nds32/ftrace: Support dynamic function graph tracer

This patch contains the implementation of dynamic function graph tracer.

Signed-off-by: Zong Li <zong@andestech.com>
Acked-by: Greentime Hu <greentime@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>

diff --git a/arch/nds32/kernel/ftrace.c b/arch/nds32/kernel/ftrace.c
index 3ca676b75d976d7099d18b61fb6c86ed9bb74f27..a646a833905205aa0eab90e64443c2933a629fcd 100644 (file)
--- a/arch/nds32/kernel/ftrace.c
+++ b/arch/nds32/kernel/ftrace.c
@@ -74,6 +74,14 @@ void _ftrace_caller(unsigned long parent_ip)
                "nop                    \n\t"
                "nop                    \n\t");
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+       /* a placeholder for the call to ftrace_graph_caller */
+       __asm__ __volatile__ (
+               "ftrace_graph_call:     \n\t"
+               "nop                    \n\t"
+               "nop                    \n\t"
+               "nop                    \n\t");
+#endif
        /* restore all state needed by the compiler epilogue */
 }
 
@@ -258,4 +266,32 @@ void __naked return_to_handler(void)
                "lmw.bim $r0,[$sp],$r1,#0x0  \n\t");
 }
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern unsigned long ftrace_graph_call;
+
+static int ftrace_modify_graph_caller(bool enable)
+{
+       unsigned long pc = (unsigned long)&ftrace_graph_call;
+       unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+       unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
+
+       ftrace_gen_call_insn(call_insn, (unsigned long)ftrace_graph_caller);
+
+       if (enable)
+               return ftrace_modify_code(pc, nop_insn, call_insn, true);
+       else
+               return ftrace_modify_code(pc, call_insn, nop_insn, true);
+}
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+       return ftrace_modify_graph_caller(true);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+       return ftrace_modify_graph_caller(false);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */