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52a6e82a | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
97e1c18e MD |
2 | #ifndef _LINUX_TRACEPOINT_H |
3 | #define _LINUX_TRACEPOINT_H | |
4 | ||
5 | /* | |
6 | * Kernel Tracepoint API. | |
7 | * | |
ec15872d | 8 | * See Documentation/trace/tracepoints.rst. |
97e1c18e | 9 | * |
de7b2973 | 10 | * Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
97e1c18e MD |
11 | * |
12 | * Heavily inspired from the Linux Kernel Markers. | |
97e1c18e MD |
13 | */ |
14 | ||
f3775549 | 15 | #include <linux/smp.h> |
e6753f23 | 16 | #include <linux/srcu.h> |
b70e4f05 | 17 | #include <linux/errno.h> |
97e1c18e | 18 | #include <linux/types.h> |
f3775549 | 19 | #include <linux/cpumask.h> |
97e1c18e | 20 | #include <linux/rcupdate.h> |
bd2a634d | 21 | #include <linux/tracepoint-defs.h> |
d25e37d8 | 22 | #include <linux/static_call.h> |
97e1c18e MD |
23 | |
24 | struct module; | |
25 | struct tracepoint; | |
de7b2973 | 26 | struct notifier_block; |
97e1c18e | 27 | |
00f4b652 | 28 | struct trace_eval_map { |
0c564a53 | 29 | const char *system; |
00f4b652 JL |
30 | const char *eval_string; |
31 | unsigned long eval_value; | |
0c564a53 SRRH |
32 | }; |
33 | ||
7904b5c4 SRRH |
34 | #define TRACEPOINT_DEFAULT_PRIO 10 |
35 | ||
e6753f23 JFG |
36 | extern struct srcu_struct tracepoint_srcu; |
37 | ||
38516ab5 | 38 | extern int |
de7b2973 MD |
39 | tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data); |
40 | extern int | |
7904b5c4 SRRH |
41 | tracepoint_probe_register_prio(struct tracepoint *tp, void *probe, void *data, |
42 | int prio); | |
43 | extern int | |
9913d574 SRV |
44 | tracepoint_probe_register_prio_may_exist(struct tracepoint *tp, void *probe, void *data, |
45 | int prio); | |
46 | extern int | |
de7b2973 | 47 | tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data); |
9913d574 SRV |
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 | } | |
de7b2973 MD |
55 | extern void |
56 | for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv), | |
57 | void *priv); | |
2e26ca71 | 58 | |
b75ef8b4 MD |
59 | #ifdef CONFIG_MODULES |
60 | struct tp_module { | |
61 | struct list_head list; | |
eb7d035c | 62 | struct module *mod; |
b75ef8b4 | 63 | }; |
de7b2973 | 64 | |
45ab2813 | 65 | bool trace_module_has_bad_taint(struct module *mod); |
de7b2973 MD |
66 | extern int register_tracepoint_module_notifier(struct notifier_block *nb); |
67 | extern int unregister_tracepoint_module_notifier(struct notifier_block *nb); | |
45ab2813 SRRH |
68 | #else |
69 | static inline bool trace_module_has_bad_taint(struct module *mod) | |
70 | { | |
71 | return false; | |
72 | } | |
de7b2973 MD |
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 | } | |
b75ef8b4 MD |
83 | #endif /* CONFIG_MODULES */ |
84 | ||
2e26ca71 SR |
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 | */ | |
e6753f23 | 90 | #ifdef CONFIG_TRACEPOINTS |
2e26ca71 SR |
91 | static inline void tracepoint_synchronize_unregister(void) |
92 | { | |
e6753f23 | 93 | synchronize_srcu(&tracepoint_srcu); |
74401729 | 94 | synchronize_rcu(); |
2e26ca71 | 95 | } |
e6753f23 JFG |
96 | #else |
97 | static inline void tracepoint_synchronize_unregister(void) | |
98 | { } | |
99 | #endif | |
2e26ca71 | 100 | |
b725dfea | 101 | #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS |
8cf868af | 102 | extern int syscall_regfunc(void); |
b725dfea MD |
103 | extern void syscall_unregfunc(void); |
104 | #endif /* CONFIG_HAVE_SYSCALL_TRACEPOINTS */ | |
105 | ||
d25e37d8 | 106 | #ifndef PARAMS |
2e26ca71 | 107 | #define PARAMS(args...) args |
d25e37d8 | 108 | #endif |
2e26ca71 | 109 | |
0c564a53 | 110 | #define TRACE_DEFINE_ENUM(x) |
4f0dfd76 | 111 | #define TRACE_DEFINE_SIZEOF(x) |
