include/lttng/tracepoint.h

   1 #ifndef _LTTNG_TRACEPOINT_H
   2 #define _LTTNG_TRACEPOINT_H
   3
   4 /*
   5  * Copyright 2011-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  */
  17
  18 #include <lttng/tracepoint-types.h>
  19 #include <lttng/tracepoint-rcu.h>
  20 #include <urcu/compiler.h>
  21 #include <dlfcn.h>      /* for dlopen */
  22 #include <string.h>     /* for memset */
  23 #include <assert.h>
  24 #include <lttng/ust-config.h>   /* for sdt */
  25 #include <lttng/ust-compiler.h>
  26
  27 #ifdef LTTNG_UST_HAVE_SDT_INTEGRATION
  28 #define SDT_USE_VARIADIC
  29 #include <sys/sdt.h>
  30 #else
  31 #define STAP_PROBEV(...)
  32 #endif
  33
  34 #ifdef __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 #define tracepoint(provider, name, ...)                                     \
  39         do {                                                                \
  40                 TRACEPOINT_CALLSITE(provider, name);                        \
  41                 STAP_PROBEV(provider, name, ## __VA_ARGS__);                \
  42                 if (caa_unlikely(__tracepoint_##provider##___##name.state)) \
  43                         __tracepoint_cb_##provider##___##name(__VA_ARGS__); \
  44         } while (0)
  45
  46 #define TP_ARGS(...)       __VA_ARGS__
  47
  48 /*
  49  * TP_ARGS takes tuples of type, argument separated by a comma.
  50  * It can take up to 10 tuples (which means that less than 10 tuples is
  51  * fine too).
  52  * Each tuple is also separated by a comma.
  53  */
  54 #define __TP_COMBINE_TOKENS(_tokena, _tokenb)                           \
  55                 _tokena##_tokenb
  56 #define _TP_COMBINE_TOKENS(_tokena, _tokenb)                            \
  57                 __TP_COMBINE_TOKENS(_tokena, _tokenb)
  58 #define __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                 \
  59                 _tokena##_tokenb##_tokenc
  60 #define _TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)                  \
  61                 __TP_COMBINE_TOKENS3(_tokena, _tokenb, _tokenc)
  62 #define __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)        \
  63                 _tokena##_tokenb##_tokenc##_tokend
  64 #define _TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)         \
  65                 __TP_COMBINE_TOKENS4(_tokena, _tokenb, _tokenc, _tokend)
  66
  67 /*
  68  * _TP_EXVAR* extract the var names.
  69  * _TP_EXVAR1 and _TP_EXDATA_VAR1 are needed for -std=c99.
  70  */
  71 #define _TP_EXVAR0()
  72 #define _TP_EXVAR1(a)
  73 #define _TP_EXVAR2(a,b)                                         b
  74 #define _TP_EXVAR4(a,b,c,d)                                     b,d
  75 #define _TP_EXVAR6(a,b,c,d,e,f)                                 b,d,f
  76 #define _TP_EXVAR8(a,b,c,d,e,f,g,h)                             b,d,f,h
  77 #define _TP_EXVAR10(a,b,c,d,e,f,g,h,i,j)                        b,d,f,h,j
  78 #define _TP_EXVAR12(a,b,c,d,e,f,g,h,i,j,k,l)                    b,d,f,h,j,l
  79 #define _TP_EXVAR14(a,b,c,d,e,f,g,h,i,j,k,l,m,n)                b,d,f,h,j,l,n
  80 #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
  81 #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
  82 #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
  83
  84 #define _TP_EXDATA_VAR0()                                               __tp_data
  85 #define _TP_EXDATA_VAR1(a)                                              __tp_data
  86 #define _TP_EXDATA_VAR2(a,b)                                            __tp_data,b
  87 #define _TP_EXDATA_VAR4(a,b,c,d)                                        __tp_data,b,d
  88 #define _TP_EXDATA_VAR6(a,b,c,d,e,f)                                    __tp_data,b,d,f
  89 #define _TP_EXDATA_VAR8(a,b,c,d,e,f,g,h)                                __tp_data,b,d,f,h
  90 #define _TP_EXDATA_VAR10(a,b,c,d,e,f,g,h,i,j)                           __tp_data,b,d,f,h,j
  91 #define _TP_EXDATA_VAR12(a,b,c,d,e,f,g,h,i,j,k,l)                       __tp_data,b,d,f,h,j,l
  92 #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
  93 #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
  94 #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
  95 #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
  96
  97 /*
  98  * _TP_EXPROTO* extract tuples of type, var.
