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Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04001#ifndef _LINUX_TRACEPOINT_H
2#define _LINUX_TRACEPOINT_H
3
4/*
5 * Kernel Tracepoint API.
6 *
Li Hong8cd09a52009-09-22 18:00:44 +08007 * See Documentation/trace/tracepoints.txt.
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -04008 *
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
20struct module;
21struct tracepoint;
22
Steven Rostedt38516ab2010-04-20 17:04:50 -040023struct tracepoint_func {
24 void *func;
25 void *data;
26};
27
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -040028struct tracepoint {
29 const char *name; /* Tracepoint name */
30 int state; /* State. */
Josh Stone97419872009-08-24 14:43:13 -070031 void (*regfunc)(void);
32 void (*unregfunc)(void);
Steven Rostedt38516ab2010-04-20 17:04:50 -040033 struct tracepoint_func *funcs;
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -050034} __attribute__((aligned(32))); /*
35 * Aligned on 32 bytes because it is
36 * globally visible and gcc happily
37 * align these on the structure size.
38 * Keep in sync with vmlinux.lds.h.
39 */
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -040040
Steven Rostedt2e26ca72010-05-05 10:52:31 -040041/*
42 * Connect a probe to a tracepoint.
43 * Internal API, should not be used directly.
44 */
Steven Rostedt38516ab2010-04-20 17:04:50 -040045extern int tracepoint_probe_register(const char *name, void *probe, void *data);
Steven Rostedt2e26ca72010-05-05 10:52:31 -040046
47/*
48 * Disconnect a probe from a tracepoint.
49 * Internal API, should not be used directly.
50 */
Steven Rostedt38516ab2010-04-20 17:04:50 -040051extern int
52tracepoint_probe_unregister(const char *name, void *probe, void *data);
Steven Rostedt2e26ca72010-05-05 10:52:31 -040053
Steven Rostedt38516ab2010-04-20 17:04:50 -040054extern int tracepoint_probe_register_noupdate(const char *name, void *probe,
55 void *data);
56extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
57 void *data);
Steven Rostedt2e26ca72010-05-05 10:52:31 -040058extern void tracepoint_probe_update_all(void);
59
60struct tracepoint_iter {
61 struct module *module;
62 struct tracepoint *tracepoint;
63};
64
65extern void tracepoint_iter_start(struct tracepoint_iter *iter);
66extern void tracepoint_iter_next(struct tracepoint_iter *iter);
67extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
68extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
69extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
70 struct tracepoint *begin, struct tracepoint *end);
71
72/*
73 * tracepoint_synchronize_unregister must be called between the last tracepoint
74 * probe unregistration and the end of module exit to make sure there is no
75 * caller executing a probe when it is freed.
76 */
77static inline void tracepoint_synchronize_unregister(void)
78{
79 synchronize_sched();
80}
81
82#define PARAMS(args...) args
83
84#ifdef CONFIG_TRACEPOINTS
85extern void tracepoint_update_probe_range(struct tracepoint *begin,
86 struct tracepoint *end);
87#else
88static inline void tracepoint_update_probe_range(struct tracepoint *begin,
89 struct tracepoint *end)
90{ }
91#endif /* CONFIG_TRACEPOINTS */
92
93#endif /* _LINUX_TRACEPOINT_H */
94
95/*
96 * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
97 * file ifdef protection.
98 * This is due to the way trace events work. If a file includes two
99 * trace event headers under one "CREATE_TRACE_POINTS" the first include
100 * will override the TRACE_EVENT and break the second include.
101 */
102
Steven Rostedtea20d922009-04-10 08:54:16 -0400103#ifndef DECLARE_TRACE
104
Steven Rostedt2939b042009-03-09 15:47:18 -0400105#define TP_PROTO(args...) args
Li Hong8cd09a52009-09-22 18:00:44 +0800106#define TP_ARGS(args...) args
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400107
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.
Steven Rostedt38516ab2010-04-20 17:04:50 -0400113 *
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".
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400119 */
120#define __DO_TRACE(tp, proto, args) \
121 do { \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400122 struct tracepoint_func *it_func_ptr; \
123 void *it_func; \
124 void *__data; \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400125 \
Mathieu Desnoyersda7b3ea2008-11-14 17:47:43 -0500126 rcu_read_lock_sched_notrace(); \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400127 it_func_ptr = rcu_dereference_sched((tp)->funcs); \
128 if (it_func_ptr) { \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400129 do { \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400130 it_func = (it_func_ptr)->func; \
131 __data = (it_func_ptr)->data; \
132 ((void(*)(proto))(it_func))(args); \
133 } while ((++it_func_ptr)->func); \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400134 } \
Mathieu Desnoyersda7b3ea2008-11-14 17:47:43 -0500135 rcu_read_unlock_sched_notrace(); \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400136 } while (0)
137
138/*
139 * Make sure the alignment of the structure in the __tracepoints section will
140 * not add unwanted padding between the beginning of the section and the
141 * structure. Force alignment to the same alignment as the section start.
