| 1 | #ifndef _UST_TRACEPOINT_H |
| 2 | #define _UST_TRACEPOINT_H |
| 3 | |
| 4 | /* |
| 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> |
| 8 | * |
| 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. |
| 13 | * |
| 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. |
| 18 | * |
| 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 |
| 22 | * |
| 23 | * Heavily inspired from the Linux Kernel Markers. |
| 24 | * |
| 25 | * Ported to userspace by Pierre-Marc Fournier. |
| 26 | */ |
| 27 | |
| 28 | #include <urcu-bp.h> |
| 29 | #include <urcu/list.h> |
| 30 | |
| 31 | #ifdef __cplusplus |
| 32 | extern "C" { |
| 33 | #endif |
| 34 | |
| 35 | struct tracepoint_probe { |
| 36 | void *func; |
| 37 | void *data; |
| 38 | }; |
| 39 | |
| 40 | struct tracepoint { |
| 41 | const char *name; /* Tracepoint name */ |
| 42 | char state; /* State. */ |
| 43 | struct tracepoint_probe *probes; |
| 44 | }; |
| 45 | |
| 46 | /* |
| 47 | * Tracepoints should be added to the instrumented code using the |
| 48 | * "tracepoint()" macro. |
| 49 | */ |
| 50 | #define tracepoint(name, args...) __trace_##name(args) |
| 51 | |
| 52 | /* |
| 53 | * it_func[0] is never NULL because there is at least one element in the array |
| 54 | * when the array itself is non NULL. |
| 55 | */ |
| 56 | #define __DO_TRACE(tp, proto, args) \ |
| 57 | do { \ |
| 58 | struct tracepoint_probe *__tp_it_probe_ptr; \ |
| 59 | void *__tp_it_func; \ |
| 60 | void *__tp_cb_data; \ |
| 61 | \ |
| 62 | rcu_read_lock(); \ |
| 63 | __tp_it_probe_ptr = rcu_dereference((tp)->probes); \ |
| 64 | if (__tp_it_probe_ptr) { \ |
| 65 | do { \ |
| 66 | __tp_it_func = __tp_it_probe_ptr->func; \ |
| 67 | __tp_cb_data = __tp_it_probe_ptr->data; \ |
| 68 | URCU_FORCE_CAST(void(*)(proto), __tp_it_func)(args); \ |
| 69 | } while ((++__tp_it_probe_ptr)->func); \ |
| 70 | } \ |
| 71 | rcu_read_unlock(); \ |
| 72 | } while (0) |
| 73 | |
| 74 | #define TP_PARAMS(args...) args |
| 75 | #define TP_PROTO(args...) args |
| 76 | #define TP_ARGS(args...) args |
| 77 | |
| 78 | #define __CHECK_TRACE(name, proto, args) \ |
| 79 | do { \ |
| 80 | if (unlikely(__tracepoint_##name.state)) \ |
| 81 | __DO_TRACE(&__tracepoint_##name, \ |
| 82 | TP_PROTO(proto), TP_ARGS(args)); \ |
| 83 | } while (0) |
| 84 | |
| 85 | /* |
| 86 | * Make sure the alignment of the structure in the __tracepoints section will |
| 87 | * not add unwanted padding between the beginning of the section and the |
| 88 | * structure. Force alignment to the same alignment as the section start. |
| 89 | */ |
| 90 | #define __DECLARE_TRACEPOINT(name, proto, args, data_proto, data_args) \ |
| 91 | extern struct tracepoint __tracepoint_##name; \ |
| 92 | static inline void __trace_##name(proto) \ |
| 93 | { \ |
| 94 | __CHECK_TRACE(name, TP_PROTO(data_proto), \ |
| 95 | TP_ARGS(data_args)); \ |
| 96 | } \ |
| 97 | static inline int \ |
| 98 | __register_trace_##name(void (*probe)(data_proto), void *data) \ |
| 99 | { \ |
| 100 | return __tracepoint_probe_register(#name, (void *)probe,\ |
| 101 | data); \ |
| 102 | } \ |
| 103 | static inline int \ |
| 104 | __unregister_trace_##name(void (*probe)(data_proto), void *data)\ |
| 105 | { \ |
| 106 | return __tracepoint_probe_unregister(#name, (void *)probe, \ |
| 107 | data); \ |
| 108 | } |
| 109 | |
| 110 | /* |
| 111 | * The need for the _DECLARE_TRACEPOINT_NOARGS() is to handle the prototype |
| 112 | * (void). "void" is a special value in a function prototype and can |
| 113 | * not be combined with other arguments. Since the DECLARE_TRACEPOINT() |
| 114 | * macro adds a data element at the beginning of the prototype, |
| 115 | * we need a way to differentiate "(void *data, proto)" from |
| 116 | * "(void *data, void)". The second prototype is invalid. |
| 117 | * |
| 118 | * DECLARE_TRACEPOINT_NOARGS() passes "void" as the tracepoint prototype |
| 119 | * and "void *__tp_cb_data" as the callback prototype. |
| 120 | * |
| 121 | * DECLARE_TRACEPOINT() passes "proto" as the tracepoint protoype and |
| 122 | * "void *__tp_cb_data, proto" as the callback prototype. |
| 123 | */ |
| 124 | #define _DECLARE_TRACEPOINT_NOARGS(name) \ |
| 125 | __DECLARE_TRACEPOINT(name, void, , void *__tp_cb_data, __tp_cb_data) |
| 126 | |
| 127 | #define _DECLARE_TRACEPOINT(name, proto, args) \ |
| 128 | __DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args), \ |
| 129 | TP_PARAMS(void *__tp_cb_data, proto), \ |
| 130 | TP_PARAMS(__tp_cb_data, args)) |
| 131 | |
| 132 | /* |
| 133 | * __tracepoints_ptrs section is not const (read-only) to let the linker update |
| 134 | * the pointer, allowing PIC code. |
| 135 | */ |
| 136 | #define _DEFINE_TRACEPOINT(name) \ |
| 137 | static const char __tpstrtab_##name[] \ |
| 138 | __attribute__((section("__tracepoints_strings"))) = #name; \ |
| 139 | struct tracepoint __tracepoint_##name \ |
| 140 | __attribute__((section("__tracepoints"))) = \ |
| 141 | { __tpstrtab_##name, 0, NULL }; \ |
| 142 | static struct tracepoint * __tracepoint_ptr_##name \ |
| 143 | __attribute__((used, section("__tracepoints_ptrs"))) = \ |
| 144 | &__tracepoint_##name; |
| 145 | |
| 146 | |
| 147 | #define __register_tracepoint(name, probe, data) \ |
| 148 | __register_trace_##name(probe, data) |
| 149 | #define __unregister_tracepoint(name, probe, data) \ |
| 150 | __unregister_trace_##name(probe, data) |
| 151 | |
| 152 | /* |
| 153 | * Connect a probe to a tracepoint. |
| 154 | * Internal API. |
| 155 | */ |
| 156 | extern |
| 157 | int __tracepoint_probe_register(const char *name, void *probe, void *data); |
| 158 | |
| 159 | /* |
| 160 | * Disconnect a probe from a tracepoint. |
| 161 | * Internal API. |
| 162 | */ |
| 163 | extern |
| 164 | int __tracepoint_probe_unregister(const char *name, void *probe, void *data); |
| 165 | |
| 166 | extern |
| 167 | int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, |
| 168 | int tracepoints_count); |
| 169 | extern |
| 170 | int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start); |
| 171 | |
| 172 | /* |
| 173 | * These weak symbols, the constructor, and destructor take care of |
| 174 | * registering only _one_ instance of the tracepoints per shared-ojbect |
| 175 | * (or for the whole main program). |
| 176 | */ |
| 177 | extern struct tracepoint * const __start___tracepoints_ptrs[] |
| 178 | __attribute__((weak, visibility("hidden"))); |