0c564a53 | 112 | |
9c0be3f6 MD |
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 \ | |
33def849 | 132 | __section("__tracepoints_ptrs") = &__tracepoint_##name |
9c0be3f6 MD |
133 | #endif |
134 | ||
2e26ca71 SR |
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 | ||
ea20d929 SR |
145 | #ifndef DECLARE_TRACE |
146 | ||
2939b046 | 147 | #define TP_PROTO(args...) args |
8cd09a59 | 148 | #define TP_ARGS(args...) args |
287050d3 | 149 | #define TP_CONDITION(args...) args |
97e1c18e | 150 | |
c63b7682 TS |
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 | |
97e1c18e | 163 | |
d25e37d8 | 164 | #ifdef CONFIG_HAVE_STATIC_CALL |
d9a1be1b SRV |
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) | |
d25e37d8 | 176 | #else |
d9a1be1b | 177 | #define __DO_TRACE_CALL(name, args) __traceiter_##name(NULL, args) |
d25e37d8 SRV |
178 | #endif /* CONFIG_HAVE_STATIC_CALL */ |
179 | ||
97e1c18e MD |
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 | */ | |
1746fd44 | 184 | #define __DO_TRACE(name, args, cond, rcuidle) \ |
97e1c18e | 185 | do { \ |
0c7a52e4 | 186 | int __maybe_unused __idx = 0; \ |
97e1c18e | 187 | \ |
287050d3 SR |
188 | if (!(cond)) \ |
189 | return; \ | |
e6753f23 JFG |
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 | */ \ | |
865e63b0 | 201 | if (rcuidle) { \ |
0c7a52e4 | 202 | __idx = srcu_read_lock_notrace(&tracepoint_srcu);\ |
865e63b0 SRV |
203 | rcu_irq_enter_irqson(); \ |
204 | } \ | |
e6753f23 | 205 | \ |
d9a1be1b | 206 | __DO_TRACE_CALL(name, TP_ARGS(args)); \ |
e6753f23 | 207 | \ |
865e63b0 SRV |
208 | if (rcuidle) { \ |
209 | rcu_irq_exit_irqson(); \ | |
0c7a52e4 | 210 | srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\ |
865e63b0 | 211 | } \ |
e6753f23 JFG |
212 | \ |
213 | preempt_enable_notrace(); \ | |
97e1c18e MD |
214 | } while (0) |
215 | ||
7ece55a4 | 216 | #ifndef MODULE |
1746fd44 | 217 | #define __DECLARE_TRACE_RCU(name, proto, args, cond) \ |
7ece55a4 JT |
218 | static inline void trace_##name##_rcuidle(proto) \ |
219 | { \ | |
220 | if (static_key_false(&__tracepoint_##name.key)) \ | |
d25e37d8 | 221 | __DO_TRACE(name, \ |
1746fd44 | 222 | TP_ARGS(args), \ |
d54b6eeb | 223 | TP_CONDITION(cond), 1); \ |
7ece55a4 JT |
224 | } |
225 | #else | |
1746fd44 | 226 | #define __DECLARE_TRACE_RCU(name, proto, args, cond) |
7ece55a4 JT |
227 | #endif |
228 | ||
97e1c18e MD |
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. | |
3a630178 DH |
233 | * |
234 | * When lockdep is enabled, we make sure to always do the RCU portions of | |
a15920be MD |
235 | * the tracepoint code, regardless of whether tracing is on. However, |
236 | * don't check if the condition is false, due to interaction with idle | |
237 | * instrumentation. This lets us find RCU issues triggered with tracepoints | |
238 | * even when this tracepoint is off. This code has no purpose other than | |
239 | * poking RCU a bit. | |
97e1c18e | 240 | */ |
1746fd44 | 241 | #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ |
de394e75 | 242 | extern int __traceiter_##name(data_proto); \ |
243 | DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \ | |
7e066fb8 | 244 | extern struct tracepoint __tracepoint_##name; \ |
97e1c18e MD |
245 | static inline void trace_##name(proto) \ |
246 | { \ | |
c5905afb | 247 | if (static_key_false(&__tracepoint_##name.key)) \ |
d25e37d8 | 248 | __DO_TRACE(name, \ |
1746fd44 | 249 | TP_ARGS(args), \ |
d54b6eeb | 250 | TP_CONDITION(cond), 0); \ |
a05d59a5 | 251 | if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ |
3a630178 DH |
252 | rcu_read_lock_sched_notrace(); \ |
253 | rcu_dereference_sched(__tracepoint_##name.funcs);\ | |
254 | rcu_read_unlock_sched_notrace(); \ | |
255 | } \ | |
2fbb90db | 256 | } \ |