  99  * _TP_EXPROTO1 and _TP_EXDATA_PROTO1 are needed for -std=c99.
 100  */
 101 #define _TP_EXPROTO0()                                          void
 102 #define _TP_EXPROTO1(a)                                         void
 103 #define _TP_EXPROTO2(a,b)                                       a b
 104 #define _TP_EXPROTO4(a,b,c,d)                                   a b,c d
 105 #define _TP_EXPROTO6(a,b,c,d,e,f)                               a b,c d,e f
 106 #define _TP_EXPROTO8(a,b,c,d,e,f,g,h)                           a b,c d,e f,g h
 107 #define _TP_EXPROTO10(a,b,c,d,e,f,g,h,i,j)                      a b,c d,e f,g h,i j
 108 #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
 109 #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
 110 #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
 111 #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
 112 #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
 113
 114 #define _TP_EXDATA_PROTO0()                                             void *__tp_data
 115 #define _TP_EXDATA_PROTO1(a)                                            void *__tp_data
 116 #define _TP_EXDATA_PROTO2(a,b)                                          void *__tp_data,a b
 117 #define _TP_EXDATA_PROTO4(a,b,c,d)                                      void *__tp_data,a b,c d
 118 #define _TP_EXDATA_PROTO6(a,b,c,d,e,f)                                  void *__tp_data,a b,c d,e f
 119 #define _TP_EXDATA_PROTO8(a,b,c,d,e,f,g,h)                              void *__tp_data,a b,c d,e f,g h
 120 #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
 121 #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
 122 #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
 123 #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
 124 #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
 125 #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
 126
 127 /* Preprocessor trick to count arguments. Inspired from sdt.h. */
 128 #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)
 129 #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
 130 #define _TP_PROTO_N(N, ...)             _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXPROTO, N)(__VA_ARGS__))
 131 #define _TP_VAR_N(N, ...)               _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXVAR, N)(__VA_ARGS__))
 132 #define _TP_DATA_PROTO_N(N, ...)        _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_PROTO, N)(__VA_ARGS__))
 133 #define _TP_DATA_VAR_N(N, ...)          _TP_PARAMS(_TP_COMBINE_TOKENS(_TP_EXDATA_VAR, N)(__VA_ARGS__))
 134 #define _TP_ARGS_PROTO(...)             _TP_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 135 #define _TP_ARGS_VAR(...)               _TP_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 136 #define _TP_ARGS_DATA_PROTO(...)        _TP_DATA_PROTO_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 137 #define _TP_ARGS_DATA_VAR(...)          _TP_DATA_VAR_N(_TP_NARGS(0, ##__VA_ARGS__), ##__VA_ARGS__)
 138 #define _TP_PARAMS(...)                 __VA_ARGS__
 139
 140 #define _DECLARE_TRACEPOINT(_provider, _name, ...)                                      \
 141 extern struct tracepoint __tracepoint_##_provider##___##_name;                          \
 142 static inline lttng_ust_notrace                                                         \
 143 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__));              \
 144 static inline                                                                           \
 145 void __tracepoint_cb_##_provider##___##_name(_TP_ARGS_PROTO(__VA_ARGS__))               \
 146 {                                                                                       \
 147         struct tracepoint_probe *__tp_probe;                                            \
 148                                                                                         \
 149         if (!TP_RCU_LINK_TEST())                                                        \
 150                 return;                                                                 \
 151         tp_rcu_read_lock_bp();                                                          \
 152         __tp_probe = tp_rcu_dereference_bp(__tracepoint_##_provider##___##_name.probes); \
 153         if (caa_unlikely(!__tp_probe))                                                  \
 154                 goto end;                                                               \
 155         do {                                                                            \
 156                 void (*__tp_cb)(void) = __tp_probe->func;                                       \
 157                 void *__tp_data = __tp_probe->data;                                     \
 158                                                                                         \
 159                 URCU_FORCE_CAST(void (*)(_TP_ARGS_DATA_PROTO(__VA_ARGS__)), __tp_cb)    \
 160                                 (_TP_ARGS_DATA_VAR(__VA_ARGS__));                       \
 161         } while ((++__tp_probe)->func);                                                 \
