4 * Copyright (C) 2009 Analog Devices Inc.
5 * Licensed under the GPL-2 or later.
8 #include <linux/ftrace.h>
9 #include <linux/kernel.h>
10 #include <linux/sched.h>
11 #include <asm/atomic.h>
13 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
16 * Hook the return address and push it in the stack of return addrs
17 * in current thread info.
19 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
20 unsigned long frame_pointer)
22 struct ftrace_graph_ent trace;
23 unsigned long return_hooker = (unsigned long)&return_to_handler;
25 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
28 if (ftrace_push_return_trace(*parent, self_addr, &trace.depth,
29 frame_pointer) == -EBUSY)
32 trace.func = self_addr;
34 /* Only trace if the calling function expects to */
35 if (!ftrace_graph_entry(&trace)) {
36 current->curr_ret_stack--;
40 /* all is well in the world ! hijack RETS ... */
41 *parent = return_hooker;