ftrace: add pretty print to selected fuction traces

This patch adds a call back for the tracers that have hooks to
selected functions. This allows the tracer to show better output
in the set_ftrace_filter file.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>

2 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 13918c4400ad..b331e216d8a1 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -106,12 +106,18 @@ struct ftrace_func_command {
 /* asm/ftrace.h must be defined for archs supporting dynamic ftrace */
 #include <asm/ftrace.h>
 
+struct seq_file;
+
 struct ftrace_hook_ops {
         void                    (*func)(unsigned long ip,
                                         unsigned long parent_ip,
                                         void **data);
         int                     (*callback)(unsigned long ip, void **data);
         void                    (*free)(void **data);
+        int                     (*print)(struct seq_file *m,
+                                         unsigned long ip,
+                                         struct ftrace_hook_ops *ops,
+                                         void *data);
 };
 
 extern int
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1e058848cddb..6533c1d20155 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -834,6 +834,9 @@ static int t_hash_show(struct seq_file *m, void *v)
 
         rec = hlist_entry(hnd, struct ftrace_func_hook, node);
 
+        if (rec->ops->print)
+                return rec->ops->print(m, rec->ip, rec->ops, rec->data);
+
         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
         seq_printf(m, "%s:", str);