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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
Wu Zhangjinb70e4f02010-06-21 19:09:09 +080017#include <linux/errno.h>
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -040018#include <linux/types.h>
19#include <linux/rcupdate.h>
20
21struct module;
22struct tracepoint;
23
Steven Rostedt38516ab2010-04-20 17:04:50 -040024struct tracepoint_func {
25 void *func;
26 void *data;
27};
28
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -040029struct tracepoint {
30 const char *name; /* Tracepoint name */
31 int state; /* State. */
Josh Stone97419872009-08-24 14:43:13 -070032 void (*regfunc)(void);
33 void (*unregfunc)(void);
Steven Rostedt38516ab2010-04-20 17:04:50 -040034 struct tracepoint_func *funcs;
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -050035} __attribute__((aligned(32))); /*
36 * Aligned on 32 bytes because it is
37 * globally visible and gcc happily
38 * align these on the structure size.
39 * Keep in sync with vmlinux.lds.h.
40 */
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -040041
Steven Rostedt2e26ca72010-05-05 10:52:31 -040042/*
43 * Connect a probe to a tracepoint.
44 * Internal API, should not be used directly.
45 */
Steven Rostedt38516ab2010-04-20 17:04:50 -040046extern int tracepoint_probe_register(const char *name, void *probe, void *data);
Steven Rostedt2e26ca72010-05-05 10:52:31 -040047
48/*
49 * Disconnect a probe from a tracepoint.
50 * Internal API, should not be used directly.
51 */
Steven Rostedt38516ab2010-04-20 17:04:50 -040052extern int
53tracepoint_probe_unregister(const char *name, void *probe, void *data);
Steven Rostedt2e26ca72010-05-05 10:52:31 -040054
Steven Rostedt38516ab2010-04-20 17:04:50 -040055extern int tracepoint_probe_register_noupdate(const char *name, void *probe,
56 void *data);
57extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
58 void *data);
Steven Rostedt2e26ca72010-05-05 10:52:31 -040059extern void tracepoint_probe_update_all(void);
60
61struct tracepoint_iter {
62 struct module *module;
63 struct tracepoint *tracepoint;
64};
65
66extern void tracepoint_iter_start(struct tracepoint_iter *iter);
67extern void tracepoint_iter_next(struct tracepoint_iter *iter);
68extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
69extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
70extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
71 struct tracepoint *begin, struct tracepoint *end);
72
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 */
78static inline void tracepoint_synchronize_unregister(void)
79{
80 synchronize_sched();
81}
82
83#define PARAMS(args...) args
84
85#ifdef CONFIG_TRACEPOINTS
86extern void tracepoint_update_probe_range(struct tracepoint *begin,
87 struct tracepoint *end);
88#else
89static inline void tracepoint_update_probe_range(struct tracepoint *begin,
90 struct tracepoint *end)
91{ }
92#endif /* CONFIG_TRACEPOINTS */
93
94#endif /* _LINUX_TRACEPOINT_H */
95
96/*
97 * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
98 * file ifdef protection.
99 * This is due to the way trace events work. If a file includes two
100 * trace event headers under one "CREATE_TRACE_POINTS" the first include
101 * will override the TRACE_EVENT and break the second include.
102 */
103
Steven Rostedtea20d922009-04-10 08:54:16 -0400104#ifndef DECLARE_TRACE
105
Steven Rostedt2939b042009-03-09 15:47:18 -0400106#define TP_PROTO(args...) args
Li Hong8cd09a52009-09-22 18:00:44 +0800107#define TP_ARGS(args...) args
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400108
109#ifdef CONFIG_TRACEPOINTS
110
111/*
112 * it_func[0] is never NULL because there is at least one element in the array
113 * when the array itself is non NULL.
Steven Rostedt38516ab2010-04-20 17:04:50 -0400114 *
115 * Note, the proto and args passed in includes "__data" as the first parameter.
116 * The reason for this is to handle the "void" prototype. If a tracepoint
117 * has a "void" prototype, then it is invalid to declare a function
118 * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
119 * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto".
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400120 */
121#define __DO_TRACE(tp, proto, args) \
122 do { \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400123 struct tracepoint_func *it_func_ptr; \
124 void *it_func; \
125 void *__data; \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400126 \
Mathieu Desnoyersda7b3ea2008-11-14 17:47:43 -0500127 rcu_read_lock_sched_notrace(); \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400128 it_func_ptr = rcu_dereference_sched((tp)->funcs); \
129 if (it_func_ptr) { \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400130 do { \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400131 it_func = (it_func_ptr)->func; \
132 __data = (it_func_ptr)->data; \
133 ((void(*)(proto))(it_func))(args); \
134 } while ((++it_func_ptr)->func); \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400135 } \
Mathieu Desnoyersda7b3ea2008-11-14 17:47:43 -0500136 rcu_read_unlock_sched_notrace(); \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400137 } while (0)
138
139/*
140 * Make sure the alignment of the structure in the __tracepoints section will
141 * not add unwanted padding between the beginning of the section and the
142 * structure. Force alignment to the same alignment as the section start.
