blob: f2c85ac6f2daf7dcfa47628a893b3993a15eeedc [file] [log] [blame]
/*
* ftrace graph code
*
* Copyright (C) 2009 Analog Devices Inc.
* Licensed under the GPL-2 or later.
*/
#include <linux/ftrace.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <asm/atomic.h>
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/*
* Hook the return address and push it in the stack of return addrs
* in current thread info.
*/
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
{
struct ftrace_graph_ent trace;
unsigned long return_hooker = (unsigned long)&return_to_handler;
if (unlikely(atomic_read(&current->tracing_graph_pause)))
return;
if (ftrace_push_return_trace(*parent, self_addr, &trace.depth, 0) == -EBUSY)
return;
trace.func = self_addr;
/* Only trace if the calling function expects to */
if (!ftrace_graph_entry(&trace)) {
current->curr_ret_stack--;
return;
}
/* all is well in the world ! hijack RETS ... */
*parent = return_hooker;
}
#endif