ftrace/x86: Have save_mcount_regs store RIP in %rdi for first parameter
ftrace/x86: Have save_mcount_regs store RIP in %rdi for first parameter

Instead of having save_mcount_regs store the RIP in %rdx as a temp register
to place it in the proper location of the pt_regs on the stack. Use the
%rdi register as the temp register. This lets us remove the extra store
in the ftrace_caller_setup macro.

Link: http://lkml.kernel.org/r/CA+55aFwF+qCGSKdGaEgW4p6N65GZ5_XTV=1NbtWDvxnd5yYLiw@mail.gmail.com
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1411262304010.3961@nanos

Reviewed-by: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>
Suggested-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>
Signed-off-by: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs