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

#ifndef _LINUX_TRACEPOINT_H
#define _LINUX_TRACEPOINT_H

/*
 * Kernel Tracepoint API.
 *
 * See Documentation/tracepoint.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/types.h>
#include <linux/rcupdate.h>

struct module;
struct tracepoint;

struct tracepoint {
	const char *name;		/* Tracepoint name */
	int state;			/* State. */
	void **funcs;
} __attribute__((aligned(32)));		/*
					 * Aligned on 32 bytes because it is
					 * globally visible and gcc happily
					 * align these on the structure size.
					 * Keep in sync with vmlinux.lds.h.
					 */

#define TPPROTO(args...)	args
#define TPARGS(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.
 */
#define __DO_TRACE(tp, proto, args)					\
	do {								\
		void **it_func;						\
									\
		rcu_read_lock_sched_notrace();				\
		it_func = rcu_dereference((tp)->funcs);			\
		if (it_func) {						\
			do {						\
				((void(*)(proto))(*it_func))(args);	\
			} while (*(++it_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)				\
	extern struct tracepoint __tracepoint_##name;			\
	static inline void trace_##name(proto)				\
	{								\
		if (unlikely(__tracepoint_##name.state))		\
			__DO_TRACE(&__tracepoint_##name,		\
				TPPROTO(proto), TPARGS(args));		\
	}								\
	static inline int register_trace_##name(void (*probe)(proto))	\
	{								\
		return tracepoint_probe_register(#name, (void *)probe);	\
	}								\
	static inline int unregister_trace_##name(void (*probe)(proto))	\
	{								\
		return tracepoint_probe_unregister(#name, (void *)probe);\
	}

#define DEFINE_TRACE(name)						\
	static const char __tpstrtab_##name[]				\
	__attribute__((section("__tracepoints_strings"))) = #name;	\
	struct tracepoint __tracepoint_##name				\
	__attribute__((section("__tracepoints"), aligned(32))) =	\
		{ __tpstrtab_##name, 0, NULL }

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

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

#else /* !CONFIG_TRACEPOINTS */
#define DECLARE_TRACE(name, proto, args)				\
	static inline void _do_trace_##name(struct tracepoint *tp, proto) \
	{ }								\
	static inline void trace_##name(proto)				\
	{ }								\
	static inline int register_trace_##name(void (*probe)(proto))	\
	{								\
		return -ENOSYS;						\
	}								\
	static inline int unregister_trace_##name(void (*probe)(proto))	\
	{								\
		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 */

/*
 * Connect a probe to a tracepoint.
 * Internal API, should not be used directly.
 */
extern int tracepoint_probe_register(const char *name, void *probe);

/*
 * Disconnect a probe from a tracepoint.
 * Internal API, should not be used directly.
 */
extern int tracepoint_probe_unregister(const char *name, void *probe);

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

struct tracepoint_iter {
	struct module *module;
	struct tracepoint *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 **tracepoint,
	struct tracepoint *begin, struct tracepoint *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();
}

