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...) \
39 __trace_##provider##___##name(args)
42 * it_func[0] is never NULL because there is at least one element in the array
43 * when the array itself is non NULL.
45 #define __DO_TRACE(tp, proto, vars) \
47 struct tracepoint_probe *__tp_it_probe_ptr; \
52 __tp_it_probe_ptr = rcu_dereference((tp)->probes); \
53 if (__tp_it_probe_ptr) { \
55 __tp_it_func = __tp_it_probe_ptr->func; \
56 __tp_cb_data = __tp_it_probe_ptr->data; \
57 URCU_FORCE_CAST(void(*)(proto), __tp_it_func)(vars); \
58 } while ((++__tp_it_probe_ptr)->func); \
63 #define TP_PARAMS(args...) args
64 #define TP_ARGS(args...) args
67 * TP_ARGS takes tuples of type, argument separated by a comma. It can
68 * take up to 10 tuples (which means that less than 10 tuples is fine
69 * too). Each tuple is also separated by a comma.
72 #define TP_COMBINE_TOKENS1(_tokena, _tokenb) _tokena##_tokenb
73 #define TP_COMBINE_TOKENS(_tokena, _tokenb) TP_COMBINE_TOKENS1(_tokena, _tokenb)
75 /* _TP_EVEN* extracts the vars names. */
77 #define _TP_EVEN2(a,b) b
78 #define _TP_EVEN4(a,b,c,d) b,d
79 #define _TP_EVEN6(a,b,c,d,e,f) b,d,f
80 #define _TP_EVEN8(a,b,c,d,e,f,g,h) b,d,f,h
81 #define _TP_EVEN10(a,b,c,d,e,f,g,h,i,j) b,d,f,h,j
82 #define _TP_EVEN12(a,b,c,d,e,f,g,h,i,j,k,l) b,d,f,h,j,l
83 #define _TP_EVEN14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) b,d,f,h,j,l,n
84 #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
85 #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
86 #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
88 #define _TP_EVEN_DATA0() __tp_cb_data
89 #define _TP_EVEN_DATA2(a,b) __tp_cb_data,b
90 #define _TP_EVEN_DATA4(a,b,c,d) __tp_cb_data,b,d
91 #define _TP_EVEN_DATA6(a,b,c,d,e,f) __tp_cb_data,b,d,f
92 #define _TP_EVEN_DATA8(a,b,c,d,e,f,g,h) __tp_cb_data,b,d,f,h
93 #define _TP_EVEN_DATA10(a,b,c,d,e,f,g,h,i,j) __tp_cb_data,b,d,f,h,j
94 #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
95 #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
96 #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
97 #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
98 #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
100 /* _TP_SPLIT extracts tuples of type, var */
102 #define _TP_SPLIT2(a,b) a b
103 #define _TP_SPLIT4(a,b,c,d) a b,c d
104 #define _TP_SPLIT6(a,b,c,d,e,f) a b,c d,e f
105 #define _TP_SPLIT8(a,b,c,d,e,f,g,h) a b,c d,e f,g h
106 #define _TP_SPLIT10(a,b,c,d,e,f,g,h,i,j) a b,c d,e f,g h,i j
107 #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
108 #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
109 #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
110 #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
111 #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
113 #define _TP_SPLIT_DATA0() void *__tp_cb_data
114 #define _TP_SPLIT_DATA2(a,b) void *__tp_cb_data,a b
115 #define _TP_SPLIT_DATA4(a,b,c,d) void *__tp_cb_data,a b,c d
116 #define _TP_SPLIT_DATA6(a,b,c,d,e,f) void *__tp_cb_data,a b,c d,e f
117 #define _TP_SPLIT_DATA8(a,b,c,d,e,f,g,h) void *__tp_cb_data,a b,c d,e f,g h
118 #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
119 #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
120 #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
121 #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
122 #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
123 #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
125 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
126 #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)
127 #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
