From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]) by bombadil.infradead.org with esmtp (Exim 4.72 #1 (Red Hat Linux)) id 1OjLZT-0005c2-9H for kexec@lists.infradead.org; Thu, 12 Aug 2010 00:23:00 +0000 From: ebiederm@xmission.com (Eric W. Biederman) References: <20100811194734.GD23317@hmsreliant.think-freely.org> <4C6301C2.5020808@zytor.com> <4C631DF0.2040908@zytor.com> Date: Wed, 11 Aug 2010 17:22:49 -0700 In-Reply-To: <4C631DF0.2040908@zytor.com> (H. Peter Anvin's message of "Wed, 11 Aug 2010 15:02:24 -0700") Message-ID: MIME-Version: 1.0 Subject: Re: Question regardin intel64 arch and page table setup List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: "H. Peter Anvin" Cc: kexec@lists.infradead.org, Neil Horman "H. Peter Anvin" 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 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec