1 #ifndef _LTTNG_TRACEPOINT_H
2 #define _LTTNG_TRACEPOINT_H
5 * Copyright (C) 2008-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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.
27 #include <urcu/list.h>
28 #include <lttng/tracepoint-types.h>
35 * Tracepoints should be added to the instrumented code using the
36 * "tracepoint()" macro.
38 #define tracepoint(provider, name, args...) \
40 if (caa_unlikely(__tracepoint_##provider##___##name.state)) \
41 __trace_##provider##___##name(args); \
45 * it_func[0] is never NULL because there is at least one element in the array
46 * when the array itself is non NULL.
48 #define __DO_TRACE(tp, proto, vars) \
50 struct tracepoint_probe *__tp_it_probe_ptr; \
55 __tp_it_probe_ptr = rcu_dereference((tp)->probes); \
56 if (__tp_it_probe_ptr) { \
58 __tp_it_func = __tp_it_probe_ptr->func; \
59 __tp_cb_data = __tp_it_probe_ptr->data; \
60 URCU_FORCE_CAST(void(*)(proto), __tp_it_func)(vars); \
61 } while ((++__tp_it_probe_ptr)->func); \
66 #define TP_PARAMS(args...) args
67 #define TP_ARGS(args...) args
70 * TP_ARGS takes tuples of type, argument separated by a comma. It can
71 * take up to 10 tuples (which means that less than 10 tuples is fine
72 * too). Each tuple is also separated by a comma.
75 #define TP_COMBINE_TOKENS1(_tokena, _tokenb) _tokena##_tokenb
76 #define TP_COMBINE_TOKENS(_tokena, _tokenb) TP_COMBINE_TOKENS1(_tokena, _tokenb)
78 /* _TP_EVEN* extracts the vars names. */
79 /* 0 and 1 are for void */
82 #define _TP_EVEN2(a,b) b
83 #define _TP_EVEN4(a,b,c,d) b,d
84 #define _TP_EVEN6(a,b,c,d,e,f) b,d,f
85 #define _TP_EVEN8(a,b,c,d,e,f,g,h) b,d,f,h
86 #define _TP_EVEN10(a,b,c,d,e,f,g,h,i,j) b,d,f,h,j
87 #define _TP_EVEN12(a,b,c,d,e,f,g,h,i,j,k,l) b,d,f,h,j,l
88 #define _TP_EVEN14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) b,d,f,h,j,l,n
89 #define _TP_EVEN16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) b,d,f,h,j,l,n,p
90 #define _TP_EVEN18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r) b,d,f,h,j,l,n,p,r
91 #define _TP_EVEN20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t) b,d,f,h,j,l,n,p,r,t
93 /* 0 and 1 are for void */
94 #define _TP_EVEN_DATA0() __tp_cb_data
95 #define _TP_EVEN_DATA1(a) __tp_cb_data
96 #define _TP_EVEN_DATA2(a,b) __tp_cb_data,b
97 #define _TP_EVEN_DATA4(a,b,c,d) __tp_cb_data,b,d
98 #define _TP_EVEN_DATA6(a,b,c,d,e,f) __tp_cb_data,b,d,f
99 #define _TP_EVEN_DATA8(a,b,c,d,e,f,g,h) __tp_cb_data,b,d,f,h
100 #define _TP_EVEN_DATA10(a,b,c,d,e,f,g,h,i,j) __tp_cb_data,b,d,f,h,j
101 #define _TP_EVEN_DATA12(a,b,c,d,e,f,g,h,i,j,k,l) __tp_cb_data,b,d,f,h,j,l
102 #define _TP_EVEN_DATA14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) __tp_cb_data,b,d,f,h,j,l,n
103 #define _TP_EVEN_DATA16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) __tp_cb_data,b,d,f,h,j,l,n,p
104 #define _TP_EVEN_DATA18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r) __tp_cb_data,b,d,f,h,j,l,n,p,r
105 #define _TP_EVEN_DATA20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t) __tp_cb_data,b,d,f,h,j,l,n,p,r,t
107 /* _TP_SPLIT extracts tuples of type, var */
108 /* 0 and 1 are for void */
110 #define _TP_SPLIT1(a)
111 #define _TP_SPLIT2(a,b) a b
112 #define _TP_SPLIT4(a,b,c,d) a b,c d
113 #define _TP_SPLIT6(a,b,c,d,e,f) a b,c d,e f
114 #define _TP_SPLIT8(a,b,c,d,e,f,g,h) a b,c d,e f,g h
115 #define _TP_SPLIT10(a,b,c,d,e,f,g,h,i,j) a b,c d,e f,g h,i j
116 #define _TP_SPLIT12(a,b,c,d,e,f,g,h,i,j,k,l) a b,c d,e f,g h,i j,k l
117 #define _TP_SPLIT14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) a b,c d,e f,g h,i j,k l,m n
118 #define _TP_SPLIT16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) a b,c d,e f,g h,i j,k l,m n,o p
119 #define _TP_SPLIT18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r) a b,c d,e f,g h,i j,k l,m n,o p,q r
120 #define _TP_SPLIT20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t) a b,c d,e f,g h,i j,k l,m n,o p,q r,s t
122 /* 0 and 1 are for void */
123 #define _TP_SPLIT_DATA0() void *__tp_cb_data
124 #define _TP_SPLIT_DATA1(a) void *__tp_cb_data
125 #define _TP_SPLIT_DATA2(a,b) void *__tp_cb_data,a b
126 #define _TP_SPLIT_DATA4(a,b,c,d) void *__tp_cb_data,a b,c d
127 #define _TP_SPLIT_DATA6(a,b,c,d,e,f) void *__tp_cb_data,a b,c d,e f
128 #define _TP_SPLIT_DATA8(a,b,c,d,e,f,g,h) void *__tp_cb_data,a b,c d,e f,g h
129 #define _TP_SPLIT_DATA10(a,b,c,d,e,f,g,h,i,j) void *__tp_cb_data,a b,c d,e f,g h,i j
130 #define _TP_SPLIT_DATA12(a,b,c,d,e,f,g,h,i,j,k,l) void *__tp_cb_data,a b,c d,e f,g h,i j,k l
131 #define _TP_SPLIT_DATA14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) void *__tp_cb_data,a b,c d,e f,g h,i j,k l,m n
132 #define _TP_SPLIT_DATA16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) void *__tp_cb_data,a b,c d,e f,g h,i j,k l,m n,o p
133 #define _TP_SPLIT_DATA18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r) void *__tp_cb_data,a b,c d,e f,g h,i j,k l,m n,o p,q r
134 #define _TP_SPLIT_DATA20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t) void *__tp_cb_data,a b,c d,e f,g h,i j,k l,m n,o p,q r,s t
136 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
137 #define _TP_NARGS(...) __TP_NARGS(__VA_ARGS__, 20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0)
138 #define __TP_NARGS(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12,_13,_14,_15,_16,_17,_18,_19,_20, N, ...) N
139 #define _TP_PROTO_N(N, ...) \
140 TP_PARAMS(TP_COMBINE_TOKENS(_TP_SPLIT, N)(__VA_ARGS__))
141 #define _TP_VARS_N(N, ...) \
142 TP_PARAMS(TP_COMBINE_TOKENS(_TP_EVEN, N)(__VA_ARGS__))
143 #define _TP_PROTO_DATA_N(N, ...) \
144 TP_PARAMS(TP_COMBINE_TOKENS(_TP_SPLIT_DATA, N)(__VA_ARGS__))
145 #define _TP_VARS_DATA_N(N, ...) \
146 TP_PARAMS(TP_COMBINE_TOKENS(_TP_EVEN_DATA, N)(__VA_ARGS__))
148 #define _TP_ARGS_PROTO(...) _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
149 #define _TP_ARGS_VARS(...) _TP_VARS_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
151 #define _TP_ARGS_PROTO_DATA(...) _TP_PROTO_DATA_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
152 #define _TP_ARGS_VARS_DATA(...) _TP_VARS_DATA_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
155 * Make sure the alignment of the structure in the __tracepoints section will
156 * not add unwanted padding between the beginning of the section and the
157 * structure. Force alignment to the same alignment as the section start.
159 #define __DECLARE_TRACEPOINT(provider, name, proto, args, data_proto, data_args) \
160 extern struct tracepoint __tracepoint_##provider##___##name; \
161 static inline void __trace_##provider##___##name(proto) \
163 __DO_TRACE(&__tracepoint_##provider##___##name, \
164 TP_PARAMS(data_proto), TP_PARAMS(data_args)); \
167 __register_trace_##provider##___##name(void (*probe)(data_proto), void *data) \
169 return __tracepoint_probe_register(#provider ":" #name, (void *) probe, \
173 __unregister_trace_##provider##___##name(void (*probe)(data_proto), void *data) \
175 return __tracepoint_probe_unregister(#provider ":" #name, (void *) probe, \
179 #define _DECLARE_TRACEPOINT(provider, name, args) \
180 __DECLARE_TRACEPOINT(provider, name, _TP_ARGS_PROTO(args), _TP_ARGS_VARS(args), \
181 _TP_ARGS_PROTO_DATA(args), _TP_ARGS_VARS_DATA(args))
184 * __tracepoints_ptrs section is not const (read-only) to let the linker update
185 * the pointer, allowing PIC code.
