Tracepoints: add wrapper tracepoint() macro
[ust.git] / include / ust / tracepoint.h
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1#ifndef _UST_TRACEPOINT_H
2#define _UST_TRACEPOINT_H
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3
4/*
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5 * Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
6 * Copyright (C) 2009 Pierre-Marc Fournier
22d72948 7 * Copyright (C) 2009 Steven Rostedt <rostedt@goodmis.org>
f99be407 8 *
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9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
f99be407 13 *
8fc2d8db 14 * This library is distributed in the hope that it will be useful,
1f8b0dff 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
1f8b0dff 18 *
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19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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22 *
23 * Heavily inspired from the Linux Kernel Markers.
24 *
1f8b0dff 25 * Ported to userspace by Pierre-Marc Fournier.
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26 */
27
872037bb 28#define _LGPL_SOURCE
b7ea1a1c 29#include <urcu-bp.h>
93d0f2ea 30#include <ust/immediate.h>
518d7abb 31#include <ust/core.h>
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32
33struct module;
34struct tracepoint;
35
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36struct probe {
37 void *func;
38 void *data;
39};
40
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41struct tracepoint {
42 const char *name; /* Tracepoint name */
43 DEFINE_IMV(char, state); /* State. */
9dec086e 44 struct probe *probes;
f218ff28 45};
f99be407 46
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47#define PARAMS(args...) args
48
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49#define TP_PROTO(args...) args
50#define TP_ARGS(args...) args
f99be407 51
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52/*
53 * Tracepoints should be added to the instrumented code using the
54 * "tracepoint()" macro.
55 */
56#define tracepoint(name, args...) __trace_##name(args)
57
58#define register_tracepoint(name, probe, data) \
59 __register_trace_##name(probe, data)
60
61#define unregister_tracepoint(name, probe, data) \
62 __unregister_trace_##name(probe, data)
63
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64#define CONFIG_TRACEPOINTS
65#ifdef CONFIG_TRACEPOINTS
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66
67/*
68 * it_func[0] is never NULL because there is at least one element in the array
69 * when the array itself is non NULL.
70 */
71#define __DO_TRACE(tp, proto, args) \
72 do { \
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73 struct probe *it_probe_ptr; \
74 void *it_func; \
75 void *__data; \
f99be407 76 \
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77 rcu_read_lock(); \
78 it_probe_ptr = rcu_dereference((tp)->probes); \
79 if (it_probe_ptr) { \
f99be407 80 do { \
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81 it_func = (it_probe_ptr)->func; \
82 __data = (it_probe_ptr)->data; \
83 ((void(*)(proto))(it_func))(args); \
84 } while ((++it_probe_ptr)->func); \
f99be407 85 } \
9dec086e 86 rcu_read_unlock(); \
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87 } while (0)
88
89#define __CHECK_TRACE(name, generic, proto, args) \
90 do { \
91 if (!generic) { \
92 if (unlikely(imv_read(__tracepoint_##name.state))) \
93 __DO_TRACE(&__tracepoint_##name, \
7166e240 94 TP_PROTO(proto), TP_ARGS(args)); \
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95 } else { \
96 if (unlikely(_imv_read(__tracepoint_##name.state))) \
97 __DO_TRACE(&__tracepoint_##name, \
7166e240 98 TP_PROTO(proto), TP_ARGS(args)); \
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99 } \
100 } while (0)
101
102/*
103 * Make sure the alignment of the structure in the __tracepoints section will
104 * not add unwanted padding between the beginning of the section and the
105 * structure. Force alignment to the same alignment as the section start.
106 *
107 * The "generic" argument, passed to the declared __trace_##name inline
108 * function controls which tracepoint enabling mechanism must be used.
109 * If generic is true, a variable read is used.
110 * If generic is false, immediate values are used.
