ade567726e9c4cffeffc5e0c39d61a8b66927a35
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.
29 #include <urcu/list.h>
30 #include <urcu/compiler.h>
32 struct tracepoint_probe
{
38 const char *name
; /* Tracepoint name */
39 char state
; /* State. */
40 struct tracepoint_probe
*probes
;
44 * Tracepoints should be added to the instrumented code using the
45 * "tracepoint()" macro.
47 #define tracepoint(name, args...) __trace_##name(args)
50 * Library should be made known to libust by declaring TRACEPOINT_LIB in
51 * the source file. (Usually at the end of the file, in the outermost
54 #define TRACEPOINT_LIB \
55 extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
56 extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
57 static struct tracepoint * __tracepoint_ptr_dummy \
58 __attribute__((used, section("__tracepoints_ptrs"))); \
59 static void __attribute__((constructor)) __tracepoints__init(void) \
61 tracepoint_register_lib(__start___tracepoints_ptrs, \
62 __stop___tracepoints_ptrs - \
63 __start___tracepoints_ptrs); \
66 static void __attribute__((destructor)) __tracepoints__destroy(void) \
68 tracepoint_unregister_lib(__start___tracepoints_ptrs); \
72 * it_func[0] is never NULL because there is at least one element in the array
73 * when the array itself is non NULL.
74 * __attribute__((unused)) is for backward compatibility API.
76 #define __DO_TRACE(tp, proto, args) \
78 struct tracepoint_probe *__tp_it_probe_ptr; \
80 void *__tp_cb_data __attribute__((unused)); \
83 __tp_it_probe_ptr = rcu_dereference((tp)->probes); \
84 if (__tp_it_probe_ptr) { \
86 __tp_it_func = __tp_it_probe_ptr->func; \
87 __tp_cb_data = __tp_it_probe_ptr->data; \
88 ((void(*)(proto))__tp_it_func)(args); \
89 } while ((++__tp_it_probe_ptr)->func); \
94 #define TP_PARAMS(args...) args
95 #define TP_PROTO(args...) args
96 #define TP_ARGS(args...) args
98 #define __CHECK_TRACE(name, proto, args) \
100 if (caa_unlikely(__tracepoint_##name.state)) \
101 __DO_TRACE(&__tracepoint_##name, \
102 TP_PROTO(proto), TP_ARGS(args)); \
106 * Make sure the alignment of the structure in the __tracepoints section will
107 * not add unwanted padding between the beginning of the section and the
108 * structure. Force alignment to the same alignment as the section start.
110 #define __DECLARE_TRACEPOINT(name, proto, args, data_proto, data_args) \
111 extern struct tracepoint __tracepoint_##name; \
112 static inline void __trace_##name(proto) \
114 __CHECK_TRACE(name, TP_PROTO(data_proto), \
115 TP_ARGS(data_args)); \
118 __register_trace_##name(void (*probe)(data_proto), void *data) \
120 return __tracepoint_probe_register(#name, (void *)probe,\
125 __unregister_trace_##name(void (*probe)(data_proto), void *data)\
127 return __tracepoint_probe_unregister(#name, (void *)probe, \
131 * Backward-compatibility API (will be deprecated): \
134 * unregister_trace_* \
136 static inline void trace_##name(proto) \
138 __CHECK_TRACE(name, TP_PROTO(proto), \
142 register_trace_##name(void (*probe)(proto)) \
144 return __tracepoint_probe_register(#name, (void *)probe,\
148 unregister_trace_##name(void (*probe)(proto)) \
150 return __tracepoint_probe_unregister(#name, (void *)probe, \
155 * The need for the _DECLARE_TRACEPOINT_NOARGS() is to handle the prototype
156 * (void). "void" is a special value in a function prototype and can
157 * not be combined with other arguments. Since the DECLARE_TRACEPOINT()
158 * macro adds a data element at the beginning of the prototype,
159 * we need a way to differentiate "(void *data, proto)" from
160 * "(void *data, void)". The second prototype is invalid.
162 * DECLARE_TRACEPOINT_NOARGS() passes "void" as the tracepoint prototype
163 * and "void *__tp_cb_data" as the callback prototype.
165 * DECLARE_TRACEPOINT() passes "proto" as the tracepoint protoype and
166 * "void *__tp_cb_data, proto" as the callback prototype.
168 #define _DECLARE_TRACEPOINT_NOARGS(name) \
169 __DECLARE_TRACEPOINT(name, void, , void *__tp_cb_data, __tp_cb_data)
171 #define _DECLARE_TRACEPOINT(name, proto, args) \
172 __DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args), \
173 TP_PARAMS(void *__tp_cb_data, proto), \
174 TP_PARAMS(__tp_cb_data, args))
177 * __tracepoints_ptrs section is not const (read-only) to let the linker update
178 * the pointer, allowing PIC code.
180 #define _DEFINE_TRACEPOINT(name) \
181 static const char __tpstrtab_##name[] \
182 __attribute__((section("__tracepoints_strings"))) = #name; \
183 struct tracepoint __tracepoint_##name \
184 __attribute__((section("__tracepoints"))) = \
185 { __tpstrtab_##name, 0, NULL }; \
186 static struct tracepoint * __tracepoint_ptr_##name \
187 __attribute__((used, section("__tracepoints_ptrs"))) = \
188 &__tracepoint_##name;
191 #define __register_tracepoint(name, probe, data) \
192 __register_trace_##name(probe, data)
193 #define __unregister_tracepoint(name, probe, data) \
194 __unregister_trace_##name(probe, data)
197 * Connect a probe to a tracepoint.
