include/linux/tracepoint.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 #ifndef _LINUX_TRACEPOINT_H
   3 #define _LINUX_TRACEPOINT_H
   4
   5 /*
   6  * Kernel Tracepoint API.
   7  *
   8  * See Documentation/trace/tracepoints.rst.
   9  *
  10  * Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  11  *
  12  * Heavily inspired from the Linux Kernel Markers.
  13  */
  14
  15 #include <linux/smp.h>
  16 #include <linux/srcu.h>
  17 #include <linux/errno.h>
  18 #include <linux/types.h>
  19 #include <linux/cpumask.h>
  20 #include <linux/rcupdate.h>
  21 #include <linux/tracepoint-defs.h>
  22 #include <linux/static_call.h>
  23
  24 struct module;
  25 struct tracepoint;
  26 struct notifier_block;
  27
  28 struct trace_eval_map {
  29         const char              *system;
  30         const char              *eval_string;
  31         unsigned long           eval_value;
  32 };
  33
  34 #define TRACEPOINT_DEFAULT_PRIO 10
  35
  36 extern struct srcu_struct tracepoint_srcu;
  37
  38 extern int
  39 tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
  40 extern int
  41 tracepoint_probe_register_prio(struct tracepoint *tp, void *probe, void *data,
  42                                int prio);
  43 extern int
  44 tracepoint_probe_register_prio_may_exist(struct tracepoint *tp, void *probe, void *data,
  45                                          int prio);
  46 extern int
  47 tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data);
  48 static inline int
  49 tracepoint_probe_register_may_exist(struct tracepoint *tp, void *probe,
  50                                     void *data)
  51 {
  52         return tracepoint_probe_register_prio_may_exist(tp, probe, data,
  53                                                         TRACEPOINT_DEFAULT_PRIO);
  54 }
  55 extern void
  56 for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
  57                 void *priv);
  58
  59 #ifdef CONFIG_MODULES
  60 struct tp_module {
  61         struct list_head list;
  62         struct module *mod;
  63 };
  64
  65 bool trace_module_has_bad_taint(struct module *mod);
  66 extern int register_tracepoint_module_notifier(struct notifier_block *nb);
  67 extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
  68 #else
  69 static inline bool trace_module_has_bad_taint(struct module *mod)
  70 {
  71         return false;
  72 }
  73 static inline
  74 int register_tracepoint_module_notifier(struct notifier_block *nb)
  75 {
  76         return 0;
  77 }
  78 static inline
  79 int unregister_tracepoint_module_notifier(struct notifier_block *nb)
  80 {
  81         return 0;
  82 }
  83 #endif /* CONFIG_MODULES */
  84
  85 /*
  86  * tracepoint_synchronize_unregister must be called between the last tracepoint
  87  * probe unregistration and the end of module exit to make sure there is no
  88  * caller executing a probe when it is freed.
  89  */
  90 #ifdef CONFIG_TRACEPOINTS
  91 static inline void tracepoint_synchronize_unregister(void)
  92 {
  93         synchronize_srcu(&tracepoint_srcu);
  94         synchronize_rcu();
  95 }
  96 #else
  97 static inline void tracepoint_synchronize_unregister(void)
  98 { }
  99 #endif
 100
 101 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 102 extern int syscall_regfunc(void);
 103 extern void syscall_unregfunc(void);
 104 #endif /* CONFIG_HAVE_SYSCALL_TRACEPOINTS */
 105
 106 #ifndef PARAMS
 107 #define PARAMS(args...) args
 108 #endif
 109
 110 #define TRACE_DEFINE_ENUM(x)
 111 #define TRACE_DEFINE_SIZEOF(x)
 112
 113 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
 114 static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 115 {
 116         return offset_to_ptr(p);
 117 }
 118
 119 #define __TRACEPOINT_ENTRY(name)                                        \
 120         asm("   .section \"__tracepoints_ptrs\", \"a\"          \n"     \
 121             "   .balign 4                                       \n"     \
 122             "   .long   __tracepoint_" #name " - .              \n"     \
 123             "   .previous                                       \n")
 124 #else
 125 static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 126 {
 127         return *p;
 128 }
 129
 130 #define __TRACEPOINT_ENTRY(name)                                         \
 131         static tracepoint_ptr_t __tracepoint_ptr_##name __used           \
 132         __section("__tracepoints_ptrs") = &__tracepoint_##name
 133 #endif
 134
 135 #endif /* _LINUX_TRACEPOINT_H */
 136
 137 /*
 138  * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
 139  *  file ifdef protection.
