From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [RFC][PATCH] Randomize kernel base address on boot
Date: Fri, 27 May 2011 18:07:20 +0200
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Cc: Dan Rosenberg <drosenberg@vsecurity.com>, Tony Luck <tony.luck@gmail.com>,
        linux-kernel@vger.kernel.org, davej@redhat.com,
        kees.cook@canonical.com, davem@davemloft.net, eranian@google.com,
        torvalds@linux-foundation.org, adobriyan@gmail.com, penberg@kernel.org,
        Arjan van de Ven <arjan@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>, Valdis.Kletnieks@vt.edu,
        Ingo Molnar <mingo@elte.hu>, pageexec@freemail.hu
References: <1306269105.21443.20.camel@dan> <201105270018.36835.rjw@sisk.pl> <4DDED4ED.7020806@zytor.com>
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On Friday, May 27, 2011, H. Peter Anvin wrote:
> On 05/26/2011 03:18 PM, Rafael J. Wysocki wrote:
> > 
> > Well, as far as I can tell, this feature is going to break hibernation on
> > both x86_32 and x86_64 at the moment, unless you can guarantee that the
> > randomized kernel location will be the same for both the boot and the target
> > kernels.
> > 
> 
> Obviously we can't and we don't.  I'm a bit surprised at that
> constraint... how can that constraint not break things like kernels of
> slightly different size?

Our hibernation code generally requires that the kernel used for loading
the image be the same as the hibernated one.  This requirement is slightly
lifted for x86_64, but still we don't have a mechanism for passing the
jump address into the hibernated header in the image header.

I planned to add that, but then didn't have the time to work on it.

Thanks,
Rafael
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