Tracepoints: add noargs support
[ust.git] / include / ust / tracepoint.h
index 05e5c11dd902c0c01ae2713b3d1d44952fd9dcc5..626f8af545dfea3d9c5136503ad7a61c44fae6ef 100644 (file)
@@ -49,6 +49,18 @@ struct tracepoint {
 #define TP_PROTO(args...)      args
 #define TP_ARGS(args...)       args
 
+/*
+ * Tracepoints should be added to the instrumented code using the
+ * "tracepoint()" macro.
+ */
+#define tracepoint(name, args...)      __trace_##name(args)
+
+#define register_tracepoint(name, probe, data)                 \
+               __register_trace_##name(probe, data)
+
+#define unregister_tracepoint(name, probe, data)               \
+               __unregister_trace_##name(probe, data)
+
 #define CONFIG_TRACEPOINTS
 #ifdef CONFIG_TRACEPOINTS
 
@@ -99,7 +111,7 @@ struct tracepoint {
  */
 #define __DECLARE_TRACE(name, proto, args, data_proto, data_args)      \
        extern struct tracepoint __tracepoint_##name;                   \
-       static inline void trace_##name(proto)                          \
+       static inline void __trace_##name(proto)                        \
        {                                                               \
                __CHECK_TRACE(name, 0, TP_PROTO(data_proto),            \
                              TP_ARGS(data_args));                      \
@@ -110,14 +122,14 @@ struct tracepoint {
                              TP_ARGS(data_args));                      \
        }                                                               \
        static inline int                                               \
-       register_trace_##name(void (*probe)(data_proto), void *data)    \
+       __register_trace_##name(void (*probe)(data_proto), void *data)  \
        {                                                               \
                return tracepoint_probe_register(#name, (void *)probe,  \
                                                 data);                 \
                                                                        \
        }                                                               \
        static inline int                                               \
-       unregister_trace_##name(void (*probe)(data_proto), void *data)  \
+       __unregister_trace_##name(void (*probe)(data_proto), void *data)\
        {                                                               \
                return tracepoint_probe_unregister(#name, (void *)probe, \
                                                   data);               \
@@ -145,11 +157,11 @@ extern void tracepoint_update_probe_range(struct tracepoint * const *begin,
        { }                                                             \
        static inline void _trace_##name(proto)                         \
        { }                                                             \
-       static inline int register_trace_##name(void (*probe)(proto), void *data)       \
+       static inline int __register_trace_##name(void (*probe)(proto), void *data)     \
        {                                                               \
                return -ENOSYS;                                         \
        }                                                               \
-       static inline int unregister_trace_##name(void (*probe)(proto), void *data)     \
+       static inline int __unregister_trace_##name(void (*probe)(proto), void *data)   \
        {                                                               \
                return -ENOSYS;                                         \
        }
@@ -163,10 +175,27 @@ static inline void tracepoint_update_probe_range(struct tracepoint *begin,
 { }
 #endif /* CONFIG_TRACEPOINTS */
 
-#define DECLARE_TRACE(name, proto, args)                       \
-       __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args),      \
-                       PARAMS(void *__data, proto),            \
-                       PARAMS(__data, args))
+/*
+ * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
+ * (void). "void" is a special value in a function prototype and can
+ * not be combined with other arguments. Since the DECLARE_TRACE()
+ * macro adds a data element at the beginning of the prototype,
+ * we need a way to differentiate "(void *data, proto)" from
+ * "(void *data, void)". The second prototype is invalid.
+ *
+ * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
+ * and "void *__data" as the callback prototype.
+ *
+ * DECLARE_TRACE() passes "proto" as the tracepoint protoype and
+ * "void *__data, proto" as the callback prototype.
+ */
+#define DECLARE_TRACE_NOARGS(name)                                     \
+               __DECLARE_TRACE(name, void, , void *__data, __data)
+
+#define DECLARE_TRACE(name, proto, args)                               \
+               __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args),      \
+                               PARAMS(void *__data, proto),            \
+                               PARAMS(__data, args))
 
 /*
  * Connect a probe to a tracepoint.
@@ -220,17 +249,20 @@ extern int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
 extern int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
 
