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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 | ||
b70e4f05 | 17 | #include <linux/errno.h> |
97e1c18e MD |
18 | #include <linux/types.h> |
19 | #include <linux/rcupdate.h> | |
8f7b50c5 | 20 | #include <linux/jump_label.h> |
97e1c18e MD |
21 | |
22 | struct module; | |
23 | struct tracepoint; | |
24 | ||
38516ab5 SR |
25 | struct tracepoint_func { |
26 | void *func; | |
27 | void *data; | |
28 | }; | |
29 | ||
97e1c18e MD |
30 | struct tracepoint { |
31 | const char *name; /* Tracepoint name */ | |
32 | int state; /* State. */ | |
97419875 JS |
33 | void (*regfunc)(void); |
34 | void (*unregfunc)(void); | |
38516ab5 | 35 | struct tracepoint_func *funcs; |
7e066fb8 MD |
36 | } __attribute__((aligned(32))); /* |
37 | * Aligned on 32 bytes because it is | |
38 | * globally visible and gcc happily | |
39 | * align these on the structure size. | |
40 | * Keep in sync with vmlinux.lds.h. | |
41 | */ | |
97e1c18e | 42 | |
2e26ca71 SR |
43 | /* |
44 | * Connect a probe to a tracepoint. | |
45 | * Internal API, should not be used directly. | |
46 | */ | |
38516ab5 | 47 | extern int tracepoint_probe_register(const char *name, void *probe, void *data); |
2e26ca71 SR |
48 | |
49 | /* | |
50 | * Disconnect a probe from a tracepoint. | |
51 | * Internal API, should not be used directly. | |
52 | */ | |
38516ab5 SR |
53 | extern int |
54 | tracepoint_probe_unregister(const char *name, void *probe, void *data); | |
2e26ca71 | 55 | |
38516ab5 SR |
56 | extern int tracepoint_probe_register_noupdate(const char *name, void *probe, |
57 | void *data); | |
58 | extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe, | |
59 | void *data); | |
2e26ca71 SR |
60 | extern void tracepoint_probe_update_all(void); |
61 | ||
62 | struct tracepoint_iter { | |
63 | struct module *module; | |
64 | struct tracepoint *tracepoint; | |
65 | }; | |
66 | ||
67 | extern void tracepoint_iter_start(struct tracepoint_iter *iter); | |
68 | extern void tracepoint_iter_next(struct tracepoint_iter *iter); | |
69 | extern void tracepoint_iter_stop(struct tracepoint_iter *iter); | |
70 | extern void tracepoint_iter_reset(struct tracepoint_iter *iter); | |
71 | extern int tracepoint_get_iter_range(struct tracepoint **tracepoint, | |
72 | struct tracepoint *begin, struct tracepoint *end); | |
73 | ||
74 | /* | |
75 | * tracepoint_synchronize_unregister must be called between the last tracepoint | |
76 | * probe unregistration and the end of module exit to make sure there is no | |
77 | * caller executing a probe when it is freed. | |
78 | */ | |
79 | static inline void tracepoint_synchronize_unregister(void) | |
80 | { | |
81 | synchronize_sched(); | |
82 | } | |
83 | ||
84 | #define PARAMS(args...) args | |
85 | ||
86 | #ifdef CONFIG_TRACEPOINTS | |
87 | extern void tracepoint_update_probe_range(struct tracepoint *begin, | |
88 | struct tracepoint *end); | |
89 | #else | |
90 | static inline void tracepoint_update_probe_range(struct tracepoint *begin, | |
91 | struct tracepoint *end) | |
92 | { } | |
93 | #endif /* CONFIG_TRACEPOINTS */ | |
94 | ||
95 | #endif /* _LINUX_TRACEPOINT_H */ | |
96 | ||
97 | /* | |
98 | * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include | |
99 | * file ifdef protection. | |
100 | * This is due to the way trace events work. If a file includes two | |
101 | * trace event headers under one "CREATE_TRACE_POINTS" the first include | |
102 | * will override the TRACE_EVENT and break the second include. | |
103 | */ | |
104 | ||
ea20d929 SR |
105 | #ifndef DECLARE_TRACE |
106 | ||
2939b046 | 107 | #define TP_PROTO(args...) args |
