoint_##name)
	192	#define EXPORT_TRACEPOINT_SYMBOL(name) \
	193	EXPORT_SYMBOL(__tracepoint_##name)
	194
97e1c18e	195	#else /* !CONFIG_TRACEPOINTS */
287050d3	196	#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
97e1c18e MD	197	static inline void trace_##name(proto) \
97e1c18e MD	198	{ } \
38516ab5 SR	199	static inline int \
	200	register_trace_##name(void (*probe)(data_proto), \
	201	void *data) \
97e1c18e MD	202	{ \
	203	return -ENOSYS; \
	204	} \
38516ab5 SR	205	static inline int \
	206	unregister_trace_##name(void (*probe)(data_proto), \
	207	void *data) \
c420970e MD	208	{ \
c420970e MD	209	return -ENOSYS; \
53da59aa	210	} \
38516ab5	211	static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
53da59aa	212	{ \
c420970e	213	}
97e1c18e	214
97419875	215	#define DEFINE_TRACE_FN(name, reg, unreg)
7e066fb8 MD	216	#define DEFINE_TRACE(name)
	217	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
	218	#define EXPORT_TRACEPOINT_SYMBOL(name)
	219
97e1c18e	220	#endif /* CONFIG_TRACEPOINTS */
38516ab5 SR	221
	222	/*
	223	* The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
	224	* (void). "void" is a special value in a function prototype and can
	225	* not be combined with other arguments. Since the DECLARE_TRACE()
	226	* macro adds a data element at the beginning of the prototype,
	227	* we need a way to differentiate "(void *data, proto)" from
	228	* "(void *data, void)". The second prototype is invalid.
	229	*
	230	* DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
	231	* and "void *__data" as the callback prototype.
	232	*
	233	* DECLARE_TRACE() passes "proto" as the tracepoint protoype and
	234	* "void *__data, proto" as the callback prototype.
	235	*/
	236	#define DECLARE_TRACE_NOARGS(name) \
287050d3	237	__DECLARE_TRACE(name, void, , 1, void *__data, __data)
38516ab5 SR	238
38516ab5 SR	239	#define DECLARE_TRACE(name, proto, args) \
287050d3	240	__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), 1, \
38516ab5 SR	241	PARAMS(void *__data, proto), \
	242	PARAMS(__data, args))
	243
287050d3 SR	244	#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
	245	__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), PARAMS(cond), \
	246	PARAMS(void *__data, proto), \
	247	PARAMS(__data, args))
	248
1ed0c597 FW	249	#define TRACE_EVENT_FLAGS(event, flag)
1ed0c597 FW	250
ea20d929	251	#endif /* DECLARE_TRACE */
97e1c18e	252
ea20d929	253	#ifndef TRACE_EVENT
823f9124 SR	254	/*
	255	* For use with the TRACE_EVENT macro:
	256	*
	257	* We define a tracepoint, its arguments, its printk format
	258	* and its 'fast binay record' layout.
	259	*
	260	* Firstly, name your tracepoint via TRACE_EVENT(name : the
	261	* 'subsystem_event' notation is fine.
	262	*
	263	* Think about this whole construct as the
	264	* 'trace_sched_switch() function' from now on.
	265	*
	266	*
	267	* TRACE_EVENT(sched_switch,
	268	*
	269	* *
	270	* * A function has a regular function arguments
	271	* * prototype, declare it via TP_PROTO():
	272	* *
	273	*
ef18012b SR	274	* TP_PROTO(struct rq rq, struct task_struct prev,
ef18012b SR	275	* struct task_struct *next),
823f9124 SR	276	*
	277	* *
	278	* * Define the call signature of the 'function'.
	279	* * (Design sidenote: we use this instead of a
	280	* * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
	281	* *
	282	*
ef18012b	283	* TP_ARGS(rq, prev, next),
823f9124 SR	284	*
	285	* *
	286	* * Fast binary tracing: define the trace record via
	287	* * TP_STRUCT__entry(). You can think about it like a
	288	* * regular C structure local variable definition.
