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