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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 20FB8C28CC0 for ; Thu, 30 May 2019 17:15:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E594425E35 for ; Thu, 30 May 2019 17:15:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726808AbfE3RPu (ORCPT ); Thu, 30 May 2019 13:15:50 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:40400 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725961AbfE3RPt (ORCPT ); Thu, 30 May 2019 13:15:49 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0E146341; Thu, 30 May 2019 10:15:49 -0700 (PDT) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 32A333F5AF; Thu, 30 May 2019 10:15:43 -0700 (PDT) Date: Thu, 30 May 2019 18:15:40 +0100 From: Catalin Marinas To: Andrey Konovalov Cc: Kees Cook , Evgenii Stepanov , Linux ARM , Linux Memory Management List , LKML , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK" , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Yishai Hadas , Felix Kuehling , Alexander Deucher , Christian Koenig , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , Leon Romanovsky , Dmitry Vyukov , Kostya Serebryany , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Robin Murphy , Luc Van Oostenryck , Dave Martin , Kevin Brodsky , Szabolcs Nagy , Elliott Hughes , Khalid Aziz Subject: Re: [PATCH v15 00/17] arm64: untag user pointers passed to the kernel Message-ID: <20190530171540.GD35418@arrakis.emea.arm.com> References: <20190517144931.GA56186@arrakis.emea.arm.com> <20190521182932.sm4vxweuwo5ermyd@mbp> <201905211633.6C0BF0C2@keescook> <6049844a-65f5-f513-5b58-7141588fef2b@oracle.com> <20190523201105.oifkksus4rzcwqt4@mbp> <20190524101139.36yre4af22bkvatx@mbp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 28, 2019 at 04:14:45PM +0200, Andrey Konovalov wrote: > Thanks for a lot of valuable input! I've read through all the replies > and got somewhat lost. What are the changes I need to do to this > series? > > 1. Should I move untagging for memory syscalls back to the generic > code so other arches would make use of it as well, or should I keep > the arm64 specific memory syscalls wrappers and address the comments > on that patch? Keep them generic again but make sure we get agreement with Khalid on the actual ABI implications for sparc. > 2. Should I make untagging opt-in and controlled by a command line argument? Opt-in, yes, but per task rather than kernel command line option. prctl() is a possibility of opting in. > 3. Should I "add Documentation/core-api/user-addresses.rst to describe > proper care and handling of user space pointers with untagged_addr(), > with examples based on all the cases seen so far in this series"? > Which examples specifically should it cover? I think we can leave 3 for now as not too urgent. What I'd like is for Vincenzo's TBI user ABI document to go into a more common place since we can expand it to cover both sparc and arm64. We'd need an arm64-specific doc as well for things like prctl() and later MTE that sparc may support differently. -- Catalin