include/ust/tracepoint.h

   1 #ifndef _UST_TRACEPOINT_H
   2 #define _UST_TRACEPOINT_H
   3
   4 /*
   5  * Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   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; either
  12  * version 2.1 of the License, or (at your option) any later version.
  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 #define _LGPL_SOURCE
  29 #include <urcu-bp.h>
  30 #include <ust/immediate.h>
  31 #include <ust/core.h>
  32
  33 struct module;
  34 struct tracepoint;
  35
  36 struct probe {
  37         void *func;
  38         void *data;
  39 };
  40
  41 struct tracepoint {
  42         const char *name;               /* Tracepoint name */
  43         DEFINE_IMV(char, state);        /* State. */
  44         struct probe *probes;
  45 };
  46
  47 #define PARAMS(args...) args
  48
  49 #define TP_PROTO(args...)       args
  50 #define TP_ARGS(args...)        args
  51
  52 #define CONFIG_TRACEPOINTS
  53 #ifdef CONFIG_TRACEPOINTS
  54
  55 /*
  56  * it_func[0] is never NULL because there is at least one element in the array
  57  * when the array itself is non NULL.
  58  */
  59 #define __DO_TRACE(tp, proto, args)                                     \
  60         do {                                                            \
  61                 struct probe *it_probe_ptr;                             \
  62                 void *it_func;                                          \
  63                 void *__data;                                           \
  64                                                                         \
  65                 rcu_read_lock();                                        \
  66                 it_probe_ptr = rcu_dereference((tp)->probes);           \
  67                 if (it_probe_ptr) {                                     \
  68                         do {                                            \
  69                                 it_func = (it_probe_ptr)->func;         \
  70                                 __data = (it_probe_ptr)->data;          \
  71                                 ((void(*)(proto))(it_func))(args);      \
  72                         } while ((++it_probe_ptr)->func);               \
  73                 }                                                       \
  74                 rcu_read_unlock();                                      \
  75         } while (0)
  76
  77 #define __CHECK_TRACE(name, generic, proto, args)                       \
  78         do {                                                            \
  79                 if (!generic) {                                         \
  80                         if (unlikely(imv_read(__tracepoint_##name.state))) \
  81                                 __DO_TRACE(&__tracepoint_##name,        \
  82                                         TP_PROTO(proto), TP_ARGS(args));        \
  83                 } else {                                                \
  84                         if (unlikely(_imv_read(__tracepoint_##name.state))) \
  85                                 __DO_TRACE(&__tracepoint_##name,        \
  86                                         TP_PROTO(proto), TP_ARGS(args));        \
  87                 }                                                       \
  88         } while (0)
  89
  90 /*
  91  * Make sure the alignment of the structure in the __tracepoints section will
  92  * not add unwanted padding between the beginning of the section and the
  93  * structure. Force alignment to the same alignment as the section start.
  94  *
  95  * The "generic" argument, passed to the declared __trace_##name inline
  96  * function controls which tracepoint enabling mechanism must be used.
  97  * If generic is true, a variable read is used.
  98  * If generic is false, immediate values are used.
