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27b052e3 PMF |
1 | #ifndef _UST_TRACEPOINT_H |
2 | #define _UST_TRACEPOINT_H | |
f99be407 PMF |
3 | |
4 | /* | |
1f8b0dff PMF |
5 | * Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
6 | * Copyright (C) 2009 Pierre-Marc Fournier | |
22d72948 | 7 | * Copyright (C) 2009 Steven Rostedt <rostedt@goodmis.org> |
f99be407 | 8 | * |
8fc2d8db PMF |
9 | * This library is free software; you can redistribute it and/or |
10 | * modify it under the terms of the GNU Lesser General Public | |
f37142a4 MD |
11 | * License as published by the Free Software Foundation; |
12 | * version 2.1 of the License. | |
f99be407 | 13 | * |
8fc2d8db | 14 | * This library is distributed in the hope that it will be useful, |
1f8b0dff | 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
8fc2d8db PMF |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
17 | * Lesser General Public License for more details. | |
1f8b0dff | 18 | * |
8fc2d8db PMF |
19 | * You should have received a copy of the GNU Lesser General Public |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
f99be407 PMF |
22 | * |
23 | * Heavily inspired from the Linux Kernel Markers. | |
24 | * | |
1f8b0dff | 25 | * Ported to userspace by Pierre-Marc Fournier. |
f99be407 PMF |
26 | */ |
27 | ||
b7ea1a1c | 28 | #include <urcu-bp.h> |
518d7abb | 29 | #include <ust/core.h> |
b0c4126f | 30 | #include <urcu/list.h> |
f99be407 | 31 | |
b979b346 | 32 | struct tracepoint_probe { |
9dec086e NC |
33 | void *func; |
34 | void *data; | |
35 | }; | |
36 | ||
f99be407 PMF |
37 | struct tracepoint { |
38 | const char *name; /* Tracepoint name */ | |
f36c12ab | 39 | char state; /* State. */ |
b979b346 | 40 | struct tracepoint_probe *probes; |
f218ff28 | 41 | }; |
f99be407 | 42 | |
cc7b66ba MD |
43 | /* |
44 | * Tracepoints should be added to the instrumented code using the | |
45 | * "tracepoint()" macro. | |
46 | */ | |
47 | #define tracepoint(name, args...) __trace_##name(args) | |
48 | ||
81614639 MD |
49 | /* |
50 | * Library should be made known to libust by declaring TRACEPOINT_LIB in | |
51 | * the source file. (Usually at the end of the file, in the outermost | |
52 | * scope). | |
53 | */ | |
54 | #define TRACEPOINT_LIB \ | |
55 | extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \ | |
56 | extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \ | |
57 | static struct tracepoint * __tracepoint_ptr_dummy \ | |
58 | __attribute__((used, section("__tracepoints_ptrs"))); \ | |
59 | static void __attribute__((constructor)) __tracepoints__init(void) \ | |
60 | { \ | |
61 | tracepoint_register_lib(__start___tracepoints_ptrs, \ | |
62 | __stop___tracepoints_ptrs - \ | |
63 | __start___tracepoints_ptrs); \ | |
64 | } \ | |
65 | \ | |
66 | static void __attribute__((destructor)) __tracepoints__destroy(void) \ | |
67 | { \ | |
68 | tracepoint_unregister_lib(__start___tracepoints_ptrs); \ | |
69 | } | |
f99be407 PMF |
70 | |
71 | /* | |
72 | * it_func[0] is never NULL because there is at least one element in the array | |
73 | * when the array itself is non NULL. | |
74 | */ | |
75 | #define __DO_TRACE(tp, proto, args) \ | |
76 | do { \ | |
b979b346 MD |
77 | struct tracepoint_probe *__tp_it_probe_ptr; \ |
78 | void *__tp_it_func; \ | |
79 | void *__tp_cb_data; \ | |
f99be407 | 80 | \ |
9dec086e | 81 | rcu_read_lock(); \ |
b979b346 MD |
82 | __tp_it_probe_ptr = rcu_dereference((tp)->probes); \ |
83 | if (__tp_it_probe_ptr) { \ | |
f99be407 | 84 | do { \ |
b979b346 MD |
85 | __tp_it_func = __tp_it_probe_ptr->func; \ |
