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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 69EF6C56201 for ; Sat, 21 Nov 2020 02:36:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D8052240C for ; Sat, 21 Nov 2020 02:36:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727076AbgKUCgf (ORCPT ); Fri, 20 Nov 2020 21:36:35 -0500 Received: from mga14.intel.com ([192.55.52.115]:47088 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726913AbgKUCge (ORCPT ); Fri, 20 Nov 2020 21:36:34 -0500 IronPort-SDR: zIM9XqYtKJUCbueBsOQ3EL9xXpfMu6tAb8mRAiA516QxIk5ZYdt+TEsM1mikk4RgCL1jqEvNI+ /AMTXNY30qWA== X-IronPort-AV: E=McAfee;i="6000,8403,9811"; a="170788364" X-IronPort-AV: E=Sophos;i="5.78,358,1599548400"; d="scan'208";a="170788364" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Nov 2020 18:36:33 -0800 IronPort-SDR: G3NCkE9fNLARNqATFu2TWohqwDxmxe+wpsMnN06PwDvjj4sE12M8dko3nXZZCjmKK3HBKWExf2 e9qFY2ZkCfGw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,358,1599548400"; d="scan'208";a="431759885" Received: from otcwcpicx6.sc.intel.com ([172.25.55.29]) by fmsmga001.fm.intel.com with ESMTP; 20 Nov 2020 18:36:33 -0800 From: Fenghua Yu To: "Thomas Gleixner" , "Borislav Petkov" , "Ingo Molnar" , "Peter Zijlstra" , "Tony Luck" , "Randy Dunlap" , "Xiaoyao Li " , "Ravi V Shankar" Cc: "linux-kernel" , "x86" , Fenghua Yu Subject: [PATCH v3 4/4] Documentation/admin-guide: Change doc for split_lock_detect parameter Date: Sat, 21 Nov 2020 02:36:24 +0000 Message-Id: <20201121023624.3604415-5-fenghua.yu@intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201121023624.3604415-1-fenghua.yu@intel.com> References: <20201121023624.3604415-1-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 --- Change Log: v3: - Enable Bus Lock Detection when fatal to handle bus lock from non-WB (PeterZ). v1: - Fix a few wording issues (Randy). RFC v2: - Simplify the documentation (Randy). .../admin-guide/kernel-parameters.txt | 31 +++++++++++++++---- 1 file changed, 25 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 44fde25bb221..dcdb4fd3597d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5051,27 +5051,46 @@ 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 + 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. + exception or the #DB exception. This mode is + the default on CPUs that support split lock + detection or bus lock detection. Default + behavior is by #DB if both features are + 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. If both features are enabled in + hardware, split lock triggers #AC and bus + lock from non-WB triggers #DB. + + 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 + users. + + 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. -- 2.29.2