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,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 65162C4360F for ; Wed, 3 Apr 2019 21:30:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 361F52082C for ; Wed, 3 Apr 2019 21:30:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727346AbfDCVaw (ORCPT ); Wed, 3 Apr 2019 17:30:52 -0400 Received: from mga05.intel.com ([192.55.52.43]:37332 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726805AbfDCVaW (ORCPT ); Wed, 3 Apr 2019 17:30:22 -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 fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Apr 2019 14:30:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,306,1549958400"; d="scan'208";a="334754263" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by fmsmga005.fm.intel.com with ESMTP; 03 Apr 2019 14:30:11 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "H Peter Anvin" , "Dave Hansen" , "Paolo Bonzini" , "Ashok Raj" , "Peter Zijlstra" , "Kalle Valo" , "Xiaoyao Li " , "Michael Chan" , "Ravi V Shankar" Cc: "linux-kernel" , "x86" , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, kvm@vger.kernel.org, Fenghua Yu Subject: [PATCH v6 13/20] x86/split_lock: Enable split lock detection by default Date: Wed, 3 Apr 2019 14:21:59 -0700 Message-Id: <1554326526-172295-14-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1554326526-172295-1-git-send-email-fenghua.yu@intel.com> References: <1554326526-172295-1-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 A split locked access locks bus and degrades overall memory access performance. When split lock detection feature is enumerated, enable the feature by default to find any split lock issue and then fix the issue. Signed-off-by: Fenghua Yu --- arch/x86/kernel/cpu/intel.c | 42 +++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 7f6943af35dc..ae3e327d5e35 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -31,6 +31,12 @@ #include #endif +#define DISABLE_SPLIT_LOCK_DETECT 0 +#define ENABLE_SPLIT_LOCK_DETECT 1 + +static DEFINE_MUTEX(split_lock_detect_mutex); +static int split_lock_detect_val; + /* * Just in case our CPU detection goes bad, or you have a weird system, * allow a way to override the automatic disabling of MPX. @@ -161,10 +167,45 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c) return false; } +static u32 new_sp_test_ctl_val(u32 test_ctl_val) +{ + /* Change the split lock setting. */ + if (READ_ONCE(split_lock_detect_val) == DISABLE_SPLIT_LOCK_DETECT) + test_ctl_val &= ~TEST_CTL_ENABLE_SPLIT_LOCK_DETECT; + else + test_ctl_val |= TEST_CTL_ENABLE_SPLIT_LOCK_DETECT; + + return test_ctl_val; +} + +static inline void show_split_lock_detection_info(void) +{ + if (READ_ONCE(split_lock_detect_val)) + pr_info_once("x86/split_lock: split lock detection enabled\n"); + else + pr_info_once("x86/split_lock: split lock detection disabled\n"); +} + +static void init_split_lock_detect(struct cpuinfo_x86 *c) +{ + if (cpu_has(c, X86_FEATURE_SPLIT_LOCK_DETECT)) { + u32 l, h; + + mutex_lock(&split_lock_detect_mutex); + rdmsr(MSR_TEST_CTL, l, h); + l = new_sp_test_ctl_val(l); + wrmsr(MSR_TEST_CTL, l, h); + show_split_lock_detection_info(); + mutex_unlock(&split_lock_detect_mutex); + } +} + static void early_init_intel(struct cpuinfo_x86 *c) { u64 misc_enable; + init_split_lock_detect(c); + /* Unmask CPUID levels if masked: */ if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { if (msr_clear_bit(MSR_IA32_MISC_ENABLE, @@ -1032,6 +1073,7 @@ cpu_dev_register(intel_cpu_dev); static void __init set_split_lock_detect(void) { setup_force_cpu_cap(X86_FEATURE_SPLIT_LOCK_DETECT); + split_lock_detect_val = 1; } void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) -- 2.19.1