86 | __tp_cb_data = __tp_it_probe_ptr->data; \ | |
87 | ((void(*)(proto))__tp_it_func)(args); \ | |
88 | } while ((++__tp_it_probe_ptr)->func); \ | |
f99be407 | 89 | } \ |
9dec086e | 90 | rcu_read_unlock(); \ |
f99be407 PMF |
91 | } while (0) |
92 | ||
81614639 MD |
93 | #define TP_PARAMS(args...) args |
94 | #define TP_PROTO(args...) args | |
95 | #define TP_ARGS(args...) args | |
96 | ||
f36c12ab | 97 | #define __CHECK_TRACE(name, proto, args) \ |
f99be407 | 98 | do { \ |
f36c12ab MD |
99 | if (unlikely(__tracepoint_##name.state)) \ |
100 | __DO_TRACE(&__tracepoint_##name, \ | |
101 | TP_PROTO(proto), TP_ARGS(args)); \ | |
f99be407 PMF |
102 | } while (0) |
103 | ||
104 | /* | |
105 | * Make sure the alignment of the structure in the __tracepoints section will | |
106 | * not add unwanted padding between the beginning of the section and the | |
107 | * structure. Force alignment to the same alignment as the section start. | |
f99be407 | 108 | */ |
8d71973c | 109 | #define __DECLARE_TRACEPOINT(name, proto, args, data_proto, data_args) \ |
f99be407 | 110 | extern struct tracepoint __tracepoint_##name; \ |
cc7b66ba | 111 | static inline void __trace_##name(proto) \ |
f99be407 | 112 | { \ |
f36c12ab | 113 | __CHECK_TRACE(name, TP_PROTO(data_proto), \ |
9dec086e | 114 | TP_ARGS(data_args)); \ |
f99be407 | 115 | } \ |
9dec086e | 116 | static inline int \ |
cc7b66ba | 117 | __register_trace_##name(void (*probe)(data_proto), void *data) \ |
f99be407 | 118 | { \ |
81614639 | 119 | return __tracepoint_probe_register(#name, (void *)probe,\ |
9dec086e NC |
120 | data); \ |
121 | \ | |
f99be407 | 122 | } \ |
9dec086e | 123 | static inline int \ |
cc7b66ba | 124 | __unregister_trace_##name(void (*probe)(data_proto), void *data)\ |
f99be407 | 125 | { \ |
81614639 | 126 | return __tracepoint_probe_unregister(#name, (void *)probe, \ |
9dec086e | 127 | data); \ |
f99be407 PMF |
128 | } |
129 | ||
332b3a18 | 130 | /* |
81614639 | 131 | * The need for the _DECLARE_TRACEPOINT_NOARGS() is to handle the prototype |
377d33ed | 132 | * (void). "void" is a special value in a function prototype and can |
8d71973c | 133 | * not be combined with other arguments. Since the DECLARE_TRACEPOINT() |
377d33ed MD |
134 | * macro adds a data element at the beginning of the prototype, |
135 | * we need a way to differentiate "(void *data, proto)" from | |
136 | * "(void *data, void)". The second prototype is invalid. | |
137 | * | |
8d71973c | 138 | * DECLARE_TRACEPOINT_NOARGS() passes "void" as the tracepoint prototype |
b979b346 | 139 | * and "void *__tp_cb_data" as the callback prototype. |
377d33ed | 140 | * |
8d71973c | 141 | * DECLARE_TRACEPOINT() passes "proto" as the tracepoint protoype and |
b979b346 | 142 | * "void *__tp_cb_data, proto" as the callback prototype. |
377d33ed | 143 | */ |
81614639 MD |
144 | #define _DECLARE_TRACEPOINT_NOARGS(name) \ |
145 | __DECLARE_TRACEPOINT(name, void, , void *__tp_cb_data, __tp_cb_data) | |
377d33ed | 146 | |
81614639 MD |
147 | #define _DECLARE_TRACEPOINT(name, proto, args) \ |
148 | __DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args), \ | |
149 | TP_PARAMS(void *__tp_cb_data, proto), \ | |
150 | TP_PARAMS(__tp_cb_data, args)) | |
9dec086e | 151 | |
f99be407 | 152 | /* |
81614639 MD |
153 | * __tracepoints_ptrs section is not const (read-only) to let the linker update |
154 | * the pointer, allowing PIC code. | |
f99be407 | 155 | */ |
81614639 MD |
156 | #define _DEFINE_TRACEPOINT(name) \ |
157 | static const char __tpstrtab_##name[] \ | |
