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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 B8361C388F2 for ; Sun, 8 Nov 2020 04:29:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C3C720760 for ; Sun, 8 Nov 2020 04:29:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728080AbgKHE3n (ORCPT ); Sat, 7 Nov 2020 23:29:43 -0500 Received: from mga14.intel.com ([192.55.52.115]:27416 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726607AbgKHE3k (ORCPT ); Sat, 7 Nov 2020 23:29:40 -0500 IronPort-SDR: G4kjsxqUxWIUIhTqtH0Hhu8RoAU6VZXBex9TLdP3Xote9PmRsrh61lO5Nz8Ant752DP4LbvkBD MNVdwFoMK98w== X-IronPort-AV: E=McAfee;i="6000,8403,9798"; a="168900976" X-IronPort-AV: E=Sophos;i="5.77,460,1596524400"; d="scan'208";a="168900976" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Nov 2020 20:29:38 -0800 IronPort-SDR: 2k7IFovx7mVJVQc/CKRHPIXUnxRtpg+dBWXddR78h33l4Q74BIcw9/en11zhp9DA3VChausuVV KeUVHNmim4oQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,460,1596524400"; d="scan'208";a="307244989" Received: from otcwcpicx6.sc.intel.com ([172.25.55.29]) by fmsmga008.fm.intel.com with ESMTP; 07 Nov 2020 20:29:38 -0800 From: Fenghua Yu To: "Borislav Petkov" , "Thomas Gleixner" , "Ingo Molnar" , "Peter Zijlstra" , "Tony Luck" , "Randy Dunlap" , "Xiaoyao Li " , "Ravi V Shankar" Cc: "linux-kernel" , "x86" , Fenghua Yu Subject: [PATCH 4/4] Documentation/admin-guide: Change doc for split_lock_detect parameter Date: Sun, 8 Nov 2020 04:29:18 +0000 Message-Id: <20201108042918.1011889-5-fenghua.yu@intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201108042918.1011889-1-fenghua.yu@intel.com> References: <20201108042918.1011889-1-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: - Fix a few wording issues (Randy). RFC v2: - Simplify the documentation (Randy). .../admin-guide/kernel-parameters.txt | 30 +++++++++++++++---- 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 526d65d8573a..215e119f6ca7 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 + 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. Default behavior 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 + 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