[mirror_ubuntu-artful-kernel.git] / include / linux / tracepoint.h

#ifndef _LINUX_TRACEPOINT_H
#define _LINUX_TRACEPOINT_H

/*
 * Kernel Tracepoint API.
 *
 * See Documentation/trace/tracepoints.txt.
 *
 * Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * 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/static_key.h>

struct module;
struct tracepoint;
struct notifier_block;

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

struct tracepoint {
	const char *name;		/* Tracepoint name */
	struct static_key key;
	void (*regfunc)(void);
	void (*unregfunc)(void);
	struct tracepoint_func __rcu *funcs;
};

extern int
tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
extern int
tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data);
extern void
for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
		void *priv);

#ifdef CONFIG_MODULES
struct tp_module {
	struct list_head list;
	struct module *mod;
};

bool trace_module_has_bad_taint(struct module *mod);
extern int register_tracepoint_module_notifier(struct notifier_block *nb);
extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
#else
static inline bool trace_module_has_bad_taint(struct module *mod)
{
	return false;
}
static inline
int register_tracepoint_module_notifier(struct notifier_block *nb)
{
	return 0;
}
static inline
int unregister_tracepoint_module_notifier(struct notifier_block *nb)
{
	return 0;
}
#endif /* CONFIG_MODULES */

/*
 * 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, prercu, postrcu)		\
	do {								\
		struct tracepoint_func *it_func_ptr;			\
		void *it_func;						\
		void *__data;						\
									\
		if (!(cond))						\
			return;						\
		prercu;							\
		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();			\
		postrcu;						\
	} while (0)

#ifndef MODULE
#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)	\
	static inline void trace_##name##_rcuidle(proto)		\
	{								\
		if (static_key_false(&__tracepoint_##name.key))		\
			__DO_TRACE(&__tracepoint_##name,		\
				TP_PROTO(data_proto),			\
				TP_ARGS(data_args),			\
				TP_CONDITION(cond),			\
				rcu_irq_enter(),			\
				rcu_irq_exit());			\
	}
#else
#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)
#endif

/*
 * 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_key_false(&__tracepoint_##name.key))		\
			__DO_TRACE(&__tracepoint_##name,		\
				TP_PROTO(data_proto),			\
				TP_ARGS(data_args),			\
				TP_CONDITION(cond),,);			\
	}								\
	__DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args),		\
		PARAMS(cond), PARAMS(data_proto), PARAMS(data_args))	\
	static inline int						\
	register_trace_##name(void (*probe)(data_proto), void *data)	\
	{								\
		return tracepoint_probe_register(&__tracepoint_##name,	\
						(void *)probe, data);	\
	}								\
	static inline int						\
	unregister_trace_##name(void (*probe)(data_proto), void *data)	\
	{								\
		return tracepoint_probe_unregister(&__tracepoint_##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, STATIC_KEY_INIT_FALSE, 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 void trace_##name##_rcuidle(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)

#define TRACE_EVENT_PERF_PERM(event, expr...)

#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 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 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_FN(template, name, proto, args, reg, unreg)\
	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)

#define TRACE_EVENT_PERF_PERM(event, expr...)