201 int __tracepoint_probe_register(const char *name
, void *probe
, void *data
);
204 * Disconnect a probe from a tracepoint.
208 int __tracepoint_probe_unregister(const char *name
, void *probe
, void *data
);
210 struct tracepoint_lib
{
211 struct tracepoint
* const *tracepoints_start
;
212 int tracepoints_count
;
213 struct cds_list_head list
;
217 int tracepoint_register_lib(struct tracepoint
* const *tracepoints_start
,
218 int tracepoints_count
);
220 int tracepoint_unregister_lib(struct tracepoint
* const *tracepoints_start
);
223 * Backward-compatibility API (will be deprecated):
226 * register_tracepoint
227 * unregister_tracepoint
229 #define DEFINE_TRACE _DEFINE_TRACEPOINT
230 #define DECLARE_TRACE(name, proto, args) \
231 _DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args))
233 #ifndef TRACEPOINT_EVENT
235 * For use with the TRACEPOINT_EVENT macro:
237 * We define a tracepoint, its arguments, its printf format
238 * and its 'fast binary record' layout.
240 * Firstly, name your tracepoint via TRACEPOINT_EVENT(name : the
241 * 'subsystem_event' notation is fine.
243 * Think about this whole construct as the
244 * 'trace_sched_switch() function' from now on.
247 * TRACEPOINT_EVENT(sched_switch,
250 * * A function has a regular function arguments
251 * * prototype, declare it via TP_PROTO():
254 * TP_PROTO(struct rq *rq, struct task_struct *prev,
255 * struct task_struct *next),
258 * * Define the call signature of the 'function'.
259 * * (Design sidenote: we use this instead of a
260 * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
263 * TP_ARGS(rq, prev, next),
266 * * Fast binary tracing: define the trace record via
267 * * TP_FIELDS(). You can think about it like a
268 * * regular C structure local variable definition.
270 * * This is how the trace record is structured and will
271 * * be saved into the ring buffer. These are the fields
272 * * that will be exposed to readers.
274 * * tp_field(pid_t, prev_pid, prev->pid) is equivalent
275 * * to a standard declaraton:
279 * * followed by an assignment:
281 * * prev_pid = prev->pid;
283 * * tp_array(char, prev_comm, TASK_COMM_LEN, prev->comm) is
286 * * char prev_comm[TASK_COMM_LEN];
288 * * followed by an assignment:
290 * * memcpy(prev_comm, prev->comm, TASK_COMM_LEN);
294 * tp_array(char, prev_comm, TASK_COMM_LEN, prev->comm)
295 * tp_field(pid_t, prev_pid, prev->pid)
296 * tp_field(int, prev_prio, prev->prio)
297 * tp_array(char, next_comm, TASK_COMM_LEN, next->comm)
298 * tp_field(pid_t, next_pid, next->pid)
299 * tp_field(int, next_prio, next->prio)
304 #define TRACEPOINT_EVENT(name, proto, args, fields) \
305 _DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args))
307 #define TRACEPOINT_EVENT_CLASS(name, proto, args, fields)
308 #define TRACEPOINT_EVENT_INSTANCE(template, name, proto, args) \
309 _DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args))
312 * Declaration of tracepoints that take 0 argument.
314 #define TRACEPOINT_EVENT_NOARGS(name, fields) \
315 _DECLARE_TRACEPOINT_NOARGS(name)
317 #define TRACEPOINT_EVENT_CLASS_NOARGS(name, fields)
318 #define TRACEPOINT_EVENT_INSTANCE_NOARGS(template, name) \
319 _DECLARE_TRACEPOINT_NOARGS(name)
323 #define TRACEPOINT_EVENT_LIB \
324 extern struct trace_event * const __start___trace_events_ptrs[] \
325 __attribute__((weak, visibility("hidden"))); \
326 extern struct trace_event * const __stop___trace_events_ptrs[] \
327 __attribute__((weak, visibility("hidden"))); \
328 static struct trace_event * __event_ptrs_dummy \
329 __attribute__((used, section("__trace_events_ptrs"))); \
330 static void __attribute__((constructor)) \
331 __trace_events__init(void) \
333 trace_event_register_lib(__start___trace_events_ptrs, \
334 __stop___trace_events_ptrs - \
335 __start___trace_events_ptrs); \
338 static void __attribute__((destructor)) \
339 __trace_event__destroy(void) \
341 trace_event_unregister_lib(__start___trace_events_ptrs);\
348 struct trace_event_lib
{
349 struct trace_event
* const *trace_events_start
;
350 int trace_events_count
;
351 struct cds_list_head list
;
355 int trace_event_register_lib(struct trace_event
* const *start_trace_events
,
356 int trace_event_count
);
358 int trace_event_unregister_lib(struct trace_event
* const *start_trace_events
);
360 #endif /* #ifndef TRACEPOINT_EVENT */
362 #endif /* _UST_TRACEPOINT_H */
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