1 #ifndef _UST_TRACEPOINT_H
2 #define _UST_TRACEPOINT_H
5 * Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
6 * Copyright (C) 2009 Pierre-Marc Fournier
7 * Copyright (C) 2009 Steven Rostedt <rostedt@goodmis.org>
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;
12 * version 2.1 of the License.
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
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
23 * Heavily inspired from the Linux Kernel Markers.
25 * Ported to userspace by Pierre-Marc Fournier.
30 #include <urcu/list.h>
34 struct tracepoint_probe
{
40 const char *name
; /* Tracepoint name */
41 char state
; /* State. */
42 struct tracepoint_probe
*probes
;
45 #define TP_PARAMS(args...) args
46 #define TP_PROTO(args...) args
47 #define TP_ARGS(args...) args
50 * Tracepoints should be added to the instrumented code using the
51 * "tracepoint()" macro.
53 #define tracepoint(name, args...) __trace_##name(args)
55 #define register_tracepoint(name, probe, data) \
56 __register_trace_##name(probe, data)
58 #define unregister_tracepoint(name, probe, data) \
59 __unregister_trace_##name(probe, data)
61 #define CONFIG_TRACEPOINTS
62 #ifdef CONFIG_TRACEPOINTS
65 * it_func[0] is never NULL because there is at least one element in the array
66 * when the array itself is non NULL.
68 #define __DO_TRACE(tp, proto, args) \
70 struct tracepoint_probe *__tp_it_probe_ptr; \
75 __tp_it_probe_ptr = rcu_dereference((tp)->probes); \
76 if (__tp_it_probe_ptr) { \
78 __tp_it_func = __tp_it_probe_ptr->func; \
79 __tp_cb_data = __tp_it_probe_ptr->data; \
80 ((void(*)(proto))__tp_it_func)(args); \
81 } while ((++__tp_it_probe_ptr)->func); \
86 #define __CHECK_TRACE(name, proto, args) \
88 if (unlikely(__tracepoint_##name.state)) \
89 __DO_TRACE(&__tracepoint_##name, \
90 TP_PROTO(proto), TP_ARGS(args)); \
94 * Make sure the alignment of the structure in the __tracepoints section will
95 * not add unwanted padding between the beginning of the section and the
96 * structure. Force alignment to the same alignment as the section start.
98 #define __DECLARE_TRACEPOINT(name, proto, args, data_proto, data_args) \
99 extern struct tracepoint __tracepoint_##name; \
100 static inline void __trace_##name(proto) \
102 __CHECK_TRACE(name, TP_PROTO(data_proto), \
103 TP_ARGS(data_args)); \
106 __register_trace_##name(void (*probe)(data_proto), void *data) \
108 return tracepoint_probe_register(#name, (void *)probe, \
113 __unregister_trace_##name(void (*probe)(data_proto), void *data)\
115 return tracepoint_probe_unregister(#name, (void *)probe, \
120 * __tracepoints_ptrs section is not const (read-only) to let the linker update
121 * the pointer, allowing PIC code.
123 #define DEFINE_TRACEPOINT_FN(name, reg, unreg) \
124 static const char __tpstrtab_##name[] \
125 __attribute__((section("__tracepoints_strings"))) = #name; \
126 struct tracepoint __tracepoint_##name \
127 __attribute__((section("__tracepoints"))) = \
128 { __tpstrtab_##name, 0, NULL }; \
129 static struct tracepoint * __tracepoint_ptr_##name \
130 __attribute__((used, section("__tracepoints_ptrs"))) = \
131 &__tracepoint_##name;
133 #define DEFINE_TRACEPOINT(name) \
134 DEFINE_TRACEPOINT_FN(name, NULL, NULL)
136 extern void tracepoint_update_probe_range(struct tracepoint
* const *begin
,
137 struct tracepoint
* const *end
);
139 #else /* !CONFIG_TRACEPOINTS */
140 #define __DECLARE_TRACEPOINT(name, proto, args) \
141 static inline void trace_##name(proto) \
143 static inline void _trace_##name(proto) \
145 static inline int __register_trace_##name(void (*probe)(proto), void *data) \
149 static inline int __unregister_trace_##name(void (*probe)(proto), void *data) \
154 #define DEFINE_TRACEPOINT(name)
155 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
156 #define EXPORT_TRACEPOINT_SYMBOL(name)
158 static inline void tracepoint_update_probe_range(struct tracepoint
*begin
,
159 struct tracepoint
*end
)
161 #endif /* CONFIG_TRACEPOINTS */
164 * The need for the DECLARE_TRACEPOINT_NOARGS() is to handle the prototype
165 * (void). "void" is a special value in a function prototype and can
166 * not be combined with other arguments. Since the DECLARE_TRACEPOINT()
167 * macro adds a data element at the beginning of the prototype,
168 * we need a way to differentiate "(void *data, proto)" from
169 * "(void *data, void)". The second prototype is invalid.
171 * DECLARE_TRACEPOINT_NOARGS() passes "void" as the tracepoint prototype
172 * and "void *__tp_cb_data" as the callback prototype.
174 * DECLARE_TRACEPOINT() passes "proto" as the tracepoint protoype and
175 * "void *__tp_cb_data, proto" as the callback prototype.
177 #define DECLARE_TRACEPOINT_NOARGS(name) \
178 __DECLARE_TRACEPOINT(name, void, , void *__tp_cb_data, __tp_cb_data)
180 #define DECLARE_TRACEPOINT(name, proto, args) \
181 __DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args),\
182 TP_PARAMS(void *__tp_cb_data, proto), \
183 TP_PARAMS(__tp_cb_data, args))
186 * Connect a probe to a tracepoint.
187 * Internal API, should not be used directly.
189 extern int tracepoint_probe_register(const char *name
, void *probe
, void *data
);
192 * Disconnect a probe from a tracepoint.
193 * Internal API, should not be used directly.
195 extern int tracepoint_probe_unregister(const char *name
, void *probe
, void *data
);
197 extern int tracepoint_probe_register_noupdate(const char *name
, void *probe
,
199 extern int tracepoint_probe_unregister_noupdate(const char *name
, void *probe
,
201 extern void tracepoint_probe_update_all(void);
203 struct tracepoint_iter
{
204 struct tracepoint_lib
*lib
;
205 struct tracepoint
* const *tracepoint
;
208 extern void tracepoint_iter_start(struct tracepoint_iter
*iter
);
209 extern void tracepoint_iter_next(struct tracepoint_iter
*iter
);
210 extern void tracepoint_iter_stop(struct tracepoint_iter
*iter
);
211 extern void tracepoint_iter_reset(struct tracepoint_iter
*iter
);
212 extern int tracepoint_get_iter_range(struct tracepoint
* const **tracepoint
,
213 struct tracepoint
* const *begin
, struct tracepoint
* const *end
);
216 * tracepoint_synchronize_unregister must be called between the last tracepoint
217 * probe unregistration and the end of module exit to make sure there is no
218 * caller executing a probe when it is freed.
220 static inline void tracepoint_synchronize_unregister(void)
222 //ust// synchronize_sched();
225 struct tracepoint_lib
{
226 struct tracepoint
* const *tracepoints_start
;
227 int tracepoints_count
;
228 struct cds_list_head list
;
231 extern int tracepoint_register_lib(struct tracepoint
* const *tracepoints_start
,
232 int tracepoints_count
);
233 extern int tracepoint_unregister_lib(struct tracepoint
* const *tracepoints_start
);
235 #define TRACEPOINT_LIB \
236 extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
237 extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
238 static struct tracepoint * __tracepoint_ptr_dummy \
239 __attribute__((used, section("__tracepoints_ptrs"))); \
240 static void __attribute__((constructor)) __tracepoints__init(void) \
242 tracepoint_register_lib(__start___tracepoints_ptrs, \
243 __stop___tracepoints_ptrs - \
244 __start___tracepoints_ptrs); \
247 static void __attribute__((destructor)) __tracepoints__destroy(void) \
249 tracepoint_unregister_lib(__start___tracepoints_ptrs); \
253 #ifndef TRACEPOINT_EVENT
255 * For use with the TRACEPOINT_EVENT macro:
257 * We define a tracepoint, its arguments, its printf format
258 * and its 'fast binary record' layout.
260 * Firstly, name your tracepoint via TRACEPOINT_EVENT(name : the
261 * 'subsystem_event' notation is fine.
263 * Think about this whole construct as the
264 * 'trace_sched_switch() function' from now on.
267 * TRACEPOINT_EVENT(sched_switch,
270 * * A function has a regular function arguments
271 * * prototype, declare it via TP_PROTO():
274 * TP_PROTO(struct rq *rq, struct task_struct *prev,
275 * struct task_struct *next),
278 * * Define the call signature of the 'function'.
279 * * (Design sidenote: we use this instead of a
280 * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
283 * TP_ARGS(rq, prev, next),
286 * * Fast binary tracing: define the trace record via
287 * * TP_STRUCT__entry(). You can think about it like a
288 * * regular C structure local variable definition.
