Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

From: HATAYAMA Daisuke
Date: Mon Sep 09 2013 - 02:21:21 EST


(2013/09/04 15:12), Borislav Petkov wrote:
On Mon, Sep 02, 2013 at 06:42:44PM +0900, HATAYAMA Daisuke wrote:
The reason why I don't lookup BSP flag in MSR is that it's impossible.
To read MSR of some CPU, we need to use rdmsr instruction on the CPU.
However, in case of this issue, the BSP is halting or running in
the kdump 1st kernel.

Yes, and on the AP, that flag would be cleared which makes it not a BSP.

A whole explanation is written in the patch description.

Those tend to get lost in git history when a bunch of whitespace jerk
offs appear ontop. So a nicely written comment in the code could be very
helpful.

Thanks.


Yes, that's the point this patch series misses. I'll describe the explanation
in Documentation/kexec/kexec.txt and point it in the comment of boot-up code.

--
Thanks.
HATAYAMA, Daisuke

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