#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	8	*
de7b2973	9	* Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
97e1c18e MD	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>
c5905afb	20	#include <linux/static_key.h>
97e1c18e MD	21
	22	struct module;
	23	struct tracepoint;
de7b2973	24	struct notifier_block;
97e1c18e	25
38516ab5 SR	26	struct tracepoint_func {
	27	void *func;
	28	void *data;
	29	};
	30
97e1c18e MD	31	struct tracepoint {
97e1c18e MD	32	const char name; / Tracepoint name */
c5905afb	33	struct static_key key;
97419875 JS	34	void (*regfunc)(void);
97419875 JS	35	void (*unregfunc)(void);
bd1c8b22	36	struct tracepoint_func __rcu *funcs;
65498646	37	};
97e1c18e	38
38516ab5	39	extern int
de7b2973 MD	40	tracepoint_probe_register(struct tracepoint tp, void probe, void *data);
	41	extern int
	42	tracepoint_probe_unregister(struct tracepoint tp, void probe, void *data);
	43	extern void
	44	for_each_kernel_tracepoint(void (fct)(struct tracepoint tp, void *priv),
	45	void *priv);
2e26ca71	46
b75ef8b4 MD	47	#ifdef CONFIG_MODULES
	48	struct tp_module {
	49	struct list_head list;
eb7d035c	50	struct module *mod;
b75ef8b4	51	};
de7b2973	52
45ab2813	53	bool trace_module_has_bad_taint(struct module *mod);
de7b2973 MD	54	extern int register_tracepoint_module_notifier(struct notifier_block *nb);
de7b2973 MD	55	extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
45ab2813 SRRH	56	#else
	57	static inline bool trace_module_has_bad_taint(struct module *mod)
	58	{
	59	return false;
	60	}
de7b2973 MD	61	static inline
	62	int register_tracepoint_module_notifier(struct notifier_block *nb)
	63	{
	64	return 0;
	65	}
	66	static inline
	67	int unregister_tracepoint_module_notifier(struct notifier_block *nb)
	68	{
	69	return 0;
	70	}
b75ef8b4 MD	71	#endif /* CONFIG_MODULES */
b75ef8b4 MD	72
2e26ca71 SR	73	/*
	74	* tracepoint_synchronize_unregister must be called between the last tracepoint
	75	* probe unregistration and the end of module exit to make sure there is no
	76	* caller executing a probe when it is freed.
	77	*/
	78	static inline void tracepoint_synchronize_unregister(void)
	79	{
	80	synchronize_sched();
	81	}
	82
	83	#define PARAMS(args...) args
	84
2e26ca71 SR	85	#endif /* _LINUX_TRACEPOINT_H */
	86
	87	/*
	88	* Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
	89	* file ifdef protection.
	90	* This is due to the way trace events work. If a file includes two
	91	* trace event headers under one "CREATE_TRACE_POINTS" the first include
	92	* will override the TRACE_EVENT and break the second include.
	93	*/
	94
ea20d929 SR	95	#ifndef DECLARE_TRACE
ea20d929 SR	96
2939b046	97	#define TP_PROTO(args...) args
8cd09a59	98	#define TP_ARGS(args...) args
287050d3	99	#define TP_CONDITION(args...) args
97e1c18e MD	100
	101	#ifdef CONFIG_TRACEPOINTS
	102
	103	/*
	104	* it_func[0] is never NULL because there is at least one element in the array
	105	* when the array itself is non NULL.
38516ab5 SR	106	*
	107	* Note, the proto and args passed in includes "__data" as the first parameter.
	108	* The reason for this is to handle the "void" prototype. If a tracepoint
	109	* has a "void" prototype, then it is invalid to declare a function
	110	* as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
	111	* "void data", where as the DECLARE_TRACE() will pass in "void data, proto".
97e1c18e	112	*/
2fbb90db	113	#define __DO_TRACE(tp, proto, args, cond, prercu, postrcu) \
97e1c18e	114	do { \
38516ab5 SR	115	struct tracepoint_func *it_func_ptr; \
	116	void *it_func; \
	117	void *__data; \
97e1c18e	118	\
287050d3 SR	119	if (!(cond)) \
287050d3 SR	120	return; \
2fbb90db	121	prercu; \
da7b3eab	122	rcu_read_lock_sched_notrace(); \
38516ab5 SR	123	it_func_ptr = rcu_dereference_sched((tp)->funcs); \
