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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 90279C55179 for ; Thu, 29 Oct 2020 02:44:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F06E2076A for ; Thu, 29 Oct 2020 02:44:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404469AbgJ2Coc (ORCPT ); Wed, 28 Oct 2020 22:44:32 -0400 Received: from mga14.intel.com ([192.55.52.115]:47178 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726583AbgJ1Ve3 (ORCPT ); Wed, 28 Oct 2020 17:34:29 -0400 IronPort-SDR: ofYcoGZcB+n8lU0zhvO4SzILSO+F6If3V06yAY1oOOnRf97a/McFv6Vk0IO/7cV2z8w65mur5s PtqdskJcjUWA== X-IronPort-AV: E=McAfee;i="6000,8403,9788"; a="167551732" X-IronPort-AV: E=Sophos;i="5.77,428,1596524400"; d="scan'208";a="167551732" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Oct 2020 13:28:16 -0700 IronPort-SDR: SFG7HTid7wqrQJCsF+ljZA3BpGC2I0gxvYesRLCSYfz7ZV7x10k7ETzDE6B0yrBAJOcv+2d7EX pcckhknQkmEw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,428,1596524400"; d="scan'208";a="526467877" Received: from otcwcpicx6.sc.intel.com ([172.25.55.29]) by fmsmga005.fm.intel.com with ESMTP; 28 Oct 2020 13:28:16 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Borislav Petkov" , "Ingo Molnar" , "Peter Zijlstra" , "Tony Luck" , "Christopherson Sean J" , "Ashok Raj" , "Ravi V Shankar" Cc: "linux-kernel" , "x86" , Fenghua Yu Subject: [PATCH RFC v2 4/4] Documentation: Change doc for split_lock_detect parameter Date: Wed, 28 Oct 2020 20:28:04 +0000 Message-Id: <20201028202804.3562179-5-fenghua.yu@intel.com> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201028202804.3562179-1-fenghua.yu@intel.com> References: <20201028202804.3562179-1-fenghua.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since #DB for bus lock detect changes the split_lock_detect parameter, update the documentation for the changes. Signed-off-by: Fenghua Yu Reviewed-by: Tony Luck --- .../admin-guide/kernel-parameters.txt | 47 +++++++++++++++---- 1 file changed, 39 insertions(+), 8 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 526d65d8573a..51312484c2b6 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5044,27 +5044,58 @@ 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 an debug exception for + bus lock detection. off - not enabled - warn - the kernel will emit rate limited warnings - about applications triggering the #AC - exception. This mode is the default on CPUs - that supports split lock detection. + warn - Default mode. - fatal - the kernel will send SIGBUS to applications - that trigger the #AC exception. + If split lock detection is enabled in + hardware, the kernel will emit rate limited + warnings about applications triggering the #AC + exception. + + If bus lock detection is enabled in hardware, + the kernel will emit rate limited warnings + about applications triggering the #DB + exception. + + Default behavior is from bus lock detection + if both features are enabled in hardware. + + fatal - If split lock detection is enabled in + hardware, the kernel will send SIGBUS to + applications that trigger the #AC exception. + + If bus lock detection is enabled in hardware, + the kernel will send SIGBUS to application + that trigger the #DB exception. + + Default behavior is from split lock detection + if both 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 + user. + + N/A for split lock detection. If an #AC exception is hit in the kernel or in firmware (i.e. not while executing in user mode) the kernel will oops in either "warn" or "fatal" mode. + #DB exception for bus lock is triggered only when + CPL > 0. + srbds= [X86,INTEL] Control the Special Register Buffer Data Sampling (SRBDS) mitigation. -- 2.29.0