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97e1c18e MD |
1 | #ifndef _LINUX_TRACEPOINT_H |
2 | #define _LINUX_TRACEPOINT_H | |
3 | ||
4 | /* | |
5 | * Kernel Tracepoint API. | |
6 | * | |
8cd09a59 | 7 | * See Documentation/trace/tracepoints.txt. |
97e1c18e MD |
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/types.h> | |
18 | #include <linux/rcupdate.h> | |
19 | ||
20 | struct module; | |
21 | struct tracepoint; | |
22 | ||
38516ab5 SR |
23 | struct tracepoint_func { |
24 | void *func; | |
25 | void *data; | |
26 | }; | |
27 | ||
97e1c18e MD |
28 | struct tracepoint { |
29 | const char *name; /* Tracepoint name */ | |
30 | int state; /* State. */ | |
97419875 JS |
31 | void (*regfunc)(void); |
32 | void (*unregfunc)(void); | |
38516ab5 | 33 | struct tracepoint_func *funcs; |
7e066fb8 MD |
34 | } __attribute__((aligned(32))); /* |
35 | * Aligned on 32 bytes because it is | |
36 | * globally visible and gcc happily | |
37 | * align these on the structure size. | |
38 | * Keep in sync with vmlinux.lds.h. | |
39 | */ | |
97e1c18e | 40 | |
2e26ca71 SR |
41 | /* |
42 | * Connect a probe to a tracepoint. | |
43 | * Internal API, should not be used directly. | |
44 | */ | |
38516ab5 | 45 | extern int tracepoint_probe_register(const char *name, void *probe, void *data); |
2e26ca71 SR |
46 | |
47 | /* | |
48 | * Disconnect a probe from a tracepoint. | |
49 | * Internal API, should not be used directly. | |
50 | */ | |
38516ab5 SR |
51 | extern int |
52 | tracepoint_probe_unregister(const char *name, void *probe, void *data); | |
2e26ca71 | 53 | |
38516ab5 SR |
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); | |
2e26ca71 SR |
58 | extern void tracepoint_probe_update_all(void); |
59 | ||
60 | struct tracepoint_iter { | |
61 | struct module *module; | |
62 | struct tracepoint *tracepoint; | |
63 | }; | |
64 | ||
65 | extern void tracepoint_iter_start(struct tracepoint_iter *iter); | |
66 | extern void tracepoint_iter_next(struct tracepoint_iter *iter); | |
67 | extern void tracepoint_iter_stop(struct tracepoint_iter *iter); | |
68 | extern void tracepoint_iter_reset(struct tracepoint_iter *iter); | |
69 | extern int tracepoint_get_iter_range(struct tracepoint **tracepoint, | |
70 | struct tracepoint *begin, struct tracepoint *end); | |
71 | ||
72 | /* | |
73 | * tracepoint_synchronize_unregister must be called between the last tracepoint | |
74 | * probe unregistration and the end of module exit to make sure there is no | |
75 | * caller executing a probe when it is freed. | |
76 | */ | |
77 | static inline void tracepoint_synchronize_unregister(void) | |
78 | { | |
79 | synchronize_sched(); | |
80 | } | |
81 | ||
82 | #define PARAMS(args...) args | |
83 | ||
84 | #ifdef CONFIG_TRACEPOINTS | |
85 | extern void tracepoint_update_probe_range(struct tracepoint *begin, | |
86 | struct tracepoint *end); | |
87 | #else | |
88 | static inline void tracepoint_update_probe_range(struct tracepoint *begin, | |
89 | struct tracepoint *end) | |
90 | { } | |
91 | #endif /* CONFIG_TRACEPOINTS */ | |
92 | ||
93 | #endif /* _LINUX_TRACEPOINT_H */ | |
94 | ||
95 | /* | |
96 | * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include | |
97 | * file ifdef protection. | |
98 | * This is due to the way trace events work. If a file includes two | |
99 | * trace event headers under one "CREATE_TRACE_POINTS" the first include | |
100 | * will override the TRACE_EVENT and break the second include. | |
101 | */ | |
102 | ||
ea20d929 SR |
103 | #ifndef DECLARE_TRACE |
104 | ||
2939b046 | 105 | #define TP_PROTO(args...) args |
