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Date: Tue, 19 Jul 2011 15:20:25 -0400
From: Don Zickus <dzickus@redhat.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>, Matthew Garrett <mjg@redhat.com>,
        "kexec@lists.infradead.org" <kexec@lists.infradead.org>,
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	<dle-develop@lists.sourceforge.net>,
        Satoru Moriya <satoru.moriya@hds.com>
Subject: Re: [RFC][PATCH -mmotm 1/4] Add static function calls of pstore to
 kexec path
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On Tue, Jul 19, 2011 at 03:02:12PM -0400, Vivek Goyal wrote:
> > Another interesting question is do we need to log anything in the kdump
> > path?  Isn't kdump generating the same info?  What added value do we get
> > over kdump?
> 
> I had the same question. The argument is that kdump can fail and they
> can not afford to not capture any info at all. So before kdump executes
> they want to save some state to NVRAM.
> 
> I am wondering that saving this info to NVRAM, can it be done early in
> second kernel? I guess we are not supposed to take any EFI services in
> second kernel so it might not be possible.

Actually the write to NVRAM wouldn't be so bad if ERST supported it.  It
would just be an equvialent to a memcpy.  Currently it uses a complicated
state machine to a persistent storage which complicates things.  As a
result I get nervous if ERST firmware issues would block us from executing
kdump.

Cheers,
Don