sparc64: Add function graph tracer support.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 58 insertions, 0 deletions

diff --git a/arch/sparc/kernel/ftrace.c b/arch/sparc/kernel/ftrace.c
index 2ea6e4ff7fd..03ab022e51c 100644
--- a/arch/sparc/kernel/ftrace.c
+++ b/arch/sparc/kernel/ftrace.c
@@ -91,3 +91,61 @@ int __init ftrace_dyn_arch_init(void *data)
 	return 0;
 }
 #endif
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern void ftrace_graph_call(void);
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+	unsigned long ip = (unsigned long)(&ftrace_graph_call);
+	u32 old, new;
+
+	old = *(u32 *) &ftrace_graph_call;
+	new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller);
+	return ftrace_modify_code(ip, old, new);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+	unsigned long ip = (unsigned long)(&ftrace_graph_call);
+	u32 old, new;
+
+	old = *(u32 *) &ftrace_graph_call;
+	new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub);
+
+	return ftrace_modify_code(ip, old, new);
+}
+
+#endif /* !CONFIG_DYNAMIC_FTRACE */
+
+/*
+ * Hook the return address and push it in the stack of return addrs
+ * in current thread info.
+ */
+unsigned long prepare_ftrace_return(unsigned long parent,
+				    unsigned long self_addr,
+				    unsigned long frame_pointer)
+{
+	unsigned long return_hooker = (unsigned long) &return_to_handler;
+	struct ftrace_graph_ent trace;
+
+	if (unlikely(atomic_read(&current->tracing_graph_pause)))
+		return parent + 8UL;
+
+	if (ftrace_push_return_trace(parent, self_addr, &trace.depth,
+				     frame_pointer) == -EBUSY)
+		return parent + 8UL;
+
+	trace.func = self_addr;
+
+	/* Only trace if the calling function expects to */
+	if (!ftrace_graph_entry(&trace)) {
+		current->curr_ret_stack--;
+		return parent + 8UL;
+	}
+
+	return return_hooker;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */