[PATCH 2/2] powerpc/cpu: post the event cpux add/remove instead of online/offline during hotplug

[Michael Ellerman]

Hi Pingfan,

Pingfan Liu <kernelfans at gmail.com> writes:
> Technically speaking, echo 1/0 > cpuX/online is only a subset of cpu
> hotplug/unplug, i.e. add/remove. The latter one includes the physical
> adding/removing of a cpu device. Some user space tools such as kexec-tools
> resort to the event add/remove to automatically rebuild dtb.
> If the dtb is not rebuilt correctly, we may hang on 2nd kernel due to
> lack the info of boot-cpu-hwid in dtb.

I notice you also sent a patch for ppc64_cpu to deal with CPUs being
removed rather than just offlined.

If I apply this patch then existing ppc64_cpu (without your other patch)
will break. Is that right?

cheers