From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94B46C43142 for ; Thu, 21 Jun 2018 19:47:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3FFDD21D5B for ; Thu, 21 Jun 2018 19:47:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="qjuTpZns" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FFDD21D5B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933262AbeFUTrJ (ORCPT ); Thu, 21 Jun 2018 15:47:09 -0400 Received: from merlin.infradead.org ([205.233.59.134]:33196 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932938AbeFUTrI (ORCPT ); Thu, 21 Jun 2018 15:47:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=dKdoQVcn+6m/IbgEsL3ircDvr5obJhV5m/yv5lJzpKE=; b=qjuTpZnsEPMnynJGGerZA6BVu U3yFJRHig4RI7hc29BzY9Xat7y48FGC5sXFKpFM2MIUjnn0w/naY6n9E0oHu0EbsNPN0UGg1JY2V+ cZDr7O8shNRk38GLzIGT2MqTRg49D0P649BuKJ46HEiBhw7DKH5pDmzX6RpcmKgmjaD8NfCwFhYoI OnyD0Rsm6Qtxq9jO4LU3MRXckDe1mOGilo7rvbFSOYDu2jfsFeCpOZigGeW8ekbcqsfuznzS+ikVv VDxQ13yk/TbaB+6GSTs8eQgbHC2kUfcrey1joTCS5tS5HdLq6jccZvzpvukkRPI4glKLXZdNZ8Win R2LSOGPlQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fW5Xn-0001FK-Ej; Thu, 21 Jun 2018 19:46:59 +0000 Received: by worktop (Postfix, from userid 1000) id 5E1D06E093E; Thu, 21 Jun 2018 21:46:56 +0200 (CEST) Date: Thu, 21 Jun 2018 21:46:56 +0200 From: Peter Zijlstra To: Fenghua Yu Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Ashok Raj , Dave Hansen , Rafael Wysocki , Tony Luck , Alan Cox , Ravi V Shankar , Arjan van de Ven , linux-kernel , x86 Subject: Re: [RFC PATCH 02/16] x86/split_lock: Handle #AC exception for split lock in kernel mode Message-ID: <20180621194656.GB13636@worktop.programming.kicks-ass.net> References: <1527435965-202085-1-git-send-email-fenghua.yu@intel.com> <1527435965-202085-3-git-send-email-fenghua.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1527435965-202085-3-git-send-email-fenghua.yu@intel.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 27, 2018 at 08:45:51AM -0700, Fenghua Yu wrote: > When #AC exception for split lock is triggered from a kernel instruction, > by default we don't want the exception to panic the whole system. Instead, > the exception handler should log the fault information for debug and > continue the instruction execution. This should not happen today, did you find any unaligned LOCK insns? This is a lot of code to 'handle' something that really should not ever happen. Maybe just WARN and clear the MSR bit, nothing complicated. Also, fix your "disgusting drug-induced crap" comments.