187 #define _DEFINE_TRACEPOINT(provider, name) \
188 static const char __tpstrtab_##provider##___##name[] \
189 __attribute__((section("__tracepoints_strings"))) = \
190 #provider ":" #name; \
191 struct tracepoint __tracepoint_##provider##___##name \
192 __attribute__((section("__tracepoints"))) = \
193 { __tpstrtab_##provider##___##name, 0, NULL }; \
194 static struct tracepoint * __tracepoint_ptr_##provider##___##name \
195 __attribute__((used, section("__tracepoints_ptrs"))) = \
196 &__tracepoint_##provider##___##name;
199 #define __register_tracepoint(provider, name, probe, data) \
200 __register_trace_##provider##___##name(probe, data)
201 #define __unregister_tracepoint(provider, name, probe, data) \
202 __unregister_trace_##provider##___##name(probe, data)
205 * Connect a probe to a tracepoint.
209 int __tracepoint_probe_register(const char *name
, void *probe
, void *data
);
212 * Disconnect a probe from a tracepoint.
216 int __tracepoint_probe_unregister(const char *name
, void *probe
, void *data
);
219 int tracepoint_register_lib(struct tracepoint
* const *tracepoints_start
,
220 int tracepoints_count
);
222 int tracepoint_unregister_lib(struct tracepoint
* const *tracepoints_start
);
225 * These weak symbols, the constructor, and destructor take care of
226 * registering only _one_ instance of the tracepoints per shared-ojbect
227 * (or for the whole main program).
229 extern struct tracepoint
* const __start___tracepoints_ptrs
[]
230 __attribute__((weak
, visibility("hidden")));
231 extern struct tracepoint
* const __stop___tracepoints_ptrs
[]
232 __attribute__((weak
, visibility("hidden")));
233 int __tracepoint_registered
234 __attribute__((weak
, visibility("hidden")));
236 static void __attribute__((constructor
)) __tracepoints__init(void)
238 if (__tracepoint_registered
++)
240 tracepoint_register_lib(__start___tracepoints_ptrs
,
241 __stop___tracepoints_ptrs
-
242 __start___tracepoints_ptrs
);
245 static void __attribute__((destructor
)) __tracepoints__destroy(void)
247 if (--__tracepoint_registered
)
249 tracepoint_unregister_lib(__start___tracepoints_ptrs
);
256 #endif /* _LTTNG_TRACEPOINT_H */
259 * For multiple probe generation, we need to redefine TRACEPOINT_EVENT
260 * each time tracepoint.h is included.
263 #ifndef TRACEPOINT_EVENT
265 * Usage of the TRACEPOINT_EVENT macro:
267 * In short, an example:
269 * TRACEPOINT_EVENT(< [com_company_]project[_component] >, < event >,
271 * * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
273 * TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
274 * long *, arg4, size_t, arg4_len),
277 * * Integer, printed in base 10 *
278 * ctf_integer(int, field_a, arg0)
280 * * Integer, printed with 0x base 16 *
281 * ctf_integer_hex(unsigned long, field_d, arg1)
283 * * Array Sequence, printed as UTF8-encoded array of bytes *
284 * ctf_array_text(char, field_b, string, FIXED_LEN)
285 * ctf_sequence_text(char, field_c, string, size_t, strlen)
287 * * String, printed as UTF8-encoded string *
288 * ctf_string(field_e, string)
290 * * Array sequence of signed integer values *
291 * ctf_array(long, field_f, arg4, FIXED_LEN4)
292 * ctf_sequence(long, field_g, arg4, size_t, arg4_len)
298 * We define a tracepoint, its arguments, and its 'fast binary record'
301 * Firstly, name your tracepoint via TRACEPOINT_EVENT(provider, name,
303 * The provider and name should be a proper C99 identifier.
304 * The "provider" and "name" MUST follow these rules to ensure no
305 * namespace clash occurs:
307 * For projects (applications and libraries) for which an entity
308 * specific to the project controls the source code and thus its
309 * tracepoints (typically with a scope larger than a single company):
312 * project_component, event
316 * Where "project" is the name of the project,
317 * "component" is the name of the project component (which may
318 * include several levels of sub-components, e.g.
319 * ...component_subcomponent_...) where the tracepoint is located
321 * "event" is the name of the tracepoint event.
323 * For projects issued from a single company wishing to advertise that
324 * the company controls the source code and thus the tracepoints, the
325 * "com_" prefix should be used:
328 * com_company_project_component, event
330 * com_company_project, event
332 * Where "company" is the name of the company,
333 * "project" is the name of the project,
334 * "component" is the name of the project component (which may
335 * include several levels of sub-components, e.g.
336 * ...component_subcomponent_...) where the tracepoint is located
338 * "event" is the name of the tracepoint event.
340 * the provider:event identifier is limited to 127 characters.