 162 end:                                                                                    \
 163         tp_rcu_read_unlock_bp();                                                        \
 164 }                                                                                       \
 165 static inline lttng_ust_notrace                                                         \
 166 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 167                 void (*func)(void), void *data);                                        \
 168 static inline                                                                           \
 169 void __tracepoint_register_##_provider##___##_name(char *name,                          \
 170                 void (*func)(void), void *data)                                         \
 171 {                                                                                       \
 172         __tracepoint_probe_register(name, func, data,                                   \
 173                 __tracepoint_##_provider##___##_name.signature);                        \
 174 }                                                                                       \
 175 static inline lttng_ust_notrace                                                         \
 176 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 177                 void (*func)(void), void *data);                                        \
 178 static inline                                                                           \
 179 void __tracepoint_unregister_##_provider##___##_name(char *name,                        \
 180                 void (*func)(void), void *data)                                         \
 181 {                                                                                       \
 182         __tracepoint_probe_unregister(name, func, data);                                \
 183 }
 184
 185 extern int __tracepoint_probe_register(const char *name, void (*func)(void),
 186                 void *data, const char *signature);
 187 extern int __tracepoint_probe_unregister(const char *name, void (*func)(void),
 188                 void *data);
 189
 190 /*
 191  * tracepoint dynamic linkage handling (callbacks). Hidden visibility:
 192  * shared across objects in a module/main executable.
 193  */
 194 struct tracepoint_dlopen {
 195         void *liblttngust_handle;
 196
 197         int (*tracepoint_register_lib)(struct tracepoint * const *tracepoints_start,
 198                 int tracepoints_count);
 199         int (*tracepoint_unregister_lib)(struct tracepoint * const *tracepoints_start);
 200 #ifndef _LGPL_SOURCE
 201         void (*rcu_read_lock_sym_bp)(void);
 202         void (*rcu_read_unlock_sym_bp)(void);
 203         void *(*rcu_dereference_sym_bp)(void *p);
 204 #endif
 205 };
 206
 207 extern struct tracepoint_dlopen tracepoint_dlopen;
 208
 209 struct tracepoint_callsite_dlopen {
 210         void *liblttngust_handle;
 211
 212         int (*tracepoint_register_lib_callsite)(struct tracepoint_callsite * const *tp_start,
 213                 int tp_count);
 214         int (*tracepoint_unregister_lib_callsite)(struct tracepoint_callsite * const *tp_start,
 215                 int tp_count);
 216 };
 217
 218 struct tracepoint_callsite_dlopen tracepoint_callsite_dlopen
 219         __attribute__((weak, visibility("hidden")));
 220 int __tracepoint_callsite_registered
 221         __attribute__((weak, visibility("hidden")));
 222
 223 /*
 224  * Note: to allow PIC code, we need to allow the linker to update the pointers
 225  * in the __tracepoints_callsite_ptrs section.
 226  * Therefore, this section is _not_ const (read-only).
 227  */
 228 #define TRACEPOINT_CALLSITE(_provider, _name)                                   \
 229         static struct tracepoint_callsite                                       \
 230                 __tracepoint_callsite_##_provider##___##_name                   \
 231                 __attribute__((section("__tracepoint_callsite"))) =             \
 232                 {                                                               \
 233                         .tp = &__tracepoint_##_provider##___##_name,            \
 234                         .func = __func__,                                       \
 235                         .file = __FILE__,                                       \
 236                         .lineno = __LINE__,                                     \
 237                 };                                                              \
 238         static struct tracepoint_callsite *                                     \
 239                 __tracepoint_callsite_ptr_##_provider##___##_name               \
 240                 __attribute__((used, section("__tracepoint_callsite_ptrs"))) =  \
 241                         &__tracepoint_callsite_##_provider##___##_name
 242
 243 /*
 244  * These weak symbols, the constructor, and destructor take care of
 245  * registering only _one_ instance of the tracepoint callsite per
 246  * shared-ojbect (or for the whole main program).