 140  *  This is due to the way trace events work. If a file includes two
 141  *  trace event headers under one "CREATE_TRACE_POINTS" the first include
 142  *  will override the TRACE_EVENT and break the second include.
 143  */
 144
 145 #ifndef DECLARE_TRACE
 146
 147 #define TP_PROTO(args...)       args
 148 #define TP_ARGS(args...)        args
 149 #define TP_CONDITION(args...)   args
 150
 151 /*
 152  * Individual subsystem my have a separate configuration to
 153  * enable their tracepoints. By default, this file will create
 154  * the tracepoints if CONFIG_TRACEPOINT is defined. If a subsystem
 155  * wants to be able to disable its tracepoints from being created
 156  * it can define NOTRACE before including the tracepoint headers.
 157  */
 158 #if defined(CONFIG_TRACEPOINTS) && !defined(NOTRACE)
 159 #define TRACEPOINTS_ENABLED
 160 #endif
 161
 162 #ifdef TRACEPOINTS_ENABLED
 163
 164 #ifdef CONFIG_HAVE_STATIC_CALL
 165 #define __DO_TRACE_CALL(name, args)                                     \
 166         do {                                                            \
 167                 struct tracepoint_func *it_func_ptr;                    \
 168                 void *__data;                                           \
 169                 it_func_ptr =                                           \
 170                         rcu_dereference_raw((&__tracepoint_##name)->funcs); \
 171                 if (it_func_ptr) {                                      \
 172                         __data = (it_func_ptr)->data;                   \
 173                         static_call(tp_func_##name)(__data, args);      \
 174                 }                                                       \
 175         } while (0)
 176 #else
 177 #define __DO_TRACE_CALL(name, args)     __traceiter_##name(NULL, args)
 178 #endif /* CONFIG_HAVE_STATIC_CALL */
 179
 180 /*
 181  * it_func[0] is never NULL because there is at least one element in the array
 182  * when the array itself is non NULL.
 183  */
 184 #define __DO_TRACE(name, args, cond, rcuidle)                           \
 185         do {                                                            \
 186                 int __maybe_unused __idx = 0;                           \
 187                                                                         \
 188                 if (!(cond))                                            \
 189                         return;                                         \
 190                                                                         \
 191                 /* srcu can't be used from NMI */                       \
 192                 WARN_ON_ONCE(rcuidle && in_nmi());                      \
 193                                                                         \
 194                 /* keep srcu and sched-rcu usage consistent */          \
 195                 preempt_disable_notrace();                              \
 196                                                                         \
 197                 /*                                                      \
 198                  * For rcuidle callers, use srcu since sched-rcu        \
 199                  * doesn't work from the idle path.                     \
 200                  */                                                     \
 201                 if (rcuidle) {                                          \
 202                         __idx = srcu_read_lock_notrace(&tracepoint_srcu);\
 203                         rcu_irq_enter_irqson();                         \
 204                 }                                                       \
 205                                                                         \
 206                 __DO_TRACE_CALL(name, TP_ARGS(args));                   \
 207                                                                         \
 208                 if (rcuidle) {                                          \
 209                         rcu_irq_exit_irqson();                          \
 210                         srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\
 211                 }                                                       \
 212                                                                         \
 213                 preempt_enable_notrace();                               \
 214         } while (0)
 215
 216 #ifndef MODULE
 217 #define __DECLARE_TRACE_RCU(name, proto, args, cond)                    \
 218         static inline void trace_##name##_rcuidle(proto)                \
 219         {                                                               \
 220                 if (static_key_false(&__tracepoint_##name.key))         \
 221                         __DO_TRACE(name,                                \
 222                                 TP_ARGS(args),                          \
 223                                 TP_CONDITION(cond), 1);                 \
 224         }
 225 #else
 226 #define __DECLARE_TRACE_RCU(name, proto, args, cond)
 227 #endif
 228
 229 /*
 230  * Make sure the alignment of the structure in the __tracepoints section will
 231  * not add unwanted padding between the beginning of the section and the
 232  * structure. Force alignment to the same alignment as the section start.
