ftrace: add command interface for function selection

Allow for other tracers to add their own commands for function
selection. This interface gives a trace the ability to name a
command for function selection. Right now it is pretty limited
in what it offers, but this is a building step for more features.

The :mod: command is converted to this interface and also serves
as a template for other implementations.

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

1 files changed, 16 insertions, 0 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 106b7909d500..f0a0ecc63b5c 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -95,6 +95,13 @@ stack_trace_sysctl(struct ctl_table *table, int write,
 		   loff_t *ppos);
 #endif
 
+struct ftrace_func_command {
+	struct list_head	list;
+	char			*name;
+	int			(*func)(char *func, char *cmd,
+					char *params, int enable);
+};
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 /* asm/ftrace.h must be defined for archs supporting dynamic ftrace */
 #include <asm/ftrace.h>
@@ -119,6 +126,9 @@ struct dyn_ftrace {
 int ftrace_force_update(void);
 void ftrace_set_filter(unsigned char *buf, int len, int reset);
 
+int register_ftrace_command(struct ftrace_func_command *cmd);
+int unregister_ftrace_command(struct ftrace_func_command *cmd);
+
 /* defined in arch */
 extern int ftrace_ip_converted(unsigned long ip);
 extern int ftrace_dyn_arch_init(void *data);
@@ -202,6 +212,12 @@ extern void ftrace_enable_daemon(void);
 # define ftrace_disable_daemon()		do { } while (0)
 # define ftrace_enable_daemon()			do { } while (0)
 static inline void ftrace_release(void *start, unsigned long size) { }
+static inline int register_ftrace_command(struct ftrace_func_command *cmd)
+{
+}
+static inline int unregister_ftrace_command(char *cmd_name)
+{
+}
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 /* totally disable ftrace - can not re-enable after this */