7ece55a4 | 257 | __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \ |
1746fd44 | 258 | PARAMS(cond)) \ |
38516ab5 SR |
259 | static inline int \ |
260 | register_trace_##name(void (*probe)(data_proto), void *data) \ | |
97e1c18e | 261 | { \ |
de7b2973 MD |
262 | return tracepoint_probe_register(&__tracepoint_##name, \ |
263 | (void *)probe, data); \ | |
97e1c18e | 264 | } \ |
38516ab5 | 265 | static inline int \ |
7904b5c4 SRRH |
266 | register_trace_prio_##name(void (*probe)(data_proto), void *data,\ |
267 | int prio) \ | |
268 | { \ | |
269 | return tracepoint_probe_register_prio(&__tracepoint_##name, \ | |
270 | (void *)probe, data, prio); \ | |
271 | } \ | |
272 | static inline int \ | |
38516ab5 | 273 | unregister_trace_##name(void (*probe)(data_proto), void *data) \ |
97e1c18e | 274 | { \ |
de7b2973 MD |
275 | return tracepoint_probe_unregister(&__tracepoint_##name,\ |
276 | (void *)probe, data); \ | |
53da59aa | 277 | } \ |
38516ab5 SR |
278 | static inline void \ |
279 | check_trace_callback_type_##name(void (*cb)(data_proto)) \ | |
53da59aa | 280 | { \ |
7c65bbc7 SRRH |
281 | } \ |
282 | static inline bool \ | |
283 | trace_##name##_enabled(void) \ | |
284 | { \ | |
285 | return static_key_false(&__tracepoint_##name.key); \ | |
97e1c18e MD |
286 | } |
287 | ||
65498646 MD |
288 | /* |
289 | * We have no guarantee that gcc and the linker won't up-align the tracepoint | |
290 | * structures, so we create an array of pointers that will be used for iteration | |
291 | * on the tracepoints. | |
292 | */ | |
d25e37d8 SRV |
293 | #define DEFINE_TRACE_FN(_name, _reg, _unreg, proto, args) \ |
294 | static const char __tpstrtab_##_name[] \ | |
33def849 | 295 | __section("__tracepoints_strings") = #_name; \ |
d25e37d8 | 296 | extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name); \ |
de394e75 | 297 | int __traceiter_##_name(void *__data, proto); \ |
d25e37d8 | 298 | struct tracepoint __tracepoint_##_name __used \ |
33def849 | 299 | __section("__tracepoints") = { \ |
d25e37d8 SRV |
300 | .name = __tpstrtab_##_name, \ |
301 | .key = STATIC_KEY_INIT_FALSE, \ | |
302 | .static_call_key = &STATIC_CALL_KEY(tp_func_##_name), \ | |
303 | .static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \ | |
de394e75 | 304 | .iterator = &__traceiter_##_name, \ |
d25e37d8 SRV |
305 | .regfunc = _reg, \ |
306 | .unregfunc = _unreg, \ | |
307 | .funcs = NULL }; \ | |
308 | __TRACEPOINT_ENTRY(_name); \ | |
de394e75 | 309 | int __traceiter_##_name(void *__data, proto) \ |
d25e37d8 SRV |
310 | { \ |
311 | struct tracepoint_func *it_func_ptr; \ | |
312 | void *it_func; \ | |
313 | \ | |
314 | it_func_ptr = \ | |
315 | rcu_dereference_raw((&__tracepoint_##_name)->funcs); \ | |
c8b186a8 AK |
316 | if (it_func_ptr) { \ |
317 | do { \ | |
7211f0a2 | 318 | it_func = READ_ONCE((it_func_ptr)->func); \ |
c8b186a8 AK |
319 | __data = (it_func_ptr)->data; \ |
320 | ((void(*)(void *, proto))(it_func))(__data, args); \ | |
321 | } while ((++it_func_ptr)->func); \ | |
322 | } \ | |
d25e37d8 SRV |
323 | return 0; \ |
324 | } \ | |
de394e75 | 325 | DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); |
97419875 | 326 | |
d25e37d8 SRV |
327 | #define DEFINE_TRACE(name, proto, args) \ |
328 | DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args)); | |
7e066fb8 MD |
329 | |
330 | #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \ | |
d25e37d8 | 331 | EXPORT_SYMBOL_GPL(__tracepoint_##name); \ |
de394e75 | 332 | EXPORT_SYMBOL_GPL(__traceiter_##name); \ |
d25e37d8 | 333 | EXPORT_STATIC_CALL_GPL(tp_func_##name) |
7e066fb8 | 334 | #define EXPORT_TRACEPOINT_SYMBOL(name) \ |
d25e37d8 | 335 | EXPORT_SYMBOL(__tracepoint_##name); \ |
de394e75 | 336 | EXPORT_SYMBOL(__traceiter_##name); \ |