38516ab5 SR	124	if (it_func_ptr) { \
97e1c18e	125	do { \
38516ab5 SR	126	it_func = (it_func_ptr)->func; \
	127	__data = (it_func_ptr)->data; \
	128	((void(*)(proto))(it_func))(args); \
	129	} while ((++it_func_ptr)->func); \
97e1c18e	130	} \
da7b3eab	131	rcu_read_unlock_sched_notrace(); \
2fbb90db	132	postrcu; \
97e1c18e MD	133	} while (0)
97e1c18e MD	134
7ece55a4 JT	135	#ifndef MODULE
	136	#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) \
	137	static inline void trace_##name##_rcuidle(proto) \
	138	{ \
	139	if (static_key_false(&__tracepoint_##name.key)) \
	140	__DO_TRACE(&__tracepoint_##name, \
	141	TP_PROTO(data_proto), \
	142	TP_ARGS(data_args), \
	143	TP_CONDITION(cond), \
d6284099 PM	144	rcu_irq_enter(), \
d6284099 PM	145	rcu_irq_exit()); \
7ece55a4 JT	146	}
	147	#else
	148	#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)
	149	#endif
	150
97e1c18e MD	151	/*
	152	* Make sure the alignment of the structure in the __tracepoints section will
	153	* not add unwanted padding between the beginning of the section and the
	154	* structure. Force alignment to the same alignment as the section start.
	155	*/
2fbb90db	156	#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
7e066fb8	157	extern struct tracepoint __tracepoint_##name; \
97e1c18e MD	158	static inline void trace_##name(proto) \
97e1c18e MD	159	{ \
c5905afb	160	if (static_key_false(&__tracepoint_##name.key)) \
97e1c18e	161	__DO_TRACE(&__tracepoint_##name, \
38516ab5	162	TP_PROTO(data_proto), \
287050d3	163	TP_ARGS(data_args), \
2fbb90db SR	164	TP_CONDITION(cond),,); \
2fbb90db SR	165	} \
7ece55a4 JT	166	__DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \
7ece55a4 JT	167	PARAMS(cond), PARAMS(data_proto), PARAMS(data_args)) \
38516ab5 SR	168	static inline int \
38516ab5 SR	169	register_trace_##name(void (probe)(data_proto), void data) \
97e1c18e	170	{ \
de7b2973 MD	171	return tracepoint_probe_register(&__tracepoint_##name, \
de7b2973 MD	172	(void *)probe, data); \
97e1c18e	173	} \
38516ab5 SR	174	static inline int \
38516ab5 SR	175	unregister_trace_##name(void (probe)(data_proto), void data) \
97e1c18e	176	{ \
de7b2973 MD	177	return tracepoint_probe_unregister(&__tracepoint_##name,\
de7b2973 MD	178	(void *)probe, data); \
53da59aa	179	} \
38516ab5 SR	180	static inline void \
38516ab5 SR	181	check_trace_callback_type_##name(void (*cb)(data_proto)) \
53da59aa	182	{ \
97e1c18e MD	183	}
97e1c18e MD	184
65498646 MD	185	/*
	186	* We have no guarantee that gcc and the linker won't up-align the tracepoint
	187	* structures, so we create an array of pointers that will be used for iteration
	188	* on the tracepoints.
	189	*/
d430d3d7 JB	190	#define DEFINE_TRACE_FN(name, reg, unreg) \
	191	static const char __tpstrtab_##name[] \
	192	__attribute__((section("__tracepoints_strings"))) = #name; \
	193	struct tracepoint __tracepoint_##name \
	194	__attribute__((section("__tracepoints"))) = \
c5905afb	195	{ __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
d430d3d7 JB	196	static struct tracepoint * const __tracepoint_ptr_##name __used \
d430d3d7 JB	197	__attribute__((section("__tracepoints_ptrs"))) = \
65498646	198	&__tracepoint_##name;
97419875 JS	199
	200	#define DEFINE_TRACE(name) \
	201	DEFINE_TRACE_FN(name, NULL, NULL);
7e066fb8 MD	202
	203	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
	204	EXPORT_SYMBOL_GPL(__tracepoint_##name)
	205	#define EXPORT_TRACEPOINT_SYMBOL(name) \
	206	EXPORT_SYMBOL(__tracepoint_##name)
	207
97e1c18e	208	#else /* !CONFIG_TRACEPOINTS */
2fbb90db	209	#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
97e1c18e MD	210	static inline void trace_##name(proto) \
97e1c18e MD	211	{ } \
2fbb90db SR	212	static inline void trace_##name##_rcuidle(proto) \
