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 */
27 #define tracepoint(provider, name, ...) \
29 if (caa_unlikely(__tracepoint_##provider##___##name.state)) \
30 __tracepoint_cb_##provider##___##name(__VA_ARGS__); \
33 #define TP_ARGS(...) __VA_ARGS__
36 * TP_ARGS takes tuples of type, argument separated by a comma.
37 * It can take up to 10 tuples (which means that less than 10 tuples is
39 * Each tuple is also separated by a comma.
41 #define __TP_COMBINE_TOKENS(_tokena, _tokenb) \
43 #define _TP_COMBINE_TOKENS(_tokena, _tokenb) \
44 __TP_COMBINE_TOKENS(_tokena, _tokenb)
45 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc) \
46 _tokena##_tokenb##_tokenc
47 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc) \
48 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
49 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend) \
50 _tokena##_tokenb##_tokenc##_tokend
51 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend) \
52 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
54 /* _TP_EXVAR* extract the var names. */
56 #define _TP_EXVAR2(a,b) b
57 #define _TP_EXVAR4(a,b,c,d) b,d
58 #define _TP_EXVAR6(a,b,c,d,e,f) b,d,f
59 #define _TP_EXVAR8(a,b,c,d,e,f,g,h) b,d,f,h
60 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j) b,d,f,h,j
61 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l) b,d,f,h,j,l
62 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n) b,d,f,h,j,l,n
63 #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
64 #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
65 #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
67 #define _TP_EXDATA_VAR0() __tp_data
68 #define _TP_EXDATA_VAR2(a,b) __tp_data,b
69 #define _TP_EXDATA_VAR4(a,b,c,d) __tp_data,b,d
70 #define _TP_EXDATA_VAR6(a,b,c,d,e,f) __tp_data,b,d,f
71 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h) __tp_data,b,d,f,h
72 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j) __tp_data,b,d,f,h,j
73 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l) __tp_data,b,d,f,h,j,l
74 #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
75 #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
76 #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
77 #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
79 /* _TP_EXPROTO* extract tuples of type, var */
80 #define _TP_EXPROTO0()
81 #define _TP_EXPROTO2(a,b) a b
82 #define _TP_EXPROTO4(a,b,c,d) a b,c d
83 #define _TP_EXPROTO6(a,b,c,d,e,f) a b,c d,e f
84 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h) a b,c d,e f,g h
85 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j) a b,c d,e f,g h,i j
86 #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
87 #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
88 #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
89 #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
90 #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
92 #define _TP_EXDATA_PROTO0() void *__tp_data
93 #define _TP_EXDATA_PROTO2(a,b) void *__tp_data,a b
94 #define _TP_EXDATA_PROTO4(a,b,c,d) void *__tp_data,a b,c d
95 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f) void *__tp_data,a b,c d,e f
96 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h) void *__tp_data,a b,c d,e f,g h
97 #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
98 #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
99 #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
100 #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
101 #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
102 #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
104 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
105 #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)
106 #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
107 #define _TP_PROTO_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
108 #define _TP_VAR_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
109 #define _TP_DATA_PROTO_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
110 #define _TP_DATA_VAR_N(N, ...) _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
111 #define _TP_ARGS_PROTO(...) _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
112 #define _TP_ARGS_VAR(...) _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
113 #define _TP_ARGS_DATA_PROTO(...) _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
114 #define _TP_ARGS_DATA_VAR(...) _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
115 #define _TP_PARAMS(...) __VA_ARGS__
117 #define _DECLARE_TRACEPOINT(provider, name, ...) \
118 extern struct tracepoint __tracepoint_##provider##___##name; \
119 static inline void __tracepoint_cb_##provider##___##name(_TP_ARGS_PROTO(__VA_ARGS__)) \
121 struct tracepoint_probe *__tp_probe; \
123 if (!TP_RCU_LINK_TEST()) \
125 tp_rcu_read_lock_bp(); \
126 __tp_probe = tp_rcu_dereference_bp(__tracepoint_##provider##___##name.probes); \
127 if (caa_unlikely(!__tp_probe)) \
130 void *__tp_cb = __tp_probe->func; \
131 void *__tp_data = __tp_probe->data; \
133 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb) \
134 (_TP_ARGS_DATA_VAR(__VA_ARGS__)); \
135 } while ((++__tp_probe)->func); \
137 tp_rcu_read_unlock_bp(); \
139 static inline void __tracepoint_register_##provider##___##name(char *name, \
140 void *func, void *data) \
142 __tracepoint_probe_register(name, func, data); \
144 static inline void __tracepoint_unregister_##provider##___##name(char *name, \
145 void *func, void *data) \
147 __tracepoint_probe_unregister(name, func, data); \
150 extern int __tracepoint_probe_register(const char *name
, void *func
, void *data
);
151 extern int __tracepoint_probe_unregister(const char *name
, void *func
, void *data
);
153 #ifdef TRACEPOINT_DEFINE
156 * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
157 * unresolved symbol that requires the provider to be linked in. When
158 * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
159 * unresolved symbol that depends on having the provider linked in,
160 * otherwise the linker complains. This deals with use of static
161 * libraries, ensuring that the linker does not remove the provider
162 * object from the executable.
