tracing: Allow events to share their print functions

Multiple events may use the same method to print their data.
Instead of having all events have a pointer to their print funtions,
the trace_event structure now points to a trace_event_functions structure
that will hold the way to print ouf the event.

The event itself is now passed to the print function to let the print
function know what kind of event it should print.

This opens the door to consolidating the way several events print
their output.

   text	   data	    bss	    dec	    hex	filename
4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
4900382	1048964	 861512	6810858	 67ecea	vmlinux.init
4900446	1049028	 861512	6810986	 67ed6a	vmlinux.preprint

This change slightly increases the size but is needed for the next change.

v3: Fix the branch tracer events to handle this change.

v2: Fix the new function graph tracer event calls to handle this change.

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 20 insertions, 7 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 393a8394df0e..4f77932b0983 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -70,18 +70,25 @@ struct trace_iterator {
 };
 
 
+struct trace_event;
+
 typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
-                                              int flags);
-struct trace_event {
-        struct hlist_node       node;
-        struct list_head        list;
-        int                     type;
+                                      int flags, struct trace_event *event);
+
+struct trace_event_functions {
         trace_print_func        trace;
         trace_print_func        raw;
         trace_print_func        hex;
         trace_print_func        binary;
 };
 
+struct trace_event {
+        struct hlist_node               node;
+        struct list_head                list;
+        int                             type;
+        struct trace_event_functions    *funcs;
+};
+
 extern int register_ftrace_event(struct trace_event *event);
 extern int unregister_ftrace_event(struct trace_event *event);
 
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 211c704a71ed..f7256770a20f 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -125,9 +125,12 @@ extern struct ftrace_event_class event_class_syscall_exit;
         static struct syscall_metadata __syscall_meta_##sname;          \
         static struct ftrace_event_call                                 \
         __attribute__((__aligned__(4))) event_enter_##sname;            \
-        static struct trace_event enter_syscall_print_##sname = {       \
+        static struct trace_event_functions enter_syscall_print_funcs_##sname = { \
                 .trace                  = print_syscall_enter,          \
         };                                                              \
+        static struct trace_event enter_syscall_print_##sname = {       \
+                .funcs                  = &enter_syscall_print_funcs_##sname, \
+        };                                                              \
         static struct ftrace_event_call __used                          \
           __attribute__((__aligned__(4)))                               \
           __attribute__((section("_ftrace_events")))                    \
@@ -142,9 +145,12 @@ extern struct ftrace_event_class event_class_syscall_exit;
         static struct syscall_metadata __syscall_meta_##sname;          \
         static struct ftrace_event_call                                 \
         __attribute__((__aligned__(4))) event_exit_##sname;             \
-        static struct trace_event exit_syscall_print_##sname = {        \
+        static struct trace_event_functions exit_syscall_print_funcs_##sname = { \
                 .trace                  = print_syscall_exit,           \
         };                                                              \
+        static struct trace_event exit_syscall_print_##sname = {        \
+                .funcs                  = &exit_syscall_print_funcs_##sname, \
+        };                                                              \
         static struct ftrace_event_call __used                          \
           __attribute__((__aligned__(4)))                               \
           __attribute__((section("_ftrace_events")))                    \