 233  *
 234  * When lockdep is enabled, we make sure to always test if RCU is
 235  * "watching" regardless if the tracepoint is enabled or not. Tracepoints
 236  * require RCU to be active, and it should always warn at the tracepoint
 237  * site if it is not watching, as it will need to be active when the
 238  * tracepoint is enabled.
 239  */
 240 #define __DECLARE_TRACE(name, proto, args, cond, data_proto)            \
 241         extern int __traceiter_##name(data_proto);                      \
 242         DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name);        \
 243         extern struct tracepoint __tracepoint_##name;                   \
 244         static inline void trace_##name(proto)                          \
 245         {                                                               \
 246                 if (static_key_false(&__tracepoint_##name.key))         \
 247                         __DO_TRACE(name,                                \
 248                                 TP_ARGS(args),                          \
 249                                 TP_CONDITION(cond), 0);                 \
 250                 if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) {             \
 251                         WARN_ON_ONCE(!rcu_is_watching());               \
 252                 }                                                       \
 253         }                                                               \
 254         __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args),          \
 255                             PARAMS(cond))                               \
 256         static inline int                                               \
 257         register_trace_##name(void (*probe)(data_proto), void *data)    \
 258         {                                                               \
 259                 return tracepoint_probe_register(&__tracepoint_##name,  \
 260                                                 (void *)probe, data);   \
 261         }                                                               \
 262         static inline int                                               \
 263         register_trace_prio_##name(void (*probe)(data_proto), void *data,\
 264                                    int prio)                            \
 265         {                                                               \
 266                 return tracepoint_probe_register_prio(&__tracepoint_##name, \
 267                                               (void *)probe, data, prio); \
 268         }                                                               \
 269         static inline int                                               \
 270         unregister_trace_##name(void (*probe)(data_proto), void *data)  \
 271         {                                                               \
 272                 return tracepoint_probe_unregister(&__tracepoint_##name,\
 273                                                 (void *)probe, data);   \
 274         }                                                               \
 275         static inline void                                              \
 276         check_trace_callback_type_##name(void (*cb)(data_proto))        \
 277         {                                                               \
 278         }                                                               \
 279         static inline bool                                              \
 280         trace_##name##_enabled(void)                                    \
 281         {                                                               \
 282                 return static_key_false(&__tracepoint_##name.key);      \
 283         }
 284
 285 /*
 286  * We have no guarantee that gcc and the linker won't up-align the tracepoint
 287  * structures, so we create an array of pointers that will be used for iteration
 288  * on the tracepoints.