 247  */
 248 extern struct tracepoint_callsite * const __start___tracepoint_callsite_ptrs[]
 249         __attribute__((weak, visibility("hidden")));
 250 extern struct tracepoint_callsite * const __stop___tracepoint_callsite_ptrs[]
 251         __attribute__((weak, visibility("hidden")));
 252
 253 /*
 254  * We need at least one pointer in the section.
 255  */
 256 static struct tracepoint_callsite *
 257         __tracepoint_callsite_ptr_dummy
 258         __attribute__((used, section("__tracepoint_callsite_ptrs"))) =
 259                 NULL;
 260
 261 static void lttng_ust_notrace __attribute__((constructor))
 262 __tracepoint_callsite__init(void);
 263 static void
 264 __tracepoint_callsite__init(void)
 265 {
 266         if (__tracepoint_callsite_registered++)
 267                 return;
 268
 269         tracepoint_callsite_dlopen.liblttngust_handle =
 270                 dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 271         if (!tracepoint_callsite_dlopen.liblttngust_handle)
 272                 return;
 273         tracepoint_callsite_dlopen.tracepoint_register_lib_callsite =
 274                 URCU_FORCE_CAST(int (*)(struct tracepoint_callsite * const *, int),
 275                                 dlsym(tracepoint_callsite_dlopen.liblttngust_handle,
 276                                         "tracepoint_register_lib_callsite"));
 277         tracepoint_callsite_dlopen.tracepoint_unregister_lib_callsite =
 278                 URCU_FORCE_CAST(int (*)(struct tracepoint_callsite * const *, int),
 279                                 dlsym(tracepoint_callsite_dlopen.liblttngust_handle,
 280                                         "tracepoint_unregister_lib_callsite"));
 281         tracepoint_callsite_dlopen.tracepoint_register_lib_callsite(__start___tracepoint_callsite_ptrs,
 282                                 __stop___tracepoint_callsite_ptrs -
 283                                 __start___tracepoint_callsite_ptrs);
 284 }
 285
 286 static void lttng_ust_notrace __attribute__((destructor))
 287 __tracepoint_callsite__destroy(void);
 288 static void
 289 __tracepoint_callsite__destroy(void)
 290 {
 291         int ret;
 292
 293         if (--__tracepoint_callsite_registered)
 294                 return;
 295         if (tracepoint_callsite_dlopen.tracepoint_unregister_lib_callsite)
 296                 tracepoint_callsite_dlopen.tracepoint_unregister_lib_callsite(__start___tracepoint_callsite_ptrs,
 297                                 __stop___tracepoint_callsite_ptrs -
 298                                 __start___tracepoint_callsite_ptrs);
 299         if (tracepoint_callsite_dlopen.liblttngust_handle) {
 300                 ret = dlclose(tracepoint_callsite_dlopen.liblttngust_handle);
 301                 assert(!ret);
 302                 memset(&tracepoint_callsite_dlopen, 0, sizeof(tracepoint_callsite_dlopen));
 303         }
 304 }
 305
 306 #ifdef TRACEPOINT_DEFINE
 307
 308 /*
 309  * When TRACEPOINT_PROBE_DYNAMIC_LINKAGE is defined, we do not emit a
 310  * unresolved symbol that requires the provider to be linked in. When
 311  * TRACEPOINT_PROBE_DYNAMIC_LINKAGE is not defined, we emit an
 312  * unresolved symbol that depends on having the provider linked in,
 313  * otherwise the linker complains. This deals with use of static
 314  * libraries, ensuring that the linker does not remove the provider
 315  * object from the executable.
 316  */
 317 #ifdef TRACEPOINT_PROBE_DYNAMIC_LINKAGE
 318 #define _TRACEPOINT_UNDEFINED_REF(provider)     NULL
 319 #else   /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 320 #define _TRACEPOINT_UNDEFINED_REF(provider)     &__tracepoint_provider_##provider
 321 #endif /* TRACEPOINT_PROBE_DYNAMIC_LINKAGE */
 322
 323 /*
 324  * Note: to allow PIC code, we need to allow the linker to update the pointers
 325  * in the __tracepoints_ptrs section.
