From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753054AbXCPH7p (ORCPT ); Fri, 16 Mar 2007 03:59:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753057AbXCPH7o (ORCPT ); Fri, 16 Mar 2007 03:59:44 -0400 Received: from mu-out-0910.google.com ([209.85.134.188]:32638 "EHLO mu-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753052AbXCPH7o (ORCPT ); Fri, 16 Mar 2007 03:59:44 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=bjVc2lUmTBRzMPHaZ3cAO1AWLplqtuNy2zXTv0ECpdmNT1rJKB5g2VRn73Oa7MWm612R8DZ+uS+1RoD+VM0HjHIQpYEuyajtUsZ8pnmLqG5vTLjKdxnTEUIZiUNF4550lvpaH+ULTA8hbJF2z3zGLwZBBgxSuiheWT+uDr71/NY= Message-ID: Date: Fri, 16 Mar 2007 16:59:42 +0900 From: "Magnus Damm" To: "Ian Campbell" Subject: Re: [Fastboot] [PATCH 1/1] Allow i386 crash kernels to handle x86_64 dumps Cc: Horms , "Vivek Goyal" , fastboot@lists.osdl.org, linux-kernel@vger.kernel.org In-Reply-To: <1174030097.28658.37.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <1173891609.8591.41.camel@localhost.localdomain> <20070315014635.GC28396@verge.net.au> <20070315045536.GA6766@in.ibm.com> <20070315050754.GB22329@verge.net.au> <20070315054726.GC6766@in.ibm.com> <1173961378.8591.63.camel@localhost.localdomain> <20070315132616.GH6766@in.ibm.com> <20070315234807.GB10861@verge.net.au> <1174030097.28658.37.camel@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 3/16/07, Ian Campbell wrote: > On Fri, 2007-03-16 at 11:40 +0900, Magnus Damm wrote: > > Right. And maybe it's a good idea to make sure that this feature is > > actually supported by kexec-tools before adding code to the kernel? > > I sent patches to the fastboot list at the same time I sent these ones > to support differences in the underlying hypervisor architecture in the > tools. Oh, that's good news. I have not seen them yet... > They haven't appeared in the archives yet so I fear they have gone > astray. I'll resend when I get to the office in a bit. ... so please resend. We've just frozen the kexec-tools-testing tree for an upcoming release, but if you resend soon and your patches are trivial you may be able to talk us into merging your changes before the release.. > The tools already have support for introducing a SHIM when kexecing > between different architectures (at least in the 64->32 direction if I > understand kexec-tools-testing/purgatory/arch/i386/compat_x86_64.S and > k-t-t.../kexec/arch/i386/compat_x86_64.S correctly). This is really just > an extension of that. Right, the mode switching code in purgatory. > > My gut feeling about this is that you are begging for trouble. The > > kexec/kdump solution is fragile just by itself, and trying to go > > between architectures is just going to be painful. > > It works fine under Xen and I think going from 64Xen+32Kernel->32Kernel > makes more sense than going from 64Xen+32Kernel->64Kernel. As I said > originally I'm not so convinced it makes sense in the native case but I > see no reason to outlaw it (people get to keep both pieces etc...) For kexec I think it is just fine. But for kdump, are you sure things will work out ok? There are some differences between the i386 and x86_64 kexec-tools code and I wonder if feeding i386 info into an x86_64 kernel will work properly. Thanks! / magnus