From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756062AbZHYTTJ (ORCPT ); Tue, 25 Aug 2009 15:19:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755995AbZHYTTI (ORCPT ); Tue, 25 Aug 2009 15:19:08 -0400 Received: from hera.kernel.org ([140.211.167.34]:53641 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755940AbZHYTTH (ORCPT ); Tue, 25 Aug 2009 15:19:07 -0400 Message-ID: <4A9438D1.4030608@kernel.org> Date: Tue, 25 Aug 2009 12:17:37 -0700 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.22 (X11/20090605) MIME-Version: 1.0 To: Ingo Molnar CC: Linus Torvalds , Cyrill Gorcunov , Ravikiran G Thirumalai , linux-kernel@vger.kernel.org, shai@scalex86.org, Suresh Siddha Subject: Re: [patch] x86: 2.6.31-rc7 crash due to buggy flat_phys_pkg_id References: <20090824182659.GA6842@localdomain> <4A932809.1000103@kernel.org> <20090825012632.GB6842@localdomain> <4A9372A1.9090905@kernel.org> <20090825171716.GC6456@localdomain> <20090825181500.GB3277@elte.hu> <20090825183130.GA5806@lenovo> <4A943290.5080606@kernel.org> <20090825191231.GA22821@elte.hu> In-Reply-To: <20090825191231.GA22821@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > * Linus Torvalds wrote: > >> On Tue, 25 Aug 2009, Yinghai Lu wrote: >>> initial apic id and apic id could be different. >>> >>> and we should use initial apic id to get correct phys pkg id in >>> case BIOS set crazy apic id. >> Yinghai - I think you missed Cyrills' point. Let me repeat it: >> >> "cpu_has_apic bit turned off" >> >> there's no apic. No "initial apic id". No "phys pkg id". No >> nothing. >> >> Discussions about "correct phys pkg id" are pointless. > > that's not the case here though: > > [ 8.713916] Total of 32 processors activated (162314.96 BogoMIPS). > > so APICs are active. The real difference is i think this aspect of > commit 2759c3287: > > static int flat_phys_pkg_id(int initial_apic_id, int index_msb) > { > - return hard_smp_processor_id() >> index_msb; > + return initial_apic_id >> index_msb; > } > > We need to revert back to .30 behavior here. (In case of which > environment to trust we almost always trust whatever booted millions > of Linux boxes in the past already.) > > Furthermore, commit 2759c3287 did not declare any side-effects and > clearly causes a side-effect on vSMP which apparently has an > overlapping set of initial APIC ids. > > Ravikiran, your patch does not do a clear revert of this bit though. > If you do a plain revert of the line above alone, does that fix the > problem too? how about patch phys_pkg_id for vsmp? diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c index f3b1037..65edc18 100644 --- a/arch/x86/kernel/apic/probe_64.c +++ b/arch/x86/kernel/apic/probe_64.c @@ -44,6 +44,11 @@ static struct apic *apic_probe[] __initdata = { NULL, }; +static int apicid_phys_pkg_id(int initial_apic_id, int index_msb) +{ + return hard_smp_processor_id() >> index_msb; +} + /* * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode. */ @@ -69,6 +74,11 @@ void __init default_setup_apic_routing(void) printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); } + if (is_vsmp_box()) { + /* need to update phys_pkg_id */ + apic->phys_pkg_id = apicid_phys_pkg_id; + } + /* * Now that apic routing model is selected, configure the * fault handling for intr remapping.