290 * * This is how the trace record is structured and will
291 * * be saved into the ring buffer. These are the fields
292 * * that will be exposed to readers.
294 * * The declared 'local variable' is called '__entry'
296 * * __field(pid_t, prev_prid) is equivalent to a standard declariton:
300 * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
302 * * char prev_comm[TASK_COMM_LEN];
306 * __array( char, prev_comm, TASK_COMM_LEN )
307 * __field( pid_t, prev_pid )
308 * __field( int, prev_prio )
309 * __array( char, next_comm, TASK_COMM_LEN )
310 * __field( pid_t, next_pid )
311 * __field( int, next_prio )
315 * * Assign the entry into the trace record, by embedding
316 * * a full C statement block into TP_fast_assign(). You
317 * * can refer to the trace record as '__entry' -
318 * * otherwise you can put arbitrary C code in here.
320 * * Note: this C code will execute every time a trace event
321 * * happens, on an active tracepoint.
325 * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
326 * __entry->prev_pid = prev->pid;
327 * __entry->prev_prio = prev->prio;
328 * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
329 * __entry->next_pid = next->pid;
330 * __entry->next_prio = next->prio;
334 * * Formatted output of a trace record via TP_printf().
335 * * This is how the tracepoint will appear under debugging
338 * * (raw-binary tracing wont actually perform this step.)
341 * TP_printf("task %s:%d [%d] ==> %s:%d [%d]",
342 * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
343 * __entry->next_comm, __entry->next_pid, __entry->next_prio),
347 * This macro construct is thus used for the regular printf format
350 * A set of (un)registration functions can be passed to the variant
351 * TRACEPOINT_EVENT_FN to perform any (un)registration work.
356 int (*regfunc
)(void *data
);
357 int (*unregfunc
)(void *data
);
360 struct trace_event_lib
{
361 struct trace_event
* const *trace_events_start
;
362 int trace_events_count
;
363 struct cds_list_head list
;
366 struct trace_event_iter
{
367 struct trace_event_lib
*lib
;
368 struct trace_event
* const *trace_event
;
371 extern void lock_trace_events(void);
372 extern void unlock_trace_events(void);
374 extern void trace_event_iter_start(struct trace_event_iter
*iter
);
375 extern void trace_event_iter_next(struct trace_event_iter
*iter
);
376 extern void trace_event_iter_reset(struct trace_event_iter
*iter
);
378 extern int trace_event_get_iter_range(struct trace_event
* const **trace_event
,
379 struct trace_event
* const *begin
,
380 struct trace_event
* const *end
);
382 extern void trace_event_update_process(void);
383 extern int is_trace_event_enabled(const char *channel
, const char *name
);
385 extern int trace_event_register_lib(struct trace_event
* const *start_trace_events
,
386 int trace_event_count
);
388 extern int trace_event_unregister_lib(struct trace_event
* const *start_trace_events
);
390 #define TRACEPOINT_EVENT_LIB \
391 extern struct trace_event * const __start___trace_events_ptrs[] \
392 __attribute__((weak, visibility("hidden"))); \
393 extern struct trace_event * const __stop___trace_events_ptrs[] \
394 __attribute__((weak, visibility("hidden"))); \
395 static struct trace_event * __event_ptrs_dummy \
396 __attribute__((used, section("__trace_events_ptrs"))); \
397 static void __attribute__((constructor)) \
398 __trace_events__init(void) \
400 trace_event_register_lib(__start___trace_events_ptrs, \
401 __stop___trace_events_ptrs - \
402 __start___trace_events_ptrs); \
405 static void __attribute__((destructor)) \
406 __trace_event__destroy(void) \
408 trace_event_unregister_lib(__start___trace_events_ptrs);\
411 #define DECLARE_TRACEPOINT_EVENT_CLASS(name, proto, args, tstruct, assign, print)
412 #define DEFINE_TRACEPOINT_EVENT(template, name, proto, args) \
413 DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args))
414 #define DEFINE_TRACEPOINT_EVENT_PRINT(template, name, proto, args, print)\
415 DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args))
417 #define TRACEPOINT_EVENT(name, proto, args, struct, assign, print) \
418 DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args))
419 #define TRACEPOINT_EVENT_FN(name, proto, args, struct, \
420 assign, print, reg, unreg) \
421 DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args))
423 #endif /* ifdef TRACEPOINT_EVENT (see note above) */
426 #endif /* _UST_TRACEPOINT_H */
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