164 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
165 #define _TRACEPOINT_UNDEFINED_REF(provider)
166 #else /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
167 #define _TRACEPOINT_UNDEFINED_REF(provider) \
168 &__tracepoint_provider_##provider,
169 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
172 * Note: to allow PIC code, we need to allow the linker to update the pointers
173 * in the __tracepoints_ptrs section.
174 * Therefore, this section is _not_ const (read-only).
176 #define _DEFINE_TRACEPOINT(provider, name) \
177 extern int __tracepoint_provider_##provider; \
178 static const char __tp_strtab_##provider##___##name[] \
179 __attribute__((section("__tracepoints_strings"))) = \
180 #provider ":" #name; \
181 struct tracepoint __tracepoint_##provider##___##name \
182 __attribute__((section("__tracepoints"))) = \
183 { __tp_strtab_##provider##___##name, 0, NULL, _TRACEPOINT_UNDEFINED_REF(provider) }; \
184 static struct tracepoint * __tracepoint_ptr_##provider##___##name \
185 __attribute__((used, section("__tracepoints_ptrs"))) = \
186 &__tracepoint_##provider##___##name;
188 static int (*tracepoint_register_lib
)(struct tracepoint
* const *tracepoints_start
,
189 int tracepoints_count
);
190 static int (*tracepoint_unregister_lib
)(struct tracepoint
* const *tracepoints_start
);
191 static void *liblttngust_handle
;
194 * These weak symbols, the constructor, and destructor take care of
195 * registering only _one_ instance of the tracepoints per shared-ojbect
196 * (or for the whole main program).
198 extern struct tracepoint
* const __start___tracepoints_ptrs
[]
199 __attribute__((weak
, visibility("hidden")));
200 extern struct tracepoint
* const __stop___tracepoints_ptrs
[]
201 __attribute__((weak
, visibility("hidden")));
202 int __tracepoint_registered
203 __attribute__((weak
, visibility("hidden")));
205 static void __attribute__((constructor
)) __tracepoints__init(void)
207 if (__tracepoint_registered
++)
210 liblttngust_handle
= dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW
| RTLD_GLOBAL
);
211 if (!liblttngust_handle
)
213 tracepoint_register_lib
=
214 URCU_FORCE_CAST(int (*)(struct tracepoint
* const *, int),
215 dlsym(liblttngust_handle
,
216 "tracepoint_register_lib"));
217 tracepoint_unregister_lib
=
218 URCU_FORCE_CAST(int (*)(struct tracepoint
* const *),
219 dlsym(liblttngust_handle
,
220 "tracepoint_unregister_lib"));
222 tp_rcu_read_lock_bp
=
223 URCU_FORCE_CAST(void (*)(void),
224 dlsym(liblttngust_handle
,
225 "tp_rcu_read_lock_bp"));
226 tp_rcu_read_unlock_bp
=
227 URCU_FORCE_CAST(void (*)(void),
228 dlsym(liblttngust_handle
,
229 "tp_rcu_read_unlock_bp"));
230 tp_rcu_dereference_sym_bp
=
231 URCU_FORCE_CAST(void *(*)(void *p
),
232 dlsym(liblttngust_handle
,
233 "tp_rcu_dereference_sym_bp"));
235 tracepoint_register_lib(__start___tracepoints_ptrs
,
236 __stop___tracepoints_ptrs
-
237 __start___tracepoints_ptrs
);
240 static void __attribute__((destructor
)) __tracepoints__destroy(void)
243 if (--__tracepoint_registered
)
245 if (tracepoint_unregister_lib
)
246 tracepoint_unregister_lib(__start___tracepoints_ptrs
);
247 if (liblttngust_handle
) {
248 tracepoint_unregister_lib
= NULL
;
249 tracepoint_register_lib
= NULL
;
250 ret
= dlclose(liblttngust_handle
);
255 #else /* TRACEPOINT_DEFINE */
257 #define _DEFINE_TRACEPOINT(provider, name)
259 #endif /* #else TRACEPOINT_DEFINE */
265 #endif /* _LTTNG_TRACEPOINT_H */
267 /* The following declarations must be outside re-inclusion protection. */
269 #ifndef TRACEPOINT_EVENT
272 * How to use the TRACEPOINT_EVENT macro:
276 * TRACEPOINT_EVENT(someproject_component, event_name,
278 * * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
280 * TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
281 * long *, arg4, size_t, arg4_len),
283 * * TP_FIELDS describes the event payload layout in the trace *
286 * * Integer, printed in base 10 *
287 * ctf_integer(int, field_a, arg0)
289 * * Integer, printed with 0x base 16 *
290 * ctf_integer_hex(unsigned long, field_d, arg1)
292 * * Array Sequence, printed as UTF8-encoded array of bytes *
293 * ctf_array_text(char, field_b, string, FIXED_LEN)
294 * ctf_sequence_text(char, field_c, string, size_t, strlen)
296 * * String, printed as UTF8-encoded string *
297 * ctf_string(field_e, string)
299 * * Array sequence of signed integer values *
300 * ctf_array(long, field_f, arg4, FIXED_LEN4)
301 * ctf_sequence(long, field_g, arg4, size_t, arg4_len)
305 * More detailed explanation:
307 * The name of the tracepoint is expressed as a tuple with the provider
308 * and name arguments.
