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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 6ACDDC282DC for ; Wed, 17 Apr 2019 21:42:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 392BE21850 for ; Wed, 17 Apr 2019 21:42:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387679AbfDQVmf (ORCPT ); Wed, 17 Apr 2019 17:42:35 -0400 Received: from mga12.intel.com ([192.55.52.136]:20166 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387596AbfDQVm2 (ORCPT ); Wed, 17 Apr 2019 17:42:28 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Apr 2019 14:42:27 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,363,1549958400"; d="scan'208";a="224441200" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by orsmga001.jf.intel.com with ESMTP; 17 Apr 2019 14:42:26 -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 v7 15/21] x86/split_lock: Add a sysfs interface to enable/disable split lock detection during run time Date: Wed, 17 Apr 2019 14:34:05 -0700 Message-Id: <1555536851-17462-16-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1555536851-17462-1-git-send-email-fenghua.yu@intel.com> References: <1555536851-17462-1-git-send-email-fenghua.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The interface /sys/device/system/cpu/split_lock_detect is added to allow user to control split lock detection and show current split lock detection setting. Writing [yY1] or [oO][nN] to the file enables split lock detection and writing [nN0] or [oO][fF] disables split lock detection. Split lock detection is enabled or disabled on all CPUs. Reading the file returns current global split lock detection setting: 0: disabled 1: enabled Signed-off-by: Fenghua Yu --- arch/x86/kernel/cpu/intel.c | 45 +++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 6a692d215bef..f2c04aa36d78 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -34,6 +34,7 @@ DEFINE_PER_CPU(u64, msr_test_ctl_cache); EXPORT_PER_CPU_SYMBOL_GPL(msr_test_ctl_cache); +static DEFINE_MUTEX(split_lock_detect_mutex); static bool split_lock_detect_enable; /* @@ -1097,3 +1098,47 @@ void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) if (ia32_core_cap & CORE_CAP_SPLIT_LOCK_DETECT) set_split_lock_detect(); } + +static ssize_t +split_lock_detect_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return sprintf(buf, "%u\n", split_lock_detect_enable); +} + +static ssize_t +split_lock_detect_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + bool val; + int ret; + + ret = strtobool(buf, &val); + if (ret) + return ret; + + mutex_lock(&split_lock_detect_mutex); + + split_lock_detect_enable = val; + + /* Update the split lock detection setting in MSR on all online CPUs. */ + on_each_cpu(split_lock_update_msr, NULL, 1); + + show_split_lock_detection_info(); + + mutex_unlock(&split_lock_detect_mutex); + + return count; +} + +static DEVICE_ATTR_RW(split_lock_detect); + +static int __init split_lock_init(void) +{ + if (!boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) + return -ENODEV; + + return device_create_file(cpu_subsys.dev_root, + &dev_attr_split_lock_detect); +} +subsys_initcall(split_lock_init); -- 2.19.1