From patchwork Thu Apr 1 22:58:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ira Weiny X-Patchwork-Id: 12179787 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=unavailable 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 063C6C4361B for ; Thu, 1 Apr 2021 22:58:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA4E461105 for ; Thu, 1 Apr 2021 22:58:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235888AbhDAW6n (ORCPT ); Thu, 1 Apr 2021 18:58:43 -0400 Received: from mga04.intel.com ([192.55.52.120]:11530 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235373AbhDAW6i (ORCPT ); Thu, 1 Apr 2021 18:58:38 -0400 IronPort-SDR: dui/g2P/GGrVuqZk2FY7siuSxrKXhN57D6ClSJOiBYJyRdY83+muKkkxoAG4pg8IDieNX72Epl tPxASwsBrIJQ== X-IronPort-AV: E=McAfee;i="6000,8403,9941"; a="190117107" X-IronPort-AV: E=Sophos;i="5.81,296,1610438400"; d="scan'208";a="190117107" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2021 15:58:37 -0700 IronPort-SDR: Iu6fTwQoZ98uMmFHDB6Z8+rKIc+0xugOW7VluQv1j6K3mita2jQ/Fub6hUzbaajpXc3KEAqIyg qCFecINMnZVA== X-IronPort-AV: E=Sophos;i="5.81,296,1610438400"; d="scan'208";a="611092362" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Apr 2021 15:58:37 -0700 From: ira.weiny@intel.com To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra Cc: Ira Weiny , Sean Christopherson , Dan Williams , Dave Hansen , x86@kernel.org, linux-kernel@vger.kernel.org, Fenghua Yu , linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH V6 06/10] x86/fault: Adjust WARN_ON for PKey fault Date: Thu, 1 Apr 2021 15:58:29 -0700 Message-Id: <20210401225833.566238-7-ira.weiny@intel.com> X-Mailer: git-send-email 2.28.0.rc0.12.gb6a658bd00c9 In-Reply-To: <20210401225833.566238-1-ira.weiny@intel.com> References: <20210401225833.566238-1-ira.weiny@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Ira Weiny Previously if a Protection key fault occurred it indicated something very wrong because user page mappings are not supposed to be in the kernel address space. Now PKey faults may happen on kernel mappings if the feature is enabled. Remove the warning in the fault path and allow the oops to occur without extra debugging if PKS is enabled. Cc: Sean Christopherson Cc: Dan Williams Signed-off-by: Ira Weiny --- Changes from V5: From Dave Hansen Remove 'we' from comment Changes from V4: From Sean Christopherson Clean up commit message and comment Change cpu_feature_enabled to be in WARN_ON check --- arch/x86/mm/fault.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index a73347e2cdfc..0e0e90968f57 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1141,11 +1141,15 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code, unsigned long address) { /* - * Protection keys exceptions only happen on user pages. We - * have no user pages in the kernel portion of the address - * space, so do not expect them here. + * X86_PF_PK (Protection key exceptions) may occur on kernel addresses + * when PKS (PKeys Supervisor) is enabled. + * + * However, if PKS is not enabled WARN if this exception is seen + * because there are no user pages in the kernel portion of the address + * space. */ - WARN_ON_ONCE(hw_error_code & X86_PF_PK); + WARN_ON_ONCE(!cpu_feature_enabled(X86_FEATURE_PKS) && + (hw_error_code & X86_PF_PK)); #ifdef CONFIG_X86_32 /*