1 #ifndef _LTTNG_TRACEPOINT_H
2 #define _LTTNG_TRACEPOINT_H
5 * Copyright (c) 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
10 * Permission is hereby granted to use or copy this program
11 * for any purpose, provided the above notices are retained on all copies.
12 * Permission to modify the code and to distribute modified code is granted,
13 * provided the above notices are retained, and a notice that the code was
14 * modified is included with the above copyright notice.
17 #include <lttng/tracepoint-types.h>
18 #include <lttng/tracepoint-rcu.h>
19 #include <urcu/compiler.h>
20 #include <dlfcn.h> /* for dlopen */
21 #include <string.h> /* for memset */
28 #define tracepoint(provider, name, ...) \
30 if (caa_unlikely(__tracepoint_##provider##___##name.state)) \
31 __tracepoint_cb_##provider##___##name(__VA_ARGS__); \
34 #define TP_ARGS(...) __VA_ARGS__
37 * TP_ARGS takes tuples of type, argument separated by a comma.
38 * It can take up to 10 tuples (which means that less than 10 tuples is
40 * Each tuple is also separated by a comma.
42 #define __TP_COMBINE_TOKENS(_tokena, _tokenb) \
44 #define _TP_COMBINE_TOKENS(_tokena, _tokenb) \
45 __TP_COMBINE_TOKENS(_tokena, _tokenb)
46 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc) \
47 _tokena##_tokenb##_tokenc
48 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc) \
49 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
50 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend) \
51 _tokena##_tokenb##_tokenc##_tokend
52 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend) \
53 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
55 /* _TP_EXVAR* extract the var names. */
57 #define _TP_EXVAR2(a,b) b
58 #define _TP_EXVAR4(a,b,c,d) b,d
59 #define _TP_EXVAR6(a,b,c,d,e,f) b,d,f
60 #define _TP_EXVAR8(a,b,c,d,e,f,g,h) b,d,f,h
61 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j) b,d,f,h,j
62 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l) b,d,f,h,j,l
63 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) b,d,f,h,j,l,n
64 #define _TP_EXVAR16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) b,d,f,h,j,l,n,p
65 #define _TP_EXVAR18(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
66 #define _TP_EXVAR20(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
68 #define _TP_EXDATA_VAR0() __tp_data
69 #define _TP_EXDATA_VAR2(a,b) __tp_data,b
70 #define _TP_EXDATA_VAR4(a,b,c,d) __tp_data,b,d
71 #define _TP_EXDATA_VAR6(a,b,c,d,e,f) __tp_data,b,d,f
72 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h) __tp_data,b,d,f,h
73 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j) __tp_data,b,d,f,h,j
74 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l) __tp_data,b,d,f,h,j,l
75 #define _TP_EXDATA_VAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) __tp_data,b,d,f,h,j,l,n
76 #define _TP_EXDATA_VAR16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) __tp_data,b,d,f,h,j,l,n,p
77 #define _TP_EXDATA_VAR18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r) __tp_data,b,d,f,h,j,l,n,p,r
78 #define _TP_EXDATA_VAR20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t) __tp_data,b,d,f,h,j,l,n,p,r,t
80 /* _TP_EXPROTO* extract tuples of type, var */
81 #define _TP_EXPROTO0()
82 #define _TP_EXPROTO2(a,b) a b
83 #define _TP_EXPROTO4(a,b,c,d) a b,c d
84 #define _TP_EXPROTO6(a,b,c,d,e,f) a b,c d,e f
85 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h) a b,c d,e f,g h
86 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j) a b,c d,e f,g h,i j
87 #define _TP_EXPROTO12(a,b,c,d,e,f,g,h,i,j,k,l) a b,c d,e f,g h,i j,k l
88 #define _TP_EXPROTO14(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
89 #define _TP_EXPROTO16(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
90 #define _TP_EXPROTO18(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
91 #define _TP_EXPROTO20(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
93 #define _TP_EXDATA_PROTO0() void *__tp_data
94 #define _TP_EXDATA_PROTO2(a,b) void *__tp_data,a b
95 #define _TP_EXDATA_PROTO4(a,b,c,d) void *__tp_data,a b,c d
96 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f) void *__tp_data,a b,c d,e f
97 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h) void *__tp_data,a b,c d,e f,g h
98 #define _TP_EXDATA_PROTO10(a,b,c,d,e,f,g,h,i,j) void *__tp_data,a b,c d,e f,g h,i j
