Re: [PATCH 4/9] x86, NMI: Remove DIE_NMI_IPI and add priorties tohandlers

From: Andi Kleen
Date: Wed Dec 01 2010 - 16:30:42 EST


On Wed, Dec 01, 2010 at 09:41:28PM +0300, Cyrill Gorcunov wrote:
> On Tue, Nov 30, 2010 at 05:27:25PM -0500, Don Zickus wrote:
> > When re-ordering how the NMI handles its callbacks, a conversation started
> > asking what DIE_NMI_IPI meant. No one could answer it.
>
> It should have came from commit
>
> | commit c4b2bffee2a4115fed2825530f2b906ee2f17bd7
> | Author: Andi Kleen <ak@xxxxxxx>
> | Date: Fri Jan 23 18:46:40 2004 -0800
> |
> | [PATCH] x86-64 merge
> |
> | Mainly lots of bug fixes and a few minor features. One change is that
> | it uses drivers/Kconfig now like i386. This requires a few minor changes in
> | outside Kconfig files which I am sending separately.
> ...
>
> Andi do you remember what the initial idea was? Didn't find any user of it
> even in this old commit. Just curious.

The original die names were pretty much a 1:1 conversion of the hooks
used by both the external KDB and KGDB patchkits floating around
at that time.

IIRC DIE_NMI_IPI was the one that was early in the NMI handler
and DIE_NMI late when everything else failed.

So you could use NMI_IPI when you just wanted to stop
all CPUs with a broadcast NMI and can check that reliable
through some memory location, and NMI when you wanted
to drop into the debugger as a last resort.


-Andi

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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