| 179 | extern struct tracepoint * const __stop___tracepoints_ptrs[] |
| 180 | __attribute__((weak, visibility("hidden"))); |
| 181 | int __tracepoint_registered |
| 182 | __attribute__((weak, visibility("hidden"))); |
| 183 | |
| 184 | static void __attribute__((constructor)) __tracepoints__init(void) |
| 185 | { |
| 186 | if (__tracepoint_registered++) |
| 187 | return; |
| 188 | tracepoint_register_lib(__start___tracepoints_ptrs, |
| 189 | __stop___tracepoints_ptrs - |
| 190 | __start___tracepoints_ptrs); |
| 191 | } |
| 192 | |
| 193 | static void __attribute__((destructor)) __tracepoints__destroy(void) |
| 194 | { |
| 195 | if (--__tracepoint_registered) |
| 196 | return; |
| 197 | tracepoint_unregister_lib(__start___tracepoints_ptrs); |
| 198 | } |
| 199 | |
| 200 | #ifndef TRACEPOINT_EVENT |
| 201 | /* |
| 202 | * Usage of the TRACEPOINT_EVENT macro: |
| 203 | * |
| 204 | * In short, an example: |
| 205 | * |
| 206 | * TRACEPOINT_EVENT(< [com_company_]project_[component_]event >, |
| 207 | * TP_PROTO(int arg0, void *arg1, char *string, size_t strlen, |
| 208 | * long *arg4, size_t arg4_len), |
| 209 | * TP_ARGS(arg0, arg1, string, strlen, arg4, arg4_len), |
| 210 | * TP_FIELDS( |
| 211 | * |
| 212 | * * Integer, printed in base 10 * |
| 213 | * ctf_integer(int, field_a, arg0) |
| 214 | * |
| 215 | * * Integer, printed with 0x base 16 * |
| 216 | * ctf_integer_hex(unsigned long, field_d, arg1) |
| 217 | * |
| 218 | * * Array Sequence, printed as UTF8-encoded array of bytes * |
| 219 | * ctf_array_text(char, field_b, string, FIXED_LEN) |
| 220 | * ctf_sequence_text(char, field_c, string, size_t, strlen) |
| 221 | * |
| 222 | * * String, printed as UTF8-encoded string * |
| 223 | * ctf_string(field_e, string) |
| 224 | * |
| 225 | * * Array sequence of signed integer values * |
| 226 | * ctf_array(long, field_f, arg4, FIXED_LEN4) |
| 227 | * ctf_sequence(long, field_g, arg4, size_t, arg4_len) |
| 228 | * ) |
| 229 | * ) |
| 230 | * |
| 231 | * In more detail: |
| 232 | * |
| 233 | * We define a tracepoint, its arguments, and its 'fast binary record' |
| 234 | * layout. |
| 235 | * |
| 236 | * Firstly, name your tracepoint via TRACEPOINT_EVENT(name, |
| 237 | * |
| 238 | * The name should be a proper C99 identifier. |
| 239 | * The "name" MUST follow these rules to ensure no namespace clash |
| 240 | * occurs: |
| 241 | * |
| 242 | * For projects (applications and libraries) for which an entity |
| 243 | * specific to the project controls the source code and thus its |
| 244 | * tracepoints (typically with a scope larger than a single company): |
| 245 | * |
| 246 | * either: |
| 247 | * project_component_event |
| 248 | * or: |
| 249 | * project_event |
| 250 | * |
| 251 | * Where "project" is the name of the project, |
| 252 | * "component" is the name of the project component (which may |
| 253 | * include several levels of sub-components, e.g. |
| 254 | * ...component_subcomponent_...) where the tracepoint is located |
| 255 | * (optional), |
| 256 | * "event" is the name of the tracepoint event. |
| 257 | * |
| 258 | * For projects issued from a single company wishing to advertise that |
