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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 2454AC7618B for ; Wed, 24 Jul 2019 14:02:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED8CC22BE8 for ; Wed, 24 Jul 2019 14:02:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563976948; bh=akL4t3WLQfvH/sx6baSCdRPzrJPet6bQ0ZZAPYisZi4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=oAlcGHPkjIPxo6YB/CsoGvGZHKb9Ki0/nD3ZMnf47fxpzZ2UlP2RbhBFtLCGvsxOS s2hvXFT+miUQEKtc4GAlWdvofcrLxkyUqQVO/DWqP9qzq9fsiKrEYLQQMQX6WZVTaI kP4N3e2l7Ery/ug6iv2c4aIwLRlaaiVqGpFMCYN0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728234AbfGXOCY (ORCPT ); Wed, 24 Jul 2019 10:02:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:44322 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725870AbfGXOCY (ORCPT ); Wed, 24 Jul 2019 10:02:24 -0400 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0A09422BE8; Wed, 24 Jul 2019 14:02:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563976942; bh=akL4t3WLQfvH/sx6baSCdRPzrJPet6bQ0ZZAPYisZi4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HGjiQdK87WShqPUCUDRg97LnVe6uyeIf9yy5HPpwultEhX+41Yn3D/DKXjIK8Af4f 0ygT0V9wgzsE+RPZ4QFVtqujFkiagNZGrOWFPz6QtW3TCSySYN2+CMJ5pNSGE1vClG 0S7ixJF2Qf9InXHgM9sSGPD0ag6vRkrIxQa7ibh4= Date: Wed, 24 Jul 2019 15:02:12 +0100 From: Will Deacon To: Andrey Konovalov Cc: Andrew Morton , Catalin Marinas , Mark Rutland , kvm@vger.kernel.org, Szabolcs Nagy , Will Deacon , dri-devel@lists.freedesktop.org, Kostya Serebryany , Khalid Aziz , "open list:KERNEL SELFTEST FRAMEWORK" , Felix Kuehling , Vincenzo Frascino , Jacob Bramley , Leon Romanovsky , linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , Jason Gunthorpe , Linux ARM , Dave Martin , Evgeniy Stepanov , linux-media@vger.kernel.org, Kevin Brodsky , Kees Cook , Ruben Ayrapetyan , Ramana Radhakrishnan , Alex Williamson , Mauro Carvalho Chehab , Dmitry Vyukov , Linux Memory Management List , Greg Kroah-Hartman , Yishai Hadas , LKML , Jens Wiklander , Lee Smith , Alexander Deucher , enh , Robin Murphy , Christian Koenig , Luc Van Oostenryck Subject: Re: [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Message-ID: <20190724140212.qzvbcx5j2gi5lcoj@willie-the-truck> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org Hi Andrey, On Tue, Jul 23, 2019 at 08:03:29PM +0200, Andrey Konovalov wrote: > On Tue, Jul 23, 2019 at 7:59 PM Andrey Konovalov wrote: > > > > === Overview > > > > arm64 has a feature called Top Byte Ignore, which allows to embed pointer > > tags into the top byte of each pointer. Userspace programs (such as > > HWASan, a memory debugging tool [1]) might use this feature and pass > > tagged user pointers to the kernel through syscalls or other interfaces. > > > > Right now the kernel is already able to handle user faults with tagged > > pointers, due to these patches: > > > > 1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a > > tagged pointer") > > 2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged > > pointers") > > 3. 276e9327 ("arm64: entry: improve data abort handling of tagged > > pointers") > > > > This patchset extends tagged pointer support to syscall arguments. [...] > Do you think this is ready to be merged? > > Should this go through the mm or the arm tree? I would certainly prefer to take at least the arm64 bits via the arm64 tree (i.e. patches 1, 2 and 15). We also need a Documentation patch describing the new ABI. Will 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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 32BFCC41514 for ; Wed, 24 Jul 2019 14:02:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EAEB822C7D for ; Wed, 24 Jul 2019 