From: "H. Peter Anvin" <hpa@zytor.com>
To: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: X86-ML <x86@kernel.org>, KEXEC-ML <kexec@lists.infradead.org>,
Haren Myneni <hbabu@us.ibm.com>,
Simon Horman <horms@verge.net.au>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Ingo Molnar <mingo@elte.hu>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: Saveoops: Making Kexec purgatory position-independent?
Date: Sat, 26 Feb 2011 13:38:22 -0800 [thread overview]
Message-ID: <4D6972CE.8040401@zytor.com> (raw)
In-Reply-To: <20110226162008.GA23879@laptop>
On 02/26/2011 08:20 AM, Ahmed S. Darwish wrote:
> Hi,
>
> I'm continuing work on 'Saveoops', saving both early and normal Linux
> oops log to disk upon panic [*], using Kexec and bootloaders this time.
>
> Purgatory, the transitional mini-kernel used by kexec, is a relocatable
> ELF file. Userspace kexec-tools finds the final load address of such
> code (by parsing /proc/iomem, etc) and then applies the relocations
> itself before passing the now-ready executable image to kernel.
>
> Since capturing early oopses is the major goal, doing such relocation
> in userspace won't fit my purposes. Two options remain:
> - relocate purgatory entries in the kernel early boot path
> - or compile purgatory as position-independent, thus simplifying
> the kernel load logic
>
> The former will add extra logic in a sensitive path (early boot), while
> the latter will require changes inside the purgatory code itself,
> especially i386 assembly files.
>
> Any preferable option from our kexec and x86 maintainers?
>
> thanks!
>
> [*] http://news.gmane.org/find-root.php?message_id=<20110125134748.GA10051@laptop>
> http://news.gmane.org/find-root.php?message_id=<20110126124954.GC24527@laptop>
>
I can't see any sane reason to *not* make kexec purgatory
position-independent. It is the obvious thing to do.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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next prev parent reply other threads:[~2011-02-26 21:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-26 16:20 Saveoops: Making Kexec purgatory position-independent? Ahmed S. Darwish
2011-02-26 21:38 ` H. Peter Anvin [this message]
2011-02-27 0:57 ` Eric W. Biederman
2011-02-27 1:15 ` H. Peter Anvin
2011-02-27 13:24 ` Ahmed S. Darwish
2011-02-27 14:16 ` Vivek Goyal
2011-02-27 15:43 ` Ahmed S. Darwish
2011-02-27 18:32 ` Eric W. Biederman
2011-02-28 1:38 ` Simon Horman
2011-02-28 1:39 ` H. Peter Anvin
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