[PATCH] x86-64: Safe interrupts in oops_begin/end

Rather than blindly re-enabling interrupts in oops_end(), save their state
in oope_begin() and then restore that state.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>