  99  */
 100 #define __DECLARE_TRACE(name, proto, args, data_proto, data_args)       \
 101         extern struct tracepoint __tracepoint_##name;                   \
 102         static inline void trace_##name(proto)                          \
 103         {                                                               \
 104                 __CHECK_TRACE(name, 0, TP_PROTO(data_proto),            \
 105                               TP_ARGS(data_args));                      \
 106         }                                                               \
 107         static inline void _trace_##name(proto)                         \
 108         {                                                               \
 109                 __CHECK_TRACE(name, 1, TP_PROTO(data_proto),            \
 110                               TP_ARGS(data_args));                      \
 111         }                                                               \
 112         static inline int                                               \
 113         register_trace_##name(void (*probe)(data_proto), void *data)    \
 114         {                                                               \
 115                 return tracepoint_probe_register(#name, (void *)probe,  \
 116                                                  data);                 \
 117                                                                         \
 118         }                                                               \
 119         static inline int                                               \
 120         unregister_trace_##name(void (*probe)(data_proto), void *data)  \
 121         {                                                               \
 122                 return tracepoint_probe_unregister(#name, (void *)probe, \
 123                                                    data);               \
 124         }
 125
 126 #define DEFINE_TRACE_FN(name, reg, unreg)                               \
 127         static const char __tpstrtab_##name[]                           \
 128         __attribute__((section("__tracepoints_strings"))) = #name;      \
 129         struct tracepoint __tracepoint_##name                           \
 130         __attribute__((section("__tracepoints"))) =                     \
 131                 { __tpstrtab_##name, 0, NULL };                         \
 132         static struct tracepoint * const __tracepoint_ptr_##name        \
 133         __attribute__((used, section("__tracepoints_ptrs"))) =          \
 134                 &__tracepoint_##name;
 135
 136 #define DEFINE_TRACE(name)                                              \
 137         DEFINE_TRACE_FN(name, NULL, NULL)
 138
 139 extern void tracepoint_update_probe_range(struct tracepoint * const *begin,
 140         struct tracepoint * const *end);
 141
 142 #else /* !CONFIG_TRACEPOINTS */
 143 #define __DECLARE_TRACE(name, proto, args)                              \
 144         static inline void trace_##name(proto)                          \
 145         { }                                                             \
 146         static inline void _trace_##name(proto)                         \
 147         { }                                                             \
 148         static inline int register_trace_##name(void (*probe)(proto), void *data)       \
 149         {                                                               \
 150                 return -ENOSYS;                                         \
 151         }                                                               \
 152         static inline int unregister_trace_##name(void (*probe)(proto), void *data)     \
 153         {                                                               \
 154                 return -ENOSYS;                                         \
 155         }
 156
 157 #define DEFINE_TRACE(name)
 158 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
 159 #define EXPORT_TRACEPOINT_SYMBOL(name)
 160
 161 static inline void tracepoint_update_probe_range(struct tracepoint *begin,
 162         struct tracepoint *end)
 163 { }
 164 #endif /* CONFIG_TRACEPOINTS */
 165
 166 #define DECLARE_TRACE(name, proto, args)                        \
 167         __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args),      \
 168                         PARAMS(void *__data, proto),            \
 169                         PARAMS(__data, args))
 170
 171 /*
 172  * Connect a probe to a tracepoint.
 173  * Internal API, should not be used directly.
 174  */
 175 extern int tracepoint_probe_register(const char *name, void *probe, void *data);
 176
 177 /*
 178  * Disconnect a probe from a tracepoint.
 179  * Internal API, should not be used directly.
 180  */
 181 extern int tracepoint_probe_unregister(const char *name, void *probe, void *data);
 182
 183 extern int tracepoint_probe_register_noupdate(const char *name, void *probe,
 184                                               void *data);
 185 extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
 186                                                 void *data);
 187 extern void tracepoint_probe_update_all(void);
 188
 189 struct tracepoint_iter {
 190 //ust// struct module *module;
 191         struct tracepoint_lib *lib;
 192         struct tracepoint * const *tracepoint;
 193 };
 194
 195 extern void tracepoint_iter_start(struct tracepoint_iter *iter);
 196 extern void tracepoint_iter_next(struct tracepoint_iter *iter);
 197 extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
 198 extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
 199 extern int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
 200         struct tracepoint * const *begin, struct tracepoint * const *end);
 201
 202 /*
 203  * tracepoint_synchronize_unregister must be called between the last tracepoint
 204  * probe unregistration and the end of module exit to make sure there is no
 205  * caller executing a probe when it is freed.