	289	* *
	290	* * This is how the trace record is structured and will
	291	* * be saved into the ring buffer. These are the fields
	292	* * that will be exposed to user-space in
156f5a78	293	* * /sys/kernel/debug/tracing/events/<*>/format.
823f9124 SR	294	* *
	295	* * The declared 'local variable' is called '__entry'
	296	* *
	297	* * __field(pid_t, prev_prid) is equivalent to a standard declariton:
	298	* *
	299	* * pid_t prev_pid;
	300	* *
	301	* * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
	302	* *
	303	* * char prev_comm[TASK_COMM_LEN];
	304	* *
	305	*
	306	* TP_STRUCT__entry(
	307	* __array( char, prev_comm, TASK_COMM_LEN )
	308	* __field( pid_t, prev_pid )
	309	* __field( int, prev_prio )
	310	* __array( char, next_comm, TASK_COMM_LEN )
	311	* __field( pid_t, next_pid )
	312	* __field( int, next_prio )
	313	* ),
	314	*
	315	* *
	316	* * Assign the entry into the trace record, by embedding
	317	* * a full C statement block into TP_fast_assign(). You
	318	* * can refer to the trace record as '__entry' -
	319	* * otherwise you can put arbitrary C code in here.
	320	* *
	321	* * Note: this C code will execute every time a trace event
	322	* * happens, on an active tracepoint.
	323	* *
	324	*
ef18012b SR	325	* TP_fast_assign(
	326	* memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
	327	* __entry->prev_pid = prev->pid;
	328	* __entry->prev_prio = prev->prio;
823f9124 SR	329	* memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
823f9124 SR	330	* __entry->next_pid = next->pid;
ef18012b	331	* __entry->next_prio = next->prio;
ec6e7c3a	332	* ),
823f9124 SR	333	*
	334	* *
	335	* * Formatted output of a trace record via TP_printk().
	336	* * This is how the tracepoint will appear under ftrace
	337	* * plugins that make use of this tracepoint.
	338	* *
	339	* * (raw-binary tracing wont actually perform this step.)
	340	* *
	341	*
	342	* TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
	343	* __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
	344	* __entry->next_comm, __entry->next_pid, __entry->next_prio),
	345	*
	346	* );
	347	*
	348	* This macro construct is thus used for the regular printk format
	349	* tracing setup, it is used to construct a function pointer based
	350	* tracepoint callback (this is used by programmatic plugins and
	351	* can also by used by generic instrumentation like SystemTap), and
	352	* it is also used to expose a structured trace record in
156f5a78	353	* /sys/kernel/debug/tracing/events/.
97419875 JS	354	*
	355	* A set of (un)registration functions can be passed to the variant
	356	* TRACE_EVENT_FN to perform any (un)registration work.
823f9124 SR	357	*/
823f9124 SR	358
091ad365	359	#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
ff038f5c SR	360	#define DEFINE_EVENT(template, name, proto, args) \
ff038f5c SR	361	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
e5bc9721 SR	362	#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
e5bc9721 SR	363	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
287050d3 SR	364	#define DEFINE_EVENT_CONDITION(template, name, proto, \
	365	args, cond) \
	366	DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
	367	PARAMS(args), PARAMS(cond))
ff038f5c	368
30a8fecc	369	#define TRACE_EVENT(name, proto, args, struct, assign, print) \
da4d0302	370	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
97419875 JS	371	#define TRACE_EVENT_FN(name, proto, args, struct, \
	372	assign, print, reg, unreg) \
	373	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
287050d3 SR	374	#define TRACE_EVENT_CONDITION(name, proto, args, cond, \
	375	struct, assign, print) \
	376	DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
	377	PARAMS(args), PARAMS(cond))
7cb2e3ee	378
1ed0c597 FW	379	#define TRACE_EVENT_FLAGS(event, flag)
1ed0c597 FW	380
7cb2e3ee	381	#endif /* ifdef TRACE_EVENT (see note above) */