1 files changed, 27 insertions, 6 deletions

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index b9dc4ca0246f..2aac8a83e89b 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -4,7 +4,7 @@
 /*
  * Kernel Tracepoint API.
  *
- * See Documentation/tracepoint.txt.
+ * See Documentation/trace/tracepoints.txt.
  *
  * (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  *
@@ -23,6 +23,8 @@ struct tracepoint;
 struct tracepoint {
         const char *name;               /* Tracepoint name */
         int state;                      /* State. */
+        void (*regfunc)(void);
+        void (*unregfunc)(void);
         void **funcs;
 } __attribute__((aligned(32)));         /*
                                          * Aligned on 32 bytes because it is
@@ -34,7 +36,7 @@ struct tracepoint {
 #ifndef DECLARE_TRACE
 
 #define TP_PROTO(args...)       args
-#define TP_ARGS(args...)                args
+#define TP_ARGS(args...)        args
 
 #ifdef CONFIG_TRACEPOINTS
 
@@ -78,12 +80,16 @@ struct tracepoint {
                 return tracepoint_probe_unregister(#name, (void *)probe);\
         }
 
-#define DEFINE_TRACE(name)                                              \
+
+#define DEFINE_TRACE_FN(name, reg, unreg)                               \
         static const char __tpstrtab_##name[]                           \
         __attribute__((section("__tracepoints_strings"))) = #name;      \
         struct tracepoint __tracepoint_##name                           \
         __attribute__((section("__tracepoints"), aligned(32))) =        \
-                { __tpstrtab_##name, 0, NULL }
+                { __tpstrtab_##name, 0, reg, unreg, NULL }
+
+#define DEFINE_TRACE(name)                                              \
+        DEFINE_TRACE_FN(name, NULL, NULL);
 
 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)                              \
         EXPORT_SYMBOL_GPL(__tracepoint_##name)
@@ -108,6 +114,7 @@ extern void tracepoint_update_probe_range(struct tracepoint *begin,
                 return -ENOSYS;                                         \
         }
 
+#define DEFINE_TRACE_FN(name, reg, unreg)
 #define DEFINE_TRACE(name)
 #define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
 #define EXPORT_TRACEPOINT_SYMBOL(name)
@@ -158,6 +165,15 @@ static inline void tracepoint_synchronize_unregister(void)
 
 #define PARAMS(args...) args
 
+#endif /* _LINUX_TRACEPOINT_H */
+
+/*
+ * Note: we keep the TRACE_EVENT outside the include file ifdef protection.
+ *  This is due to the way trace events work. If a file includes two
+ *  trace event headers under one "CREATE_TRACE_POINTS" the first include
+ *  will override the TRACE_EVENT and break the second include.
+ */
+
 #ifndef TRACE_EVENT
 /*
  * For use with the TRACE_EVENT macro:
@@ -259,10 +275,15 @@ static inline void tracepoint_synchronize_unregister(void)
  * can also by used by generic instrumentation like SystemTap), and
  * it is also used to expose a structured trace record in
  * /sys/kernel/debug/tracing/events/.
+ *
+ * A set of (un)registration functions can be passed to the variant
+ * TRACE_EVENT_FN to perform any (un)registration work.
  */
 
 #define TRACE_EVENT(name, proto, args, struct, assign, print)   \
         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
-#endif
+#define TRACE_EVENT_FN(name, proto, args, struct,               \
+                assign, print, reg, unreg)                      \
+        DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
 
-#endif
+#endif /* ifdef TRACE_EVENT (see note above) */