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 C05B8C433E1 for ; Mon, 22 Mar 2021 13:54:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 950676196C for ; Mon, 22 Mar 2021 13:54:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230479AbhCVNyQ (ORCPT ); Mon, 22 Mar 2021 09:54:16 -0400 Received: from mga11.intel.com ([192.55.52.93]:23002 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230314AbhCVNxk (ORCPT ); Mon, 22 Mar 2021 09:53:40 -0400 IronPort-SDR: dIUyfePe+cwlGMu72+2Ogsn7gV9UTeEDuu3UaBRMD9Fa3AGfxv9/9p9KFdXrza9MrTmFDH2J0U siEgUfLjjmAQ== X-IronPort-AV: E=McAfee;i="6000,8403,9931"; a="186955058" X-IronPort-AV: E=Sophos;i="5.81,269,1610438400"; d="scan'208";a="186955058" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Mar 2021 06:53:36 -0700 IronPort-SDR: uhSaJckHelzOrgxYwc+GSUbCgcpo2NyuNG4vnUsTOyxhTnFeTToV0H9D6DzhIPyOWvm1823CIg OImkCmgb4ppA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,269,1610438400"; d="scan'208";a="524463763" Received: from otcwcpicx3.sc.intel.com ([172.25.55.73]) by orsmga004.jf.intel.com with ESMTP; 22 Mar 2021 06:53:35 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "Peter Zijlstra" , "Tony Luck" , "Randy Dunlap" , "Xiaoyao Li " , "Ravi V Shankar" Cc: "linux-kernel" , "x86" , Fenghua Yu Subject: [PATCH v6 3/3] Documentation/admin-guide: Change doc for split_lock_detect parameter Date: Mon, 22 Mar 2021 13:53:25 +0000 Message-Id: <20210322135325.682257-4-fenghua.yu@intel.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20210322135325.682257-1-fenghua.yu@intel.com> References: <20210322135325.682257-1-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 Acked-by: Randy Dunlap --- Change Log: v6: - Remove the ratelimit info which will be released later in a ratelimit specific patch set (Thomas). v5: - Remove N < HZ/2 check info in the doc (Thomas). v4: - Fix a ratelimit wording issue in the doc (Randy). - Patch 4 is acked by Randy (Randy). 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 | 22 ++++++++++++++----- 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 04545725f187..aef927cec602 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5100,27 +5100,37 @@ 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 #AC 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. Default behavior is by #AC if + both features are enabled in hardware. 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. -- 2.31.0