111 */
9dec086e 112#define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \
f99be407 113 extern struct tracepoint __tracepoint_##name; \
cc7b66ba 114 static inline void __trace_##name(proto) \
f99be407 115 { \
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116 __CHECK_TRACE(name, 0, TP_PROTO(data_proto), \
117 TP_ARGS(data_args)); \
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118 } \
119 static inline void _trace_##name(proto) \
120 { \
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121 __CHECK_TRACE(name, 1, TP_PROTO(data_proto), \
122 TP_ARGS(data_args)); \
f99be407 123 } \
9dec086e 124 static inline int \
cc7b66ba 125 __register_trace_##name(void (*probe)(data_proto), void *data) \
f99be407 126 { \
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127 return tracepoint_probe_register(#name, (void *)probe, \
128 data); \
129 \
f99be407 130 } \
9dec086e 131 static inline int \
cc7b66ba 132 __unregister_trace_##name(void (*probe)(data_proto), void *data)\
f99be407 133 { \
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134 return tracepoint_probe_unregister(#name, (void *)probe, \
135 data); \
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136 }
137
f218ff28 138#define DEFINE_TRACE_FN(name, reg, unreg) \
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139 static const char __tpstrtab_##name[] \
140 __attribute__((section("__tracepoints_strings"))) = #name; \
141 struct tracepoint __tracepoint_##name \
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142 __attribute__((section("__tracepoints"))) = \
143 { __tpstrtab_##name, 0, NULL }; \
144 static struct tracepoint * const __tracepoint_ptr_##name \
145 __attribute__((used, section("__tracepoints_ptrs"))) = \
146 &__tracepoint_##name;
f99be407 147
9dec086e 148#define DEFINE_TRACE(name) \
f218ff28 149 DEFINE_TRACE_FN(name, NULL, NULL)
9dec086e 150
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151extern void tracepoint_update_probe_range(struct tracepoint * const *begin,
152 struct tracepoint * const *end);
f99be407 153
872037bb 154#else /* !CONFIG_TRACEPOINTS */
9dec086e 155#define __DECLARE_TRACE(name, proto, args) \
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156 static inline void trace_##name(proto) \
157 { } \
158 static inline void _trace_##name(proto) \
159 { } \
cc7b66ba 160 static inline int __register_trace_##name(void (*probe)(proto), void *data) \
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161 { \
162 return -ENOSYS; \
163 } \
cc7b66ba 164 static inline int __unregister_trace_##name(void (*probe)(proto), void *data) \
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165 { \
166 return -ENOSYS; \
167 }
168
169#define DEFINE_TRACE(name)
170#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
171#define EXPORT_TRACEPOINT_SYMBOL(name)
172
173static inline void tracepoint_update_probe_range(struct tracepoint *begin,
174 struct tracepoint *end)
175{ }
176#endif /* CONFIG_TRACEPOINTS */
f99be407 177
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178#define DECLARE_TRACE(name, proto, args) \
179 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
180 PARAMS(void *__data, proto), \
181 PARAMS(__data, args))
182
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183/*
184 * Connect a probe to a tracepoint.
185 * Internal API, should not be used directly.
186 */
9dec086e 187extern int tracepoint_probe_register(const char *name, void *probe, void *data);
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188
189/*
190 * Disconnect a probe from a tracepoint.
191 * Internal API, should not be used directly.
192 */
9dec086e 193extern int tracepoint_probe_unregister(const char *name, void *probe, void *data);
f99be407 194
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195extern int tracepoint_probe_register_noupdate(const char *name, void *probe,
196 void *data);
197extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
198 void *data);
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199extern void tracepoint_probe_update_all(void);
200
201struct tracepoint_iter {
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202//ust// struct module *module;
203 struct tracepoint_lib *lib;
f218ff28 204 struct tracepoint * const *tracepoint;
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205};
206
207extern void tracepoint_iter_start(struct tracepoint_iter *iter);
208extern void tracepoint_iter_next(struct tracepoint_iter *iter);
209extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
210extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
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211extern int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
212 struct tracepoint * const *begin, struct tracepoint * const *end);
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213
214/*
215 * tracepoint_synchronize_unregister must be called between the last tracepoint
216 * probe unregistration and the end of module exit to make sure there is no
217 * caller executing a probe when it is freed.
218 */
219static inline void tracepoint_synchronize_unregister(void)
220{
270c6b98 221//ust// synchronize_sched();
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222}
223
474d745f 224struct tracepoint_lib {
f218ff28 225 struct tracepoint * const *tracepoints_start;
474d745f 226 int tracepoints_count;
0222e121 227 struct cds_list_head list;
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228};
229
f218ff28 230extern int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
872037bb 231 int tracepoints_count);
f218ff28 232extern int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
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233
234#define TRACEPOINT_LIB \
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235 extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
236 extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
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237 static struct tracepoint * const __tracepoint_ptr_dummy \
238 __attribute__((used, section("__tracepoints_ptrs"))) = NULL; \
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239 static void __attribute__((constructor)) __tracepoints__init(void) \
240 { \
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241 tracepoint_register_lib(__start___tracepoints_ptrs, \
242 __stop___tracepoints_ptrs - \
243 __start___tracepoints_ptrs); \
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244 } \
245 \
246 static void __attribute__((destructor)) __tracepoints__destroy(void) \
247 { \
103fffbc 248 tracepoint_unregister_lib(__start___tracepoints_ptrs); \
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249 }
250
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251
252#ifndef TRACE_EVENT
253/*
254 * For use with the TRACE_EVENT macro:
255 *
256 * We define a tracepoint, its arguments, its printf format
257 * and its 'fast binary record' layout.
258 *
259 * Firstly, name your tracepoint via TRACE_EVENT(name : the
260 * 'subsystem_event' notation is fine.
261 *
262 * Think about this whole construct as the
263 * 'trace_sched_switch() function' from now on.
264 *
265 *
266 * TRACE_EVENT(sched_switch,
267 *
268 * *
269 * * A function has a regular function arguments
270 * * prototype, declare it via TP_PROTO():
271 * *
272 *
273 * TP_PROTO(struct rq *rq, struct task_struct *prev,
274 * struct task_struct *next),
275 *
276 * *
277 * * Define the call signature of the 'function'.
278 * * (Design sidenote: we use this instead of a
279 * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
280 * *
281 *
282 * TP_ARGS(rq, prev, next),
283 *
284 * *
285 * * Fast binary tracing: define the trace record via
286 * * TP_STRUCT__entry(). You can think about it like a
287 * * regular C structure local variable definition.