2fbb90db SR	213	{ } \
38516ab5 SR	214	static inline int \
	215	register_trace_##name(void (*probe)(data_proto), \
	216	void *data) \
97e1c18e MD	217	{ \
	218	return -ENOSYS; \
	219	} \
38516ab5 SR	220	static inline int \
	221	unregister_trace_##name(void (*probe)(data_proto), \
	222	void *data) \
c420970e MD	223	{ \
c420970e MD	224	return -ENOSYS; \
53da59aa	225	} \
38516ab5	226	static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
53da59aa	227	{ \
c420970e	228	}
97e1c18e	229
97419875	230	#define DEFINE_TRACE_FN(name, reg, unreg)
7e066fb8 MD	231	#define DEFINE_TRACE(name)
	232	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
	233	#define EXPORT_TRACEPOINT_SYMBOL(name)
	234
97e1c18e	235	#endif /* CONFIG_TRACEPOINTS */
38516ab5 SR	236
	237	/*
	238	* The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
	239	* (void). "void" is a special value in a function prototype and can
	240	* not be combined with other arguments. Since the DECLARE_TRACE()
	241	* macro adds a data element at the beginning of the prototype,
	242	* we need a way to differentiate "(void *data, proto)" from
	243	* "(void *data, void)". The second prototype is invalid.
	244	*
	245	* DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
	246	* and "void *__data" as the callback prototype.
	247	*
	248	* DECLARE_TRACE() passes "proto" as the tracepoint protoype and
	249	* "void *__data, proto" as the callback prototype.
	250	*/
	251	#define DECLARE_TRACE_NOARGS(name) \
287050d3	252	__DECLARE_TRACE(name, void, , 1, void *__data, __data)
38516ab5 SR	253
38516ab5 SR	254	#define DECLARE_TRACE(name, proto, args) \
287050d3	255	__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), 1, \
38516ab5 SR	256	PARAMS(void *__data, proto), \
	257	PARAMS(__data, args))
	258
287050d3 SR	259	#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
	260	__DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), PARAMS(cond), \
	261	PARAMS(void *__data, proto), \
	262	PARAMS(__data, args))
	263
1ed0c597 FW	264	#define TRACE_EVENT_FLAGS(event, flag)
1ed0c597 FW	265
d5b5f391 PZ	266	#define TRACE_EVENT_PERF_PERM(event, expr...)
d5b5f391 PZ	267
ea20d929	268	#endif /* DECLARE_TRACE */
97e1c18e	269
ea20d929	270	#ifndef TRACE_EVENT
823f9124 SR	271	/*
	272	* For use with the TRACE_EVENT macro:
	273	*
	274	* We define a tracepoint, its arguments, its printk format
2621bca8	275	* and its 'fast binary record' layout.
823f9124 SR	276	*
	277	* Firstly, name your tracepoint via TRACE_EVENT(name : the
	278	* 'subsystem_event' notation is fine.
	279	*
	280	* Think about this whole construct as the
	281	* 'trace_sched_switch() function' from now on.
	282	*
	283	*
	284	* TRACE_EVENT(sched_switch,
	285	*
	286	* *
	287	* * A function has a regular function arguments
	288	* * prototype, declare it via TP_PROTO():
	289	* *
	290	*
ef18012b SR	291	* TP_PROTO(struct rq rq, struct task_struct prev,
ef18012b SR	292	* struct task_struct *next),
823f9124 SR	293	*
	294	* *
	295	* * Define the call signature of the 'function'.
	296	* * (Design sidenote: we use this instead of a
	297	* * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
	298	* *
	299	*
ef18012b	300	* TP_ARGS(rq, prev, next),
823f9124 SR	301	*
	302	* *
	303	* * Fast binary tracing: define the trace record via
	304	* * TP_STRUCT__entry(). You can think about it like a
	305	* * regular C structure local variable definition.
	306	* *
	307	* * This is how the trace record is structured and will
	308	* * be saved into the ring buffer. These are the fields
	309	* * that will be exposed to user-space in
156f5a78	310	* * /sys/kernel/debug/tracing/events/<*>/format.
823f9124 SR	311	* *
	312	* * The declared 'local variable' is called '__entry'
	313	* *
