microblaze: ftrace: Add dynamic function graph tracer
This patch add support for dynamic function graph tracer.
There is one my expactation that I can do flush_icache after
all code modification. On microblaze is this safer than do
flush for every entry. For icache is used name flush but
correct should be invalidation - this will be fix in upcomming
new cache implementaion and WB support.
Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
index 0952a8b..388b31c 100644
--- a/arch/microblaze/kernel/ftrace.c
+++ b/arch/microblaze/kernel/ftrace.c
@@ -206,4 +206,32 @@
return ret;
}
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+unsigned int old_jump; /* saving place for jump instruction */
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ unsigned int ret;
+ unsigned long ip = (unsigned long)(&ftrace_call_graph);
+
+ old_jump = *(unsigned int *)ip; /* save jump over instruction */
+ ret = ftrace_modify_code(ip, MICROBLAZE_NOP);
+ flush_icache();
+
+ pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump);
+ return ret;
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ unsigned int ret;
+ unsigned long ip = (unsigned long)(&ftrace_call_graph);
+
+ ret = ftrace_modify_code(ip, old_jump);
+ flush_icache();
+
+ pr_debug("%s\n", __func__);
+ return ret;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#endif /* CONFIG_DYNAMIC_FTRACE */