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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 34C66C433E7 for ; Tue, 13 Oct 2020 18:56:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5F4920EDD for ; Tue, 13 Oct 2020 18:56:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728250AbgJMS4z (ORCPT ); Tue, 13 Oct 2020 14:56:55 -0400 Received: from mga17.intel.com ([192.55.52.151]:44127 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727033AbgJMS4z (ORCPT ); Tue, 13 Oct 2020 14:56:55 -0400 IronPort-SDR: haoDqyWVZcZww43t2U2HC9oNnz4/woBa9HxvDyAS9SXWCx7tqw2Lh3q6UuSk8SVw0NOWECs4RE l3ucVH3jlWnA== X-IronPort-AV: E=McAfee;i="6000,8403,9773"; a="145829077" X-IronPort-AV: E=Sophos;i="5.77,371,1596524400"; d="scan'208";a="145829077" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2020 11:56:54 -0700 IronPort-SDR: raLRTUXtVSOjhLMfYeYdRGnzdOVIY4ueopEECZr2H+GBbh+H95qwtBfdauyL8KJNgeuPWQS94c gW3RJpEE8e4A== X-IronPort-AV: E=Sophos;i="5.77,371,1596524400"; d="scan'208";a="346283282" Received: from murawskx-mobl.amr.corp.intel.com (HELO [10.209.9.29]) ([10.209.9.29]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2020 11:56:54 -0700 Subject: Re: [PATCH RFC V3 8/9] x86/fault: Report the PKRS state on fault To: ira.weiny@intel.com, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra Cc: x86@kernel.org, Dave Hansen , Dan Williams , Andrew Morton , Fenghua Yu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org References: <20201009194258.3207172-1-ira.weiny@intel.com> <20201009194258.3207172-9-ira.weiny@intel.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201009194258.3207172-9-ira.weiny@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org > @@ -548,6 +549,11 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad > (error_code & X86_PF_PK) ? "protection keys violation" : > "permissions violation"); > > +#ifdef CONFIG_ARCH_HAS_SUPERVISOR_PKEYS > + if (irq_state && (error_code & X86_PF_PK)) > + pr_alert("PKRS: 0x%x\n", irq_state->pkrs); > +#endif This means everyone will see 'PKRS: 0x0', even if they're on non-PKS hardware. I think I'd rather have this only show PKRS when we're on cpu_feature_enabled(PKS) hardware. ... > @@ -1148,14 +1156,15 @@ static int fault_in_kernel_space(unsigned long address) > */ > static void > do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code, > - unsigned long address) > + unsigned long address, irqentry_state_t *irq_state) > { > /* > - * 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. > + * If protection keys are not enabled for kernel space > + * do not expect Pkey errors here. > */ Let's fix the double-negative: /* * PF_PK is only expected on kernel addresses whenn * supervisor pkeys are enabled: */ > - WARN_ON_ONCE(hw_error_code & X86_PF_PK); > + if (!IS_ENABLED(CONFIG_ARCH_HAS_SUPERVISOR_PKEYS) || > + !cpu_feature_enabled(X86_FEATURE_PKS)) > + WARN_ON_ONCE(hw_error_code & X86_PF_PK); Yeah, please stick X86_FEATURE_PKS in disabled-features so you can use cpu_feature_enabled(X86_FEATURE_PKS) by itself here..