| 1 | #ifndef _UST_TRACEPOINT_H |
| 2 | #define _UST_TRACEPOINT_H |
| 3 | |
| 4 | /* |
| 5 | * Copyright (C) 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
| 6 | * Copyright (C) 2009 Pierre-Marc Fournier |
| 7 | * Copyright (C) 2009 Steven Rostedt <rostedt@goodmis.org> |
| 8 | * |
| 9 | * This library is free software; you can redistribute it and/or |
| 10 | * modify it under the terms of the GNU Lesser General Public |
| 11 | * License as published by the Free Software Foundation; |
| 12 | * version 2.1 of the License. |
| 13 | * |
| 14 | * This library is distributed in the hope that it will be useful, |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 17 | * Lesser General Public License for more details. |
| 18 | * |
| 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 |
| 22 | * |
| 23 | * Heavily inspired from the Linux Kernel Markers. |
| 24 | * |
| 25 | * Ported to userspace by Pierre-Marc Fournier. |
| 26 | */ |
| 27 | |
| 28 | #include <urcu-bp.h> |
| 29 | #include <ust/core.h> |
| 30 | #include <urcu/list.h> |
| 31 | |
| 32 | struct tracepoint_probe { |
| 33 | void *func; |
| 34 | void *data; |
| 35 | }; |
| 36 | |
| 37 | struct tracepoint { |
| 38 | const char *name; /* Tracepoint name */ |
| 39 | char state; /* State. */ |
| 40 | struct tracepoint_probe *probes; |
| 41 | }; |
| 42 | |
| 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 | |
| 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 | } |
| 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 { \ |
| 77 | struct tracepoint_probe *__tp_it_probe_ptr; \ |
| 78 | void *__tp_it_func; \ |
| 79 | void *__tp_cb_data; \ |
| 80 | \ |
| 81 | rcu_read_lock(); \ |
| 82 | __tp_it_probe_ptr = rcu_dereference((tp)->probes); \ |
| 83 | if (__tp_it_probe_ptr) { \ |
| 84 | do { \ |
| 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); \ |
| 89 | } \ |
| 90 | rcu_read_unlock(); \ |
| 91 | } while (0) |
| 92 | |
| 93 | #define TP_PARAMS(args...) args |
| 94 | #define TP_PROTO(args...) args |
| 95 | #define TP_ARGS(args...) args |
| 96 | |
| 97 | #define __CHECK_TRACE(name, proto, args) \ |
| 98 | do { \ |
| 99 | if (unlikely(__tracepoint_##name.state)) \ |
| 100 | __DO_TRACE(&__tracepoint_##name, \ |
| 101 | TP_PROTO(proto), TP_ARGS(args)); \ |
| 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. |
| 108 | */ |
| 109 | #define __DECLARE_TRACEPOINT(name, proto, args, data_proto, data_args) \ |
| 110 | extern struct tracepoint __tracepoint_##name; \ |
| 111 | static inline void __trace_##name(proto) \ |
| 112 | { \ |
| 113 | __CHECK_TRACE(name, TP_PROTO(data_proto), \ |
| 114 | TP_ARGS(data_args)); \ |
| 115 | } \ |
| 116 | static inline int \ |
| 117 | __register_trace_##name(void (*probe)(data_proto), void *data) \ |
| 118 | { \ |
| 119 | return __tracepoint_probe_register(#name, (void *)probe,\ |
| 120 | data); \ |
| 121 | \ |
| 122 | } \ |
| 123 | static inline int \ |
| 124 | __unregister_trace_##name(void (*probe)(data_proto), void *data)\ |
| 125 | { \ |
| 126 | return __tracepoint_probe_unregister(#name, (void *)probe, \ |
| 127 | data); \ |
| 128 | } |
| 129 | |
| 130 | /* |
| 131 | * The need for the _DECLARE_TRACEPOINT_NOARGS() is to handle the prototype |
| 132 | * (void). "void" is a special value in a function prototype and can |
| 133 | * not be combined with other arguments. Since the DECLARE_TRACEPOINT() |
| 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 | * |
| 138 | * DECLARE_TRACEPOINT_NOARGS() passes "void" as the tracepoint prototype |
| 139 | * and "void *__tp_cb_data" as the callback prototype. |
| 140 | * |
| 141 | * DECLARE_TRACEPOINT() passes "proto" as the tracepoint protoype and |
| 142 | * "void *__tp_cb_data, proto" as the callback prototype. |
| 143 | */ |
| 144 | #define _DECLARE_TRACEPOINT_NOARGS(name) \ |
| 145 | __DECLARE_TRACEPOINT(name, void, , void *__tp_cb_data, __tp_cb_data) |
| 146 | |
| 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)) |
| 151 | |
| 152 | /* |