288 * *
289 * * This is how the trace record is structured and will
290 * * be saved into the ring buffer. These are the fields
291 * * that will be exposed to readers.
292 * *
293 * * The declared 'local variable' is called '__entry'
294 * *
295 * * __field(pid_t, prev_prid) is equivalent to a standard declariton:
296 * *
297 * * pid_t prev_pid;
298 * *
299 * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
300 * *
301 * * char prev_comm[TASK_COMM_LEN];
302 * *
303 *
304 * TP_STRUCT__entry(
305 * __array( char, prev_comm, TASK_COMM_LEN )
306 * __field( pid_t, prev_pid )
307 * __field( int, prev_prio )
308 * __array( char, next_comm, TASK_COMM_LEN )
309 * __field( pid_t, next_pid )
310 * __field( int, next_prio )
311 * ),
312 *
313 * *
314 * * Assign the entry into the trace record, by embedding
315 * * a full C statement block into TP_fast_assign(). You
316 * * can refer to the trace record as '__entry' -
317 * * otherwise you can put arbitrary C code in here.
318 * *
319 * * Note: this C code will execute every time a trace event
320 * * happens, on an active tracepoint.
321 * *
322 *
323 * TP_fast_assign(
324 * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
325 * __entry->prev_pid = prev->pid;
326 * __entry->prev_prio = prev->prio;
327 * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
328 * __entry->next_pid = next->pid;
329 * __entry->next_prio = next->prio;
330 * )
331 *
332 * *
333 * * Formatted output of a trace record via TP_printf().
334 * * This is how the tracepoint will appear under debugging
335 * * of tracepoints.
336 * *
337 * * (raw-binary tracing wont actually perform this step.)
338 * *
339 *
340 * TP_printf("task %s:%d [%d] ==> %s:%d [%d]",
341 * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
342 * __entry->next_comm, __entry->next_pid, __entry->next_prio),
343 *
344 * );
345 *
346 * This macro construct is thus used for the regular printf format
347 * tracing setup.
348 *
349 * A set of (un)registration functions can be passed to the variant
350 * TRACE_EVENT_FN to perform any (un)registration work.
351 */
352
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353struct trace_event {
354 const char *name;
355 int (*regfunc)(void *data);
356 int (*unregfunc)(void *data);
fc1caebc 357};
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358
359struct trace_event_lib {
fc1caebc 360 struct trace_event * const *trace_events_start;
0c0686ee 361 int trace_events_count;
0222e121 362 struct cds_list_head list;
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363};
364
365struct trace_event_iter {
366 struct trace_event_lib *lib;
fc1caebc 367 struct trace_event * const *trace_event;
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368};
369
370extern void lock_trace_events(void);
371extern void unlock_trace_events(void);
372
373extern void trace_event_iter_start(struct trace_event_iter *iter);
374extern void trace_event_iter_next(struct trace_event_iter *iter);
375extern void trace_event_iter_reset(struct trace_event_iter *iter);
376
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377extern int trace_event_get_iter_range(struct trace_event * const **trace_event,
378 struct trace_event * const *begin,
379 struct trace_event * const *end);
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380
381extern void trace_event_update_process(void);
382extern int is_trace_event_enabled(const char *channel, const char *name);
383
fc1caebc 384extern int trace_event_register_lib(struct trace_event * const *start_trace_events,
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385 int trace_event_count);
386
fc1caebc 387extern int trace_event_unregister_lib(struct trace_event * const *start_trace_events);
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388
389#define TRACE_EVENT_LIB \
fc1caebc 390 extern struct trace_event * const __start___trace_events_ptrs[] \
0c0686ee 391 __attribute__((weak, visibility("hidden"))); \
fc1caebc 392 extern struct trace_event * const __stop___trace_events_ptrs[] \
0c0686ee 393 __attribute__((weak, visibility("hidden"))); \
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394 static struct trace_event * const __event_ptrs_dummy \
395 __attribute__((used, section("__trace_events_ptrs"))) = NULL; \
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396 static void __attribute__((constructor)) \
397 __trace_events__init(void) \
398 { \
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399 trace_event_register_lib(__start___trace_events_ptrs, \
400 __stop___trace_events_ptrs - \
401 __start___trace_events_ptrs); \
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402 } \
403 \
404 static void __attribute__((destructor)) \
405 __trace_event__destroy(void) \
406 { \
fc1caebc 407 trace_event_unregister_lib(__start___trace_events_ptrs);\
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408 }
409
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410#define DECLARE_TRACE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
411#define DEFINE_TRACE_EVENT(template, name, proto, args) \
412 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
413#define DEFINE_TRACE_EVENT_PRINT(template, name, proto, args, print) \
414 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
415
416#define TRACE_EVENT(name, proto, args, struct, assign, print) \
417 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
418#define TRACE_EVENT_FN(name, proto, args, struct, \
419 assign, print, reg, unreg) \
420 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
421
422#endif /* ifdef TRACE_EVENT (see note above) */
423
424
27b052e3 425#endif /* _UST_TRACEPOINT_H */
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