128 #define _TP_PROTO_N(N, ...) \
129 TP_PARAMS(TP_COMBINE_TOKENS(_TP_SPLIT, N)(__VA_ARGS__))
130 #define _TP_VARS_N(N, ...) \
131 TP_PARAMS(TP_COMBINE_TOKENS(_TP_EVEN, N)(__VA_ARGS__))
132 #define _TP_PROTO_DATA_N(N, ...) \
133 TP_PARAMS(TP_COMBINE_TOKENS(_TP_SPLIT_DATA, N)(__VA_ARGS__))
134 #define _TP_VARS_DATA_N(N, ...) \
135 TP_PARAMS(TP_COMBINE_TOKENS(_TP_EVEN_DATA, N)(__VA_ARGS__))
137 #define _TP_ARGS_PROTO(...) _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
138 #define _TP_ARGS_VARS(...) _TP_VARS_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
140 #define _TP_ARGS_PROTO_DATA(...) _TP_PROTO_DATA_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
141 #define _TP_ARGS_VARS_DATA(...) _TP_VARS_DATA_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
143 #define __CHECK_TRACE(provider, name, proto, args) \
145 if (caa_unlikely(__tracepoint_##provider##___##name.state)) \
146 __DO_TRACE(&__tracepoint_##provider##___##name, \
147 TP_PARAMS(proto), TP_PARAMS(args)); \
151 * Make sure the alignment of the structure in the __tracepoints section will
152 * not add unwanted padding between the beginning of the section and the
153 * structure. Force alignment to the same alignment as the section start.
155 #define __DECLARE_TRACEPOINT(provider, name, proto, args, data_proto, data_args) \
156 extern struct tracepoint __tracepoint_##provider##___##name; \
157 static inline void __trace_##provider##___##name(proto) \
159 __CHECK_TRACE(provider, name, TP_PARAMS(data_proto), \
160 TP_PARAMS(data_args)); \
163 __register_trace_##provider##___##name(void (*probe)(data_proto), void *data) \
165 return __tracepoint_probe_register(#provider ":" #name, (void *) probe, \
169 __unregister_trace_##provider##___##name(void (*probe)(data_proto), void *data) \
171 return __tracepoint_probe_unregister(#provider ":" #name, (void *) probe, \
175 #define _DECLARE_TRACEPOINT(provider, name, args) \
176 __DECLARE_TRACEPOINT(provider, name, _TP_ARGS_PROTO(args), _TP_ARGS_VARS(args), \
177 _TP_ARGS_PROTO_DATA(args), _TP_ARGS_VARS_DATA(args))
180 * __tracepoints_ptrs section is not const (read-only) to let the linker update
181 * the pointer, allowing PIC code.
183 #define _DEFINE_TRACEPOINT(provider, name) \
184 static const char __tpstrtab_##provider##___##name[] \
185 __attribute__((section("__tracepoints_strings"))) = \
186 #provider ":" #name; \
187 struct tracepoint __tracepoint_##provider##___##name \
188 __attribute__((section("__tracepoints"))) = \
189 { __tpstrtab_##provider##___##name, 0, NULL }; \
190 static struct tracepoint * __tracepoint_ptr_##provider##___##name \
191 __attribute__((used, section("__tracepoints_ptrs"))) = \
192 &__tracepoint_##provider##___##name;
195 #define __register_tracepoint(provider, name, probe, data) \
196 __register_trace_##provider##___##name(probe, data)
197 #define __unregister_tracepoint(provider, name, probe, data) \
198 __unregister_trace_##provider##___##name(probe, data)
201 * Connect a probe to a tracepoint.
205 int __tracepoint_probe_register(const char *name
, void *probe
, void *data
);
208 * Disconnect a probe from a tracepoint.
212 int __tracepoint_probe_unregister(const char *name
, void *probe
, void *data
);
215 int tracepoint_register_lib(struct tracepoint
* const *tracepoints_start
,
216 int tracepoints_count
);
218 int tracepoint_unregister_lib(struct tracepoint
* const *tracepoints_start
);
221 * These weak symbols, the constructor, and destructor take care of
222 * registering only _one_ instance of the tracepoints per shared-ojbect
223 * (or for the whole main program).