| 153 | * __tracepoints_ptrs section is not const (read-only) to let the linker update |
| 154 | * the pointer, allowing PIC code. |
| 155 | */ |
| 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; |
| 165 | |
| 166 | |
| 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) |
| 171 | |
| 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); |
| 178 | |
| 179 | /* |
| 180 | * Disconnect a probe from a tracepoint. |
| 181 | * Internal API. |
| 182 | */ |
| 183 | extern |
| 184 | int __tracepoint_probe_unregister(const char *name, void *probe, void *data); |
| 185 | |
| 186 | struct tracepoint_lib { |
| 187 | struct tracepoint * const *tracepoints_start; |
| 188 | int tracepoints_count; |
| 189 | struct cds_list_head list; |
| 190 | }; |
| 191 | |
| 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); |
| 197 | |
| 198 | |
| 199 | #ifndef TRACEPOINT_EVENT |
| 200 | /* |
| 201 | * For use with the TRACEPOINT_EVENT macro: |
| 202 | * |
| 203 | * We define a tracepoint, its arguments, its printf format |
| 204 | * and its 'fast binary record' layout. |
| 205 | * |
| 206 | * Firstly, name your tracepoint via TRACEPOINT_EVENT(name : the |
| 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 | * |
| 213 | * TRACEPOINT_EVENT(sched_switch, |
| 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 |
| 233 | * * TP_FIELDS(). You can think about it like a |
| 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 | * * |
| 240 | * * tp_field(pid_t, prev_pid, prev->pid) is equivalent |
| 241 | * * to a standard declaraton: |
| 242 | * * |
| 243 | * * pid_t prev_pid; |
| 244 | * * |
| 245 | * * followed by an assignment: |
| 246 | * * |
| 247 | * * prev_pid = prev->pid; |
| 248 | * * |
| 249 | * * tp_array(char, prev_comm, TASK_COMM_LEN, prev->comm) is |
| 250 | * * equivalent to: |
| 251 | * * |
| 252 | * * char prev_comm[TASK_COMM_LEN]; |
| 253 | * * |
| 254 | * * followed by an assignment: |
| 255 | * * |
| 256 | * * memcpy(prev_comm, prev->comm, TASK_COMM_LEN); |
| 257 | * * |
| 258 | * |
| 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) |
| 266 | * ) |
| 267 | * ); |
| 268 | */ |
| 269 | |
| 270 | #define TRACEPOINT_EVENT(name, proto, args, fields) \ |
| 271 | _DECLARE_TRACEPOINT(name, TP_PARAMS(proto), TP_PARAMS(args)) |
| 272 | |
| 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)) |
| 276 | |
| 277 | /* |
| 278 | * Declaration of tracepoints that take 0 argument. |
| 279 | */ |
| 280 | #define TRACEPOINT_EVENT_NOARGS(name, fields) \ |
| 281 | _DECLARE_TRACEPOINT_NOARGS(name) |
| 282 | |
| 283 | #define TRACEPOINT_EVENT_CLASS_NOARGS(name, fields) |
| 284 | #define TRACEPOINT_EVENT_INSTANCE_NOARGS(template, name) \ |
| 285 | _DECLARE_TRACEPOINT_NOARGS(name) |
| 286 | |
| 287 | |
| 288 | |
| 289 | #define TRACEPOINT_EVENT_LIB \ |
| 290 | extern struct trace_event * const __start___trace_events_ptrs[] \ |
| 291 | __attribute__((weak, visibility("hidden"))); \ |
| 292 | extern struct trace_event * const __stop___trace_events_ptrs[] \ |
| 293 | __attribute__((weak, visibility("hidden"))); \ |
| 294 | static struct trace_event * __event_ptrs_dummy \ |
| 295 | __attribute__((used, section("__trace_events_ptrs"))); \ |
| 296 | static void __attribute__((constructor)) \ |
| 297 | __trace_events__init(void) \ |
| 298 | { \ |
| 299 | trace_event_register_lib(__start___trace_events_ptrs, \ |
| 300 | __stop___trace_events_ptrs - \ |
| 301 | __start___trace_events_ptrs); \ |
| 302 | } \ |
| 303 | \ |
| 304 | static void __attribute__((destructor)) \ |
| 305 | __trace_event__destroy(void) \ |
| 306 | { \ |
| 307 | trace_event_unregister_lib(__start___trace_events_ptrs);\ |
| 308 | } |
| 309 | |
| 310 | struct trace_event { |
| 311 | const char *name; |
| 312 | }; |
| 313 | |
| 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 | }; |
| 319 | |
| 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); |
| 325 | |
| 326 | #endif /* #ifndef TRACEPOINT_EVENT */ |
| 327 | |
| 328 | #endif /* _UST_TRACEPOINT_H */ |