fix #29760792

commit 94a46d316f2b54e3de8a4fa884cb16383db7fcd8 upstream

There is no reason to have nmi_enter/exit() in the actual MCE
handlers. Move it to the entry point. This also covers the until now
uncovered initial handler which only prints.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NAlexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NAndy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200505135314.243936614@linutronix.deSigned-off-by: NZelin Deng <zelin.deng@linux.alibaba.com>
Reviewed-by: Nluanshi <zhangliguang@linux.alibaba.com>