From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760477Ab0I1Blr (ORCPT ); Mon, 27 Sep 2010 21:41:47 -0400 Received: from mga09.intel.com ([134.134.136.24]:52798 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754244Ab0I1Blq (ORCPT ); Mon, 27 Sep 2010 21:41:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.57,244,1283756400"; d="scan'208";a="661752908" Subject: Re: [PATCH -v2 7/7] x86, NMI, Remove do_nmi_callback logic From: Huang Ying To: Robert Richter Cc: Don Zickus , huang ying , Ingo Molnar , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , Andi Kleen In-Reply-To: <20100927165831.GT13563@erda.amd.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> <20100927151607.GX26290@redhat.com> <20100927165831.GT13563@erda.amd.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 28 Sep 2010 09:41:43 +0800 Message-ID: <1285638103.20791.152.camel@yhuang-dev> Mime-Version: 1.0 X-Mailer: Evolution 2.30.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2010-09-28 at 00:58 +0800, Robert Richter wrote: > On 27.09.10 11:16:07, Don Zickus wrote: > > 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. > > I agree, panic_on_unrecovered_nmi and unknown_nmi_panic almost do the > same thing, though die_nmi() is specifically for nmi handlers. In the > end we can consolidate both. We should then modify kernel.txt and > route unknown_nmi_panic to panic_on_unrecovered_nmi or vice versa. unknown_nmi_panic will cause panic for unknown NMI (can not identify the NMI sources). panic_on_unrecovered_nmi should panic for unrecovered hardware errors, for known and unknown NMI. For example, panic_on_unrecovered_nmi will cause panic in mem_parity_error too, which can be considered known NMI. Is it reasonable? Best Regards, Huang Ying