 326  * Therefore, this section is _not_ const (read-only).
 327  */
 328 #define _TP_EXTRACT_STRING(...) #__VA_ARGS__
 329
 330 #define _DEFINE_TRACEPOINT(_provider, _name, _args)                             \
 331         extern int __tracepoint_provider_##_provider;                           \
 332         static const char __tp_strtab_##_provider##___##_name[]                 \
 333                 __attribute__((section("__tracepoints_strings"))) =             \
 334                         #_provider ":" #_name;                                  \
 335         struct tracepoint __tracepoint_##_provider##___##_name                  \
 336                 __attribute__((section("__tracepoints"))) =                     \
 337                 {                                                               \
 338                         __tp_strtab_##_provider##___##_name,                    \
 339                         0,                                                      \
 340                         NULL,                                                   \
 341                         _TRACEPOINT_UNDEFINED_REF(_provider),                   \
 342                         _TP_EXTRACT_STRING(_args),                              \
 343                 };                                                              \
 344         static struct tracepoint * __tracepoint_ptr_##_provider##___##_name     \
 345                 __attribute__((used, section("__tracepoints_ptrs"))) =          \
 346                         &__tracepoint_##_provider##___##_name;
 347
 348 /*
 349  * These weak symbols, the constructor, and destructor take care of
 350  * registering only _one_ instance of the tracepoints per shared-ojbect
 351  * (or for the whole main program).
 352  */
 353 extern struct tracepoint * const __start___tracepoints_ptrs[]
 354         __attribute__((weak, visibility("hidden")));
 355 extern struct tracepoint * const __stop___tracepoints_ptrs[]
 356         __attribute__((weak, visibility("hidden")));
 357 int __tracepoint_registered
 358         __attribute__((weak, visibility("hidden")));
 359 struct tracepoint_dlopen tracepoint_dlopen
 360         __attribute__((weak, visibility("hidden")));
 361
 362 static void lttng_ust_notrace __attribute__((constructor))
 363 __tracepoints__init(void);
 364 static void
 365 __tracepoints__init(void)
 366 {
 367         if (__tracepoint_registered++)
 368                 return;
 369
 370         tracepoint_dlopen.liblttngust_handle =
 371                 dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
 372         if (!tracepoint_dlopen.liblttngust_handle)
 373                 return;
 374         tracepoint_dlopen.tracepoint_register_lib =
 375                 URCU_FORCE_CAST(int (*)(struct tracepoint * const *, int),
 376                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 377                                         "tracepoint_register_lib"));
 378         tracepoint_dlopen.tracepoint_unregister_lib =
 379                 URCU_FORCE_CAST(int (*)(struct tracepoint * const *),
 380                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 381                                         "tracepoint_unregister_lib"));
 382 #ifndef _LGPL_SOURCE
 383         tracepoint_dlopen.rcu_read_lock_sym_bp =
 384                 URCU_FORCE_CAST(void (*)(void),
 385                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 386                                         "tp_rcu_read_lock_bp"));
 387         tracepoint_dlopen.rcu_read_unlock_sym_bp =
 388                 URCU_FORCE_CAST(void (*)(void),
 389                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 390                                         "tp_rcu_read_unlock_bp"));
 391         tracepoint_dlopen.rcu_dereference_sym_bp =
 392                 URCU_FORCE_CAST(void *(*)(void *p),
 393                                 dlsym(tracepoint_dlopen.liblttngust_handle,
 394                                         "tp_rcu_dereference_sym_bp"));
 395 #endif
 396         tracepoint_dlopen.tracepoint_register_lib(__start___tracepoints_ptrs,
 397                                 __stop___tracepoints_ptrs -
