From patchwork Wed Apr 24 19:33:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fenghua Yu X-Patchwork-Id: 10915611 X-Patchwork-Delegate: johannes@sipsolutions.net Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 36B741708 for ; Wed, 24 Apr 2019 19:42:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 280C728A29 for ; Wed, 24 Apr 2019 19:42:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1B46228A71; Wed, 24 Apr 2019 19:42:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B7EF728A72 for ; Wed, 24 Apr 2019 19:42:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730041AbfDXTlo (ORCPT ); Wed, 24 Apr 2019 15:41:44 -0400 Received: from mga18.intel.com ([134.134.136.126]:44995 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729378AbfDXTln (ORCPT ); Wed, 24 Apr 2019 15:41:43 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Apr 2019 12:41:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,390,1549958400"; d="scan'208";a="340454908" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by fmsmga005.fm.intel.com with ESMTP; 24 Apr 2019 12:41:41 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "H Peter Anvin" , "Paolo Bonzini" , "Dave Hansen" , "Ashok Raj" , "Peter Zijlstra" , "Ravi V Shankar" , "Xiaoyao Li " , "Christopherson Sean J" , "Kalle Valo" , "Michael Chan" Cc: "linux-kernel" , "x86" , kvm@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, Fenghua Yu Subject: [PATCH v8 14/15] x86/split_lock: Disable split lock detection by kernel parameter "nosplit_lock_detect" Date: Wed, 24 Apr 2019 12:33:01 -0700 Message-Id: <1556134382-58814-15-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1556134382-58814-1-git-send-email-fenghua.yu@intel.com> References: <1556134382-58814-1-git-send-email-fenghua.yu@intel.com> Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP To work around or debug split lock issues, the kernel parameter "nosplit_lock_detect" is introduced to disable the feature during boot time. Signed-off-by: Fenghua Yu --- .../admin-guide/kernel-parameters.txt | 2 ++ arch/x86/kernel/cpu/intel.c | 25 ++++++++++++++++--- 2 files changed, 23 insertions(+), 4 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2b8ee90bb644..623a5f223ff1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3019,6 +3019,8 @@ nosoftlockup [KNL] Disable the soft-lockup detector. + nosplit_lock_detect [X86] Disable split lock detection + nosync [HW,M68K] Disables sync negotiation for all devices. nowatchdog [KNL] Disable both lockup detectors, i.e. diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 28cc6891ba48..959ebf25beda 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -19,6 +19,7 @@ #include #include #include +#include #ifdef CONFIG_X86_64 #include @@ -34,6 +35,8 @@ DEFINE_PER_CPU(u64, msr_test_ctl_cache); EXPORT_PER_CPU_SYMBOL_GPL(msr_test_ctl_cache); +static bool split_lock_detect_enable; + /* * Just in case our CPU detection goes bad, or you have a weird system, * allow a way to override the automatic disabling of MPX. @@ -659,9 +662,15 @@ static void init_intel_misc_features(struct cpuinfo_x86 *c) static void split_lock_update_msr(void) { - /* Enable split lock detection */ - msr_set_bit(MSR_TEST_CTL, TEST_CTL_SPLIT_LOCK_DETECT_SHIFT); - this_cpu_or(msr_test_ctl_cache, TEST_CTL_SPLIT_LOCK_DETECT); + if (split_lock_detect_enable) { + /* Enable split lock detection */ + msr_set_bit(MSR_TEST_CTL, TEST_CTL_SPLIT_LOCK_DETECT_SHIFT); + this_cpu_or(msr_test_ctl_cache, TEST_CTL_SPLIT_LOCK_DETECT); + } else { + /* Disable split lock detection */ + msr_clear_bit(MSR_TEST_CTL, TEST_CTL_SPLIT_LOCK_DETECT_SHIFT); + this_cpu_and(msr_test_ctl_cache, ~TEST_CTL_SPLIT_LOCK_DETECT); + } } static void init_split_lock_detect(struct cpuinfo_x86 *c) @@ -1060,7 +1069,15 @@ cpu_dev_register(intel_cpu_dev); static void __init set_split_lock_detect(void) { setup_force_cpu_cap(X86_FEATURE_SPLIT_LOCK_DETECT); - pr_info("enabled\n"); + + if (cmdline_find_option_bool(boot_command_line, + "nosplit_lock_detect")) { + split_lock_detect_enable = false; + pr_info("disabled\n"); + } else { + split_lock_detect_enable = true; + pr_info("enabled\n"); + } } void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c)