tracing: add run-time field descriptions for event filtering

This patch makes the field descriptions defined for event tracing
available at run-time, for the event-filtering mechanism introduced
in a subsequent patch.

The common event fields are prepended with 'common_' in the format
display, allowing them to be distinguished from the other fields
that might internally have same name and can therefore be
unambiguously used in filters.

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237710639.7703.46.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 21 insertions, 9 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 7cfb741be200..9288dc7ad14f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -775,16 +775,26 @@ enum {
         TRACE_EVENT_TYPE_RAW            = 2,
 };
 
+struct ftrace_event_field {
+        struct list_head        link;
+        char                    *name;
+        char                    *type;
+        int                     offset;
+        int                     size;
+};
+
 struct ftrace_event_call {
-        char            *name;
-        char            *system;
-        struct dentry   *dir;
-        int             enabled;
-        int             (*regfunc)(void);
-        void            (*unregfunc)(void);
-        int             id;
-        int             (*raw_init)(void);
-        int             (*show_format)(struct trace_seq *s);
+        char                    *name;
+        char                    *system;
+        struct dentry           *dir;
+        int                     enabled;
+        int                     (*regfunc)(void);
+        void                    (*unregfunc)(void);
+        int                     id;
+        int                     (*raw_init)(void);
+        int                     (*show_format)(struct trace_seq *s);
+        int                     (*define_fields)(void);
+        struct list_head        fields;
 
 #ifdef CONFIG_EVENT_PROFILE
         atomic_t        profile_count;
@@ -793,6 +803,8 @@ struct ftrace_event_call {
 #endif
 };
 
+int trace_define_field(struct ftrace_event_call *call, char *type,
+                       char *name, int offset, int size);
 void event_trace_printk(unsigned long ip, const char *fmt, ...);
 extern struct ftrace_event_call __start_ftrace_events[];
 extern struct ftrace_event_call __stop_ftrace_events[];