tracing: Add ftrace_graph_notrace boot parameter

The ftrace_graph_notrace option is for specifying notrace filter for
function graph tracer at boot time.  It can be altered after boot
using set_graph_notrace file on the debugfs.

Link: http://lkml.kernel.org/p/1402590233-22321-2-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 20 insertions, 4 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 232b898eebbd..17885a27281c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3884,6 +3884,7 @@ __setup("ftrace_filter=", set_ftrace_filter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
+static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
 static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer);
 
 static int __init set_graph_function(char *str)
@@ -3893,16 +3894,29 @@ static int __init set_graph_function(char *str)
 }
 __setup("ftrace_graph_filter=", set_graph_function);
 
-static void __init set_ftrace_early_graph(char *buf)
+static int __init set_graph_notrace_function(char *str)
+{
+        strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
+        return 1;
+}
+__setup("ftrace_graph_notrace=", set_graph_notrace_function);
+
+static void __init set_ftrace_early_graph(char *buf, int enable)
 {
         int ret;
         char *func;
+        unsigned long *table = ftrace_graph_funcs;
+        int *count = &ftrace_graph_count;
+
+        if (!enable) {
+                table = ftrace_graph_notrace_funcs;
+                count = &ftrace_graph_notrace_count;
+        }
 
         while (buf) {
                 func = strsep(&buf, ",");
                 /* we allow only one expression at a time */
-                ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
-                                      FTRACE_GRAPH_MAX_FUNCS, func);
+                ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func);
                 if (ret)
                         printk(KERN_DEBUG "ftrace: function %s not "
                                           "traceable\n", func);
@@ -3931,7 +3945,9 @@ static void __init set_ftrace_early_filters(void)
                 ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
         if (ftrace_graph_buf[0])
-                set_ftrace_early_graph(ftrace_graph_buf);
+                set_ftrace_early_graph(ftrace_graph_buf, 1);
+        if (ftrace_graph_notrace_buf[0])
+                set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 }