 398                                 __start___tracepoints_ptrs);
 399 }
 400
 401 static void lttng_ust_notrace __attribute__((destructor))
 402 __tracepoints__destroy(void);
 403 static void
 404 __tracepoints__destroy(void)
 405 {
 406         int ret;
 407
 408         if (--__tracepoint_registered)
 409                 return;
 410         if (tracepoint_dlopen.tracepoint_unregister_lib)
 411                 tracepoint_dlopen.tracepoint_unregister_lib(__start___tracepoints_ptrs);
 412         if (tracepoint_dlopen.liblttngust_handle) {
 413                 ret = dlclose(tracepoint_dlopen.liblttngust_handle);
 414                 assert(!ret);
 415                 memset(&tracepoint_dlopen, 0, sizeof(tracepoint_dlopen));
 416         }
 417 }
 418
 419 #else /* TRACEPOINT_DEFINE */
 420
 421 #define _DEFINE_TRACEPOINT(_provider, _name, _args)
 422
 423 #endif /* #else TRACEPOINT_DEFINE */
 424
 425 #ifdef __cplusplus
 426 }
 427 #endif
 428
 429 #endif /* _LTTNG_TRACEPOINT_H */
 430
 431 /* The following declarations must be outside re-inclusion protection. */
 432
 433 #ifndef TRACEPOINT_EVENT
 434
 435 /*
 436  * How to use the TRACEPOINT_EVENT macro:
 437  *
 438  * An example:
 439  *
 440  * TRACEPOINT_EVENT(someproject_component, event_name,
 441  *
 442  *     * TP_ARGS takes from 0 to 10 "type, field_name" pairs *
 443  *
 444  *     TP_ARGS(int, arg0, void *, arg1, char *, string, size_t, strlen,
 445  *             long *, arg4, size_t, arg4_len),
 446  *
 447  *      * TP_FIELDS describes the event payload layout in the trace *
 448  *
 449  *     TP_FIELDS(
 450  *         * Integer, printed in base 10 *
 451  *         ctf_integer(int, field_a, arg0)
 452  *
 453  *         * Integer, printed with 0x base 16 *
 454  *         ctf_integer_hex(unsigned long, field_d, arg1)
 455  *
 456  *         * Array Sequence, printed as UTF8-encoded array of bytes *
 457  *         ctf_array_text(char, field_b, string, FIXED_LEN)
 458  *         ctf_sequence_text(char, field_c, string, size_t, strlen)
 459  *
 460  *         * String, printed as UTF8-encoded string *
 461  *         ctf_string(field_e, string)
 462  *
 463  *         * Array sequence of signed integer values *
 464  *         ctf_array(long, field_f, arg4, FIXED_LEN4)
 465  *         ctf_sequence(long, field_g, arg4, size_t, arg4_len)
 466  *     )
 467  * )
 468  *
 469  * More detailed explanation:
 470  *
 471  * The name of the tracepoint is expressed as a tuple with the provider
 472  * and name arguments.
 473  *
 474  * The provider and name should be a proper C99 identifier.
 475  * The "provider" and "name" MUST follow these rules to ensure no
 476  * namespace clash occurs:
 477  *
 478  * For projects (applications and libraries) for which an entity
 479  * specific to the project controls the source code and thus its
 480  * tracepoints (typically with a scope larger than a single company):
 481  *
 482  * either:
 483  *   project_component, event
 484  * or:
 485  *   project, event
 486  *
 487  * Where "project" is the name of the project,
 488  *       "component" is the name of the project component (which may
 489  *       include several levels of sub-components, e.g.
 490  *       ...component_subcomponent_...) where the tracepoint is located
 491  *       (optional),
 492  *       "event" is the name of the tracepoint event.
 493  *
 494  * For projects issued from a single company wishing to advertise that
 495  * the company controls the source code and thus the tracepoints, the
 496  * "com_" prefix should be used:
 497  *
 498  * either:
 499  *   com_company_project_component, event
 500  * or:
 501  *   com_company_project, event
 502  *
 503  * Where "company" is the name of the company,
 504  *       "project" is the name of the project,
 505  *       "component" is the name of the project component (which may
 506  *       include several levels of sub-components, e.g.
 507  *       ...component_subcomponent_...) where the tracepoint is located
 508  *       (optional),
 509  *       "event" is the name of the tracepoint event.
 510  *
 511  * the provider:event identifier is limited to 127 characters.