8cd09a59 | 108 | #define TP_ARGS(args...) args |
97e1c18e MD |
109 | |
110 | #ifdef CONFIG_TRACEPOINTS | |
111 | ||
112 | /* | |
113 | * it_func[0] is never NULL because there is at least one element in the array | |
114 | * when the array itself is non NULL. | |
38516ab5 SR |
115 | * |
116 | * Note, the proto and args passed in includes "__data" as the first parameter. | |
117 | * The reason for this is to handle the "void" prototype. If a tracepoint | |
118 | * has a "void" prototype, then it is invalid to declare a function | |
119 | * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just | |
120 | * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto". | |
97e1c18e MD |
121 | */ |
122 | #define __DO_TRACE(tp, proto, args) \ | |
123 | do { \ | |
38516ab5 SR |
124 | struct tracepoint_func *it_func_ptr; \ |
125 | void *it_func; \ | |
126 | void *__data; \ | |
97e1c18e | 127 | \ |
da7b3eab | 128 | rcu_read_lock_sched_notrace(); \ |
38516ab5 SR |
129 | it_func_ptr = rcu_dereference_sched((tp)->funcs); \ |
130 | if (it_func_ptr) { \ | |
97e1c18e | 131 | do { \ |
38516ab5 SR |
132 | it_func = (it_func_ptr)->func; \ |
133 | __data = (it_func_ptr)->data; \ | |
134 | ((void(*)(proto))(it_func))(args); \ | |
135 | } while ((++it_func_ptr)->func); \ | |
97e1c18e | 136 | } \ |
da7b3eab | 137 | rcu_read_unlock_sched_notrace(); \ |
97e1c18e MD |
138 | } while (0) |
139 | ||
140 | /* | |
141 | * Make sure the alignment of the structure in the __tracepoints section will | |
142 | * not add unwanted padding between the beginning of the section and the | |
143 | * structure. Force alignment to the same alignment as the section start. | |
144 | */ | |
38516ab5 | 145 | #define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \ |
7e066fb8 | 146 | extern struct tracepoint __tracepoint_##name; \ |
97e1c18e MD |
147 | static inline void trace_##name(proto) \ |
148 | { \ | |
8f7b50c5 JB |
149 | JUMP_LABEL(&__tracepoint_##name.state, do_trace); \ |
150 | return; \ | |
151 | do_trace: \ | |
97e1c18e | 152 | __DO_TRACE(&__tracepoint_##name, \ |
38516ab5 SR |
153 | TP_PROTO(data_proto), \ |
154 | TP_ARGS(data_args)); \ | |
97e1c18e | 155 | } \ |
38516ab5 SR |
156 | static inline int \ |
157 | register_trace_##name(void (*probe)(data_proto), void *data) \ | |
97e1c18e | 158 | { \ |
38516ab5 SR |
159 | return tracepoint_probe_register(#name, (void *)probe, \ |
160 | data); \ | |
97e1c18e | 161 | } \ |
38516ab5 SR |
162 | static inline int \ |
163 | unregister_trace_##name(void (*probe)(data_proto), void *data) \ | |
97e1c18e | 164 | { \ |
38516ab5 SR |
165 | return tracepoint_probe_unregister(#name, (void *)probe, \ |
166 | data); \ | |
53da59aa | 167 | } \ |
38516ab5 SR |
168 | static inline void \ |
169 | check_trace_callback_type_##name(void (*cb)(data_proto)) \ | |
53da59aa | 170 | { \ |
97e1c18e MD |
171 | } |
172 | ||
97419875 | 173 | #define DEFINE_TRACE_FN(name, reg, unreg) \ |
7e066fb8 MD |
174 | static const char __tpstrtab_##name[] \ |
175 | __attribute__((section("__tracepoints_strings"))) = #name; \ | |
176 | struct tracepoint __tracepoint_##name \ | |
177 | __attribute__((section("__tracepoints"), aligned(32))) = \ | |
97419875 JS |
178 | { __tpstrtab_##name, 0, reg, unreg, NULL } |
179 | ||
180 | #define DEFINE_TRACE(name) \ | |
181 | DEFINE_TRACE_FN(name, NULL, NULL); | |
7e066fb8 MD |
182 | |
183 | #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \ | |
184 | EXPORT_SYMBOL_GPL(__tracepoint_##name) | |
185 | #define EXPORT_TRACEPOINT_SYMBOL(name) \ | |
186 | EXPORT_SYMBOL(__tracepoint_##name) | |
187 | ||
97e1c18e | 188 | #else /* !CONFIG_TRACEPOINTS */ |