342 * As an example, let's consider a user-space application "someproject"
343 * that would have an internal thread scheduler:
345 * TRACEPOINT_EVENT(someproject_sched, switch,
348 * * Arguments to pass to the tracepoint. Supports from
349 * * 0 to 10 "type, name" tuples.
352 * TP_ARGS(struct rq *, rq, struct task_struct *, prev,
353 * struct task_struct *, next),
356 * * Fast binary tracing: define the trace record via
357 * * TP_FIELDS(). You can think about it like a
358 * * regular C structure local variable definition.
360 * * This is how the trace record is structured and will
361 * * be saved into the ring buffer. These are the fields
362 * * that will be exposed to readers.
364 * * ctf_integer(pid_t, prev_pid, prev->pid) is equivalent
365 * * to a standard declaraton:
369 * * followed by an assignment:
371 * * prev_pid = prev->pid;
373 * * ctf_array(char, prev_comm, prev->comm, TASK_COMM_LEN) is
376 * * char prev_comm[TASK_COMM_LEN];
378 * * followed by an assignment:
380 * * memcpy(prev_comm, prev->comm, TASK_COMM_LEN);
384 * ctf_array(char, prev_comm, prev->comm, TASK_COMM_LEN)
385 * ctf_integer(pid_t, prev_pid, prev->pid)
386 * ctf_integer(int, prev_prio, prev->prio)
387 * ctf_array(char, next_comm, next->comm, TASK_COMM_LEN)
388 * ctf_integer(pid_t, next_pid, next->pid)
389 * ctf_integer(int, next_prio, next->prio)
393 * Do _NOT_ add comma (,) nor semicolon (;) after the TRACEPOINT_EVENT
396 * The TRACEPOINT_PROVIDER must be defined when declaring a
397 * TRACEPOINT_EVENT. See ust/tracepoint-event.h for information about
398 * usage of other macros controlling TRACEPOINT_EVENT.
401 #define TRACEPOINT_EVENT(provider, name, args, fields) \
402 _DECLARE_TRACEPOINT(provider, name, TP_PARAMS(args))
404 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
405 #define TRACEPOINT_EVENT_INSTANCE(provider, template, name, args)\
406 _DECLARE_TRACEPOINT(provider, name, TP_PARAMS(args))
408 #endif /* #ifndef TRACEPOINT_EVENT */
410 #ifndef TRACEPOINT_LOGLEVEL
413 * Tracepoint Loglevel Declaration Facility
415 * This is a place-holder the tracepoint loglevel declaration,
416 * overridden by the tracer implementation.
418 * Typical use of these loglevels:
420 * 1) Declare the mapping between loglevel names and an integer values
421 * within TRACEPOINT_LOGLEVEL_ENUM, using TP_LOGLEVEL for each tuple.
422 * Do _NOT_ add comma (,) nor semicolon (;) between the
423 * TRACEPOINT_LOGLEVEL_ENUM entries. Do _NOT_ add comma (,) nor
424 * semicolon (;) after the TRACEPOINT_LOGLEVEL_ENUM declaration. The
425 * name should be a proper C99 identifier.
427 * TRACEPOINT_LOGLEVEL_ENUM(
428 * TP_LOGLEVEL( < loglevel_name >, < value > )
429 * TP_LOGLEVEL( < loglevel_name >, < value > )
435 * TRACEPOINT_LOGLEVEL_ENUM(
436 * TP_LOGLEVEL(LOG_EMERG, 0)
437 * TP_LOGLEVEL(LOG_ALERT, 1)
438 * TP_LOGLEVEL(LOG_CRIT, 2)
439 * TP_LOGLEVEL(LOG_ERR, 3)
440 * TP_LOGLEVEL(LOG_WARNING, 4)
441 * TP_LOGLEVEL(LOG_NOTICE, 5)
442 * TP_LOGLEVEL(LOG_INFO, 6)
443 * TP_LOGLEVEL(LOG_DEBUG, 7)
446 * 2) Then, declare tracepoint loglevels for tracepoints. A
447 * TRACEPOINT_EVENT should be declared prior to the the
448 * TRACEPOINT_LOGLEVEL for a given tracepoint name. The first field
449 * is the name of the tracepoint, the second field is the loglevel
452 * TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
455 * The TRACEPOINT_PROVIDER must be defined when declaring a
456 * TRACEPOINT_LOGLEVEL_ENUM and TRACEPOINT_LOGLEVEL. The tracepoint
457 * loglevel enumeration apply to the entire TRACEPOINT_PROVIDER. Only one
458 * tracepoint loglevel enumeration should be declared per tracepoint
462 #define TRACEPOINT_LOGLEVEL_ENUM()
463 #define TRACEPOINT_LOGLEVEL(name, loglevel)
465 #endif /* #ifndef TRACEPOINT_LOGLEVEL */