| 1 | #ifndef _LINUX_TRACEPOINT_H |
| 2 | #define _LINUX_TRACEPOINT_H |
| 3 | |
| 4 | /* |
| 5 | * Kernel Tracepoint API. |
| 6 | * |
| 7 | * See Documentation/trace/tracepoints.txt. |
| 8 | * |
| 9 | * (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
| 10 | * |
| 11 | * Heavily inspired from the Linux Kernel Markers. |
| 12 | * |
| 13 | * This file is released under the GPLv2. |
| 14 | * See the file COPYING for more details. |
| 15 | */ |
| 16 | |
| 17 | #include <linux/smp.h> |
| 18 | #include <linux/errno.h> |
| 19 | #include <linux/types.h> |
| 20 | #include <linux/percpu.h> |
| 21 | #include <linux/cpumask.h> |
| 22 | #include <linux/rcupdate.h> |
| 23 | #include <linux/static_key.h> |
| 24 | |
| 25 | struct module; |
| 26 | struct tracepoint; |
| 27 | |
| 28 | struct tracepoint_func { |
| 29 | void *func; |
| 30 | void *data; |
| 31 | }; |
| 32 | |
| 33 | struct tracepoint { |
| 34 | const char *name; /* Tracepoint name */ |
| 35 | struct static_key key; |
| 36 | void (*regfunc)(void); |
| 37 | void (*unregfunc)(void); |
| 38 | struct tracepoint_func __rcu *funcs; |
| 39 | }; |
| 40 | |
| 41 | /* |
| 42 | * Connect a probe to a tracepoint. |
| 43 | * Internal API, should not be used directly. |
| 44 | */ |
| 45 | extern int tracepoint_probe_register(const char *name, void *probe, void *data); |
| 46 | |
| 47 | /* |
| 48 | * Disconnect a probe from a tracepoint. |
| 49 | * Internal API, should not be used directly. |
| 50 | */ |
| 51 | extern int |
| 52 | tracepoint_probe_unregister(const char *name, void *probe, void *data); |
| 53 | |
| 54 | extern int tracepoint_probe_register_noupdate(const char *name, void *probe, |
| 55 | void *data); |
| 56 | extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe, |
| 57 | void *data); |
| 58 | extern void tracepoint_probe_update_all(void); |
| 59 | |
| 60 | #ifdef CONFIG_MODULES |
| 61 | struct tp_module { |
| 62 | struct list_head list; |
| 63 | unsigned int num_tracepoints; |
| 64 | struct tracepoint * const *tracepoints_ptrs; |
| 65 | }; |
| 66 | bool trace_module_has_bad_taint(struct module *mod); |
| 67 | #else |
| 68 | static inline bool trace_module_has_bad_taint(struct module *mod) |
| 69 | { |
| 70 | return false; |
| 71 | } |
| 72 | #endif /* CONFIG_MODULES */ |
| 73 | |
| 74 | struct tracepoint_iter { |
| 75 | #ifdef CONFIG_MODULES |
| 76 | struct tp_module *module; |
| 77 | #endif /* CONFIG_MODULES */ |
| 78 | struct tracepoint * const *tracepoint; |
| 79 | }; |
| 80 | |
| 81 | extern void tracepoint_iter_start(struct tracepoint_iter *iter); |
| 82 | extern void tracepoint_iter_next(struct tracepoint_iter *iter); |
| 83 | extern void tracepoint_iter_stop(struct tracepoint_iter *iter); |
| 84 | extern void tracepoint_iter_reset(struct tracepoint_iter *iter); |
| 85 | |
| 86 | /* |
| 87 | * tracepoint_synchronize_unregister must be called between the last tracepoint |
| 88 | * probe unregistration and the end of module exit to make sure there is no |
| 89 | * caller executing a probe when it is freed. |
| 90 | */ |
| 91 | static inline void tracepoint_synchronize_unregister(void) |
| 92 | { |
| 93 | synchronize_sched(); |
| 94 | } |
| 95 | |
| 96 | #define PARAMS(args...) args |
| 97 | |
| 98 | #endif /* _LINUX_TRACEPOINT_H */ |
| 99 | |
| 100 | /* |
| 101 | * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include |
| 102 | * file ifdef protection. |
| 103 | * This is due to the way trace events work. If a file includes two |
| 104 | * trace event headers under one "CREATE_TRACE_POINTS" the first include |
| 105 | * will override the TRACE_EVENT and break the second include. |
| 106 | */ |
| 107 | |
| 108 | #ifndef DECLARE_TRACE |
| 109 | |
| 110 | #define TP_PROTO(args...) args |
| 111 | #define TP_ARGS(args...) args |
| 112 | #define TP_CONDITION(args...) args |
| 113 | |
| 114 | #ifdef CONFIG_TRACEPOINTS |
| 115 | |
| 116 | /* |
| 117 | * it_func[0] is never NULL because there is at least one element in the array |
| 118 | * when the array itself is non NULL. |