38516ab5 | 189 | #define __DECLARE_TRACE(name, proto, args, data_proto, data_args) \ |
97e1c18e MD |
190 | static inline void trace_##name(proto) \ |
191 | { } \ | |
38516ab5 SR |
192 | static inline int \ |
193 | register_trace_##name(void (*probe)(data_proto), \ | |
194 | void *data) \ | |
97e1c18e MD |
195 | { \ |
196 | return -ENOSYS; \ | |
197 | } \ | |
38516ab5 SR |
198 | static inline int \ |
199 | unregister_trace_##name(void (*probe)(data_proto), \ | |
200 | void *data) \ | |
c420970e MD |
201 | { \ |
202 | return -ENOSYS; \ | |
53da59aa | 203 | } \ |
38516ab5 | 204 | static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \ |
53da59aa | 205 | { \ |
c420970e | 206 | } |
97e1c18e | 207 | |
97419875 | 208 | #define DEFINE_TRACE_FN(name, reg, unreg) |
7e066fb8 MD |
209 | #define DEFINE_TRACE(name) |
210 | #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) | |
211 | #define EXPORT_TRACEPOINT_SYMBOL(name) | |
212 | ||
97e1c18e | 213 | #endif /* CONFIG_TRACEPOINTS */ |
38516ab5 SR |
214 | |
215 | /* | |
216 | * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype | |
217 | * (void). "void" is a special value in a function prototype and can | |
218 | * not be combined with other arguments. Since the DECLARE_TRACE() | |
219 | * macro adds a data element at the beginning of the prototype, | |
220 | * we need a way to differentiate "(void *data, proto)" from | |
221 | * "(void *data, void)". The second prototype is invalid. | |
222 | * | |
223 | * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype | |
224 | * and "void *__data" as the callback prototype. | |
225 | * | |
226 | * DECLARE_TRACE() passes "proto" as the tracepoint protoype and | |
227 | * "void *__data, proto" as the callback prototype. | |
228 | */ | |
229 | #define DECLARE_TRACE_NOARGS(name) \ | |
230 | __DECLARE_TRACE(name, void, , void *__data, __data) | |
231 | ||
232 | #define DECLARE_TRACE(name, proto, args) \ | |
233 | __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \ | |
234 | PARAMS(void *__data, proto), \ | |
235 | PARAMS(__data, args)) | |
236 | ||
ea20d929 | 237 | #endif /* DECLARE_TRACE */ |
97e1c18e | 238 | |
ea20d929 | 239 | #ifndef TRACE_EVENT |
823f9124 SR |
240 | /* |
241 | * For use with the TRACE_EVENT macro: | |
242 | * | |
243 | * We define a tracepoint, its arguments, its printk format | |
244 | * and its 'fast binay record' layout. | |
245 | * | |
246 | * Firstly, name your tracepoint via TRACE_EVENT(name : the | |
247 | * 'subsystem_event' notation is fine. | |
248 | * | |
249 | * Think about this whole construct as the | |
250 | * 'trace_sched_switch() function' from now on. | |
251 | * | |
252 | * | |
253 | * TRACE_EVENT(sched_switch, | |
254 | * | |
255 | * * | |
256 | * * A function has a regular function arguments | |
257 | * * prototype, declare it via TP_PROTO(): | |
258 | * * | |
259 | * | |
ef18012b SR |
260 | * TP_PROTO(struct rq *rq, struct task_struct *prev, |
261 | * struct task_struct *next), | |
823f9124 SR |
262 | * |
263 | * * | |
264 | * * Define the call signature of the 'function'. | |
265 | * * (Design sidenote: we use this instead of a | |
266 | * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.) | |
267 | * * | |
268 | * | |
ef18012b | 269 | * TP_ARGS(rq, prev, next), |
823f9124 SR |
270 | * |
271 | * * | |
272 | * * Fast binary tracing: define the trace record via | |
273 | * * TP_STRUCT__entry(). You can think about it like a | |
274 | * * regular C structure local variable definition. | |
275 | * * | |
276 | * * This is how the trace record is structured and will | |
277 | * * be saved into the ring buffer. These are the fields | |