99 #define _TP_EXDATA_PROTO12(a,b,c,d,e,f,g,h,i,j,k,l) void *__tp_data,a b,c d,e f,g h,i j,k l
100 #define _TP_EXDATA_PROTO14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) void *__tp_data,a b,c d,e f,g h,i j,k l,m n
101 #define _TP_EXDATA_PROTO16(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) void *__tp_data,a b,c d,e f,g h,i j,k l,m n,o p
102 #define _TP_EXDATA_PROTO18(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r) void *__tp_data,a b,c d,e f,g h,i j,k l,m n,o p,q r
103 #define _TP_EXDATA_PROTO20(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t) void *__tp_data,a b,c d,e f,g h,i j,k l,m n,o p,q r,s t
105 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
106 #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)
107 #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
108 #define _TP_PROTO_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
109 #define _TP_VAR_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
110 #define _TP_DATA_PROTO_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
111 #define _TP_DATA_VAR_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
112 #define _TP_ARGS_PROTO(...) _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
113 #define _TP_ARGS_VAR(...) _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
114 #define _TP_ARGS_DATA_PROTO(...) _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
115 #define _TP_ARGS_DATA_VAR(...) _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
116 #define _TP_PARAMS(...) __VA_ARGS__
118 #define _DECLARE_TRACEPOINT(_provider, _name, ...) \
119 extern struct tracepoint __tracepoint_##_provider##___##_name; \
120 static inline void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__)) \
122 struct tracepoint_probe *__tp_probe; \
124 if (!TP_RCU_LINK_TEST()) \
126 tp_rcu_read_lock_bp(); \
127 __tp_probe = tp_rcu_dereference_bp(__tracepoint_##_provider##___##_name.probes); \
128 if (caa_unlikely(!__tp_probe)) \
131 void *__tp_cb = __tp_probe->func; \
132 void *__tp_data = __tp_probe->data; \
134 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb) \
135 (_TP_ARGS_DATA_VAR(__VA_ARGS__)); \
136 } while ((++__tp_probe)->func); \
138 tp_rcu_read_unlock_bp(); \
140 static inline void __tracepoint_register_##_provider##___##_name(char *name, \
141 void *func, void *data) \
143 __tracepoint_probe_register(name, func, data); \
145 static inline void __tracepoint_unregister_##_provider##___##_name(char *name, \
146 void *func, void *data) \
148 __tracepoint_probe_unregister(name, func, data); \
151 extern int __tracepoint_probe_register(const char *name
, void *func
, void *data
);
152 extern int __tracepoint_probe_unregister(const char *name
, void *func
, void *data
);
155 * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
156 * shared across objects in a module/main executable.
158 struct tracepoint_dlopen
{
159 void *liblttngust_handle
;
161 int (*tracepoint_register_lib
)(struct tracepoint
* const *tracepoints_start
,
162 int tracepoints_count
);
163 int (*tracepoint_unregister_lib
)(struct tracepoint
* const *tracepoints_start
);
165 void (*rcu_read_lock_sym_bp
)(void);
166 void (*rcu_read_unlock_sym_bp
)(void);
167 void *(*rcu_dereference_sym_bp
)(void *p
);
171 extern struct tracepoint_dlopen tracepoint_dlopen
;
173 #ifdef TRACEPOINT_DEFINE
176 * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
177 * unresolved symbol that requires the provider to be linked in. When
178 * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
179 * unresolved symbol that depends on having the provider linked in,
180 * otherwise the linker complains. This deals with use of static
181 * libraries, ensuring that the linker does not remove the provider
182 * object from the executable.
184 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
185 #define _TRACEPOINT_UNDEFINED_REF(provider)
186 #else /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
187 #define _TRACEPOINT_UNDEFINED_REF(provider) \
188 &__tracepoint_provider_##provider,
189 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
192 * Note: to allow PIC code, we need to allow the linker to update the pointers
193 * in the __tracepoints_ptrs section.
194 * Therefore, this section is _not_ const (read-only).