 289  */
 290 #define DEFINE_TRACE_FN(_name, _reg, _unreg, proto, args)               \
 291         static const char __tpstrtab_##_name[]                          \
 292         __section("__tracepoints_strings") = #_name;                    \
 293         extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name); \
 294         int __traceiter_##_name(void *__data, proto);                   \
 295         struct tracepoint __tracepoint_##_name  __used                  \
 296         __section("__tracepoints") = {                                  \
 297                 .name = __tpstrtab_##_name,                             \
 298                 .key = STATIC_KEY_INIT_FALSE,                           \
 299                 .static_call_key = &STATIC_CALL_KEY(tp_func_##_name),   \
 300                 .static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \
 301                 .iterator = &__traceiter_##_name,                       \
 302                 .regfunc = _reg,                                        \
 303                 .unregfunc = _unreg,                                    \
 304                 .funcs = NULL };                                        \
 305         __TRACEPOINT_ENTRY(_name);                                      \
 306         int __traceiter_##_name(void *__data, proto)                    \
 307         {                                                               \
 308                 struct tracepoint_func *it_func_ptr;                    \
 309                 void *it_func;                                          \
 310                                                                         \
 311                 it_func_ptr =                                           \
 312                         rcu_dereference_raw((&__tracepoint_##_name)->funcs); \
 313                 if (it_func_ptr) {                                      \
 314                         do {                                            \
 315                                 it_func = READ_ONCE((it_func_ptr)->func); \
 316                                 __data = (it_func_ptr)->data;           \
 317                                 ((void(*)(void *, proto))(it_func))(__data, args); \
 318                         } while ((++it_func_ptr)->func);                \
 319                 }                                                       \
 320                 return 0;                                               \
 321         }                                                               \
 322         DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);
 323
 324 #define DEFINE_TRACE(name, proto, args)         \
 325         DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args));
 326
 327 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)                              \
 328         EXPORT_SYMBOL_GPL(__tracepoint_##name);                         \
 329         EXPORT_SYMBOL_GPL(__traceiter_##name);                          \
 330         EXPORT_STATIC_CALL_GPL(tp_func_##name)
 331 #define EXPORT_TRACEPOINT_SYMBOL(name)                                  \
 332         EXPORT_SYMBOL(__tracepoint_##name);                             \
 333         EXPORT_SYMBOL(__traceiter_##name);                              \
 334         EXPORT_STATIC_CALL(tp_func_##name)
 335
 336
 337 #else /* !TRACEPOINTS_ENABLED */
 338 #define __DECLARE_TRACE(name, proto, args, cond, data_proto)            \
 339         static inline void trace_##name(proto)                          \
 340         { }                                                             \
 341         static inline void trace_##name##_rcuidle(proto)                \
 342         { }                                                             \
 343         static inline int                                               \
 344         register_trace_##name(void (*probe)(data_proto),                \
 345                               void *data)                               \
 346         {                                                               \
 347                 return -ENOSYS;                                         \
 348         }                                                               \
 349         static inline int                                               \
 350         unregister_trace_##name(void (*probe)(data_proto),              \
 351                                 void *data)                             \
 352         {                                                               \
 353                 return -ENOSYS;                                         \
 354         }                                                               \
 355         static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
 356         {                                                               \
 357         }                                                               \
 358         static inline bool                                              \
 359         trace_##name##_enabled(void)                                    \
 360         {                                                               \
 361                 return false;                                           \
 362         }
 363
 364 #define DEFINE_TRACE_FN(name, reg, unreg, proto, args)
 365 #define DEFINE_TRACE(name, proto, args)
 366 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
 367 #define EXPORT_TRACEPOINT_SYMBOL(name)
 368
 369 #endif /* TRACEPOINTS_ENABLED */
 370
 371 #ifdef CONFIG_TRACING
 372 /**
 373  * tracepoint_string - register constant persistent string to trace system
 374  * @str - a constant persistent string that will be referenced in tracepoints
 375  *
 376  * If constant strings are being used in tracepoints, it is faster and
 377  * more efficient to just save the pointer to the string and reference
 378  * that with a printf "%s" instead of saving the string in the ring buffer
 379  * and wasting space and time.
 380  *
 381  * The problem with the above approach is that userspace tools that read
 382  * the binary output of the trace buffers do not have access to the string.
 383  * Instead they just show the address of the string which is not very
 384  * useful to users.
 385  *
 386  * With tracepoint_string(), the string will be registered to the tracing
 387  * system and exported to userspace via the debugfs/tracing/printk_formats
 388  * file that maps the string address to the string text. This way userspace
 389  * tools that read the binary buffers have a way to map the pointers to
 390  * the ASCII strings they represent.
