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