 #define TRACEPOINT_LIB                                                 \
-       extern struct tracepoint * const __start___tracepoints[] __attribute__((weak, visibility("hidden"))); \
-       extern struct tracepoint * const __stop___tracepoints[] __attribute__((weak, visibility("hidden"))); \
-       static void __attribute__((constructor)) __tracepoints__init(void) \
-       {                                                               \
-               tracepoint_register_lib(__start___tracepoints,          \
-                                       (((long)__stop___tracepoints)-((long)__start___tracepoints)) / sizeof(*__start___tracepoints)); \
-       } \
-       \
-       static void __attribute__((destructor)) __tracepoints__destroy(void) \
-       {                                                               \
-               tracepoint_unregister_lib(__start___tracepoints); \
+       extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
+       extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
+       static struct tracepoint * const __tracepoint_ptr_dummy         \
+       __attribute__((used, section("__tracepoints_ptrs"))) = NULL;    \
+       static void __attribute__((constructor)) __tracepoints__init(void)      \
+       {                                                                       \
+               tracepoint_register_lib(__start___tracepoints_ptrs,                     \
+                                       __stop___tracepoints_ptrs -                     \
+                                       __start___tracepoints_ptrs);                    \
+       }                                                                       \
+                                                                               \
+       static void __attribute__((destructor)) __tracepoints__destroy(void)    \
+       {                                                                       \
+               tracepoint_unregister_lib(__start___tracepoints_ptrs);          \
        }
 
 
@@ -339,17 +371,17 @@ struct trace_event {
        const char *name;
        int (*regfunc)(void *data);
        int (*unregfunc)(void *data);
-} __attribute__((aligned(32)));
+};
 
 struct trace_event_lib {
-       struct trace_event *trace_events_start;
+       struct trace_event * const *trace_events_start;
        int trace_events_count;
        struct cds_list_head list;
 };
 
 struct trace_event_iter {
        struct trace_event_lib *lib;
-       struct trace_event *trace_event;
+       struct trace_event * const *trace_event;
 };
 
 extern void lock_trace_events(void);
@@ -359,37 +391,37 @@ extern void trace_event_iter_start(struct trace_event_iter *iter);
 extern void trace_event_iter_next(struct trace_event_iter *iter);
 extern void trace_event_iter_reset(struct trace_event_iter *iter);
 
-extern int trace_event_get_iter_range(struct trace_event **trace_event,
-                                     struct trace_event *begin,
-                                     struct trace_event *end);
+extern int trace_event_get_iter_range(struct trace_event * const **trace_event,
+                                     struct trace_event * const *begin,
+                                     struct trace_event * const *end);
 
 extern void trace_event_update_process(void);
 extern int is_trace_event_enabled(const char *channel, const char *name);
 
-extern int trace_event_register_lib(struct trace_event *start_trace_events,
+extern int trace_event_register_lib(struct trace_event * const *start_trace_events,
                                    int trace_event_count);
 
-extern int trace_event_unregister_lib(struct trace_event *start_trace_events);
+extern int trace_event_unregister_lib(struct trace_event * const *start_trace_events);
 
 #define TRACE_EVENT_LIB                                                        \
-       extern struct trace_event __start___trace_events[]              \
+       extern struct trace_event * const __start___trace_events_ptrs[] \
        __attribute__((weak, visibility("hidden")));                    \
-       extern struct trace_event __stop___trace_events[]               \
+       extern struct trace_event * const __stop___trace_events_ptrs[]  \
        __attribute__((weak, visibility("hidden")));                    \
+       static struct trace_event * const __event_ptrs_dummy            \
+       __attribute__((used, section("__trace_events_ptrs"))) = NULL;   \
        static void __attribute__((constructor))                        \
        __trace_events__init(void)                                      \
        {                                                               \
-               long trace_event_count =((long)__stop___trace_events-   \
-                                        (long)__start___trace_events)  \
-                       /sizeof(struct trace_event);                    \
-               trace_event_register_lib(__start___trace_events,        \
-                                        trace_event_count);            \
+               trace_event_register_lib(__start___trace_events_ptrs,   \
+                                        __stop___trace_events_ptrs -   \
+                                        __start___trace_events_ptrs);  \
        }                                                               \
                                                                        \
        static void __attribute__((destructor))                         \
        __trace_event__destroy(void)                                    \
        {                                                               \
-               trace_event_unregister_lib(__start___trace_events);     \
+               trace_event_unregister_lib(__start___trace_events_ptrs);\
        }
 
 #define DECLARE_TRACE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
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