 206  */
 207 static inline void tracepoint_synchronize_unregister(void)
 208 {
 209 //ust// synchronize_sched();
 210 }
 211
 212 struct tracepoint_lib {
 213         struct tracepoint * const *tracepoints_start;
 214         int tracepoints_count;
 215         struct cds_list_head list;
 216 };
 217
 218 extern int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
 219                                    int tracepoints_count);
 220 extern int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
 221
 222 #define TRACEPOINT_LIB                                                  \
 223         extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
 224         extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
 225         static struct tracepoint * const __tracepoint_ptr_dummy         \
 226         __attribute__((used, section("__tracepoints_ptrs"))) = NULL;    \
 227         static void __attribute__((constructor)) __tracepoints__init(void)      \
 228         {                                                                       \
 229                 tracepoint_register_lib(__start___tracepoints_ptrs,                     \
 230                                         __stop___tracepoints_ptrs -                     \
 231                                         __start___tracepoints_ptrs);                    \
 232         }                                                                       \
 233                                                                                 \
 234         static void __attribute__((destructor)) __tracepoints__destroy(void)    \
 235         {                                                                       \
 236                 tracepoint_unregister_lib(__start___tracepoints_ptrs);          \
 237         }
 238
 239
 240 #ifndef TRACE_EVENT
 241 /*
 242  * For use with the TRACE_EVENT macro:
 243  *
 244  * We define a tracepoint, its arguments, its printf format
 245  * and its 'fast binary record' layout.
 246  *
 247  * Firstly, name your tracepoint via TRACE_EVENT(name : the
 248  * 'subsystem_event' notation is fine.
 249  *
 250  * Think about this whole construct as the
 251  * 'trace_sched_switch() function' from now on.
 252  *
 253  *
 254  *  TRACE_EVENT(sched_switch,
 255  *
 256  *      *
 257  *      * A function has a regular function arguments
 258  *      * prototype, declare it via TP_PROTO():
 259  *      *
 260  *
 261  *      TP_PROTO(struct rq *rq, struct task_struct *prev,
 262  *               struct task_struct *next),
 263  *
 264  *      *
 265  *      * Define the call signature of the 'function'.
 266  *      * (Design sidenote: we use this instead of a
 267  *      *  TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
 268  *      *
 269  *
 270  *      TP_ARGS(rq, prev, next),
 271  *
 272  *      *
 273  *      * Fast binary tracing: define the trace record via
 274  *      * TP_STRUCT__entry(). You can think about it like a
 275  *      * regular C structure local variable definition.
 276  *      *
 277  *      * This is how the trace record is structured and will
 278  *      * be saved into the ring buffer. These are the fields
 279  *      * that will be exposed to readers.
 280  *      *
 281  *      * The declared 'local variable' is called '__entry'
 282  *      *
 283  *      * __field(pid_t, prev_prid) is equivalent to a standard declariton:
 284  *      *
 285  *      *       pid_t   prev_pid;
 286  *      *
 287  *      * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
 288  *      *
 289  *      *       char    prev_comm[TASK_COMM_LEN];
 290  *      *
 291  *
 292  *      TP_STRUCT__entry(
 293  *              __array(        char,   prev_comm,      TASK_COMM_LEN   )
 294  *              __field(        pid_t,  prev_pid                        )
 295  *              __field(        int,    prev_prio                       )
 296  *              __array(        char,   next_comm,      TASK_COMM_LEN   )
 297  *              __field(        pid_t,  next_pid                        )
 298  *              __field(        int,    next_prio                       )
 299  *      ),
 300  *
 301  *      *
 302  *      * Assign the entry into the trace record, by embedding
 303  *      * a full C statement block into TP_fast_assign(). You
 304  *      * can refer to the trace record as '__entry' -
 305  *      * otherwise you can put arbitrary C code in here.
 306  *      *
 307  *      * Note: this C code will execute every time a trace event
 308  *      * happens, on an active tracepoint.
 309  *      *
 310  *
 311  *      TP_fast_assign(
 312  *              memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
 313  *              __entry->prev_pid       = prev->pid;
 314  *              __entry->prev_prio      = prev->prio;
 315  *              memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
 316  *              __entry->next_pid       = next->pid;
 317  *              __entry->next_prio      = next->prio;
 318  *      )
 319  *
 320  *      *
 321  *      * Formatted output of a trace record via TP_printf().
 322  *      * This is how the tracepoint will appear under debugging
 323  *      * of tracepoints.
 324  *      *
 325  *      * (raw-binary tracing wont actually perform this step.)
 326  *      *
 327  *
 328  *      TP_printf("task %s:%d [%d] ==> %s:%d [%d]",
 329  *              __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
 330  *              __entry->next_comm, __entry->next_pid, __entry->next_prio),
 331  *
 332  * );
 333  *
 334  * This macro construct is thus used for the regular printf format
 335  * tracing setup.
 336  *
 337  * A set of (un)registration functions can be passed to the variant
 338  * TRACE_EVENT_FN to perform any (un)registration work.
 339  */
 340
 341 struct trace_event {
 342         const char *name;
 343         int (*regfunc)(void *data);
 344         int (*unregfunc)(void *data);
 345 };
 346
 347 struct trace_event_lib {
 348         struct trace_event * const *trace_events_start;
 349         int trace_events_count;
 350         struct cds_list_head list;
 351 };
 352
 353 struct trace_event_iter {
 354         struct trace_event_lib *lib;
 355         struct trace_event * const *trace_event;
 356 };
 357
 358 extern void lock_trace_events(void);
 359 extern void unlock_trace_events(void);
 360
 361 extern void trace_event_iter_start(struct trace_event_iter *iter);
 362 extern void trace_event_iter_next(struct trace_event_iter *iter);
 363 extern void trace_event_iter_reset(struct trace_event_iter *iter);
 364
 365 extern int trace_event_get_iter_range(struct trace_event * const **trace_event,
 366                                       struct trace_event * const *begin,
 367                                       struct trace_event * const *end);
 368
 369 extern void trace_event_update_process(void);
 370 extern int is_trace_event_enabled(const char *channel, const char *name);
 371
 372 extern int trace_event_register_lib(struct trace_event * const *start_trace_events,
 373                                     int trace_event_count);
 374
 375 extern int trace_event_unregister_lib(struct trace_event * const *start_trace_events);
 376
 377 #define TRACE_EVENT_LIB                                                 \
 378         extern struct trace_event * const __start___trace_events_ptrs[] \
 379         __attribute__((weak, visibility("hidden")));                    \
 380         extern struct trace_event * const __stop___trace_events_ptrs[]  \
 381         __attribute__((weak, visibility("hidden")));                    \
 382         static struct trace_event * const __event_ptrs_dummy            \
 383         __attribute__((used, section("__trace_events_ptrs"))) = NULL;   \
 384         static void __attribute__((constructor))                        \
 385         __trace_events__init(void)                                      \
 386         {                                                               \
 387                 trace_event_register_lib(__start___trace_events_ptrs,   \
 388                                          __stop___trace_events_ptrs -   \
 389                                          __start___trace_events_ptrs);  \
 390         }                                                               \
 391                                                                         \
 392         static void __attribute__((destructor))                         \
 393         __trace_event__destroy(void)                                    \
 394         {                                                               \
 395                 trace_event_unregister_lib(__start___trace_events_ptrs);\
 396         }
 397
 398 #define DECLARE_TRACE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
 399 #define DEFINE_TRACE_EVENT(template, name, proto, args)         \
 400         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 401 #define DEFINE_TRACE_EVENT_PRINT(template, name, proto, args, print)    \
 402         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 403
 404 #define TRACE_EVENT(name, proto, args, struct, assign, print)   \
 405         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 406 #define TRACE_EVENT_FN(name, proto, args, struct,               \
 407                 assign, print, reg, unreg)                      \
 408         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 409
 410 #endif /* ifdef TRACE_EVENT (see note above) */
 411
 412
 413 #endif /* _UST_TRACEPOINT_H */