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