196 #define _DEFINE_TRACEPOINT(provider, name) \
197 extern int __tracepoint_provider_##provider; \
198 static const char __tp_strtab_##provider##___##name[] \
199 __attribute__((section("__tracepoints_strings"))) = \
200 #provider ":" #name; \
201 struct tracepoint __tracepoint_##provider##___##name \
202 __attribute__((section("__tracepoints"))) = \
203 { __tp_strtab_##provider##___##name, 0, NULL, _TRACEPOINT_UNDEFINED_REF(provider) }; \
204 static struct tracepoint * __tracepoint_ptr_##provider##___##name \
205 __attribute__((used, section("__tracepoints_ptrs"))) = \
206 &__tracepoint_##provider##___##name;
209 * These weak symbols, the constructor, and destructor take care of
210 * registering only _one_ instance of the tracepoints per shared-ojbect
211 * (or for the whole main program).
213 extern struct tracepoint
* const __start___tracepoints_ptrs
[]
214 __attribute__((weak
, visibility("hidden")));
215 extern struct tracepoint
* const __stop___tracepoints_ptrs
[]
216 __attribute__((weak
, visibility("hidden")));
217 int __tracepoint_registered
218 __attribute__((weak
, visibility("hidden")));
219 struct tracepoint_dlopen tracepoint_dlopen
220 __attribute__((weak
, visibility("hidden")));
222 static void __attribute__((constructor
)) __tracepoints__init(void)
224 if (__tracepoint_registered
++)
227 tracepoint_dlopen
.liblttngust_handle
=
228 dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW
| RTLD_GLOBAL
);
229 if (!tracepoint_dlopen
.liblttngust_handle
)
231 tracepoint_dlopen
.tracepoint_register_lib
=
232 URCU_FORCE_CAST(int (*)(struct tracepoint
* const *, int),
233 dlsym(tracepoint_dlopen
.liblttngust_handle
,
234 "tracepoint_register_lib"));
235 tracepoint_dlopen
.tracepoint_unregister_lib
=
236 URCU_FORCE_CAST(int (*)(struct tracepoint
* const *),
237 dlsym(tracepoint_dlopen
.liblttngust_handle
,
238 "tracepoint_unregister_lib"));
240 tracepoint_dlopen
.rcu_read_lock_sym_bp
=
241 URCU_FORCE_CAST(void (*)(void),
242 dlsym(tracepoint_dlopen
.liblttngust_handle
,
243 "tp_rcu_read_lock_bp"));
244 tracepoint_dlopen
.rcu_read_unlock_sym_bp
=
245 URCU_FORCE_CAST(void (*)(void),
246 dlsym(tracepoint_dlopen
.liblttngust_handle
,
247 "tp_rcu_read_unlock_bp"));
248 tracepoint_dlopen
.rcu_dereference_sym_bp
=
249 URCU_FORCE_CAST(void *(*)(void *p
),
250 dlsym(tracepoint_dlopen
.liblttngust_handle
,
251 "tp_rcu_dereference_sym_bp"));
253 tracepoint_dlopen
.tracepoint_register_lib(__start___tracepoints_ptrs
,
254 __stop___tracepoints_ptrs
-
255 __start___tracepoints_ptrs
);
258 static void __attribute__((destructor
)) __tracepoints__destroy(void)
262 if (--__tracepoint_registered
)
264 if (tracepoint_dlopen
.tracepoint_unregister_lib
)
265 tracepoint_dlopen
.tracepoint_unregister_lib(__start___tracepoints_ptrs
);
266 if (tracepoint_dlopen
.liblttngust_handle
) {
267 ret
= dlclose(tracepoint_dlopen
.liblttngust_handle
);
269 memset(&tracepoint_dlopen
, 0, sizeof(tracepoint_dlopen
));
273 #else /* TRACEPOINT_DEFINE */
275 #define _DEFINE_TRACEPOINT(provider, name)
277 #endif /* #else TRACEPOINT_DEFINE */
283 #endif /* _LTTNG_TRACEPOINT_H */
285 /* The following declarations must be outside re-inclusion protection. */
287 #ifndef TRACEPOINT_EVENT
290 * How to use the TRACEPOINT_EVENT macro:
294 * TRACEPOINT_EVENT(someproject_component, event_name,
296 * * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
298 * TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
299 * long *, arg4, size_t, arg4_len),
301 * * TP_FIELDS describes the event payload layout in the trace *
304 * * Integer, printed in base 10 *
305 * ctf_integer(int, field_a, arg0)
307 * * Integer, printed with 0x base 16 *
308 * ctf_integer_hex(unsigned long, field_d, arg1)
310 * * Array Sequence, printed as UTF8-encoded array of bytes *
311 * ctf_array_text(char, field_b, string, FIXED_LEN)
312 * ctf_sequence_text(char, field_c, string, size_t, strlen)
314 * * String, printed as UTF8-encoded string *
315 * ctf_string(field_e, string)
317 * * Array sequence of signed integer values *
318 * ctf_array(long, field_f, arg4, FIXED_LEN4)
319 * ctf_sequence(long, field_g, arg4, size_t, arg4_len)
323 * More detailed explanation:
325 * The name of the tracepoint is expressed as a tuple with the provider
326 * and name arguments.
