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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_MED,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 2A735C04AB6 for ; Fri, 31 May 2019 14:29:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F36A726A9A for ; Fri, 31 May 2019 14:29:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sQG2/gyF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726721AbfEaO3X (ORCPT ); Fri, 31 May 2019 10:29:23 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:44728 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726547AbfEaO3W (ORCPT ); Fri, 31 May 2019 10:29:22 -0400 Received: by mail-pl1-f195.google.com with SMTP id c5so4078601pll.11 for ; Fri, 31 May 2019 07:29:22 -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=evy368hWiI+gBYUbtpZ/Z/NwaFGt0gP/Ku0Se7jRDIs=; b=sQG2/gyFbhvQgnnYVMoq8Kda68VVztjS6NpVGpn+TJ/0x1CnUPLFGI7CfwhDx4Acpv +b2SfJPlJiXKHOPX0vraeScgQBz7b7Nl6PyJKu6e145lCoysI0y6J5myuuCSNlucfPw4 OziFqAsvBRMmxzPBSxXT6y9ZOWT1qftFo2UhubNHkIM+xAKIuSxRN1IDkqLlB5D+IEDh 9Lbkk942zOUUnqGLz1d6wvbTAZV2QEf8AYds1RPyvHK7XFYBgL+gUTiPMyMH1+mL85z0 rHLvvgL9h/d8SCsWwDzjC1mOEMEITHFigTDJGZoVkvgiZ6th+Bg/aZrVlKENNn6Dl+G9 3qvw== 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=evy368hWiI+gBYUbtpZ/Z/NwaFGt0gP/Ku0Se7jRDIs=; b=gBIzXxu7OOOgZYohRGlWxIYrOg9ZKmLhQyQxjzhUWeAZiCOxiA6WJMc9yLDutvdAyY lTLgB5lZmAjNL4N/D7S5jJgzOWOmhtUHCiGbIUxo0TZm4m3eu5i7VgwPpAIkA64bgKuO rC/4Zgb9MWRhzvTmv4qStUSp7TfzelT1GIyNrB5xvi6UZqTio6os4acGIbNpFCL9yusk fXIPikcqjIU/bwCr/vPAWW5pOYyOwT84EcxQ0N6BK5lP+f4gc8ip6O8NeqczLVkHYHAW 5SAaNHUAg0LnstABcYpJTMUYFTuICUNu9Vv4LccaYWY8kvqNd+oAePlP22wH5N4obzhh KpVQ== X-Gm-Message-State: APjAAAXrFPdriXYH7eGHoIzDhKemIslwlGWegx2vSyQ5n+n0sxoFvpub O/BDqbgg4nX1B2puryx8zgd1arbISDYTuR5AYIzIOw== X-Google-Smtp-Source: APXvYqzZNq7ZmlghEU+anyWYnwjjhfBSO821IIVYI0unmJhzupp13rZUJ7jf2s8ZHPUTRKkSRgHsOXgkfcRcIwbO8eo= X-Received: by 2002:a17:902:8609:: with SMTP id f9mr9244481plo.252.1559312961740; Fri, 31 May 2019 07:29:21 -0700 (PDT) MIME-Version: 1.0 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> <20190530171540.GD35418@arrakis.emea.arm.com> In-Reply-To: <20190530171540.GD35418@arrakis.emea.arm.com> From: Andrey Konovalov Date: Fri, 31 May 2019 16:29:10 +0200 Message-ID: Subject: Re: [PATCH v15 00/17] arm64: untag user pointers passed to the kernel To: Catalin Marinas 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 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 Thu, May 30, 2019 at 7:15 PM Catalin Marinas wrote: > > 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. OK, will do. I find it hard to understand what the ABI implications are. I'll post the next version without untagging in brk, mmap, munmap, mremap (for new_address), mmap_pgoff, remap_file_pages, shmat and shmdt. > > > 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. OK. Should I store a flag somewhere in task_struct? Should it be inheritable on clone? > > > 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. OK. > > -- > Catalin