| 119 | * |
| 120 | * Note, the proto and args passed in includes "__data" as the first parameter. |
| 121 | * The reason for this is to handle the "void" prototype. If a tracepoint |
| 122 | * has a "void" prototype, then it is invalid to declare a function |
| 123 | * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just |
| 124 | * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto". |
| 125 | */ |
| 126 | #define __DO_TRACE(tp, proto, args, cond, prercu, postrcu) \ |
| 127 | do { \ |
| 128 | struct tracepoint_func *it_func_ptr; \ |
| 129 | void *it_func; \ |
| 130 | void *__data; \ |
| 131 | \ |
| 132 | if (!(cond)) \ |
| 133 | return; \ |
| 134 | prercu; \ |
| 135 | rcu_read_lock_sched_notrace(); \ |
| 136 | it_func_ptr = rcu_dereference_sched((tp)->funcs); \ |
| 137 | if (it_func_ptr) { \ |
| 138 | do { \ |
| 139 | it_func = (it_func_ptr)->func; \ |
| 140 | __data = (it_func_ptr)->data; \ |
| 141 | ((void(*)(proto))(it_func))(args); \ |
| 142 | } while ((++it_func_ptr)->func); \ |
| 143 | } \ |
| 144 | rcu_read_unlock_sched_notrace(); \ |
| 145 | postrcu; \ |
| 146 | } while (0) |
| 147 | |
| 148 | #ifndef MODULE |
| 149 | #define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) \ |
| 150 | static inline void trace_##name##_rcuidle(proto) \ |
| 151 | { \ |
| 152 | if (static_key_false(&__tracepoint_##name.key)) \ |
| 153 | __DO_TRACE(&__tracepoint_##name, \ |
| 154 | TP_PROTO(data_proto), \ |
| 155 | TP_ARGS(data_args), \ |
| 156 | TP_CONDITION(cond), \ |
| 157 | rcu_irq_enter(), \ |
| 158 | rcu_irq_exit()); \ |
| 159 | } |
| 160 | #else |
| 161 | #define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) |
| 162 | #endif |
| 163 | |
| 164 | /* |
| 165 | * Make sure the alignment of the structure in the __tracepoints section will |
| 166 | * not add unwanted padding between the beginning of the section and the |
| 167 | * structure. Force alignment to the same alignment as the section start. |
| 168 | */ |
| 169 | #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ |
| 170 | extern struct tracepoint __tracepoint_##name; \ |
| 171 | static inline void trace_##name(proto) \ |
| 172 | { \ |
| 173 | if (static_key_false(&__tracepoint_##name.key)) \ |
| 174 | __DO_TRACE(&__tracepoint_##name, \ |
| 175 | TP_PROTO(data_proto), \ |
| 176 | TP_ARGS(data_args), \ |
| 177 | TP_CONDITION(cond),,); \ |
| 178 | } \ |
| 179 | __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \ |
| 180 | PARAMS(cond), PARAMS(data_proto), PARAMS(data_args)) \ |
| 181 | static inline int \ |
| 182 | register_trace_##name(void (*probe)(data_proto), void *data) \ |
| 183 | { \ |
| 184 | return tracepoint_probe_register(#name, (void *)probe, \ |
| 185 | data); \ |
| 186 | } \ |
| 187 | static inline int \ |
| 188 | unregister_trace_##name(void (*probe)(data_proto), void *data) \ |
| 189 | { \ |
| 190 | return tracepoint_probe_unregister(#name, (void *)probe, \ |
| 191 | data); \ |
| 192 | } \ |
| 193 | static inline void \ |
| 194 | check_trace_callback_type_##name(void (*cb)(data_proto)) \ |
| 195 | { \ |
| 196 | } |
| 197 | |
| 198 | /* |
| 199 | * We have no guarantee that gcc and the linker won't up-align the tracepoint |
| 200 | * structures, so we create an array of pointers that will be used for iteration |
| 201 | * on the tracepoints. |
| 202 | */ |
| 203 | #define DEFINE_TRACE_FN(name, reg, unreg) \ |
| 204 | static const char __tpstrtab_##name[] \ |
| 205 | __attribute__((section("__tracepoints_strings"))) = #name; \ |
| 206 | struct tracepoint __tracepoint_##name \ |
| 207 | __attribute__((section("__tracepoints"))) = \ |
| 208 | { __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\ |
| 209 | static struct tracepoint * const __tracepoint_ptr_##name __used \ |
| 210 | __attribute__((section("__tracepoints_ptrs"))) = \ |
| 211 | &__tracepoint_##name; |
| 212 | |
| 213 | #define DEFINE_TRACE(name) \ |
| 214 | DEFINE_TRACE_FN(name, NULL, NULL); |
| 215 | |
| 216 | #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \ |
