Received: by 10.192.165.156 with SMTP id m28csp883885imm; Thu, 19 Apr 2018 09:05:45 -0700 (PDT) X-Google-Smtp-Source: AIpwx4+Lm2ips+OGUgqRJgK2BHQ12Bw8BGPDqgm6xcpRmX/0C6WlJOxZo3SJlfDAmCV2dKHy8dM3 X-Received: by 10.98.104.199 with SMTP id d190mr6296720pfc.111.1524153945606; Thu, 19 Apr 2018 09:05:45 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1524153945; cv=none; d=google.com; s=arc-20160816; b=NuGLyfCHYpiYo2vXH8Ne9Ol5vNMddeBhewmYwcjEYF0EucpTQxXIfOvLd9r+dCk0D+ uT/g/7732nbj2q/5gnDKfPQJeEEvMhrCTS6omhq1cwzXcmbD5R5ugfCuRz55JElvUAYk mCUYV14txW6Bi1bodIveYzKjrKRN/37ggHpnOMRhFtzry9JYfULXZntCIbxxQpl/uIEV 6dI8ZyfDRqrJndt+f8k0wlNZva2DiOkZrchjB7pnvkt/TAzPmAK1KMGE64A0gljqIo4+ IiLF4cnBt87f2zqnEPXv9OEAN5dtFXQH3dtbkPQ5mC3u8Jkim2Ik93P2oXsRlzXq8yTD IQ5Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding :content-language:in-reply-to:mime-version:user-agent:date :message-id:from:cc:references:to:subject:arc-authentication-results; bh=kUWeCGxRp0d2iGrKX/d9UO3cGubTpJZk08YjxnWQmIg=; b=nf99oG9jlPFGwtRDzxdB7WS8XIu0cNbMdYbfIunIS09YckBQgLQFHnKuvx6X4n58LK dFuPLsdRldcue7AB0QE/GctjJGxks+uwhTV3i9iuSQIfWixozeRJqbA6DFlZ4isGx1UE ePRB6HGguA4UIID/LCF/jYuORFX9+zpgM10XEb0SpIhKpQ5V7x5KnwcV/n/H+QI0SIEx eIVzj7uMVgL0sPmk98K5iwcCI9cMNqgPW47aCimjq7pe0M14/EWFYB71a8U+L6DgM9jx fhHm7seJ5w8Bzv4VkeMiJJozWofI0hUYukTB4f8uidYtiEEEfqdQNRwPs/Dtu38J8kPy 3zUA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id a33-v6si3503917plc.507.2018.04.19.09.05.28; Thu, 19 Apr 2018 09:05:45 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753647AbeDSQCd (ORCPT + 99 others); Thu, 19 Apr 2018 12:02:33 -0400 Received: from mga01.intel.com ([192.55.52.88]:20999 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753633AbeDSQCc (ORCPT ); Thu, 19 Apr 2018 12:02:32 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Apr 2018 09:02:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,469,1517904000"; d="scan'208";a="217852409" Received: from nmnguye1-mobl.amr.corp.intel.com (HELO [10.254.72.175]) ([10.254.72.175]) by orsmga005.jf.intel.com with ESMTP; 19 Apr 2018 09:02:31 -0700 Subject: Re: [PATCH 11/11] x86/pti: leave kernel text global for !PCID To: Kees Cook References: <20180406205501.24A1A4E7@viggo.jf.intel.com> <20180406205518.E3D989EB@viggo.jf.intel.com> Cc: LKML , Linux-MM , Andrea Arcangeli , Andy Lutomirski , Linus Torvalds , Hugh Dickins , Juergen Gross , X86 ML , namit@vmware.com From: Dave Hansen Message-ID: Date: Thu, 19 Apr 2018 09:02:31 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/18/2018 05:11 PM, Kees Cook wrote: > On Fri, Apr 6, 2018 at 1:55 PM, Dave Hansen wrote: >> +/* >> + * For some configurations, map all of kernel text into the user page >> + * tables. This reduces TLB misses, especially on non-PCID systems. >> + */ >> +void pti_clone_kernel_text(void) >> +{ >> + unsigned long start = PFN_ALIGN(_text); >> + unsigned long end = ALIGN((unsigned long)_end, PMD_PAGE_SIZE); > I think this is too much set global: _end is after data, bss, and brk, > and all kinds of other stuff that could hold secrets. I think this > should match what mark_rodata_ro() is doing and use > __end_rodata_hpage_align. (And on i386, this should be maybe _etext.) Sounds reasonable to me. This does assume that there are no secrets built into the kernel image, right?