Received: by 2002:ac0:a5a7:0:0:0:0:0 with SMTP id m36-v6csp2225846imm; Tue, 10 Jul 2018 15:54:50 -0700 (PDT) X-Google-Smtp-Source: AAOMgpfoIExBn2y41xM/w1Z61QyJR6EaaOxaIThOvxc3xG41VEiCfUDVJk9zhj14Fl49kr+ISDx5 X-Received: by 2002:a62:c0a:: with SMTP id u10-v6mr27368207pfi.43.1531263290792; Tue, 10 Jul 2018 15:54:50 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1531263290; cv=none; d=google.com; s=arc-20160816; b=RLXNeEU7lZj2fpkgzzNgaQCHdUokJTn5x6HPaZ0M9WiZ/D+LDophQUq52KrhA2jtHD ey2yp9Czszj51RP3Kaabr9KM9Hor+SswMxPpcBIYY7UT1tyuXuBmKQw4N2wXTFdf5lhc FHvgGd0Q1py0NST8o/GFTnZrbTbx9/iv84rWhy7BRgy5pNRF3afxxS5uoL0PzGKjqCkY DeWe5Ivx4ElYaktdf1OAfVqgf6R364JWF0rjy6ccHyFPp2z0vrR/e28NAEiF07HjFwLI LSRBAP75UuUfyvSoLctFPpXRf6GWLwLgcK5dYDWfCPtBKMMavI1Z9hbnnDsElQTnLJF/ SvzQ== 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:autocrypt:openpgp:from:references:to:subject :arc-authentication-results; bh=v+4yyGmpCKLSjvjqKcHrMoz1XabPtSPOG0WZ3/y2Swg=; b=Seh8loZzwqxELj7j/kRBxr63rbjcIOa7E3tIDf1xBS8MUoC8WlCSWAa+tN5oFz9DJ+ jJKgWgDo9KMy1emUCDhZQOygBbDxCie/YmFF/aVcDqg8ugWHCVShfgz+WbiFMvfxCI4j YSFtZqukqjzKdBbWRkoqotVV/JvFR+EJsOBxMCehYF7wLUW9/AUdL2zMr7/r5t7t5KD0 YzpHNanFdvbK13uLDtkCNLnI4Lz5mL/adb6mrqsalmFafHiHbe/2alUG1R858jsiJsnB e3mfJRJkPz6U2TeQizj8f1/wMXpkjXFpzoLWoPM44BBQFiUkVf9N2Db5mYerRjuA9d8V DfEg== 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; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id d35-v6si17999319pla.116.2018.07.10.15.54.35; Tue, 10 Jul 2018 15:54:50 -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; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732395AbeGJWyN (ORCPT + 99 others); Tue, 10 Jul 2018 18:54:13 -0400 Received: from mga03.intel.com ([134.134.136.65]:22619 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732340AbeGJWyN (ORCPT ); Tue, 10 Jul 2018 18:54:13 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Jul 2018 15:52:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,335,1526367600"; d="scan'208";a="73773138" Received: from mgcarrol-mobl1.amr.corp.intel.com (HELO [10.252.202.182]) ([10.252.202.182]) by orsmga002.jf.intel.com with ESMTP; 10 Jul 2018 15:52:55 -0700 Subject: Re: [RFC PATCH v2 12/27] x86/mm: Shadow stack page fault error checking To: Yu-cheng Yu , x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , "Ravi V. Shankar" , Vedvyas Shanbhogue References: <20180710222639.8241-1-yu-cheng.yu@intel.com> <20180710222639.8241-13-yu-cheng.yu@intel.com> From: Dave Hansen Openpgp: preference=signencrypt Autocrypt: addr=dave.hansen@linux.intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzShEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gPGRhdmVAc3I3MS5uZXQ+wsF7BBMBAgAlAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAUCTo3k0QIZAQAKCRBoNZUwcMmSsMO2D/421Xg8pimb9mPzM5N7khT0 2MCnaGssU1T59YPE25kYdx2HntwdO0JA27Wn9xx5zYijOe6B21ufrvsyv42auCO85+oFJWfE K2R/IpLle09GDx5tcEmMAHX6KSxpHmGuJmUPibHVbfep2aCh9lKaDqQR07gXXWK5/yU1Dx0r VVFRaHTasp9fZ9AmY4K9/BSA3VkQ8v3OrxNty3OdsrmTTzO91YszpdbjjEFZK53zXy6tUD2d e1i0kBBS6NLAAsqEtneplz88T/v7MpLmpY30N9gQU3QyRC50jJ7LU9RazMjUQY1WohVsR56d ORqFxS8ChhyJs7BI34vQusYHDTp6PnZHUppb9WIzjeWlC7Jc8lSBDlEWodmqQQgp5+6AfhTD kDv1a+W5+ncq+Uo63WHRiCPuyt4di4/0zo28RVcjtzlGBZtmz2EIC3vUfmoZbO/Gn6EKbYAn rzz3iU/JWV8DwQ+sZSGu0HmvYMt6t5SmqWQo/hyHtA7uF5Wxtu1lCgolSQw4t49ZuOyOnQi5 f8R3nE7lpVCSF1TT+h8kMvFPv3VG7KunyjHr3sEptYxQs4VRxqeirSuyBv1TyxT+LdTm6j4a mulOWf+YtFRAgIYyyN5YOepDEBv4LUM8Tz98lZiNMlFyRMNrsLV6Pv6SxhrMxbT6TNVS5D+6 UorTLotDZKp5+M7BTQRUY85qARAAsgMW71BIXRgxjYNCYQ3Xs8k3TfAvQRbHccky50h99TUY sqdULbsb3KhmY29raw1bgmyM0a4DGS1YKN7qazCDsdQlxIJp9t2YYdBKXVRzPCCsfWe1dK/q 66UVhRPP8EGZ4CmFYuPTxqGY+dGRInxCeap/xzbKdvmPm01Iw3YFjAE4PQ4hTMr/H76KoDbD cq62U50oKC83ca/PRRh2QqEqACvIH4BR7jueAZSPEDnzwxvVgzyeuhwqHY05QRK/wsKuhq7s UuYtmN92Fasbxbw2tbVLZfoidklikvZAmotg0dwcFTjSRGEg0Gr3p/xBzJWNavFZZ95Rj7Et db0lCt0HDSY5q4GMR+SrFbH+jzUY/ZqfGdZCBqo0cdPPp58krVgtIGR+ja2Mkva6ah94/oQN lnCOw3udS+Eb/aRcM6detZr7XOngvxsWolBrhwTQFT9D2NH6ryAuvKd6yyAFt3/e7r+HHtkU kOy27D7IpjngqP+b4EumELI/NxPgIqT69PQmo9IZaI/oRaKorYnDaZrMXViqDrFdD37XELwQ gmLoSm2VfbOYY7fap/AhPOgOYOSqg3/Nxcapv71yoBzRRxOc4FxmZ65mn+q3rEM27yRztBW9 AnCKIc66T2i92HqXCw6AgoBJRjBkI3QnEkPgohQkZdAb8o9WGVKpfmZKbYBo4pEAEQEAAcLB XwQYAQIACQUCVGPOagIbDAAKCRBoNZUwcMmSsJeCEACCh7P/aaOLKWQxcnw47p4phIVR6pVL e4IEdR7Jf7ZL00s3vKSNT+nRqdl1ugJx9Ymsp8kXKMk9GSfmZpuMQB9c6io1qZc6nW/3TtvK pNGz7KPPtaDzvKA4S5tfrWPnDr7n15AU5vsIZvgMjU42gkbemkjJwP0B1RkifIK60yQqAAlT YZ14P0dIPdIPIlfEPiAWcg5BtLQU4Wg3cNQdpWrCJ1E3m/RIlXy/2Y3YOVVohfSy+4kvvYU3 lXUdPb04UPw4VWwjcVZPg7cgR7Izion61bGHqVqURgSALt2yvHl7cr68NYoFkzbNsGsye9ft M9ozM23JSgMkRylPSXTeh5JIK9pz2+etco3AfLCKtaRVysjvpysukmWMTrx8QnI5Nn5MOlJj 1Ov4/50JY9pXzgIDVSrgy6LYSMc4vKZ3QfCY7ipLRORyalFDF3j5AGCMRENJjHPD6O7bl3Xo 4DzMID+8eucbXxKiNEbs21IqBZbbKdY1GkcEGTE7AnkA3Y6YB7I/j9mQ3hCgm5muJuhM/2Fr OPsw5tV/LmQ5GXH0JQ/TZXWygyRFyyI2FqNTx4WHqUn3yFj8rwTAU1tluRUYyeLy0ayUlKBH ybj0N71vWO936MqP6haFERzuPAIpxj2ezwu0xb1GjTk4ynna6h5GjnKgdfOWoRtoWndMZxbA z5cecg== Message-ID: <61793360-f37c-ec19-c390-abe3c76a5f5c@linux.intel.com> Date: Tue, 10 Jul 2018 15:52:55 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180710222639.8241-13-yu-cheng.yu@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/10/2018 03:26 PM, Yu-cheng Yu wrote: > +++ b/arch/x86/include/asm/traps.h > @@ -157,6 +157,7 @@ enum { > * bit 3 == 1: use of reserved bit detected > * bit 4 == 1: fault was an instruction fetch > * bit 5 == 1: protection keys block access > + * bit 6 == 1: shadow stack access fault > */ Could we document this bit better? Is this a fault where the *processor* thought it should be a shadow stack fault? Or is it also set on faults to valid shadow stack PTEs that just happen to fault for other reasons, say protection keys?