Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757510AbXK1Tqc (ORCPT ); Wed, 28 Nov 2007 14:46:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755544AbXK1TqY (ORCPT ); Wed, 28 Nov 2007 14:46:24 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:45507 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755007AbXK1TqX (ORCPT ); Wed, 28 Nov 2007 14:46:23 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Vivek Goyal Cc: Neil Horman , Ben Woodard , Andi Kleen , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Andi Kleen , hbabu@us.ibm.com Subject: Re: [PATCH] kexec: force x86_64 arches to boot kdump kernels on boot cpu References: <200711271445.56792.ak@suse.de> <474C64CB.7080004@redhat.com> <20071127194220.GG14887@hmsendeavour.rdu.redhat.com> <20071127200011.GA3703@redhat.com> <20071127222408.GH24223@one.firstfloor.org> <474CA733.9050908@redhat.com> <20071128153649.GC3192@redhat.com> <20071128160206.GA21286@hmsendeavour.rdu.redhat.com> <20071128190525.GD3192@redhat.com> Date: Wed, 28 Nov 2007 12:42:22 -0700 In-Reply-To: <20071128190525.GD3192@redhat.com> (Vivek Goyal's message of "Wed, 28 Nov 2007 14:05:25 -0500") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1356 Lines: 35 Vivek Goyal writes: > Ok. Got it. So in this case we route the interrupts directly through LAPIC > and put LVT0 in ExtInt mode and IOAPIC is bypassed. > > I am looking at Intel Multiprocessor specification v1.4 and as per figure > 3-3 on page 3-9, 8259 is connected to LINTIN0 line, which in turn is > connected to LINTIN0 pin on all processors. If that is the case, even in > this mode, all the CPU should see the timer interrupts (which is coming > from 8259)? However things are implemented completely differently now. I don't think the coherent hypertransport domain of AMD processors actually routes ExtINT interrupts to all cpus but instead one (the default route?) is picked. So I think for the kdump case we pretty much need to use an IOAPIC in virtual wire mode for recent AMD systems. For current Intel systems I believe either scenario still works. > Can you print the LAPIC registers (print_local_APIC) during normal boot > and during kdump boot and paste here? It's worth a look. I still think we need to just use apic mode at kernel startup, and be done with it. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/