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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 44502C7618B for ; Wed, 24 Jul 2019 14:17:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 17F4322ADB for ; Wed, 24 Jul 2019 14:17:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="DWU4WjGA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727235AbfGXORC (ORCPT ); Wed, 24 Jul 2019 10:17:02 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:34887 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726699AbfGXORB (ORCPT ); Wed, 24 Jul 2019 10:17:01 -0400 Received: by mail-pf1-f195.google.com with SMTP id u14so21053293pfn.2 for ; Wed, 24 Jul 2019 07:17:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=iVEa+BrbD+ybsnA2U1ljAFs3yPdamhmoGuSiTUjWPJ4=; b=DWU4WjGAtgl8VCFFOjc8wXQ0g23uMAUtJpd38Z3oaJgwn4NfatixOvhmdpOdL+fxhG e0wlc3X1shT5Iq30jjbbWGUReEBT4OBXlYiiQUhWx2Q7uiFMfOEneT8NH6f9J2qp0V5H uul5tf2SvUAF38K7907CwJA6dKexcEorDJsv/KoSqA3HSUAO6tsOMxjz0hFsJBWrp9kB d53dWGlSvFswyl6j+n5LUh4qGYRvo3+KwFNfAV8S+2jUqD0GvKKHxnABV1FWZ1+b1OBh oB2T3ZDN/Zfw5qlFjUWW5qYsM2z/YZXngByjiqcmIeT7gWGze9CMbYqnOAvNwjkoL4TA mEew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=iVEa+BrbD+ybsnA2U1ljAFs3yPdamhmoGuSiTUjWPJ4=; b=g0R1nCRRh8N/m8EuqScKL19rTLsfD72tQlmDv2o/2BLaRBpNTO9JWX56+z/ICDzM1K koGJJjrlFvm2SiuZ+TAFVvNbVeSMpabsOqXTXxAQGxjipCX8kWVXRdsuykDl35BZiIXj X5NzcKkPWamA7E9ugcD69t//l+7CP4VyS5FhKwqC1pN4wUy6YrzbBbrASA0kVm1WLiWJ xgaIEBM73XdTRlCszcLPFGU5ezdUpgTxJtDZrZutlUHvedjQcMWcthNntaTGwEhnplwL esxffDtDya67q3Gx0e4tNDRRrpUOn36pz1Vk5s/6NnnkUDiS5GmSGH2WeYCnp11L44hZ XZsw== X-Gm-Message-State: APjAAAXxJ0g6GlVhkcc7mUysqJFdUPZDePpWg1jDz03Vw5Sv8JVZ2Q9r PQ1GRcehOwwSuT9PZxavLcCqQ+DIMMOfZOC8a1UrvQ== X-Google-Smtp-Source: APXvYqz2dMxGxnq2kAfIP49TpeG4FcaV+yTvRZ4CcUcR9QT0oeQ2GoQPtuki1B+xbKFnrASZfeBQUkyN7t1WRbfNCv8= X-Received: by 2002:aa7:86c6:: with SMTP id h6mr11779914pfo.51.1563977820600; Wed, 24 Jul 2019 07:17:00 -0700 (PDT) MIME-Version: 1.0 References: <20190724140212.qzvbcx5j2gi5lcoj@willie-the-truck> In-Reply-To: <20190724140212.qzvbcx5j2gi5lcoj@willie-the-truck> From: Andrey Konovalov Date: Wed, 24 Jul 2019 16:16:49 +0200 Message-ID: Subject: Re: [PATCH v19 00/15] arm64: untag user pointers passed to the kernel To: Will Deacon , Vincenzo Frascino 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 , 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 Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 24, 2019 at 4:02 PM Will Deacon wrote: > > 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. Sounds good! Should I post those patches together with the Documentation patches from Vincenzo as a separate patchset? Vincenzo, could you share the last version of the Documentation patches? Thanks! > > Will