278 | * * that will be exposed to user-space in | |
156f5a78 | 279 | * * /sys/kernel/debug/tracing/events/<*>/format. |
823f9124 SR |
280 | * * |
281 | * * The declared 'local variable' is called '__entry' | |
282 | * * | |
283 | * * __field(pid_t, prev_prid) is equivalent to a standard declariton: | |
284 | * * | |
285 | * * pid_t prev_pid; | |
286 | * * | |
287 | * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to: | |
288 | * * | |
289 | * * char prev_comm[TASK_COMM_LEN]; | |
290 | * * | |
291 | * | |
292 | * TP_STRUCT__entry( | |
293 | * __array( char, prev_comm, TASK_COMM_LEN ) | |
294 | * __field( pid_t, prev_pid ) | |
295 | * __field( int, prev_prio ) | |
296 | * __array( char, next_comm, TASK_COMM_LEN ) | |
297 | * __field( pid_t, next_pid ) | |
298 | * __field( int, next_prio ) | |
299 | * ), | |
300 | * | |
301 | * * | |
302 | * * Assign the entry into the trace record, by embedding | |
303 | * * a full C statement block into TP_fast_assign(). You | |
304 | * * can refer to the trace record as '__entry' - | |
305 | * * otherwise you can put arbitrary C code in here. | |
306 | * * | |
307 | * * Note: this C code will execute every time a trace event | |
308 | * * happens, on an active tracepoint. | |
309 | * * | |
310 | * | |
ef18012b SR |
311 | * TP_fast_assign( |
312 | * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); | |
313 | * __entry->prev_pid = prev->pid; | |
314 | * __entry->prev_prio = prev->prio; | |
823f9124 SR |
315 | * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); |
316 | * __entry->next_pid = next->pid; | |
ef18012b | 317 | * __entry->next_prio = next->prio; |
823f9124 SR |
318 | * ) |
319 | * | |
320 | * * | |
321 | * * Formatted output of a trace record via TP_printk(). | |
322 | * * This is how the tracepoint will appear under ftrace | |
323 | * * plugins that make use of this tracepoint. | |
324 | * * | |
325 | * * (raw-binary tracing wont actually perform this step.) | |
326 | * * | |
327 | * | |
328 | * TP_printk("task %s:%d [%d] ==> %s:%d [%d]", | |
329 | * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio, | |
330 | * __entry->next_comm, __entry->next_pid, __entry->next_prio), | |
331 | * | |
332 | * ); | |
333 | * | |
334 | * This macro construct is thus used for the regular printk format | |
335 | * tracing setup, it is used to construct a function pointer based | |
336 | * tracepoint callback (this is used by programmatic plugins and | |
337 | * can also by used by generic instrumentation like SystemTap), and | |
338 | * it is also used to expose a structured trace record in | |
156f5a78 | 339 | * /sys/kernel/debug/tracing/events/. |
97419875 JS |
340 | * |
341 | * A set of (un)registration functions can be passed to the variant | |
342 | * TRACE_EVENT_FN to perform any (un)registration work. | |
823f9124 SR |
343 | */ |
344 | ||
091ad365 | 345 | #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print) |
ff038f5c SR |
346 | #define DEFINE_EVENT(template, name, proto, args) \ |
347 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
e5bc9721 SR |
348 | #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ |
349 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
ff038f5c | 350 | |
30a8fecc | 351 | #define TRACE_EVENT(name, proto, args, struct, assign, print) \ |
da4d0302 | 352 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
97419875 JS |
353 | #define TRACE_EVENT_FN(name, proto, args, struct, \ |
354 | assign, print, reg, unreg) \ | |
355 | DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) | |
7cb2e3ee SR |
356 | |
357 | #endif /* ifdef TRACE_EVENT (see note above) */ |