158 | __attribute__((section("__tracepoints_strings"))) = #name; \ | |
159 | struct tracepoint __tracepoint_##name \ | |
160 | __attribute__((section("__tracepoints"))) = \ | |
161 | { __tpstrtab_##name, 0, NULL }; \ | |
162 | static struct tracepoint * __tracepoint_ptr_##name \ | |
163 | __attribute__((used, section("__tracepoints_ptrs"))) = \ | |
164 | &__tracepoint_##name; | |
f99be407 | 165 | |
f99be407 | 166 | |
81614639 MD |
167 | #define __register_tracepoint(name, probe, data) \ |
168 | __register_trace_##name(probe, data) | |
169 | #define __unregister_tracepoint(name, probe, data) \ | |
170 | __unregister_trace_##name(probe, data) | |
f99be407 | 171 | |
81614639 MD |
172 | /* |
173 | * Connect a probe to a tracepoint. | |
174 | * Internal API. | |
175 | */ | |
176 | extern | |
177 | int __tracepoint_probe_register(const char *name, void *probe, void *data); | |
f99be407 PMF |
178 | |
179 | /* | |
81614639 MD |
180 | * Disconnect a probe from a tracepoint. |
181 | * Internal API. | |
f99be407 | 182 | */ |
81614639 MD |
183 | extern |
184 | int __tracepoint_probe_unregister(const char *name, void *probe, void *data); | |
f99be407 | 185 | |
474d745f | 186 | struct tracepoint_lib { |
f218ff28 | 187 | struct tracepoint * const *tracepoints_start; |
474d745f | 188 | int tracepoints_count; |
0222e121 | 189 | struct cds_list_head list; |
474d745f PMF |
190 | }; |
191 | ||
81614639 MD |
192 | extern |
193 | int tracepoint_register_lib(struct tracepoint * const *tracepoints_start, | |
194 | int tracepoints_count); | |
195 | extern | |
196 | int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start); | |
872037bb | 197 | |
22d72948 | 198 | |
8d71973c | 199 | #ifndef TRACEPOINT_EVENT |
22d72948 | 200 | /* |
8d71973c | 201 | * For use with the TRACEPOINT_EVENT macro: |
22d72948 NC |
202 | * |
203 | * We define a tracepoint, its arguments, its printf format | |
204 | * and its 'fast binary record' layout. | |
205 | * | |
8d71973c | 206 | * Firstly, name your tracepoint via TRACEPOINT_EVENT(name : the |
22d72948 NC |
207 | * 'subsystem_event' notation is fine. |
208 | * | |
209 | * Think about this whole construct as the | |
210 | * 'trace_sched_switch() function' from now on. | |
211 | * | |
212 | * | |
8d71973c | 213 | * TRACEPOINT_EVENT(sched_switch, |
22d72948 NC |
214 | * |
215 | * * | |
216 | * * A function has a regular function arguments | |
217 | * * prototype, declare it via TP_PROTO(): | |
218 | * * | |
219 | * | |
220 | * TP_PROTO(struct rq *rq, struct task_struct *prev, | |
221 | * struct task_struct *next), | |
222 | * | |
223 | * * | |
224 | * * Define the call signature of the 'function'. | |
225 | * * (Design sidenote: we use this instead of a | |
226 | * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.) | |
227 | * * | |
228 | * | |
229 | * TP_ARGS(rq, prev, next), | |
230 | * | |
231 | * * | |
232 | * * Fast binary tracing: define the trace record via | |
81614639 | 233 | * * TP_FIELDS(). You can think about it like a |
22d72948 NC |
234 | * * regular C structure local variable definition. |
235 | * * | |
236 | * * This is how the trace record is structured and will | |
237 | * * be saved into the ring buffer. These are the fields | |
238 | * * that will be exposed to readers. | |
239 | * * | |
81614639 MD |
240 | * * tp_field(pid_t, prev_pid, prev->pid) is equivalent |
241 | * * to a standard declaraton: | |
22d72948 | 242 | * * |
81614639 | 243 | * * pid_t prev_pid; |
22d72948 | 244 | * * |
81614639 | 245 | * * followed by an assignment: |