| 259 | * the company controls the source code and thus the tracepoints, the |
| 260 | * "com_" prefix should be used: |
| 261 | * |
| 262 | * either: |
| 263 | * com_company_project_component_event |
| 264 | * or: |
| 265 | * com_company_project_event |
| 266 | * |
| 267 | * Where "company" is the name of the company, |
| 268 | * "project" is the name of the project, |
| 269 | * "component" is the name of the project component (which may |
| 270 | * include several levels of sub-components, e.g. |
| 271 | * ...component_subcomponent_...) where the tracepoint is located |
| 272 | * (optional), |
| 273 | * "event" is the name of the tracepoint event. |
| 274 | * |
| 275 | * |
| 276 | * As an example, let's consider a user-space application "someproject" |
| 277 | * that would have an internal thread scheduler: |
| 278 | * |
| 279 | * TRACEPOINT_EVENT(someproject_sched_switch, |
| 280 | * |
| 281 | * * |
| 282 | * * A function has a regular function arguments |
| 283 | * * prototype, declare it via TP_PROTO(): |
| 284 | * * |
| 285 | * |
| 286 | * TP_PROTO(struct rq *rq, struct task_struct *prev, |
| 287 | * struct task_struct *next), |
| 288 | * |
| 289 | * * |
| 290 | * * Define the call signature of the 'function'. |
| 291 | * * (Design sidenote: we use this instead of a |
| 292 | * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.) |
| 293 | * * |
| 294 | * |
| 295 | * TP_ARGS(rq, prev, next), |
| 296 | * |
| 297 | * * |
| 298 | * * Fast binary tracing: define the trace record via |
| 299 | * * TP_FIELDS(). You can think about it like a |
| 300 | * * regular C structure local variable definition. |
| 301 | * * |
| 302 | * * This is how the trace record is structured and will |
| 303 | * * be saved into the ring buffer. These are the fields |
| 304 | * * that will be exposed to readers. |
| 305 | * * |
| 306 | * * ctf_integer(pid_t, prev_pid, prev->pid) is equivalent |
| 307 | * * to a standard declaraton: |
| 308 | * * |
| 309 | * * pid_t prev_pid; |
| 310 | * * |
| 311 | * * followed by an assignment: |
| 312 | * * |
| 313 | * * prev_pid = prev->pid; |
| 314 | * * |
| 315 | * * ctf_array(char, prev_comm, prev->comm, TASK_COMM_LEN) is |
| 316 | * * equivalent to: |
| 317 | * * |
| 318 | * * char prev_comm[TASK_COMM_LEN]; |
| 319 | * * |
| 320 | * * followed by an assignment: |
| 321 | * * |
| 322 | * * memcpy(prev_comm, prev->comm, TASK_COMM_LEN); |
| 323 | * * |
| 324 | * |
| 325 | * TP_FIELDS( |
| 326 | * ctf_array(char, prev_comm, prev->comm, TASK_COMM_LEN) |
| 327 | * ctf_integer(pid_t, prev_pid, prev->pid) |
| 328 | * ctf_integer(int, prev_prio, prev->prio) |
| 329 | * ctf_array(char, next_comm, next->comm, TASK_COMM_LEN) |
| 330 | * ctf_integer(pid_t, next_pid, next->pid) |
| 331 | * ctf_integer(int, next_prio, next->prio) |
| 332 | * ) |
| 333 | * ) |
| 334 | * |
| 335 | * Do _NOT_ add comma (,) nor semicolon (;) after the TRACEPOINT_EVENT |
| 336 | * declaration. |
| 337 | * |
| 338 | * The TRACEPOINT_SYSTEM must be defined when declaring a |
| 339 | * TRACEPOINT_EVENT. See ust/tracepoint-event.h for information about |
| 340 | * usage of other macros controlling TRACEPOINT_EVENT. |
| 341 | */ |
| 342 | |
| 343 | #define TRACEPOINT_EVENT(name, proto, args, fields) \ |