328 * The provider and name should be a proper C99 identifier.
329 * The "provider" and "name" MUST follow these rules to ensure no
330 * namespace clash occurs:
332 * For projects (applications and libraries) for which an entity
333 * specific to the project controls the source code and thus its
334 * tracepoints (typically with a scope larger than a single company):
337 * project_component, event
341 * Where "project" is the name of the project,
342 * "component" is the name of the project component (which may
343 * include several levels of sub-components, e.g.
344 * ...component_subcomponent_...) where the tracepoint is located
346 * "event" is the name of the tracepoint event.
348 * For projects issued from a single company wishing to advertise that
349 * the company controls the source code and thus the tracepoints, the
350 * "com_" prefix should be used:
353 * com_company_project_component, event
355 * com_company_project, event
357 * Where "company" is the name of the company,
358 * "project" is the name of the project,
359 * "component" is the name of the project component (which may
360 * include several levels of sub-components, e.g.
361 * ...component_subcomponent_...) where the tracepoint is located
363 * "event" is the name of the tracepoint event.
365 * the provider:event identifier is limited to 127 characters.
368 #define TRACEPOINT_EVENT(provider, name, args, fields) \
369 _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args)) \
370 _DEFINE_TRACEPOINT(provider, name)
372 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
374 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args) \
375 _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args)) \
376 _DEFINE_TRACEPOINT(provider, name)
378 #endif /* #ifndef TRACEPOINT_EVENT */
380 #ifndef TRACEPOINT_LOGLEVEL
383 * Tracepoint Loglevels
385 * Typical use of these loglevels:
387 * The loglevels go from 0 to 14. Higher numbers imply the most
388 * verbosity (higher event throughput expected.
390 * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
391 * semantic. Loglevels 7 through 13 offer more fine-grained selection of
398 * action must be taken immediately
401 * critical conditions
410 * normal, but significant, condition
413 * informational message
415 * TRACE_DEBUG_SYSTEM 7
416 * debug information with system-level scope (set of programs)
418 * TRACE_DEBUG_PROGRAM 8
419 * debug information with program-level scope (set of processes)
421 * TRACE_DEBUG_PROCESS 9
422 * debug information with process-level scope (set of modules)
424 * TRACE_DEBUG_MODULE 10
425 * debug information with module (executable/library) scope (set of units)
427 * TRACE_DEBUG_UNIT 11
428 * debug information with compilation unit scope (set of functions)
430 * TRACE_DEBUG_FUNCTION 12
431 * debug information with function-level scope
433 * TRACE_DEBUG_LINE 13
434 * debug information with line-level scope (TRACEPOINT_EVENT default)
437 * debug-level message (trace_printf default)
439 * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
440 * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
441 * tracepoint name. The first field is the name of the tracepoint, the
442 * second field is the loglevel name.
444 * TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
447 * The TRACEPOINT_PROVIDER must be already declared before declaring a
448 * TRACEPOINT_LOGLEVEL.
459 TRACE_DEBUG_SYSTEM
= 7,
460 TRACE_DEBUG_PROGRAM
= 8,
461 TRACE_DEBUG_PROCESS
= 9,
462 TRACE_DEBUG_MODULE
= 10,
463 TRACE_DEBUG_UNIT
= 11,
464 TRACE_DEBUG_FUNCTION
= 12,
465 TRACE_DEBUG_LINE
= 13,
469 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
471 #endif /* #ifndef TRACEPOINT_LOGLEVEL */