8cd09a59 | 106 | #define TP_ARGS(args...) args |
97e1c18e MD |
107 | |
108 | #ifdef CONFIG_TRACEPOINTS | |
109 | ||
110 | /* | |
111 | * it_func[0] is never NULL because there is at least one element in the array | |
112 | * when the array itself is non NULL. | |
38516ab5 SR |
113 | * |
114 | * Note, the proto and args passed in includes "__data" as the first parameter. | |
115 | * The reason for this is to handle the "void" prototype. If a tracepoint | |
116 | * has a "void" prototype, then it is invalid to declare a function | |
117 | * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just | |
118 | * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto". | |
97e1c18e MD |
119 | */ |
120 | #define __DO_TRACE(tp, proto, args) \ | |
121 | do { \ | |
38516ab5 SR |
122 | struct tracepoint_func *it_func_ptr; \ |
123 | void *it_func; \ | |
124 | void *__data; \ | |
97e1c18e | 125 | \ |
da7b3eab | 126 | rcu_read_lock_sched_notrace(); \ |
38516ab5 SR |
127 | it_func_ptr = rcu_dereference_sched((tp)->funcs); \ |
128 | if (it_func_ptr) { \ | |
97e1c18e | 129 | do { \ |
38516ab5 SR |
130 | it_func = (it_func_ptr)->func; \ |
131 | __data = (it_func_ptr)->data; \ | |
132 | ((void(*)(proto))(it_func))(args); \ | |
133 | } while ((++it_func_ptr)->func); \ | |
97e1c18e | 134 | } \ |
da7b3eab | 135 | rcu_read_unlock_sched_notrace(); \ |
97e1c18e MD |
136 | } while (0) |
137 | ||
138 | /* | |
139 | * Make sure the alignment of the structure in the __tracepoints section will | |
140 | * not add unwanted padding between the beginning of the section and the | |
141 | * structure. Force alignment to the same alignment as the section start. | |
142 | */ | |
38516ab5 | 143 | #define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \ |
7e066fb8 | 144 | extern struct tracepoint __tracepoint_##name; \ |
97e1c18e MD |
145 | static inline void trace_##name(proto) \ |
146 | { \ | |
97e1c18e MD |
147 | if (unlikely(__tracepoint_##name.state)) \ |
148 | __DO_TRACE(&__tracepoint_##name, \ | |
38516ab5 SR |
149 | TP_PROTO(data_proto), \ |
150 | TP_ARGS(data_args)); \ | |
97e1c18e | 151 | } \ |
38516ab5 SR |
152 | static inline int \ |
153 | register_trace_##name(void (*probe)(data_proto), void *data) \ | |
97e1c18e | 154 | { \ |
38516ab5 SR |
155 | return tracepoint_probe_register(#name, (void *)probe, \ |
156 | data); \ | |
97e1c18e | 157 | } \ |
38516ab5 SR |
158 | static inline int \ |
159 | unregister_trace_##name(void (*probe)(data_proto), void *data) \ | |
97e1c18e | 160 | { \ |
38516ab5 SR |
161 | return tracepoint_probe_unregister(#name, (void *)probe, \ |
162 | data); \ | |
53da59aa | 163 | } \ |
38516ab5 SR |
164 | static inline void \ |
165 | check_trace_callback_type_##name(void (*cb)(data_proto)) \ | |
53da59aa | 166 | { \ |
97e1c18e MD |
167 | } |
168 | ||
97419875 | 169 | #define DEFINE_TRACE_FN(name, reg, unreg) \ |
7e066fb8 MD |
170 | static const char __tpstrtab_##name[] \ |
171 | __attribute__((section("__tracepoints_strings"))) = #name; \ | |
172 | struct tracepoint __tracepoint_##name \ | |
173 | __attribute__((section("__tracepoints"), aligned(32))) = \ | |
97419875 JS |
174 | { __tpstrtab_##name, 0, reg, unreg, NULL } |
175 | ||
176 | #define DEFINE_TRACE(name) \ | |
177 | DEFINE_TRACE_FN(name, NULL, NULL); | |
7e066fb8 MD |
178 | |
179 | #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \ | |
180 | EXPORT_SYMBOL_GPL(__tracepoint_##name) | |
181 | #define EXPORT_TRACEPOINT_SYMBOL(name) \ | |
182 | EXPORT_SYMBOL(__tracepoint_##name) | |
183 | ||
97e1c18e | 184 | #else /* !CONFIG_TRACEPOINTS */ |
38516ab5 | 185 | #define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \ |
97e1c18e MD |
186 | static inline void trace_##name(proto) \ |
187 | { } \ | |
38516ab5 SR |
188 | static inline int \ |
189 | register_trace_##name(void (*probe)(data_proto), \ | |
190 | void *data) \ | |
97e1c18e MD |
191 | { \ |
192 | return -ENOSYS; \ | |
193 | } \ | |
38516ab5 SR |
194 | static inline int \ |
195 | unregister_trace_##name(void (*probe)(data_proto), \ | |
196 | void *data) \ | |
c420970e MD |
197 | { \ |
198 | return -ENOSYS; \ | |
53da59aa | 199 | } \ |
38516ab5 | 200 | static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \ |
53da59aa | 201 | { \ |
c420970e | 202 | } |
97e1c18e | 203 | |
97419875 | 204 | #define DEFINE_TRACE_FN(name, reg, unreg) |
7e066fb8 MD |
205 | #define DEFINE_TRACE(name) |
206 | #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) | |
207 | #define EXPORT_TRACEPOINT_SYMBOL(name) | |
208 | ||
97e1c18e | 209 | #endif /* CONFIG_TRACEPOINTS */ |
38516ab5 SR |
210 | |
211 | /* | |
212 | * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype | |
213 | * (void). "void" is a special value in a function prototype and can | |
214 | * not be combined with other arguments. Since the DECLARE_TRACE() | |
215 | * macro adds a data element at the beginning of the prototype, | |
216 | * we need a way to differentiate "(void *data, proto)" from | |
217 | * "(void *data, void)". The second prototype is invalid. | |
218 | * | |
219 | * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype | |
220 | * and "void *__data" as the callback prototype. | |
221 | * | |
222 | * DECLARE_TRACE() passes "proto" as the tracepoint protoype and | |
223 | * "void *__data, proto" as the callback prototype. | |
224 | */ | |
225 | #define DECLARE_TRACE_NOARGS(name) \ | |
226 | __DECLARE_TRACE(name, void, , void *__data, __data) | |
227 | ||
228 | #define DECLARE_TRACE(name, proto, args) \ | |
229 | __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \ | |
230 | PARAMS(void *__data, proto), \ | |
231 | PARAMS(__data, args)) | |
232 | ||
ea20d929 | 233 | #endif /* DECLARE_TRACE */ |
97e1c18e | 234 | |
ea20d929 | 235 | #ifndef TRACE_EVENT |
823f9124 SR |
236 | /* |
237 | * For use with the TRACE_EVENT macro: | |
238 | * | |
239 | * We define a tracepoint, its arguments, its printk format | |
240 | * and its 'fast binay record' layout. | |
241 | * | |
242 | * Firstly, name your tracepoint via TRACE_EVENT(name : the | |
243 | * 'subsystem_event' notation is fine. | |
244 | * | |
245 | * Think about this whole construct as the | |
246 | * 'trace_sched_switch() function' from now on. | |
247 | * | |
248 | * | |
249 | * TRACE_EVENT(sched_switch, | |
250 | * | |
251 | * * | |
252 | * * A function has a regular function arguments | |
253 | * * prototype, declare it via TP_PROTO(): | |
254 | * * | |
255 | * | |
ef18012b SR |
256 | * TP_PROTO(struct rq *rq, struct task_struct *prev, |
257 | * struct task_struct *next), | |
823f9124 SR |
258 | * |
259 | * * | |
260 | * * Define the call signature of the 'function'. | |
261 | * * (Design sidenote: we use this instead of a | |
262 | * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.) | |
263 | * * | |
264 | * | |
ef18012b | 265 | * TP_ARGS(rq, prev, next), |
823f9124 SR |
266 | * |
267 | * * | |
268 | * * Fast binary tracing: define the trace record via | |
269 | * * TP_STRUCT__entry(). You can think about it like a | |
270 | * * regular C structure local variable definition. | |
271 | * * | |
272 | * * This is how the trace record is structured and will | |
273 | * * be saved into the ring buffer. These are the fields | |