225 extern struct tracepoint
* const __start___tracepoints_ptrs
[]
226 __attribute__((weak
, visibility("hidden")));
227 extern struct tracepoint
* const __stop___tracepoints_ptrs
[]
228 __attribute__((weak
, visibility("hidden")));
229 int __tracepoint_registered
230 __attribute__((weak
, visibility("hidden")));
232 static void __attribute__((constructor
)) __tracepoints__init(void)
234 if (__tracepoint_registered
++)
236 tracepoint_register_lib(__start___tracepoints_ptrs
,
237 __stop___tracepoints_ptrs
-
238 __start___tracepoints_ptrs
);
241 static void __attribute__((destructor
)) __tracepoints__destroy(void)
243 if (--__tracepoint_registered
)
245 tracepoint_unregister_lib(__start___tracepoints_ptrs
);
252 #endif /* _LTTNG_TRACEPOINT_H */
255 * For multiple probe generation, we need to redefine TRACEPOINT_EVENT
256 * each time tracepoint.h is included.
259 #ifndef TRACEPOINT_EVENT
261 * Usage of the TRACEPOINT_EVENT macro:
263 * In short, an example:
265 * TRACEPOINT_EVENT(< [com_company_]project[_component] >, < event >,
267 * * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
269 * TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
270 * long *, arg4, size_t, arg4_len),
273 * * Integer, printed in base 10 *
274 * ctf_integer(int, field_a, arg0)
276 * * Integer, printed with 0x base 16 *
277 * ctf_integer_hex(unsigned long, field_d, arg1)
279 * * Array Sequence, printed as UTF8-encoded array of bytes *
280 * ctf_array_text(char, field_b, string, FIXED_LEN)
281 * ctf_sequence_text(char, field_c, string, size_t, strlen)
283 * * String, printed as UTF8-encoded string *
284 * ctf_string(field_e, string)
286 * * Array sequence of signed integer values *
287 * ctf_array(long, field_f, arg4, FIXED_LEN4)
288 * ctf_sequence(long, field_g, arg4, size_t, arg4_len)
294 * We define a tracepoint, its arguments, and its 'fast binary record'
297 * Firstly, name your tracepoint via TRACEPOINT_EVENT(provider, name,
299 * The provider and name should be a proper C99 identifier.
300 * The "provider" and "name" MUST follow these rules to ensure no
301 * namespace clash occurs:
303 * For projects (applications and libraries) for which an entity
304 * specific to the project controls the source code and thus its
305 * tracepoints (typically with a scope larger than a single company):
308 * project_component, event
312 * Where "project" is the name of the project,
313 * "component" is the name of the project component (which may
314 * include several levels of sub-components, e.g.
315 * ...component_subcomponent_...) where the tracepoint is located
317 * "event" is the name of the tracepoint event.
319 * For projects issued from a single company wishing to advertise that
320 * the company controls the source code and thus the tracepoints, the
321 * "com_" prefix should be used:
324 * com_company_project_component, event
326 * com_company_project, event
328 * Where "company" is the name of the company,
329 * "project" is the name of the project,
330 * "component" is the name of the project component (which may
331 * include several levels of sub-components, e.g.
332 * ...component_subcomponent_...) where the tracepoint is located
334 * "event" is the name of the tracepoint event.
336 * the provider:event identifier is limited to 127 characters.
338 * As an example, let's consider a user-space application "someproject"
339 * that would have an internal thread scheduler:
341 * TRACEPOINT_EVENT(someproject_sched, switch,
344 * * Arguments to pass to the tracepoint. Supports from
345 * * 0 to 10 "type, name" tuples.
348 * TP_ARGS(struct rq *, rq, struct task_struct *, prev,
349 * struct task_struct *, next),
352 * * Fast binary tracing: define the trace record via
353 * * TP_FIELDS(). You can think about it like a
354 * * regular C structure local variable definition.
356 * * This is how the trace record is structured and will
357 * * be saved into the ring buffer. These are the fields
358 * * that will be exposed to readers.