142 */
Steven Rostedt38516ab2010-04-20 17:04:50 -0400143#define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -0500144 extern struct tracepoint __tracepoint_##name; \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400145 static inline void trace_##name(proto) \
146 { \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400147 if (unlikely(__tracepoint_##name.state)) \
148 __DO_TRACE(&__tracepoint_##name, \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400149 TP_PROTO(data_proto), \
150 TP_ARGS(data_args)); \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400151 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400152 static inline int \
153 register_trace_##name(void (*probe)(data_proto), void *data) \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400154 { \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400155 return tracepoint_probe_register(#name, (void *)probe, \
156 data); \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400157 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400158 static inline int \
159 unregister_trace_##name(void (*probe)(data_proto), void *data) \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400160 { \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400161 return tracepoint_probe_unregister(#name, (void *)probe, \
162 data); \
Mathieu Desnoyers53da59a2010-04-30 12:59:59 -0400163 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400164 static inline void \
165 check_trace_callback_type_##name(void (*cb)(data_proto)) \
Mathieu Desnoyers53da59a2010-04-30 12:59:59 -0400166 { \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400167 }
168
Josh Stone97419872009-08-24 14:43:13 -0700169#define DEFINE_TRACE_FN(name, reg, unreg) \
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -0500170 static const char __tpstrtab_##name[] \
171 __attribute__((section("__tracepoints_strings"))) = #name; \
172 struct tracepoint __tracepoint_##name \
173 __attribute__((section("__tracepoints"), aligned(32))) = \
Josh Stone97419872009-08-24 14:43:13 -0700174 { __tpstrtab_##name, 0, reg, unreg, NULL }
175
176#define DEFINE_TRACE(name) \
177 DEFINE_TRACE_FN(name, NULL, NULL);
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -0500178
179#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
180 EXPORT_SYMBOL_GPL(__tracepoint_##name)
181#define EXPORT_TRACEPOINT_SYMBOL(name) \
182 EXPORT_SYMBOL(__tracepoint_##name)
183
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400184#else /* !CONFIG_TRACEPOINTS */
Steven Rostedt38516ab2010-04-20 17:04:50 -0400185#define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400186 static inline void trace_##name(proto) \
187 { } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400188 static inline int \
189 register_trace_##name(void (*probe)(data_proto), \
190 void *data) \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400191 { \
192 return -ENOSYS; \
193 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400194 static inline int \
195 unregister_trace_##name(void (*probe)(data_proto), \
196 void *data) \
Mathieu Desnoyersc4209702008-11-14 17:47:44 -0500197 { \
198 return -ENOSYS; \
Mathieu Desnoyers53da59a2010-04-30 12:59:59 -0400199 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400200 static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
Mathieu Desnoyers53da59a2010-04-30 12:59:59 -0400201 { \
Mathieu Desnoyersc4209702008-11-14 17:47:44 -0500202 }
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400203
Josh Stone97419872009-08-24 14:43:13 -0700204#define DEFINE_TRACE_FN(name, reg, unreg)
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -0500205#define DEFINE_TRACE(name)
206#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
207#define EXPORT_TRACEPOINT_SYMBOL(name)
208
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400209#endif /* CONFIG_TRACEPOINTS */
Steven Rostedt38516ab2010-04-20 17:04:50 -0400210
211/*
212 * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
213 * (void). "void" is a special value in a function prototype and can
214 * not be combined with other arguments. Since the DECLARE_TRACE()
215 * macro adds a data element at the beginning of the prototype,
216 * we need a way to differentiate "(void *data, proto)" from
217 * "(void *data, void)". The second prototype is invalid.
218 *
219 * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
220 * and "void *__data" as the callback prototype.
221 *
222 * DECLARE_TRACE() passes "proto" as the tracepoint protoype and
223 * "void *__data, proto" as the callback prototype.
224 */
225#define DECLARE_TRACE_NOARGS(name) \
226 __DECLARE_TRACE(name, void, , void *__data, __data)
227
228#define DECLARE_TRACE(name, proto, args) \
229 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
230 PARAMS(void *__data, proto), \
231 PARAMS(__data, args))
232
Steven Rostedtea20d922009-04-10 08:54:16 -0400233#endif /* DECLARE_TRACE */
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400234
Steven Rostedtea20d922009-04-10 08:54:16 -0400235#ifndef TRACE_EVENT
Steven Rostedt823f9122009-03-10 12:58:51 -0400236/*
237 * For use with the TRACE_EVENT macro:
238 *
239 * We define a tracepoint, its arguments, its printk format
240 * and its 'fast binay record' layout.
241 *
242 * Firstly, name your tracepoint via TRACE_EVENT(name : the
243 * 'subsystem_event' notation is fine.
244 *
245 * Think about this whole construct as the
246 * 'trace_sched_switch() function' from now on.