| 217 | EXPORT_SYMBOL_GPL(__tracepoint_##name) |
| 218 | #define EXPORT_TRACEPOINT_SYMBOL(name) \ |
| 219 | EXPORT_SYMBOL(__tracepoint_##name) |
| 220 | |
| 221 | #else /* !CONFIG_TRACEPOINTS */ |
| 222 | #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ |
| 223 | static inline void trace_##name(proto) \ |
| 224 | { } \ |
| 225 | static inline void trace_##name##_rcuidle(proto) \ |
| 226 | { } \ |
| 227 | static inline int \ |
| 228 | register_trace_##name(void (*probe)(data_proto), \ |
| 229 | void *data) \ |
| 230 | { \ |
| 231 | return -ENOSYS; \ |
| 232 | } \ |
| 233 | static inline int \ |
| 234 | unregister_trace_##name(void (*probe)(data_proto), \ |
| 235 | void *data) \ |
| 236 | { \ |
| 237 | return -ENOSYS; \ |
| 238 | } \ |
| 239 | static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \ |
| 240 | { \ |
| 241 | } |
| 242 | |
| 243 | #define DEFINE_TRACE_FN(name, reg, unreg) |
| 244 | #define DEFINE_TRACE(name) |
| 245 | #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) |
| 246 | #define EXPORT_TRACEPOINT_SYMBOL(name) |
| 247 | |
| 248 | #endif /* CONFIG_TRACEPOINTS */ |
| 249 | |
| 250 | /* |
| 251 | * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype |
| 252 | * (void). "void" is a special value in a function prototype and can |
| 253 | * not be combined with other arguments. Since the DECLARE_TRACE() |
| 254 | * macro adds a data element at the beginning of the prototype, |
| 255 | * we need a way to differentiate "(void *data, proto)" from |
| 256 | * "(void *data, void)". The second prototype is invalid. |
| 257 | * |
| 258 | * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype |
| 259 | * and "void *__data" as the callback prototype. |
| 260 | * |
| 261 | * DECLARE_TRACE() passes "proto" as the tracepoint protoype and |
| 262 | * "void *__data, proto" as the callback prototype. |
| 263 | */ |
| 264 | #define DECLARE_TRACE_NOARGS(name) \ |
| 265 | __DECLARE_TRACE(name, void, , \ |
| 266 | cpu_online(raw_smp_processor_id()), \ |
| 267 | void *__data, __data) |
| 268 | |
| 269 | #define DECLARE_TRACE(name, proto, args) \ |
| 270 | __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \ |
| 271 | cpu_online(raw_smp_processor_id()), \ |
| 272 | PARAMS(void *__data, proto), \ |
| 273 | PARAMS(__data, args)) |
| 274 | |
| 275 | #define DECLARE_TRACE_CONDITION(name, proto, args, cond) \ |
| 276 | __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \ |
| 277 | cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \ |
| 278 | PARAMS(void *__data, proto), \ |
| 279 | PARAMS(__data, args)) |
| 280 | |
| 281 | #define TRACE_EVENT_FLAGS(event, flag) |
| 282 | |
| 283 | #endif /* DECLARE_TRACE */ |
| 284 | |
| 285 | #ifndef TRACE_EVENT |
| 286 | /* |
| 287 | * For use with the TRACE_EVENT macro: |
| 288 | * |
| 289 | * We define a tracepoint, its arguments, its printk format |
| 290 | * and its 'fast binay record' layout. |
| 291 | * |
| 292 | * Firstly, name your tracepoint via TRACE_EVENT(name : the |
| 293 | * 'subsystem_event' notation is fine. |
| 294 | * |
| 295 | * Think about this whole construct as the |
| 296 | * 'trace_sched_switch() function' from now on. |
| 297 | * |
| 298 | * |
| 299 | * TRACE_EVENT(sched_switch, |
| 300 | * |
| 301 | * * |
| 302 | * * A function has a regular function arguments |
| 303 | * * prototype, declare it via TP_PROTO(): |
| 304 | * * |
| 305 | * |
| 306 | * TP_PROTO(struct rq *rq, struct task_struct *prev, |
| 307 | * struct task_struct *next), |
| 308 | * |
| 309 | * * |
| 310 | * * Define the call signature of the 'function'. |
| 311 | * * (Design sidenote: we use this instead of a |
| 312 | * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.) |
| 313 | * * |
| 314 | * |
| 315 | * TP_ARGS(rq, prev, next), |
| 316 | * |
| 317 | * * |
| 318 | * * Fast binary tracing: define the trace record via |
| 319 | * * TP_STRUCT__entry(). You can think about it like a |
| 320 | * * regular C structure local variable definition. |
| 321 | * * |