 512  */
 513
 514 #define TRACEPOINT_EVENT(provider, name, args, fields)                  \
 515         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 516         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 517
 518 #define TRACEPOINT_EVENT_CLASS(provider, name, args, fields)
 519
 520 #define TRACEPOINT_EVENT_INSTANCE(provider, _template, name, args)      \
 521         _DECLARE_TRACEPOINT(provider, name, _TP_PARAMS(args))           \
 522         _DEFINE_TRACEPOINT(provider, name, _TP_PARAMS(args))
 523
 524 #endif /* #ifndef TRACEPOINT_EVENT */
 525
 526 #ifndef TRACEPOINT_LOGLEVEL
 527
 528 /*
 529  * Tracepoint Loglevels
 530  *
 531  * Typical use of these loglevels:
 532  *
 533  * The loglevels go from 0 to 14. Higher numbers imply the most
 534  * verbosity (higher event throughput expected.
 535  *
 536  * Loglevels 0 through 6, and loglevel 14, match syslog(3) loglevels
 537  * semantic. Loglevels 7 through 13 offer more fine-grained selection of
 538  * debug information.
 539  *
 540  * TRACE_EMERG           0
 541  * system is unusable
 542  *
 543  * TRACE_ALERT           1
 544  * action must be taken immediately
 545  *
 546  * TRACE_CRIT            2
 547  * critical conditions
 548  *
 549  * TRACE_ERR             3
 550  * error conditions
 551  *
 552  * TRACE_WARNING         4
 553  * warning conditions
 554  *
 555  * TRACE_NOTICE          5
 556  * normal, but significant, condition
 557  *
 558  * TRACE_INFO            6
 559  * informational message
 560  *
 561  * TRACE_DEBUG_SYSTEM    7
 562  * debug information with system-level scope (set of programs)
 563  *
 564  * TRACE_DEBUG_PROGRAM   8
 565  * debug information with program-level scope (set of processes)
 566  *
 567  * TRACE_DEBUG_PROCESS   9
 568  * debug information with process-level scope (set of modules)
 569  *
 570  * TRACE_DEBUG_MODULE    10
 571  * debug information with module (executable/library) scope (set of units)
 572  *
 573  * TRACE_DEBUG_UNIT      11
 574  * debug information with compilation unit scope (set of functions)
 575  *
 576  * TRACE_DEBUG_FUNCTION  12
 577  * debug information with function-level scope
 578  *
 579  * TRACE_DEBUG_LINE      13
 580  * debug information with line-level scope (TRACEPOINT_EVENT default)
 581  *
 582  * TRACE_DEBUG           14
 583  * debug-level message (trace_printf default)
 584  *
 585  * Declare tracepoint loglevels for tracepoints. A TRACEPOINT_EVENT
 586  * should be declared prior to the the TRACEPOINT_LOGLEVEL for a given
 587  * tracepoint name. The first field is the provider name, the second
 588  * field is the name of the tracepoint, the third field is the loglevel
 589  * name.
 590  *
 591  *      TRACEPOINT_LOGLEVEL(< [com_company_]project[_component] >, < event >,
 592  *              < loglevel_name >)
 593  *
 594  * The TRACEPOINT_PROVIDER must be already declared before declaring a
 595  * TRACEPOINT_LOGLEVEL.
 596  */
 597
 598 enum {
 599         TRACE_EMERG             = 0,
 600         TRACE_ALERT             = 1,
 601         TRACE_CRIT              = 2,
 602         TRACE_ERR               = 3,
 603         TRACE_WARNING           = 4,
 604         TRACE_NOTICE            = 5,
 605         TRACE_INFO              = 6,
 606         TRACE_DEBUG_SYSTEM      = 7,
 607         TRACE_DEBUG_PROGRAM     = 8,
 608         TRACE_DEBUG_PROCESS     = 9,
 609         TRACE_DEBUG_MODULE      = 10,
 610         TRACE_DEBUG_UNIT        = 11,
 611         TRACE_DEBUG_FUNCTION    = 12,
 612         TRACE_DEBUG_LINE        = 13,
 613         TRACE_DEBUG             = 14,
 614 };
 615
 616 #define TRACEPOINT_LOGLEVEL(provider, name, loglevel)
 617
 618 #endif /* #ifndef TRACEPOINT_LOGLEVEL */
 619
 620 #ifndef TRACEPOINT_MODEL_EMF_URI
 621
 622 #define TRACEPOINT_MODEL_EMF_URI(provider, name, uri)
 623
 624 #endif /* #ifndef TRACEPOINT_MODEL_EMF_URI */