143 */
Steven Rostedt38516ab2010-04-20 17:04:50 -0400144#define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -0500145 extern struct tracepoint __tracepoint_##name; \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400146 static inline void trace_##name(proto) \
147 { \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400148 if (unlikely(__tracepoint_##name.state)) \
149 __DO_TRACE(&__tracepoint_##name, \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400150 TP_PROTO(data_proto), \
151 TP_ARGS(data_args)); \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400152 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400153 static inline int \
154 register_trace_##name(void (*probe)(data_proto), void *data) \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400155 { \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400156 return tracepoint_probe_register(#name, (void *)probe, \
157 data); \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400158 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400159 static inline int \
160 unregister_trace_##name(void (*probe)(data_proto), void *data) \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400161 { \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400162 return tracepoint_probe_unregister(#name, (void *)probe, \
163 data); \
Mathieu Desnoyers53da59a2010-04-30 12:59:59 -0400164 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400165 static inline void \
166 check_trace_callback_type_##name(void (*cb)(data_proto)) \
Mathieu Desnoyers53da59a2010-04-30 12:59:59 -0400167 { \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400168 }
169
Josh Stone97419872009-08-24 14:43:13 -0700170#define DEFINE_TRACE_FN(name, reg, unreg) \
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -0500171 static const char __tpstrtab_##name[] \
172 __attribute__((section("__tracepoints_strings"))) = #name; \
173 struct tracepoint __tracepoint_##name \
174 __attribute__((section("__tracepoints"), aligned(32))) = \
Josh Stone97419872009-08-24 14:43:13 -0700175 { __tpstrtab_##name, 0, reg, unreg, NULL }
176
177#define DEFINE_TRACE(name) \
178 DEFINE_TRACE_FN(name, NULL, NULL);
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -0500179
180#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
181 EXPORT_SYMBOL_GPL(__tracepoint_##name)
182#define EXPORT_TRACEPOINT_SYMBOL(name) \
183 EXPORT_SYMBOL(__tracepoint_##name)
184
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400185#else /* !CONFIG_TRACEPOINTS */
Steven Rostedt38516ab2010-04-20 17:04:50 -0400186#define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400187 static inline void trace_##name(proto) \
188 { } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400189 static inline int \
190 register_trace_##name(void (*probe)(data_proto), \
191 void *data) \
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400192 { \
193 return -ENOSYS; \
194 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400195 static inline int \
196 unregister_trace_##name(void (*probe)(data_proto), \
197 void *data) \
Mathieu Desnoyersc4209702008-11-14 17:47:44 -0500198 { \
199 return -ENOSYS; \
Mathieu Desnoyers53da59a2010-04-30 12:59:59 -0400200 } \
Steven Rostedt38516ab2010-04-20 17:04:50 -0400201 static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
Mathieu Desnoyers53da59a2010-04-30 12:59:59 -0400202 { \
Mathieu Desnoyersc4209702008-11-14 17:47:44 -0500203 }
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400204
Josh Stone97419872009-08-24 14:43:13 -0700205#define DEFINE_TRACE_FN(name, reg, unreg)
Mathieu Desnoyers7e066fb2008-11-14 17:47:47 -0500206#define DEFINE_TRACE(name)
207#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
208#define EXPORT_TRACEPOINT_SYMBOL(name)
209
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400210#endif /* CONFIG_TRACEPOINTS */
Steven Rostedt38516ab2010-04-20 17:04:50 -0400211
212/*
213 * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
214 * (void). "void" is a special value in a function prototype and can
215 * not be combined with other arguments. Since the DECLARE_TRACE()
216 * macro adds a data element at the beginning of the prototype,
217 * we need a way to differentiate "(void *data, proto)" from
218 * "(void *data, void)". The second prototype is invalid.
219 *
220 * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
221 * and "void *__data" as the callback prototype.
222 *
223 * DECLARE_TRACE() passes "proto" as the tracepoint protoype and
224 * "void *__data, proto" as the callback prototype.
225 */
226#define DECLARE_TRACE_NOARGS(name) \
227 __DECLARE_TRACE(name, void, , void *__data, __data)
228
229#define DECLARE_TRACE(name, proto, args) \
230 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
231 PARAMS(void *__data, proto), \
232 PARAMS(__data, args))
233
Steven Rostedtea20d922009-04-10 08:54:16 -0400234#endif /* DECLARE_TRACE */
Mathieu Desnoyers97e1c182008-07-18 12:16:16 -0400235
Steven Rostedtea20d922009-04-10 08:54:16 -0400236#ifndef TRACE_EVENT
Steven Rostedt823f9122009-03-10 12:58:51 -0400237/*
238 * For use with the TRACE_EVENT macro:
239 *
240 * We define a tracepoint, its arguments, its printk format
241 * and its 'fast binay record' layout.
242 *
243 * Firstly, name your tracepoint via TRACE_EVENT(name : the
244 * 'subsystem_event' notation is fine.