360 * * ctf_integer(pid_t, prev_pid, prev->pid) is equivalent
361 * * to a standard declaraton:
365 * * followed by an assignment:
367 * * prev_pid = prev->pid;
369 * * ctf_array(char, prev_comm, prev->comm, TASK_COMM_LEN) is
372 * * char prev_comm[TASK_COMM_LEN];
374 * * followed by an assignment:
376 * * memcpy(prev_comm, prev->comm, TASK_COMM_LEN);
380 * ctf_array(char, prev_comm, prev->comm, TASK_COMM_LEN)
381 * ctf_integer(pid_t, prev_pid, prev->pid)
382 * ctf_integer(int, prev_prio, prev->prio)
383 * ctf_array(char, next_comm, next->comm, TASK_COMM_LEN)
384 * ctf_integer(pid_t, next_pid, next->pid)
385 * ctf_integer(int, next_prio, next->prio)
389 * Do _NOT_ add comma (,) nor semicolon (;) after the TRACEPOINT_EVENT
392 * The TRACEPOINT_PROVIDER must be defined when declaring a
393 * TRACEPOINT_EVENT. See ust/tracepoint-event.h for information about
394 * usage of other macros controlling TRACEPOINT_EVENT.
397 #define TRACEPOINT_EVENT(provider, name, args, fields) \
398 _DECLARE_TRACEPOINT(provider, name, TP_PARAMS(args))
400 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
401 #define TRACEPOINT_EVENT_INSTANCE(provider, template, name, args)\
402 _DECLARE_TRACEPOINT(provider, name, TP_PARAMS(args))
404 #endif /* #ifndef TRACEPOINT_EVENT */
406 #ifndef TRACEPOINT_LOGLEVEL
409 * Tracepoint Loglevel Declaration Facility
411 * This is a place-holder the tracepoint loglevel declaration,
412 * overridden by the tracer implementation.
414 * Typical use of these loglevels:
416 * 1) Declare the mapping between loglevel names and an integer values
417 * within TRACEPOINT_LOGLEVEL_ENUM, using TP_LOGLEVEL for each tuple.
418 * Do _NOT_ add comma (,) nor semicolon (;) between the
419 * TRACEPOINT_LOGLEVEL_ENUM entries. Do _NOT_ add comma (,) nor
420 * semicolon (;) after the TRACEPOINT_LOGLEVEL_ENUM declaration. The
421 * name should be a proper C99 identifier.
423 * TRACEPOINT_LOGLEVEL_ENUM(
424 * TP_LOGLEVEL( < loglevel_name >, < value > )
425 * TP_LOGLEVEL( < loglevel_name >, < value > )
431 * TRACEPOINT_LOGLEVEL_ENUM(
432 * TP_LOGLEVEL(LOG_EMERG, 0)
433 * TP_LOGLEVEL(LOG_ALERT, 1)
434 * TP_LOGLEVEL(LOG_CRIT, 2)
435 * TP_LOGLEVEL(LOG_ERR, 3)
436 * TP_LOGLEVEL(LOG_WARNING, 4)
437 * TP_LOGLEVEL(LOG_NOTICE, 5)
438 * TP_LOGLEVEL(LOG_INFO, 6)
439 * TP_LOGLEVEL(LOG_DEBUG, 7)
442 * 2) Then, declare tracepoint loglevels for tracepoints. A
443 * TRACEPOINT_EVENT should be declared prior to the the
444 * TRACEPOINT_LOGLEVEL for a given tracepoint name. The first field
445 * is the name of the tracepoint, the second field is the loglevel
448 * TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
451 * The TRACEPOINT_PROVIDER must be defined when declaring a
452 * TRACEPOINT_LOGLEVEL_ENUM and TRACEPOINT_LOGLEVEL. The tracepoint
453 * loglevel enumeration apply to the entire TRACEPOINT_PROVIDER. Only one
454 * tracepoint loglevel enumeration should be declared per tracepoint
458 #define TRACEPOINT_LOGLEVEL_ENUM()
459 #define TRACEPOINT_LOGLEVEL(name, loglevel)
461 #endif /* #ifndef TRACEPOINT_LOGLEVEL */