From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759585Ab0I0PQa (ORCPT ); Mon, 27 Sep 2010 11:16:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:28879 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753480Ab0I0PQ3 (ORCPT ); Mon, 27 Sep 2010 11:16:29 -0400 Date: Mon, 27 Sep 2010 11:16:07 -0400 From: Don Zickus To: Robert Richter Cc: huang ying , Huang Ying , Ingo Molnar , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , Andi Kleen Subject: Re: [PATCH -v2 7/7] x86, NMI, Remove do_nmi_callback logic Message-ID: <20100927151607.GX26290@redhat.com> References: <1285549026-5008-1-git-send-email-ying.huang@intel.com> <1285549026-5008-7-git-send-email-ying.huang@intel.com> <20100927104426.GD32222@erda.amd.com> <20100927134341.GQ13563@erda.amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20100927134341.GQ13563@erda.amd.com> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 27, 2010 at 03:43:41PM +0200, Robert Richter wrote: > On 27.09.10 08:56:44, huang ying wrote: > > > >> -static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu) > > >> -{ > > >> -     unsigned char reason = get_nmi_reason(); > > >> -     char buf[64]; > > >> - > > >> -     sprintf(buf, "NMI received for unknown reason %02x\n", reason); > > >> -     die_nmi(buf, regs, 1); /* Always panic here */ > > >> -     return 0; > > > > > > You are dropping this code that is different to panic(). > > > > What is the difference? Is it relevant? > > I think yes, since the code behaves different. Otherwise we could > remove die_nmi() completly and replace it by panic(). But both are > different implementions. Maybe we can merge the code, but I didn't > look at it closly. Actually die_nmi is a wrapper around panic with two important pieces. One, it dumps some registers and two it does another notifier call to DIE_NMIWATCHDOG (which correlates to another discussion in this patch series). So if we do any consolidation between panic and die_nmi, it should be convert to die_nmi. But then I wonder if that breaks the original semantics of 'panic_on_unrecovered_nmi'. I don't think so though. Cheers, Don