d25e37d8 SRV |
337 | EXPORT_STATIC_CALL(tp_func_##name) |
338 | ||
7e066fb8 | 339 | |
c63b7682 | 340 | #else /* !TRACEPOINTS_ENABLED */ |
1746fd44 | 341 | #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ |
97e1c18e MD |
342 | static inline void trace_##name(proto) \ |
343 | { } \ | |
2fbb90db SR |
344 | static inline void trace_##name##_rcuidle(proto) \ |
345 | { } \ | |
38516ab5 SR |
346 | static inline int \ |
347 | register_trace_##name(void (*probe)(data_proto), \ | |
348 | void *data) \ | |
97e1c18e MD |
349 | { \ |
350 | return -ENOSYS; \ | |
351 | } \ | |
38516ab5 SR |
352 | static inline int \ |
353 | unregister_trace_##name(void (*probe)(data_proto), \ | |
354 | void *data) \ | |
c420970e MD |
355 | { \ |
356 | return -ENOSYS; \ | |
53da59aa | 357 | } \ |
38516ab5 | 358 | static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \ |
53da59aa | 359 | { \ |
7c65bbc7 SRRH |
360 | } \ |
361 | static inline bool \ | |
362 | trace_##name##_enabled(void) \ | |
363 | { \ | |
364 | return false; \ | |
c420970e | 365 | } |
97e1c18e | 366 | |
d25e37d8 SRV |
367 | #define DEFINE_TRACE_FN(name, reg, unreg, proto, args) |
368 | #define DEFINE_TRACE(name, proto, args) | |
7e066fb8 MD |
369 | #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) |
370 | #define EXPORT_TRACEPOINT_SYMBOL(name) | |
371 | ||
c63b7682 | 372 | #endif /* TRACEPOINTS_ENABLED */ |
38516ab5 | 373 | |
3c49b52b SR |
374 | #ifdef CONFIG_TRACING |
375 | /** | |
376 | * tracepoint_string - register constant persistent string to trace system | |
377 | * @str - a constant persistent string that will be referenced in tracepoints | |
378 | * | |
379 | * If constant strings are being used in tracepoints, it is faster and | |
380 | * more efficient to just save the pointer to the string and reference | |
381 | * that with a printf "%s" instead of saving the string in the ring buffer | |
382 | * and wasting space and time. | |
383 | * | |
384 | * The problem with the above approach is that userspace tools that read | |
385 | * the binary output of the trace buffers do not have access to the string. | |
386 | * Instead they just show the address of the string which is not very | |
387 | * useful to users. | |
388 | * | |
389 | * With tracepoint_string(), the string will be registered to the tracing | |
390 | * system and exported to userspace via the debugfs/tracing/printk_formats | |
391 | * file that maps the string address to the string text. This way userspace | |
392 | * tools that read the binary buffers have a way to map the pointers to | |
393 | * the ASCII strings they represent. | |
394 | * | |
395 | * The @str used must be a constant string and persistent as it would not | |
396 | * make sense to show a string that no longer exists. But it is still fine | |
397 | * to be used with modules, because when modules are unloaded, if they | |
398 | * had tracepoints, the ring buffers are cleared too. As long as the string | |
399 | * does not change during the life of the module, it is fine to use | |
400 | * tracepoint_string() within a module. | |
401 | */ | |
402 | #define tracepoint_string(str) \ | |
403 | ({ \ | |
404 | static const char *___tp_str __tracepoint_string = str; \ | |
405 | ___tp_str; \ | |
406 | }) | |
33def849 | 407 | #define __tracepoint_string __used __section("__tracepoint_str") |
3c49b52b SR |
408 | #else |
409 | /* | |
410 | * tracepoint_string() is used to save the string address for userspace | |
411 | * tracing tools. When tracing isn't configured, there's no need to save | |
412 | * anything. | |
413 | */ | |
414 | # define tracepoint_string(str) str | |
415 | # define __tracepoint_string | |
416 | #endif | |
417 | ||
38516ab5 | 418 | #define DECLARE_TRACE(name, proto, args) \ |