245 *
246 * Think about this whole construct as the
247 * 'trace_sched_switch() function' from now on.
248 *
249 *
250 * TRACE_EVENT(sched_switch,
251 *
252 * *
253 * * A function has a regular function arguments
254 * * prototype, declare it via TP_PROTO():
255 * *
256 *
Steven Rostedtef180122009-03-10 14:10:56 -0400257 * TP_PROTO(struct rq *rq, struct task_struct *prev,
258 * struct task_struct *next),
Steven Rostedt823f9122009-03-10 12:58:51 -0400259 *
260 * *
261 * * Define the call signature of the 'function'.
262 * * (Design sidenote: we use this instead of a
263 * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
264 * *
265 *
Steven Rostedtef180122009-03-10 14:10:56 -0400266 * TP_ARGS(rq, prev, next),
Steven Rostedt823f9122009-03-10 12:58:51 -0400267 *
268 * *
269 * * Fast binary tracing: define the trace record via
270 * * TP_STRUCT__entry(). You can think about it like a
271 * * regular C structure local variable definition.
272 * *
273 * * This is how the trace record is structured and will
274 * * be saved into the ring buffer. These are the fields
275 * * that will be exposed to user-space in
GeunSik Lim156f5a72009-06-02 15:01:37 +0900276 * * /sys/kernel/debug/tracing/events/<*>/format.
Steven Rostedt823f9122009-03-10 12:58:51 -0400277 * *
278 * * The declared 'local variable' is called '__entry'
279 * *
280 * * __field(pid_t, prev_prid) is equivalent to a standard declariton:
281 * *
282 * * pid_t prev_pid;
283 * *
284 * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
285 * *
286 * * char prev_comm[TASK_COMM_LEN];
287 * *
288 *
289 * TP_STRUCT__entry(
290 * __array( char, prev_comm, TASK_COMM_LEN )
291 * __field( pid_t, prev_pid )
292 * __field( int, prev_prio )
293 * __array( char, next_comm, TASK_COMM_LEN )
294 * __field( pid_t, next_pid )
295 * __field( int, next_prio )
296 * ),
297 *
298 * *
299 * * Assign the entry into the trace record, by embedding
300 * * a full C statement block into TP_fast_assign(). You
301 * * can refer to the trace record as '__entry' -
302 * * otherwise you can put arbitrary C code in here.
303 * *
304 * * Note: this C code will execute every time a trace event
305 * * happens, on an active tracepoint.
306 * *
307 *
Steven Rostedtef180122009-03-10 14:10:56 -0400308 * TP_fast_assign(
309 * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
310 * __entry->prev_pid = prev->pid;
311 * __entry->prev_prio = prev->prio;
Steven Rostedt823f9122009-03-10 12:58:51 -0400312 * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
313 * __entry->next_pid = next->pid;
Steven Rostedtef180122009-03-10 14:10:56 -0400314 * __entry->next_prio = next->prio;
Steven Rostedt823f9122009-03-10 12:58:51 -0400315 * )
316 *
317 * *
318 * * Formatted output of a trace record via TP_printk().
319 * * This is how the tracepoint will appear under ftrace
320 * * plugins that make use of this tracepoint.
321 * *
322 * * (raw-binary tracing wont actually perform this step.)
323 * *
324 *
325 * TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
326 * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
327 * __entry->next_comm, __entry->next_pid, __entry->next_prio),
328 *
329 * );
330 *
331 * This macro construct is thus used for the regular printk format
332 * tracing setup, it is used to construct a function pointer based
333 * tracepoint callback (this is used by programmatic plugins and
334 * can also by used by generic instrumentation like SystemTap), and
335 * it is also used to expose a structured trace record in
GeunSik Lim156f5a72009-06-02 15:01:37 +0900336 * /sys/kernel/debug/tracing/events/.
Josh Stone97419872009-08-24 14:43:13 -0700337 *
338 * A set of (un)registration functions can be passed to the variant
339 * TRACE_EVENT_FN to perform any (un)registration work.
Steven Rostedt823f9122009-03-10 12:58:51 -0400340 */
341
Ingo Molnar091ad362009-11-26 09:04:55 +0100342#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
Steven Rostedtff038f52009-11-18 20:27:27 -0500343#define DEFINE_EVENT(template, name, proto, args) \
344 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
Steven Rostedte5bc9722009-11-18 20:36:26 -0500345#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
346 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
Steven Rostedtff038f52009-11-18 20:27:27 -0500347
Steven Rostedt30a8fec2009-03-10 12:41:38 -0400348#define TRACE_EVENT(name, proto, args, struct, assign, print) \
Steven Rostedtda4d0302009-03-09 17:14:30 -0400349 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
Josh Stone97419872009-08-24 14:43:13 -0700350#define TRACE_EVENT_FN(name, proto, args, struct, \
351 assign, print, reg, unreg) \
352 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
Steven Rostedt7cb2e3e2009-08-26 00:32:37 -0400353
354#endif /* ifdef TRACE_EVENT (see note above) */