Tracepoints: add noargs support

[ust.git] / include / ust / tracepoint.h

diff --git a/include/ust/tracepoint.h b/include/ust/tracepoint.h
index 49a9b6e65bcc26807b57712de321df0e6abcc069..626f8af545dfea3d9c5136503ad7a61c44fae6ef 100644 (file)
--- a/include/ust/tracepoint.h
+++ b/include/ust/tracepoint.h
@@ -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.