	314	* * __field(pid_t, prev_prid) is equivalent to a standard declariton:
	315	* *
	316	* * pid_t prev_pid;
	317	* *
	318	* * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
	319	* *
	320	* * char prev_comm[TASK_COMM_LEN];
	321	* *
	322	*
	323	* TP_STRUCT__entry(
	324	* __array( char, prev_comm, TASK_COMM_LEN )
	325	* __field( pid_t, prev_pid )
	326	* __field( int, prev_prio )
	327	* __array( char, next_comm, TASK_COMM_LEN )
	328	* __field( pid_t, next_pid )
	329	* __field( int, next_prio )
	330	* ),
	331	*
	332	* *
	333	* * Assign the entry into the trace record, by embedding
	334	* * a full C statement block into TP_fast_assign(). You
	335	* * can refer to the trace record as '__entry' -
	336	* * otherwise you can put arbitrary C code in here.
	337	* *
	338	* * Note: this C code will execute every time a trace event
	339	* * happens, on an active tracepoint.
	340	* *
	341	*
ef18012b SR	342	* TP_fast_assign(
	343	* memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
	344	* __entry->prev_pid = prev->pid;
	345	* __entry->prev_prio = prev->prio;
823f9124 SR	346	* memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
823f9124 SR	347	* __entry->next_pid = next->pid;
ef18012b	348	* __entry->next_prio = next->prio;
ec6e7c3a	349	* ),
823f9124 SR	350	*
	351	* *
	352	* * Formatted output of a trace record via TP_printk().
	353	* * This is how the tracepoint will appear under ftrace
	354	* * plugins that make use of this tracepoint.
	355	* *
	356	* * (raw-binary tracing wont actually perform this step.)
	357	* *
	358	*
	359	* TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
	360	* __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
	361	* __entry->next_comm, __entry->next_pid, __entry->next_prio),
	362	*
	363	* );
	364	*
	365	* This macro construct is thus used for the regular printk format
	366	* tracing setup, it is used to construct a function pointer based
	367	* tracepoint callback (this is used by programmatic plugins and
	368	* can also by used by generic instrumentation like SystemTap), and
	369	* it is also used to expose a structured trace record in
156f5a78	370	* /sys/kernel/debug/tracing/events/.
97419875 JS	371	*
	372	* A set of (un)registration functions can be passed to the variant
	373	* TRACE_EVENT_FN to perform any (un)registration work.
823f9124 SR	374	*/
823f9124 SR	375
091ad365	376	#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
ff038f5c SR	377	#define DEFINE_EVENT(template, name, proto, args) \
ff038f5c SR	378	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
f5abaa1b SR	379	#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\
f5abaa1b SR	380	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
e5bc9721 SR	381	#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
e5bc9721 SR	382	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
287050d3 SR	383	#define DEFINE_EVENT_CONDITION(template, name, proto, \
	384	args, cond) \
	385	DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
	386	PARAMS(args), PARAMS(cond))
ff038f5c	387
30a8fecc	388	#define TRACE_EVENT(name, proto, args, struct, assign, print) \
da4d0302	389	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
97419875 JS	390	#define TRACE_EVENT_FN(name, proto, args, struct, \
	391	assign, print, reg, unreg) \
	392	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
287050d3 SR	393	#define TRACE_EVENT_CONDITION(name, proto, args, cond, \
	394	struct, assign, print) \
	395	DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
	396	PARAMS(args), PARAMS(cond))
7cb2e3ee	397
1ed0c597 FW	398	#define TRACE_EVENT_FLAGS(event, flag)
1ed0c597 FW	399
d5b5f391 PZ	400	#define TRACE_EVENT_PERF_PERM(event, expr...)
d5b5f391 PZ	401
7cb2e3ee	402	#endif /* ifdef TRACE_EVENT (see note above) */