dc17147d SRRH |
419 | __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \ |
420 | cpu_online(raw_smp_processor_id()), \ | |
1746fd44 | 421 | PARAMS(void *__data, proto)) |
38516ab5 | 422 | |
287050d3 | 423 | #define DECLARE_TRACE_CONDITION(name, proto, args, cond) \ |
dc17147d SRRH |
424 | __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \ |
425 | cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \ | |
1746fd44 | 426 | PARAMS(void *__data, proto)) |
287050d3 | 427 | |
1ed0c597 FW |
428 | #define TRACE_EVENT_FLAGS(event, flag) |
429 | ||
d5b5f391 PZ |
430 | #define TRACE_EVENT_PERF_PERM(event, expr...) |
431 | ||
ea20d929 | 432 | #endif /* DECLARE_TRACE */ |
97e1c18e | 433 | |
ea20d929 | 434 | #ifndef TRACE_EVENT |
823f9124 SR |
435 | /* |
436 | * For use with the TRACE_EVENT macro: | |
437 | * | |
438 | * We define a tracepoint, its arguments, its printk format | |
2621bca8 | 439 | * and its 'fast binary record' layout. |
823f9124 SR |
440 | * |
441 | * Firstly, name your tracepoint via TRACE_EVENT(name : the | |
442 | * 'subsystem_event' notation is fine. | |
443 | * | |
444 | * Think about this whole construct as the | |
445 | * 'trace_sched_switch() function' from now on. | |
446 | * | |
447 | * | |
448 | * TRACE_EVENT(sched_switch, | |
449 | * | |
450 | * * | |
451 | * * A function has a regular function arguments | |
452 | * * prototype, declare it via TP_PROTO(): | |
453 | * * | |
454 | * | |
ef18012b SR |
455 | * TP_PROTO(struct rq *rq, struct task_struct *prev, |
456 | * struct task_struct *next), | |
823f9124 SR |
457 | * |
458 | * * | |
459 | * * Define the call signature of the 'function'. | |
460 | * * (Design sidenote: we use this instead of a | |
461 | * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.) | |
462 | * * | |
463 | * | |
ef18012b | 464 | * TP_ARGS(rq, prev, next), |
823f9124 SR |
465 | * |
466 | * * | |
467 | * * Fast binary tracing: define the trace record via | |
468 | * * TP_STRUCT__entry(). You can think about it like a | |
469 | * * regular C structure local variable definition. | |
470 | * * | |
471 | * * This is how the trace record is structured and will | |
472 | * * be saved into the ring buffer. These are the fields | |
473 | * * that will be exposed to user-space in | |
156f5a78 | 474 | * * /sys/kernel/debug/tracing/events/<*>/format. |
823f9124 SR |
475 | * * |
476 | * * The declared 'local variable' is called '__entry' | |
477 | * * | |
f2cc020d | 478 | * * __field(pid_t, prev_prid) is equivalent to a standard declaration: |
823f9124 SR |
479 | * * |
480 | * * pid_t prev_pid; | |
481 | * * | |
482 | * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to: | |
483 | * * | |
484 | * * char prev_comm[TASK_COMM_LEN]; | |
485 | * * | |
486 | * | |
487 | * TP_STRUCT__entry( | |
488 | * __array( char, prev_comm, TASK_COMM_LEN ) | |
489 | * __field( pid_t, prev_pid ) | |
490 | * __field( int, prev_prio ) | |
491 | * __array( char, next_comm, TASK_COMM_LEN ) | |
492 | * __field( pid_t, next_pid ) | |
493 | * __field( int, next_prio ) | |
494 | * ), | |
495 | * | |
496 | * * | |
497 | * * Assign the entry into the trace record, by embedding | |
498 | * * a full C statement block into TP_fast_assign(). You | |
499 | * * can refer to the trace record as '__entry' - | |
500 | * * otherwise you can put arbitrary C code in here. | |
501 | * * | |
502 | * * Note: this C code will execute every time a trace event | |
503 | * * happens, on an active tracepoint. | |
504 | * * | |
505 | * | |
ef18012b SR |
506 | * TP_fast_assign( |
507 | * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); | |
508 | * __entry->prev_pid = prev->pid; | |
509 | * __entry->prev_prio = prev->prio; | |
823f9124 SR |