#endif
Commit	Line	Data
97e1c18e MD	1	#ifndef _LINUX_TRACEPOINT_H
	2	#define _LINUX_TRACEPOINT_H
	3
	4	/*
	5	* Kernel Tracepoint API.
	6	*
	7	* See Documentation/tracepoint.txt.
	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
	17	#include <linux/types.h>
	18	#include <linux/rcupdate.h>
	19
	20	struct module;
	21	struct tracepoint;
	22
	23	struct tracepoint {
	24	const char name; / Tracepoint name */
	25	int state; /* State. */
	26	void **funcs;
7e066fb8 MD	27	} __attribute__((aligned(32))); /*
	28	* Aligned on 32 bytes because it is
	29	* globally visible and gcc happily
	30	* align these on the structure size.
	31	* Keep in sync with vmlinux.lds.h.
	32	*/
97e1c18e MD	33
	34	#define TPPROTO(args...) args
	35	#define TPARGS(args...) args
	36
	37	#ifdef CONFIG_TRACEPOINTS
	38
	39	/*
	40	* it_func[0] is never NULL because there is at least one element in the array
	41	* when the array itself is non NULL.
	42	*/
	43	#define __DO_TRACE(tp, proto, args) \
	44	do { \
	45	void **it_func; \
	46	\
da7b3eab	47	rcu_read_lock_sched_notrace(); \
97e1c18e MD	48	it_func = rcu_dereference((tp)->funcs); \
	49	if (it_func) { \
	50	do { \
	51	((void()(proto))(it_func))(args); \
	52	} while (*(++it_func)); \
	53	} \
da7b3eab	54	rcu_read_unlock_sched_notrace(); \
97e1c18e MD	55	} while (0)
	56
	57	/*
	58	* Make sure the alignment of the structure in the __tracepoints section will
	59	* not add unwanted padding between the beginning of the section and the
	60	* structure. Force alignment to the same alignment as the section start.
	61	*/
7e066fb8 MD	62	#define DECLARE_TRACE(name, proto, args) \
7e066fb8 MD	63	extern struct tracepoint __tracepoint_##name; \
97e1c18e MD	64	static inline void trace_##name(proto) \
97e1c18e MD	65	{ \
97e1c18e MD	66	if (unlikely(__tracepoint_##name.state)) \
	67	__DO_TRACE(&__tracepoint_##name, \
	68	TPPROTO(proto), TPARGS(args)); \
	69	} \
	70	static inline int register_trace_##name(void (*probe)(proto)) \
	71	{ \
5f382671	72	return tracepoint_probe_register(#name, (void *)probe); \
97e1c18e	73	} \
c420970e	74	static inline int unregister_trace_##name(void (*probe)(proto)) \
97e1c18e	75	{ \
5f382671	76	return tracepoint_probe_unregister(#name, (void *)probe);\
97e1c18e MD	77	}
97e1c18e MD	78
7e066fb8 MD	79	#define DEFINE_TRACE(name) \
	80	static const char __tpstrtab_##name[] \
	81	__attribute__((section("__tracepoints_strings"))) = #name; \
	82	struct tracepoint __tracepoint_##name \
	83	__attribute__((section("__tracepoints"), aligned(32))) = \
	84	{ __tpstrtab_##name, 0, NULL }
	85
	86	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
	87	EXPORT_SYMBOL_GPL(__tracepoint_##name)
	88	#define EXPORT_TRACEPOINT_SYMBOL(name) \
	89	EXPORT_SYMBOL(__tracepoint_##name)
	90
97e1c18e MD	91	extern void tracepoint_update_probe_range(struct tracepoint *begin,
	92	struct tracepoint *end);
	93
	94	#else /* !CONFIG_TRACEPOINTS */
7e066fb8	95	#define DECLARE_TRACE(name, proto, args) \
97e1c18e MD	96	static inline void _do_trace_##name(struct tracepoint *tp, proto) \
	97	{ } \
	98	static inline void trace_##name(proto) \
	99	{ } \
	100	static inline int register_trace_##name(void (*probe)(proto)) \
	101	{ \
	102	return -ENOSYS; \
	103	} \
c420970e MD	104	static inline int unregister_trace_##name(void (*probe)(proto)) \
	105	{ \
	106	return -ENOSYS; \
	107	}
97e1c18e	108
7e066fb8 MD	109	#define DEFINE_TRACE(name)
	110	#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
	111	#define EXPORT_TRACEPOINT_SYMBOL(name)
	112
97e1c18e MD	113	static inline void tracepoint_update_probe_range(struct tracepoint *begin,
	114	struct tracepoint *end)
	115	{ }
	116	#endif /* CONFIG_TRACEPOINTS */
	117
	118	/*
	119	* Connect a probe to a tracepoint.
	120	* Internal API, should not be used directly.
	121	*/
	122	extern int tracepoint_probe_register(const char name, void probe);
	123
	124	/*
	125	* Disconnect a probe from a tracepoint.
	126	* Internal API, should not be used directly.
	127	*/
	128	extern int tracepoint_probe_unregister(const char name, void probe);
	129
127cafbb LJ	130	extern int tracepoint_probe_register_noupdate(const char name, void probe);
	131	extern int tracepoint_probe_unregister_noupdate(const char name, void probe);
	132	extern void tracepoint_probe_update_all(void);
	133
97e1c18e MD	134	struct tracepoint_iter {
	135	struct module *module;
	136	struct tracepoint *tracepoint;
	137	};
	138
	139	extern void tracepoint_iter_start(struct tracepoint_iter *iter);
	140	extern void tracepoint_iter_next(struct tracepoint_iter *iter);
	141	extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
	142	extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
	143	extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
	144	struct tracepoint begin, struct tracepoint end);
	145
f2461fc8 MD	146	/*
	147	* tracepoint_synchronize_unregister must be called between the last tracepoint
	148	* probe unregistration and the end of module exit to make sure there is no
	149	* caller executing a probe when it is freed.
	150	*/
231375cc MD	151	static inline void tracepoint_synchronize_unregister(void)
	152	{
	153	synchronize_sched();
	154	}
f2461fc8	155
97e1c18e	156	#endif