arm64: ipi_nmi: Add support for NMI backtrace

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7R4EN
CVE: NA
Reference: https://www.spinics.net/lists/arm-kernel/msg851005.html



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Enable NMI backtrace support on arm64 using IPI turned as an NMI
leveraging pseudo NMIs support. It is now possible for users to get a
backtrace of a CPU stuck in hard-lockup using magic SYSRQ.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Wei Li <liwei391@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>