510 | * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); |
511 | * __entry->next_pid = next->pid; | |
ef18012b | 512 | * __entry->next_prio = next->prio; |
ec6e7c3a | 513 | * ), |
823f9124 SR |
514 | * |
515 | * * | |
516 | * * Formatted output of a trace record via TP_printk(). | |
517 | * * This is how the tracepoint will appear under ftrace | |
518 | * * plugins that make use of this tracepoint. | |
519 | * * | |
520 | * * (raw-binary tracing wont actually perform this step.) | |
521 | * * | |
522 | * | |
523 | * TP_printk("task %s:%d [%d] ==> %s:%d [%d]", | |
524 | * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio, | |
525 | * __entry->next_comm, __entry->next_pid, __entry->next_prio), | |
526 | * | |
527 | * ); | |
528 | * | |
529 | * This macro construct is thus used for the regular printk format | |
530 | * tracing setup, it is used to construct a function pointer based | |
531 | * tracepoint callback (this is used by programmatic plugins and | |
532 | * can also by used by generic instrumentation like SystemTap), and | |
533 | * it is also used to expose a structured trace record in | |
156f5a78 | 534 | * /sys/kernel/debug/tracing/events/. |
97419875 JS |
535 | * |
536 | * A set of (un)registration functions can be passed to the variant | |
537 | * TRACE_EVENT_FN to perform any (un)registration work. | |
823f9124 SR |
538 | */ |
539 | ||
091ad365 | 540 | #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print) |
ff038f5c SR |
541 | #define DEFINE_EVENT(template, name, proto, args) \ |
542 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
f5abaa1b SR |
543 | #define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\ |
544 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
e5bc9721 SR |
545 | #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ |
546 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
287050d3 SR |
547 | #define DEFINE_EVENT_CONDITION(template, name, proto, \ |
548 | args, cond) \ | |
549 | DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ | |
550 | PARAMS(args), PARAMS(cond)) | |
ff038f5c | 551 | |
30a8fecc | 552 | #define TRACE_EVENT(name, proto, args, struct, assign, print) \ |
da4d0302 | 553 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
97419875 JS |
554 | #define TRACE_EVENT_FN(name, proto, args, struct, \ |
555 | assign, print, reg, unreg) \ | |
556 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
2701121b DK |
557 | #define TRACE_EVENT_FN_COND(name, proto, args, cond, struct, \ |
558 | assign, print, reg, unreg) \ | |
559 | DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ | |
560 | PARAMS(args), PARAMS(cond)) | |
287050d3 SR |
561 | #define TRACE_EVENT_CONDITION(name, proto, args, cond, \ |
562 | struct, assign, print) \ | |
563 | DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ | |
564 | PARAMS(args), PARAMS(cond)) | |
7cb2e3ee | 565 | |
1ed0c597 FW |
566 | #define TRACE_EVENT_FLAGS(event, flag) |
567 | ||
d5b5f391 PZ |
568 | #define TRACE_EVENT_PERF_PERM(event, expr...) |
569 | ||
16336345 YS |
570 | #define DECLARE_EVENT_NOP(name, proto, args) \ |
571 | static inline void trace_##name(proto) \ | |
572 | { } \ | |
573 | static inline bool trace_##name##_enabled(void) \ | |
574 | { \ | |
575 | return false; \ | |
576 | } | |
577 | ||
578 | #define TRACE_EVENT_NOP(name, proto, args, struct, assign, print) \ | |
579 | DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args)) | |
580 | ||
581 | #define DECLARE_EVENT_CLASS_NOP(name, proto, args, tstruct, assign, print) | |
582 | #define DEFINE_EVENT_NOP(template, name, proto, args) \ | |
583 | DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args)) | |
584 | ||
7cb2e3ee | 585 | #endif /* ifdef TRACE_EVENT (see note above) */ |