From: ebiederm@xmission.com (Eric W. Biederman)
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: kexec@lists.infradead.org, Neil Horman <nhorman@tuxdriver.com>
Subject: Re: Question regardin intel64 arch and page table setup
Date: Wed, 11 Aug 2010 17:22:49 -0700 [thread overview]
Message-ID: <m17hjwllwm.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <4C631DF0.2040908@zytor.com> (H. Peter Anvin's message of "Wed, 11 Aug 2010 15:02:24 -0700")
"H. Peter Anvin" <hpa@zytor.com> writes:
> On 08/11/2010 02:51 PM, Eric W. Biederman wrote:
>>
>> 3) I would start just getting the normal kexec case to work.
>> The 64bit kernel does support starting at the 64bit entry point,
>> but I don't think it has been tested if loaded above 4G.
>>
>
> I can guarantee that it hasn't; I looked at that code not all that long
> ago and it's shock-full of 32- and 39-bit assumptions.
Ugh. I thought I had purged the 32bit assumptions. I guess it has been
a while. 39-bit assumptions are forgivable, the architecture didn't
support more than 40bit physical addresses when it was written.
I wonder if this is a problem for SGI. I remember on the ia64 NUMA
machines only node 0 had memory below 4GiB and so if you booted without
node 0 you had no memory below 4GiB. I wonder if this restriction has
carried over to the x86_64 descendants of the Altix.
What is definitely true (unless someone has added an extension since last
I looked ) is that on a normal x86 smp architecture you can't start
additional processors without memory in the low 1MiB because that is all
you can specify in the startup ipi.
Eric
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next prev parent reply other threads:[~2010-08-12 0:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-11 19:47 Question regardin intel64 arch and page table setup Neil Horman
2010-08-11 20:02 ` H. Peter Anvin
2010-08-11 21:51 ` Eric W. Biederman
2010-08-11 21:54 ` Eric W. Biederman
2010-08-11 22:02 ` H. Peter Anvin
2010-08-12 0:22 ` Eric W. Biederman [this message]
2010-08-12 1:05 ` Neil Horman
2010-08-12 1:46 ` H. Peter Anvin
2010-08-12 1:53 ` H. Peter Anvin
2010-08-12 3:21 ` Eric W. Biederman
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