Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753371AbbF2Tux (ORCPT ); Mon, 29 Jun 2015 15:50:53 -0400 Received: from terminus.zytor.com ([198.137.202.10]:33945 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751159AbbF2Tup (ORCPT ); Mon, 29 Jun 2015 15:50:45 -0400 Message-ID: <5591A177.7050802@zytor.com> Date: Mon, 29 Jun 2015 12:50:15 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Ingo Molnar , Mike Galbraith CC: Ingo Molnar , LKML , Borislav Petkov , Thomas Gleixner , Andy Lutomirski , Denys Vlasenko , Oleg Nesterov , Dave Hansen Subject: Re: [all better] Re: regression: massive trouble with fpu rework References: <1435386316.3664.23.camel@gmail.com> <1435393129.3490.7.camel@gmail.com> <20150627082514.GA10894@gmail.com> <1435395328.6545.10.camel@gmail.com> <20150629064008.GA16251@gmail.com> In-Reply-To: <20150629064008.GA16251@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1348 Lines: 48 On 06/28/2015 11:40 PM, Ingo Molnar wrote: > > Ok, so could you please move the fpu__init_system() further up and see which > position is that starts breaking with the BIOS option set? > > here's the current, broken layout of the code: > > get_cpu_cap(c); > [0] fpu__init_system(c); > > if (this_cpu->c_early_init) > this_cpu->c_early_init(c); > > [1] > c->cpu_index = 0; > [2] > filter_cpuid_features(c, false); > > [3] > if (this_cpu->c_bsp_init) > this_cpu->c_bsp_init(c); > > [4] > setup_force_cpu_cap(X86_FEATURE_ALWAYS); > [5] > } > > and we know it from your testing that moving [0] to [5] fixes the crash. > > The question is, can we move it to [4], [3], [2] or even [1] instead, without > breaking the system? > > I still don't see where the breakage comes from, but this would help us narrow it > down. > It should be moved to [4] or [5]. I would argue that the line setting X86_FEATURE_ALWAYS should moved up and then fpu__init_system(c) should be moved after the c_bsp_init() line. -hpa -- 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/