247 *
248 *
249 * TRACE_EVENT(sched_switch,
250 *
251 * *
252 * * A function has a regular function arguments
253 * * prototype, declare it via TP_PROTO():
254 * *
255 *
Steven Rostedtef180122009-03-10 14:10:56 -0400256 * TP_PROTO(struct rq *rq, struct task_struct *prev,
257 * struct task_struct *next),
Steven Rostedt823f9122009-03-10 12:58:51 -0400258 *
259 * *
260 * * Define the call signature of the 'function'.
261 * * (Design sidenote: we use this instead of a
262 * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
263 * *
264 *
Steven Rostedtef180122009-03-10 14:10:56 -0400265 * TP_ARGS(rq, prev, next),
Steven Rostedt823f9122009-03-10 12:58:51 -0400266 *
267 * *
268 * * Fast binary tracing: define the trace record via
269 * * TP_STRUCT__entry(). You can think about it like a
270 * * regular C structure local variable definition.
271 * *
272 * * This is how the trace record is structured and will
273 * * be saved into the ring buffer. These are the fields
274 * * that will be exposed to user-space in
GeunSik Lim156f5a72009-06-02 15:01:37 +0900275 * * /sys/kernel/debug/tracing/events/<*>/format.
Steven Rostedt823f9122009-03-10 12:58:51 -0400276 * *
277 * * The declared 'local variable' is called '__entry'
278 * *
279 * * __field(pid_t, prev_prid) is equivalent to a standard declariton:
280 * *
281 * * pid_t prev_pid;
282 * *
283 * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
284 * *
285 * * char prev_comm[TASK_COMM_LEN];
286 * *
287 *
288 * TP_STRUCT__entry(
289 * __array( char, prev_comm, TASK_COMM_LEN )
290 * __field( pid_t, prev_pid )
291 * __field( int, prev_prio )
292 * __array( char, next_comm, TASK_COMM_LEN )
293 * __field( pid_t, next_pid )
294 * __field( int, next_prio )
295 * ),
296 *
297 * *
298 * * Assign the entry into the trace record, by embedding
299 * * a full C statement block into TP_fast_assign(). You
300 * * can refer to the trace record as '__entry' -
301 * * otherwise you can put arbitrary C code in here.
302 * *
303 * * Note: this C code will execute every time a trace event
304 * * happens, on an active tracepoint.
305 * *
306 *
Steven Rostedtef180122009-03-10 14:10:56 -0400307 * TP_fast_assign(
308 * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
309 * __entry->prev_pid = prev->pid;
310 * __entry->prev_prio = prev->prio;
Steven Rostedt823f9122009-03-10 12:58:51 -0400311 * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
312 * __entry->next_pid = next->pid;
Steven Rostedtef180122009-03-10 14:10:56 -0400313 * __entry->next_prio = next->prio;
Steven Rostedt823f9122009-03-10 12:58:51 -0400314 * )
315 *
316 * *
317 * * Formatted output of a trace record via TP_printk().
318 * * This is how the tracepoint will appear under ftrace
319 * * plugins that make use of this tracepoint.
320 * *
321 * * (raw-binary tracing wont actually perform this step.)
322 * *
323 *
324 * TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
325 * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
326 * __entry->next_comm, __entry->next_pid, __entry->next_prio),
327 *
328 * );
329 *
330 * This macro construct is thus used for the regular printk format
331 * tracing setup, it is used to construct a function pointer based
332 * tracepoint callback (this is used by programmatic plugins and
333 * can also by used by generic instrumentation like SystemTap), and
334 * it is also used to expose a structured trace record in
GeunSik Lim156f5a72009-06-02 15:01:37 +0900335 * /sys/kernel/debug/tracing/events/.
Josh Stone97419872009-08-24 14:43:13 -0700336 *
337 * A set of (un)registration functions can be passed to the variant
338 * TRACE_EVENT_FN to perform any (un)registration work.
Steven Rostedt823f9122009-03-10 12:58:51 -0400339 */
340
Ingo Molnar091ad362009-11-26 09:04:55 +0100341#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
Steven Rostedtff038f52009-11-18 20:27:27 -0500342#define DEFINE_EVENT(template, name, proto, args) \
343 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
Steven Rostedte5bc9722009-11-18 20:36:26 -0500344#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
345 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
Steven Rostedtff038f52009-11-18 20:27:27 -0500346
Steven Rostedt30a8fec2009-03-10 12:41:38 -0400347#define TRACE_EVENT(name, proto, args, struct, assign, print) \
Steven Rostedtda4d0302009-03-09 17:14:30 -0400348 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
Josh Stone97419872009-08-24 14:43:13 -0700349#define TRACE_EVENT_FN(name, proto, args, struct, \
350 assign, print, reg, unreg) \
351 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
Steven Rostedt7cb2e3e2009-08-26 00:32:37 -0400352
353#endif /* ifdef TRACE_EVENT (see note above) */