| 344 | _DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args)) |
| 345 | |
| 346 | #define TRACEPOINT_EVENT_CLASS(name, proto, args, fields) |
| 347 | #define TRACEPOINT_EVENT_INSTANCE(template, name, proto, args) \ |
| 348 | _DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args)) |
| 349 | |
| 350 | /* |
| 351 | * Declaration of tracepoints that take 0 argument. |
| 352 | */ |
| 353 | #define TRACEPOINT_EVENT_NOARGS(name, fields) \ |
| 354 | _DECLARE_TRACEPOINT_NOARGS(name) |
| 355 | |
| 356 | #define TRACEPOINT_EVENT_CLASS_NOARGS(name, fields) |
| 357 | #define TRACEPOINT_EVENT_INSTANCE_NOARGS(template, name) \ |
| 358 | _DECLARE_TRACEPOINT_NOARGS(name) |
| 359 | |
| 360 | #endif /* #ifndef TRACEPOINT_EVENT */ |
| 361 | |
| 362 | #ifndef TRACEPOINT_LOGLEVEL |
| 363 | |
| 364 | /* |
| 365 | * Tracepoint Loglevel Declaration Facility |
| 366 | * |
| 367 | * This is a place-holder the tracepoint loglevel declaration, |
| 368 | * overridden by the tracer implementation. |
| 369 | * |
| 370 | * Typical use of these loglevels: |
| 371 | * |
| 372 | * 1) Declare the mapping between loglevel names and an integer values |
| 373 | * within TRACEPOINT_LOGLEVEL_ENUM, using TP_LOGLEVEL for each tuple. |
| 374 | * Do _NOT_ add comma (,) nor semicolon (;) between the |
| 375 | * TRACEPOINT_LOGLEVEL_ENUM entries. Do _NOT_ add comma (,) nor |
| 376 | * semicolon (;) after the TRACEPOINT_LOGLEVEL_ENUM declaration. The |
| 377 | * name should be a proper C99 identifier. |
| 378 | * |
| 379 | * TRACEPOINT_LOGLEVEL_ENUM( |
| 380 | * TP_LOGLEVEL( < loglevel_name >, < value > ) |
| 381 | * TP_LOGLEVEL( < loglevel_name >, < value > ) |
| 382 | * ... |
| 383 | * ) |
| 384 | * |
| 385 | * e.g.: |
| 386 | * |
| 387 | * TRACEPOINT_LOGLEVEL_ENUM( |
| 388 | * TP_LOGLEVEL(LOG_EMERG, 0) |
| 389 | * TP_LOGLEVEL(LOG_ALERT, 1) |
| 390 | * TP_LOGLEVEL(LOG_CRIT, 2) |
| 391 | * TP_LOGLEVEL(LOG_ERR, 3) |
| 392 | * TP_LOGLEVEL(LOG_WARNING, 4) |
| 393 | * TP_LOGLEVEL(LOG_NOTICE, 5) |
| 394 | * TP_LOGLEVEL(LOG_INFO, 6) |
| 395 | * TP_LOGLEVEL(LOG_DEBUG, 7) |
| 396 | * ) |
| 397 | * |
| 398 | * 2) Then, declare tracepoint loglevels for tracepoints. A |
| 399 | * TRACEPOINT_EVENT should be declared prior to the the |
| 400 | * TRACEPOINT_LOGLEVEL for a given tracepoint name. The first field |
| 401 | * is the name of the tracepoint, the second field is the loglevel |
| 402 | * name. |
| 403 | * |
| 404 | * TRACEPOINT_LOGLEVEL(< [com_company_]project_[component_]event >, |
| 405 | * < loglevel_name >) |
| 406 | * |
| 407 | * The TRACEPOINT_SYSTEM must be defined when declaring a |
| 408 | * TRACEPOINT_LOGLEVEL_ENUM and TRACEPOINT_LOGLEVEL. The tracepoint |
| 409 | * loglevel enumeration apply to the entire TRACEPOINT_SYSTEM. Only one |
| 410 | * tracepoint loglevel enumeration should be declared per tracepoint |
| 411 | * system. |
| 412 | */ |
| 413 | |
| 414 | #define TRACEPOINT_LOGLEVEL_ENUM() |
| 415 | #define TRACEPOINT_LOGLEVEL(name, loglevel) |
| 416 | |
| 417 | #endif /* #ifndef TRACEPOINT_LOGLEVEL */ |
| 418 | |
| 419 | #ifdef __cplusplus |
| 420 | } |
| 421 | #endif |
| 422 | |
| 423 | #endif /* _UST_TRACEPOINT_H */ |