14:02:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="HGjiQdK8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAEB822C7D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7D8A06B0007; Wed, 24 Jul 2019 10:02:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B00D6B0008; Wed, 24 Jul 2019 10:02:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69F148E0002; Wed, 24 Jul 2019 10:02:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) by kanga.kvack.org (Postfix) with ESMTP id 32AA06B0007 for ; Wed, 24 Jul 2019 10:02:25 -0400 (EDT) Received: by mail-pl1-f200.google.com with SMTP id 71so24169499pld.1 for ; Wed, 24 Jul 2019 07:02:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:date:from:to:cc:subject :message-id:references:mime-version:content-disposition:in-reply-to :user-agent; bh=1WV08YSE1XBp/V/oL6QW3i+VMnK5snm1td59dPVRgYI=; b=hUuWVfd+W09Oanu8VnAEXj9YpK5h4MhQI8NUHXuDvvkrHoGT5knLclitc0iGq2Bvi4 58XQ3tBA0Ke5Jb4tXsGaXSVjpw8v0yBBRkQlr0NTB2cfaiFoWoJyMGQjoVsvW4cvmot6 9/cySiMkwPQJeRASl7qvy0zWjiiTBWkyxN4Tv8iQ04onU9DdqkX2LtXRIMW0N5Hl3N5M rDEP2YfY/ewcq91dA5KEZiUKaqgKK2WOAnxMaDcHHpn+PROquFs9BcayV7kNsjlrgBf7 B89U21txRtjXplx2WZkVPZm4DnXXY5/oh7O6Qlq6E9locK1YWeKDjNto8DKdPnaH+fMd YEsg== X-Gm-Message-State: APjAAAVqnqTjVph19gw7YvUUFJaR9fgbjFt/q+WhID+SMRxJWwOuVLqH fbULnBM9y+M1pPWrLOGRaUQEwTGZ9DVFRPh6VBsM0kn5JF9zgV848mXCeKl+OJowyN3Ay+TwmFZ iFs2PDoqeilYNzFnbxBil83t2FS0ZiCnDFPCFdiUXUPtw0KlpS4O0Lr8XiDTyO+cTKw== X-Received: by 2002:a63:ee08:: with SMTP id e8mr27561471pgi.70.1563976944625; Wed, 24 Jul 2019 07:02:24 -0700 (PDT) X-Google-Smtp-Source: APXvYqxOFmA0uYouR46XXEsfYpKoB5CAwmamA6naTs+r35ExD4rwAuPIpnajuFnG/nfVlbAoqPdU X-Received: by 2002:a63:ee08:: with SMTP id e8mr27561300pgi.70.1563976942719; Wed, 24 Jul 2019 07:02:22 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1563976942; cv=none; d=google.com; s=arc-20160816; b=aicn6j2UlmuzJOwYJsgQ1zxgq8FwChe4WNva5jOG6yjLJnC+nojxn4C53oVIftqztn gZjOWFG6dztezQxoeSsU8z+TqQfm48Ifrb5CzitJbi3lOGWI17Z33UR/GwmHuG6+k9c8 fPp4VNUP3MqIy/Qdfl7IMFumaykfRB00rr/6q2TiJQAUXUFvKJjGZAU72nl8KaotwZUE czH2OFtYisqFeFUqS/oGzH1bmKpiXJjA2CAAv8lfgERHHJI/Sz1lHNDGL+abtZTOswen bvVVL5fDTKbv4EIWhePbWkVjqm4zS5Xztqjb8iQX5y+pzdwKSc1yoJ8koAbSvazJhXdt mX+g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature; bh=1WV08YSE1XBp/V/oL6QW3i+VMnK5snm1td59dPVRgYI=; b=UEYAniRFnhOIa+04MDRNE7dSXhNwmwVs6svUXH8tzyD9C06Iv2BKpg2Z19dWzPSSZP tk4AxJp7qxIJP0nZR0SEaWAFqxqcmgdfa/ZeUJ5NHumqZuTlMeS8qCGuW1rBk/3V/NA0 4iguL1OZZq8GRwyNDiG+aI0yX4mOoREeIetBGICBI+kPDBEEnXwOF9oCtI53/A/RZvOn 9U3b2nROniVaVXFyr920muDVs3G8/FuWDyeZHQp5uQSMFNFbHMnT3s1OeifaI9+PzvQh wzwgeyqP1bZC4Tb3Vqz4nX4H3LJtUTXNzXZ2ChuFKkHSSNIqwmTkOzVJ5gY1KT5P0LNF zg3w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=HGjiQdK8; spf=pass (google.com: domain of will@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=will@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id bd11si13116715plb.184.2019.07.24.07.02.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jul 2019 07:02:22 -0700 (PDT) Received-SPF: pass (google.com: domain of will@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=HGjiQdK8; spf=pass (google.com: domain of will@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=will@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0A09422BE8; Wed, 24 Jul 2019 14:02:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563976942; bh=akL4t3WLQfvH/sx6baSCdRPzrJPet6bQ0ZZAPYisZi4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HGjiQdK87WShqPUCUDRg97LnVe6uyeIf9yy5HPpwultEhX+41Yn3D/DKXjIK8Af4f 0ygT0V9wgzsE+RPZ4QFVtqujFkiagNZGrOWFPz6QtW3TCSySYN2+CMJ5pNSGE1vClG 0S7ixJF2Qf9InXHgM9sSGPD0ag6vRkrIxQa7ibh4= Date: Wed, 24 Jul 2019 15:02:12 +0100 From: Will Deacon To: Andrey Konovalov Cc: Andrew Morton , Catalin Marinas , Mark Rutland , kvm@vger.kernel.org, Szabolcs Nagy , Will Deacon , dri-devel@lists.freedesktop.org, Kostya Serebryany , Khalid Aziz , "open list:KERNEL SELFTEST FRAMEWORK" , Felix Kuehling , Vincenzo Frascino , Jacob Bramley , Leon Romanovsky , linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , Jason Gunthorpe , Linux ARM , Dave Martin , Evgeniy Stepanov , linux-media@vger.kernel.org, Kevin Brodsky , Kees Cook , Ruben Ayrapetyan , Ramana Radhakrishnan , Alex Williamson , Mauro Carvalho Chehab , Dmitry Vyukov , Linux Memory Management List , Greg Kroah-Hartman , Yishai Hadas , LKML , Jens Wiklander , Lee Smith , Alexander Deucher , enh , Robin Murphy , Christian Koenig , Luc Van Oostenryck Subject: Re: [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Message-ID: <20190724140212.qzvbcx5j2gi5lcoj@willie-the-truck> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Andrey, On Tue, Jul 23, 2019 at 08:03:29PM +0200, Andrey Konovalov wrote: > On Tue, Jul 23, 2019 at 7:59 PM Andrey Konovalov wrote: > > > > === Overview > > > > arm64 has a feature called Top Byte Ignore, which allows to embed pointer > > tags into the top byte of each pointer. Userspace programs (such as > > HWASan, a memory debugging tool [1]) might use this feature and pass > > tagged user pointers to the kernel through syscalls or other interfaces. > > > > Right now the kernel is already able to handle user faults with tagged > > pointers, due to these patches: > > > > 1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a > > tagged pointer") > > 2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged > > pointers") > > 3. 276e9327 ("arm64: entry: improve data abort handling of tagged > > pointers") > > > > This patchset extends tagged pointer support to syscall arguments. [...] > Do you think this is ready to be merged? > > Should this go through the mm or the arm tree? I would certainly prefer to take at least the arm64 bits via the arm64 tree (i.e. patches 1, 2 and 15). We also need a Documentation patch describing the new ABI. Will 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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,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 F25F8C76191 for ; Wed, 24 Jul 2019 14:02:25 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C605722BF3 for ; Wed, 24 Jul 2019 14:02:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="blNDYJDc"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="HGjiQdK8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C605722BF3 Authentication-Results: mail.kernel.org; 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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hqHqb-0007ZO-6D; Wed, 24 Jul 2019 14:02:25 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hqHqY-0007YE-RU for linux-arm-kernel@lists.infradead.org; Wed, 24 Jul 2019 14:02:24 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0A09422BE8; Wed, 24 Jul 2019 14:02:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563976942; bh=akL4t3WLQfvH/sx6baSCdRPzrJPet6bQ0ZZAPYisZi4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HGjiQdK87WShqPUCUDRg97LnVe6uyeIf9yy5HPpwultEhX+41Yn3D/DKXjIK8Af4f 0ygT0V9wgzsE+RPZ4QFVtqujFkiagNZGrOWFPz6QtW3TCSySYN2+CMJ5pNSGE1vClG 0S7ixJF2Qf9InXHgM9sSGPD0ag6vRkrIxQa7ibh4= Date: Wed, 24 Jul 2019 15:02:12 +0100 From: Will Deacon To: Andrey Konovalov Subject: Re: [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Message-ID: <20190724140212.qzvbcx5j2gi5lcoj@willie-the-truck> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190724_070222_930577_781950F5 X-CRM114-Status: GOOD ( 15.90 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , kvm@vger.kernel.org, Christian