function_graph: Implement fgraph_reserve_data() and fgraph_retrieve_data()
Added functions that can be called by a fgraph_ops entryfunc and retfunc to
store state between the entry of the function being traced to the exit of
the same function. The fgraph_ops entryfunc() may call fgraph_reserve_data()
to store up to 4 words onto the task's shadow ret_stack and this then can be
retrived by fgraph_retrieve_data() called by the corresponding retfunc().
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2 files changed
