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=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 959F1C4742C for ; Mon, 2 Nov 2020 17:03:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64986223AB for ; Mon, 2 Nov 2020 17:03:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727430AbgKBRDV (ORCPT ); Mon, 2 Nov 2020 12:03:21 -0500 Received: from mga09.intel.com ([134.134.136.24]:57706 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727144AbgKBRDU (ORCPT ); Mon, 2 Nov 2020 12:03:20 -0500 IronPort-SDR: fbBPK8TksxOC/RS4oEA6vMHoto2IKDKgcsv+8vSDSxjEeFVmHDWcT2xSsIerslTHLJH7ZJaYN/ tbLPXK9Cq8Aw== X-IronPort-AV: E=McAfee;i="6000,8403,9793"; a="169049448" X-IronPort-AV: E=Sophos;i="5.77,445,1596524400"; d="scan'208";a="169049448" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2020 09:03:19 -0800 IronPort-SDR: q5kmdPiKEtQDKNNWp+n72w+wUAUyWfY3tUxS3k3CVvY5IEgUBiU1BFDs6Dk5GONGTIi/F68pAa dRiql6loEmvg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,445,1596524400"; d="scan'208";a="352870894" Received: from otcwcpicx6.sc.intel.com ([172.25.55.29]) by fmsmga004.fm.intel.com with ESMTP; 02 Nov 2020 09:03:18 -0800 Date: Mon, 2 Nov 2020 17:03:18 +0000 From: Fenghua Yu To: Randy Dunlap Cc: Thomas Gleixner , Borislav Petkov , Ingo Molnar , Peter Zijlstra , Tony Luck , Christopherson Sean J , Ashok Raj , Ravi V Shankar , linux-kernel , x86 Subject: Re: [PATCH RFC v3 4/4] Documentation/admin-guide: Change doc for split_lock_detect parameter Message-ID: <20201102170318.GA3666727@otcwcpicx6.sc.intel.com> References: <20201031002714.3649728-1-fenghua.yu@intel.com> <20201031002714.3649728-5-fenghua.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Randy, On Fri, Oct 30, 2020 at 08:14:15PM -0700, Randy Dunlap wrote: > On 10/30/20 5:27 PM, Fenghua Yu wrote: > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index 526d65d8573a..ee419ce659f5 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -5044,27 +5044,45 @@ > > spia_peddr= > > > > split_lock_detect= > > - [X86] Enable split lock detection > > + [X86] Enable split lock detection or bus lock detection > > > > When enabled (and if hardware support is present), atomic > > instructions that access data across cache line > > - boundaries will result in an alignment check exception. > > + boundaries will result in an alignment check exception > > + for split lock detection or a debug exception for > > + bus lock detection. > > > > off - not enabled > > > > warn - the kernel will emit rate limited warnings > > rate-limited > > > about applications triggering the #AC > > - exception. This mode is the default on CPUs > > - that supports split lock detection. > > + exception or the #DB exception. This mode is > > + the default on CPUs that supports split lock > > support > > > + detection or bus lock detection. Default > > + behavior is from #DB if both features are > > I would say is by #DB > > > + enabled in hardware. > > > > fatal - the kernel will send SIGBUS to applications > > - that trigger the #AC exception. > > + that trigger the #AC exception or the #DB > > + exception. Default behavior is from #AC > > and is by #AC > > > + if both features are enabled in hardware. > > + > > + ratelimit:N - > > + Set rate limit to N bus locks per second > > + for bus lock detection. 0 < N <= HZ/2 and > > + N is approximate. Only applied to non root > > non-root > > > + user. > > users. I'll fix the issues in the next version. Thank you very much for your review! -Fenghua