 391  *
 392  * The @str used must be a constant string and persistent as it would not
 393  * make sense to show a string that no longer exists. But it is still fine
 394  * to be used with modules, because when modules are unloaded, if they
 395  * had tracepoints, the ring buffers are cleared too. As long as the string
 396  * does not change during the life of the module, it is fine to use
 397  * tracepoint_string() within a module.
 398  */
 399 #define tracepoint_string(str)                                          \
 400         ({                                                              \
 401                 static const char *___tp_str __tracepoint_string = str; \
 402                 ___tp_str;                                              \
 403         })
 404 #define __tracepoint_string     __used __section("__tracepoint_str")
 405 #else
 406 /*
 407  * tracepoint_string() is used to save the string address for userspace
 408  * tracing tools. When tracing isn't configured, there's no need to save
 409  * anything.
 410  */
 411 # define tracepoint_string(str) str
 412 # define __tracepoint_string
 413 #endif
 414
 415 #define DECLARE_TRACE(name, proto, args)                                \
 416         __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args),              \
 417                         cpu_online(raw_smp_processor_id()),             \
 418                         PARAMS(void *__data, proto))
 419
 420 #define DECLARE_TRACE_CONDITION(name, proto, args, cond)                \
 421         __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args),              \
 422                         cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \
 423                         PARAMS(void *__data, proto))
 424
 425 #define TRACE_EVENT_FLAGS(event, flag)
 426
 427 #define TRACE_EVENT_PERF_PERM(event, expr...)
 428
 429 #endif /* DECLARE_TRACE */
 430
 431 #ifndef TRACE_EVENT
 432 /*
 433  * For use with the TRACE_EVENT macro:
 434  *
 435  * We define a tracepoint, its arguments, its printk format
 436  * and its 'fast binary record' layout.
 437  *
 438  * Firstly, name your tracepoint via TRACE_EVENT(name : the
 439  * 'subsystem_event' notation is fine.
 440  *
 441  * Think about this whole construct as the
 442  * 'trace_sched_switch() function' from now on.
 443  *
 444  *
 445  *  TRACE_EVENT(sched_switch,
 446  *
 447  *      *
 448  *      * A function has a regular function arguments
 449  *      * prototype, declare it via TP_PROTO():
 450  *      *
 451  *
 452  *      TP_PROTO(struct rq *rq, struct task_struct *prev,
 453  *               struct task_struct *next),
 454  *
 455  *      *
 456  *      * Define the call signature of the 'function'.
 457  *      * (Design sidenote: we use this instead of a
 458  *      *  TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
 459  *      *
 460  *
 461  *      TP_ARGS(rq, prev, next),
 462  *
 463  *      *
 464  *      * Fast binary tracing: define the trace record via
 465  *      * TP_STRUCT__entry(). You can think about it like a
 466  *      * regular C structure local variable definition.
 467  *      *
 468  *      * This is how the trace record is structured and will
 469  *      * be saved into the ring buffer. These are the fields
 470  *      * that will be exposed to user-space in
 471  *      * /sys/kernel/debug/tracing/events/<*>/format.
 472  *      *
 473  *      * The declared 'local variable' is called '__entry'
 474  *      *
 475  *      * __field(pid_t, prev_pid) is equivalent to a standard declaration:
 476  *      *
 477  *      *       pid_t   prev_pid;
 478  *      *
 479  *      * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
 480  *      *
 481  *      *       char    prev_comm[TASK_COMM_LEN];
 482  *      *
 483  *
 484  *      TP_STRUCT__entry(
 485  *              __array(        char,   prev_comm,      TASK_COMM_LEN   )
 486  *              __field(        pid_t,  prev_pid                        )
 487  *              __field(        int,    prev_prio                       )
 488  *              __array(        char,   next_comm,      TASK_COMM_LEN   )
 489  *              __field(        pid_t,  next_pid                        )
 490  *              __field(        int,    next_prio                       )
 491  *      ),
 492  *
 493  *      *
 494  *      * Assign the entry into the trace record, by embedding
 495  *      * a full C statement block into TP_fast_assign(). You
 496  *      * can refer to the trace record as '__entry' -
 497  *      * otherwise you can put arbitrary C code in here.