274 | * * that will be exposed to user-space in | |
156f5a78 | 275 | * * /sys/kernel/debug/tracing/events/<*>/format. |
823f9124 SR |
276 | * * |
277 | * * The declared 'local variable' is called '__entry' | |
278 | * * | |
279 | * * __field(pid_t, prev_prid) is equivalent to a standard declariton: | |
280 | * * | |
281 | * * pid_t prev_pid; | |
282 | * * | |
283 | * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to: | |
284 | * * | |
285 | * * char prev_comm[TASK_COMM_LEN]; | |
286 | * * | |
287 | * | |
288 | * TP_STRUCT__entry( | |
289 | * __array( char, prev_comm, TASK_COMM_LEN ) | |
290 | * __field( pid_t, prev_pid ) | |
291 | * __field( int, prev_prio ) | |
292 | * __array( char, next_comm, TASK_COMM_LEN ) | |
293 | * __field( pid_t, next_pid ) | |
294 | * __field( int, next_prio ) | |
295 | * ), | |
296 | * | |
297 | * * | |
298 | * * Assign the entry into the trace record, by embedding | |
299 | * * a full C statement block into TP_fast_assign(). You | |
300 | * * can refer to the trace record as '__entry' - | |
301 | * * otherwise you can put arbitrary C code in here. | |
302 | * * | |
303 | * * Note: this C code will execute every time a trace event | |
304 | * * happens, on an active tracepoint. | |
305 | * * | |
306 | * | |
ef18012b SR |
307 | * TP_fast_assign( |
308 | * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); | |
309 | * __entry->prev_pid = prev->pid; | |
310 | * __entry->prev_prio = prev->prio; | |
823f9124 SR |
311 | * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); |
312 | * __entry->next_pid = next->pid; | |
ef18012b | 313 | * __entry->next_prio = next->prio; |
823f9124 SR |
314 | * ) |
315 | * | |
316 | * * | |
317 | * * Formatted output of a trace record via TP_printk(). | |
318 | * * This is how the tracepoint will appear under ftrace | |
319 | * * plugins that make use of this tracepoint. | |
320 | * * | |
321 | * * (raw-binary tracing wont actually perform this step.) | |
322 | * * | |
323 | * | |
324 | * TP_printk("task %s:%d [%d] ==> %s:%d [%d]", | |
325 | * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio, | |
326 | * __entry->next_comm, __entry->next_pid, __entry->next_prio), | |
327 | * | |
328 | * ); | |
329 | * | |
330 | * This macro construct is thus used for the regular printk format | |
331 | * tracing setup, it is used to construct a function pointer based | |
332 | * tracepoint callback (this is used by programmatic plugins and | |
333 | * can also by used by generic instrumentation like SystemTap), and | |
334 | * it is also used to expose a structured trace record in | |
156f5a78 | 335 | * /sys/kernel/debug/tracing/events/. |
97419875 JS |
336 | * |
337 | * A set of (un)registration functions can be passed to the variant | |
338 | * TRACE_EVENT_FN to perform any (un)registration work. | |
823f9124 SR |
339 | */ |
340 | ||
091ad365 | 341 | #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print) |
ff038f5c SR |
342 | #define DEFINE_EVENT(template, name, proto, args) \ |
343 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
e5bc9721 SR |
344 | #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ |
345 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
ff038f5c | 346 | |
30a8fecc | 347 | #define TRACE_EVENT(name, proto, args, struct, assign, print) \ |
da4d0302 | 348 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
97419875 JS |
349 | #define TRACE_EVENT_FN(name, proto, args, struct, \ |
350 | assign, print, reg, unreg) \ | |
351 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
7cb2e3ee SR |
352 | |
353 | #endif /* ifdef TRACE_EVENT (see note above) */ |