22d72948 | 246 | * * |
81614639 | 247 | * * prev_pid = prev->pid; |
22d72948 | 248 | * * |
81614639 MD |
249 | * * tp_array(char, prev_comm, TASK_COMM_LEN, prev->comm) is |
250 | * * equivalent to: | |
22d72948 | 251 | * * |
81614639 | 252 | * * char prev_comm[TASK_COMM_LEN]; |
22d72948 | 253 | * * |
81614639 | 254 | * * followed by an assignment: |
22d72948 | 255 | * * |
81614639 | 256 | * * memcpy(prev_comm, prev->comm, TASK_COMM_LEN); |
22d72948 NC |
257 | * * |
258 | * | |
81614639 MD |
259 | * TP_FIELDS( |
260 | * tp_array(char, prev_comm, TASK_COMM_LEN, prev->comm) | |
261 | * tp_field(pid_t, prev_pid, prev->pid) | |
262 | * tp_field(int, prev_prio, prev->prio) | |
263 | * tp_array(char, next_comm, TASK_COMM_LEN, next->comm) | |
264 | * tp_field(pid_t, next_pid, next->pid) | |
265 | * tp_field(int, next_prio, next->prio) | |
22d72948 | 266 | * ) |
22d72948 | 267 | * ); |
22d72948 NC |
268 | */ |
269 | ||
81614639 MD |
270 | #define TRACEPOINT_EVENT(name, proto, args, fields) \ |
271 | _DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args)) | |
0c0686ee | 272 | |
81614639 MD |
273 | #define TRACEPOINT_EVENT_CLASS(name, proto, args, fields) |
274 | #define TRACEPOINT_EVENT_INSTANCE(template, name, proto, args) \ | |
275 | _DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args)) | |
0c0686ee | 276 | |
81614639 MD |
277 | /* |
278 | * Declaration of tracepoints that take 0 argument. | |
279 | */ | |
280 | #define TRACEPOINT_EVENT_NOARGS(name, fields) \ | |
281 | _DECLARE_TRACEPOINT_NOARGS(name) | |
0c0686ee | 282 | |
81614639 MD |
283 | #define TRACEPOINT_EVENT_CLASS_NOARGS(name, fields) |
284 | #define TRACEPOINT_EVENT_INSTANCE_NOARGS(template, name) \ | |
285 | _DECLARE_TRACEPOINT_NOARGS(name) | |
0c0686ee | 286 | |
0c0686ee | 287 | |
0c0686ee | 288 | |
8d71973c | 289 | #define TRACEPOINT_EVENT_LIB \ |
fc1caebc | 290 | extern struct trace_event * const __start___trace_events_ptrs[] \ |
0c0686ee | 291 | __attribute__((weak, visibility("hidden"))); \ |
fc1caebc | 292 | extern struct trace_event * const __stop___trace_events_ptrs[] \ |
0c0686ee | 293 | __attribute__((weak, visibility("hidden"))); \ |
332b3a18 MD |
294 | static struct trace_event * __event_ptrs_dummy \ |
295 | __attribute__((used, section("__trace_events_ptrs"))); \ | |
0c0686ee NC |
296 | static void __attribute__((constructor)) \ |
297 | __trace_events__init(void) \ | |
298 | { \ | |
fc1caebc MD |
299 | trace_event_register_lib(__start___trace_events_ptrs, \ |
300 | __stop___trace_events_ptrs - \ | |
301 | __start___trace_events_ptrs); \ | |
0c0686ee NC |
302 | } \ |
303 | \ | |
304 | static void __attribute__((destructor)) \ | |
305 | __trace_event__destroy(void) \ | |
306 | { \ | |
fc1caebc | 307 | trace_event_unregister_lib(__start___trace_events_ptrs);\ |
0c0686ee NC |
308 | } |
309 | ||
81614639 MD |
310 | struct trace_event { |
311 | const char *name; | |
312 | }; | |
22d72948 | 313 | |
81614639 MD |
314 | struct trace_event_lib { |
315 | struct trace_event * const *trace_events_start; | |
316 | int trace_events_count; | |
317 | struct cds_list_head list; | |
318 | }; | |
22d72948 | 319 | |
81614639 MD |
320 | extern |
321 | int trace_event_register_lib(struct trace_event * const *start_trace_events, | |
322 | int trace_event_count); | |
323 | extern | |
324 | int trace_event_unregister_lib(struct trace_event * const *start_trace_events); | |
22d72948 | 325 | |
81614639 | 326 | #endif /* #ifndef TRACEPOINT_EVENT */ |
22d72948 | 327 | |
27b052e3 | 328 | #endif /* _UST_TRACEPOINT_H */ |