| 322 | * * This is how the trace record is structured and will |
| 323 | * * be saved into the ring buffer. These are the fields |
| 324 | * * that will be exposed to user-space in |
| 325 | * * /sys/kernel/debug/tracing/events/<*>/format. |
| 326 | * * |
| 327 | * * The declared 'local variable' is called '__entry' |
| 328 | * * |
| 329 | * * __field(pid_t, prev_prid) is equivalent to a standard declariton: |
| 330 | * * |
| 331 | * * pid_t prev_pid; |
| 332 | * * |
| 333 | * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to: |
| 334 | * * |
| 335 | * * char prev_comm[TASK_COMM_LEN]; |
| 336 | * * |
| 337 | * |
| 338 | * TP_STRUCT__entry( |
| 339 | * __array( char, prev_comm, TASK_COMM_LEN ) |
| 340 | * __field( pid_t, prev_pid ) |
| 341 | * __field( int, prev_prio ) |
| 342 | * __array( char, next_comm, TASK_COMM_LEN ) |
| 343 | * __field( pid_t, next_pid ) |
| 344 | * __field( int, next_prio ) |
| 345 | * ), |
| 346 | * |
| 347 | * * |
| 348 | * * Assign the entry into the trace record, by embedding |
| 349 | * * a full C statement block into TP_fast_assign(). You |
| 350 | * * can refer to the trace record as '__entry' - |
| 351 | * * otherwise you can put arbitrary C code in here. |
| 352 | * * |
| 353 | * * Note: this C code will execute every time a trace event |
| 354 | * * happens, on an active tracepoint. |
| 355 | * * |
| 356 | * |
| 357 | * TP_fast_assign( |
| 358 | * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); |
| 359 | * __entry->prev_pid = prev->pid; |
| 360 | * __entry->prev_prio = prev->prio; |
| 361 | * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); |
| 362 | * __entry->next_pid = next->pid; |
| 363 | * __entry->next_prio = next->prio; |
| 364 | * ), |
| 365 | * |
| 366 | * * |
| 367 | * * Formatted output of a trace record via TP_printk(). |
| 368 | * * This is how the tracepoint will appear under ftrace |
| 369 | * * plugins that make use of this tracepoint. |
| 370 | * * |
| 371 | * * (raw-binary tracing wont actually perform this step.) |
| 372 | * * |
| 373 | * |
| 374 | * TP_printk("task %s:%d [%d] ==> %s:%d [%d]", |
| 375 | * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio, |
| 376 | * __entry->next_comm, __entry->next_pid, __entry->next_prio), |
| 377 | * |
| 378 | * ); |
| 379 | * |
| 380 | * This macro construct is thus used for the regular printk format |
| 381 | * tracing setup, it is used to construct a function pointer based |
| 382 | * tracepoint callback (this is used by programmatic plugins and |
| 383 | * can also by used by generic instrumentation like SystemTap), and |
| 384 | * it is also used to expose a structured trace record in |
| 385 | * /sys/kernel/debug/tracing/events/. |
| 386 | * |
| 387 | * A set of (un)registration functions can be passed to the variant |
| 388 | * TRACE_EVENT_FN to perform any (un)registration work. |
| 389 | */ |
| 390 | |
| 391 | #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print) |
| 392 | #define DEFINE_EVENT(template, name, proto, args) \ |
| 393 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| 394 | #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ |
| 395 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| 396 | #define DEFINE_EVENT_CONDITION(template, name, proto, \ |
| 397 | args, cond) \ |
| 398 | DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ |
| 399 | PARAMS(args), PARAMS(cond)) |
| 400 | |
| 401 | #define TRACE_EVENT(name, proto, args, struct, assign, print) \ |
| 402 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| 403 | #define TRACE_EVENT_FN(name, proto, args, struct, \ |
| 404 | assign, print, reg, unreg) \ |
| 405 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| 406 | #define TRACE_EVENT_CONDITION(name, proto, args, cond, \ |
| 407 | struct, assign, print) \ |
| 408 | DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ |
| 409 | PARAMS(args), PARAMS(cond)) |
| 410 | |
| 411 | #define TRACE_EVENT_FLAGS(event, flag) |
| 412 | |
| 413 | #endif /* ifdef TRACE_EVENT (see note above) */ |