 498  *      *
 499  *      * Note: this C code will execute every time a trace event
 500  *      * happens, on an active tracepoint.
 501  *      *
 502  *
 503  *      TP_fast_assign(
 504  *              memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
 505  *              __entry->prev_pid       = prev->pid;
 506  *              __entry->prev_prio      = prev->prio;
 507  *              memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
 508  *              __entry->next_pid       = next->pid;
 509  *              __entry->next_prio      = next->prio;
 510  *      ),
 511  *
 512  *      *
 513  *      * Formatted output of a trace record via TP_printk().
 514  *      * This is how the tracepoint will appear under ftrace
 515  *      * plugins that make use of this tracepoint.
 516  *      *
 517  *      * (raw-binary tracing wont actually perform this step.)
 518  *      *
 519  *
 520  *      TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
 521  *              __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
 522  *              __entry->next_comm, __entry->next_pid, __entry->next_prio),
 523  *
 524  * );
 525  *
 526  * This macro construct is thus used for the regular printk format
 527  * tracing setup, it is used to construct a function pointer based
 528  * tracepoint callback (this is used by programmatic plugins and
 529  * can also by used by generic instrumentation like SystemTap), and
 530  * it is also used to expose a structured trace record in
 531  * /sys/kernel/debug/tracing/events/.
 532  *
 533  * A set of (un)registration functions can be passed to the variant
 534  * TRACE_EVENT_FN to perform any (un)registration work.
 535  */
 536
 537 #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
 538 #define DEFINE_EVENT(template, name, proto, args)               \
 539         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 540 #define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\
 541         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 542 #define DEFINE_EVENT_PRINT(template, name, proto, args, print)  \
 543         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 544 #define DEFINE_EVENT_CONDITION(template, name, proto,           \
 545                                args, cond)                      \
 546         DECLARE_TRACE_CONDITION(name, PARAMS(proto),            \
 547                                 PARAMS(args), PARAMS(cond))
 548
 549 #define TRACE_EVENT(name, proto, args, struct, assign, print)   \
 550         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 551 #define TRACE_EVENT_FN(name, proto, args, struct,               \
 552                 assign, print, reg, unreg)                      \
 553         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 554 #define TRACE_EVENT_FN_COND(name, proto, args, cond, struct,            \
 555                 assign, print, reg, unreg)                      \
 556         DECLARE_TRACE_CONDITION(name, PARAMS(proto),    \
 557                         PARAMS(args), PARAMS(cond))
 558 #define TRACE_EVENT_CONDITION(name, proto, args, cond,          \
 559                               struct, assign, print)            \
 560         DECLARE_TRACE_CONDITION(name, PARAMS(proto),            \
 561                                 PARAMS(args), PARAMS(cond))
 562
 563 #define TRACE_EVENT_FLAGS(event, flag)
 564
 565 #define TRACE_EVENT_PERF_PERM(event, expr...)
 566
 567 #define DECLARE_EVENT_NOP(name, proto, args)                            \
 568         static inline void trace_##name(proto)                          \
 569         { }                                                             \
 570         static inline bool trace_##name##_enabled(void)                 \
 571         {                                                               \
 572                 return false;                                           \
 573         }
 574
 575 #define TRACE_EVENT_NOP(name, proto, args, struct, assign, print)       \
 576         DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
 577
 578 #define DECLARE_EVENT_CLASS_NOP(name, proto, args, tstruct, assign, print)
 579 #define DEFINE_EVENT_NOP(template, name, proto, args)                   \
 580         DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
 581
 582 #endif /* ifdef TRACE_EVENT (see note above) */