Koenig , Szabolcs Nagy , Catalin Marinas , Will Deacon , dri-devel@lists.freedesktop.org, Kostya Serebryany , Khalid Aziz , Lee Smith , "open list:KERNEL SELFTEST FRAMEWORK" , Vincenzo Frascino , Jacob Bramley , Leon Romanovsky , linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , Jason Gunthorpe , Dmitry Vyukov , Dave Martin , Evgeniy Stepanov , linux-media@vger.kernel.org, Kees Cook , Ruben Ayrapetyan , Kevin Brodsky , Alex Williamson , Mauro Carvalho Chehab , Linux ARM , Linux Memory Management List , Greg Kroah-Hartman , Felix Kuehling , LKML , Jens Wiklander , Ramana Radhakrishnan , Alexander Deucher , Andrew Morton , enh , Robin Murphy , Yishai Hadas , Luc Van Oostenryck Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Andrey, On Tue, Jul 23, 2019 at 08:03:29PM +0200, Andrey Konovalov wrote: > On Tue, Jul 23, 2019 at 7:59 PM Andrey Konovalov wrote: > > > > === Overview > > > > arm64 has a feature called Top Byte Ignore, which allows to embed pointer > > tags into the top byte of each pointer. Userspace programs (such as > > HWASan, a memory debugging tool [1]) might use this feature and pass > > tagged user pointers to the kernel through syscalls or other interfaces. > > > > Right now the kernel is already able to handle user faults with tagged > > pointers, due to these patches: > > > > 1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a > > tagged pointer") > > 2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged > > pointers") > > 3. 276e9327 ("arm64: entry: improve data abort handling of tagged > > pointers") > > > > This patchset extends tagged pointer support to syscall arguments. [...] > Do you think this is ready to be merged? > > Should this go through the mm or the arm tree? I would certainly prefer to take at least the arm64 bits via the arm64 tree (i.e. patches 1, 2 and 15). We also need a Documentation patch describing the new ABI. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Date: Wed, 24 Jul 2019 15:02:12 +0100 Message-ID: <20190724140212.qzvbcx5j2gi5lcoj@willie-the-truck> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Andrey Konovalov Cc: Andrew Morton , Catalin Marinas , Mark Rutland , kvm@vger.kernel.org, Szabolcs Nagy , Will Deacon , dri-devel@lists.freedesktop.org, Kostya Serebryany , Khalid Aziz , "open list:KERNEL SELFTEST FRAMEWORK" , Felix Kuehling , Vincenzo Frascino , Jacob Bramley , Leon Romanovsky , linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , Jason Gunthorpe , Linux ARM , Dave List-Id: dri-devel@lists.freedesktop.org Hi Andrey, On Tue, Jul 23, 2019 at 08:03:29PM +0200, Andrey Konovalov wrote: > On Tue, Jul 23, 2019 at 7:59 PM Andrey Konovalov wrote: > > > > === Overview > > > > arm64 has a feature called Top Byte Ignore, which allows to embed pointer > > tags into the top byte of each pointer. Userspace programs (such as > > HWASan, a memory debugging tool [1]) might use this feature and pass > > tagged user pointers to the kernel through syscalls or other interfaces. > > > > Right now the kernel is already able to handle user faults with tagged > > pointers, due to these patches: > > > > 1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a > > tagged pointer") > > 2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged > > pointers") > > 3. 276e9327 ("arm64: entry: improve data abort handling of tagged > > pointers") > > > > This patchset extends tagged pointer support to syscall arguments. [...] > Do you think this is ready to be merged? > > Should this go through the mm or the arm tree? I would certainly prefer to take at least the arm64 bits via the arm64 tree (i.e. patches 1, 2 and 15). We also need a Documentation patch describing the new ABI. Will