310 * The provider and name should be a proper C99 identifier.
311 * The "provider" and "name" MUST follow these rules to ensure no
312 * namespace clash occurs:
314 * For projects (applications and libraries) for which an entity
315 * specific to the project controls the source code and thus its
316 * tracepoints (typically with a scope larger than a single company):
319 * project_component, event
323 * Where "project" is the name of the project,
324 * "component" is the name of the project component (which may
325 * include several levels of sub-components, e.g.
326 * ...component_subcomponent_...) where the tracepoint is located
328 * "event" is the name of the tracepoint event.
330 * For projects issued from a single company wishing to advertise that
331 * the company controls the source code and thus the tracepoints, the
332 * "com_" prefix should be used:
335 * com_company_project_component, event
337 * com_company_project, event
339 * Where "company" is the name of the company,
340 * "project" is the name of the project,
341 * "component" is the name of the project component (which may
342 * include several levels of sub-components, e.g.
343 * ...component_subcomponent_...) where the tracepoint is located
345 * "event" is the name of the tracepoint event.
347 * the provider:event identifier is limited to 127 characters.
350 #define TRACEPOINT_EVENT(provider, name, args, fields) \
351 _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args)) \
352 _DEFINE_TRACEPOINT(provider, name)
354 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
356 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args) \
357 _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args)) \
358 _DEFINE_TRACEPOINT(provider, name)
360 #endif /* #ifndef TRACEPOINT_EVENT */
362 #ifndef TRACEPOINT_LOGLEVEL
365 * Tracepoint Loglevels
367 * Typical use of these loglevels:
369 * The loglevels go from 0 to 14. Higher numbers imply the most
370 * verbosity (higher event throughput expected.
372 * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
373 * semantic. Loglevels 7 through 13 offer more fine-grained selection of
380 * action must be taken immediately
383 * critical conditions
392 * normal, but significant, condition
395 * informational message
397 * TRACE_DEBUG_SYSTEM 7
398 * debug information with system-level scope (set of programs)
400 * TRACE_DEBUG_PROGRAM 8
401 * debug information with program-level scope (set of processes)
403 * TRACE_DEBUG_PROCESS 9
404 * debug information with process-level scope (set of modules)
406 * TRACE_DEBUG_MODULE 10
407 * debug information with module (executable/library) scope (set of units)
409 * TRACE_DEBUG_UNIT 11
410 * debug information with compilation unit scope (set of functions)
412 * TRACE_DEBUG_FUNCTION 12
413 * debug information with function-level scope
415 * TRACE_DEBUG_LINE 13
416 * debug information with line-level scope (TRACEPOINT_EVENT default)
419 * debug-level message (trace_printf default)
421 * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
422 * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
423 * tracepoint name. The first field is the name of the tracepoint, the
424 * second field is the loglevel name.
426 * TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
429 * The TRACEPOINT_PROVIDER must be already declared before declaring a
430 * TRACEPOINT_LOGLEVEL.
441 TRACE_DEBUG_SYSTEM
= 7,
442 TRACE_DEBUG_PROGRAM
= 8,
443 TRACE_DEBUG_PROCESS
= 9,
444 TRACE_DEBUG_MODULE
= 10,
445 TRACE_DEBUG_UNIT
= 11,
446 TRACE_DEBUG_FUNCTION
= 12,
447 TRACE_DEBUG_LINE
= 13,
451 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
453 #endif /* #ifndef TRACEPOINT_LOGLEVEL */