!356 x86/boot/compressed: Register dummy NMI handler in EFI boot loader, to avoid kdump crashes

Merge Pull Request from: @henryze 
 
The artificially test code causes the panic cpu to be under the mce context which cannot respond to interrupts(includes NMIs) for a long time. At this duration, watchdog timer could send NMI timeout interrupt to the cpu.

Until the panic cpu runs into the EFI loader, because of the function of switching page tables newly added by the community, the `iret` instruction let cpu restore the ability to respond to nmi interrupts, but the loader does not register the nmi interrupt handler in idt, that results an abnormal restart of the hardware, and the kdump process has been interrupted so far.

The repair patch registers the nmi handler for the EFI loader. After a page fault exits, even if nmi is raised, it can be processed correctly to ensure the smooth completion of the kdump process. 
 
Link:https://gitee.com/openeuler/kernel/pulls/356

 

Reviewed-by: Wei Li <liwei391@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>