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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 DA029C433FF for ; Fri, 9 Aug 2019 09:28:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5F9D20C01 for ; Fri, 9 Aug 2019 09:28:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727063AbfHIJ2J (ORCPT ); Fri, 9 Aug 2019 05:28:09 -0400 Received: from foss.arm.com ([217.140.110.172]:44118 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726233AbfHIJ2J (ORCPT ); Fri, 9 Aug 2019 05:28:09 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D4D7415A2; Fri, 9 Aug 2019 02:28:07 -0700 (PDT) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EA7C43F575; Fri, 9 Aug 2019 02:28:02 -0700 (PDT) Date: Fri, 9 Aug 2019 10:28:00 +0100 From: Dave Martin To: Catalin Marinas Cc: Kees Cook , Mark Rutland , kvm@vger.kernel.org, Christian Koenig , Szabolcs Nagy , Will Deacon , dri-devel@lists.freedesktop.org, Kostya Serebryany , Khalid Aziz , Lee Smith , "open list:KERNEL SELFTEST FRAMEWORK" , Vincenzo Frascino , Will Deacon , Jacob Bramley , Leon Romanovsky , linux-rdma@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , Jason Gunthorpe , Dmitry Vyukov , Evgeniy Stepanov , linux-media@vger.kernel.org, Ruben Ayrapetyan , Andrey Konovalov , Kevin Brodsky , Alex Williamson , Mauro Carvalho Chehab , Linux ARM , Linux Memory Management List , Greg Kroah-Hartman , Felix Kuehling , Dave Hansen , LKML , Jens Wiklander , Ramana Radhakrishnan , Alexander Deucher , Andrew Morton , enh , Robin Murphy , Yishai Hadas , Luc Van Oostenryck Subject: Re: [PATCH v19 00/15] arm64: untag user pointers passed to the kernel Message-ID: <20190809092758.GK10425@arm.com> References: <20190724140212.qzvbcx5j2gi5lcoj@willie-the-truck> <20190724142059.GC21234@fuggles.cambridge.arm.com> <20190806171335.4dzjex5asoertaob@willie-the-truck> <201908081410.C16D2BD@keescook> <20190808153300.09d3eb80772515f0ea062833@linux-foundation.org> <201908081608.A4F6711@keescook> <20190809090016.GA23083@arrakis.emea.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190809090016.GA23083@arrakis.emea.arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Fri, Aug 09, 2019 at 10:00:17AM +0100, Catalin Marinas wrote: > On Thu, Aug 08, 2019 at 04:09:04PM -0700, Kees Cook wrote: > > On Thu, Aug 08, 2019 at 03:33:00PM -0700, Andrew Morton wrote: > > > On Thu, 8 Aug 2019 14:12:19 -0700 Kees Cook wrote: > > > > > > > > The ones that are left are the mm ones: 4, 5, 6, 7 and 8. > > > > > > > > > > Andrew, could you take a look and give your Acked-by or pick them up directly? > > > > > > > > Given the subsystem Acks, it seems like 3-10 and 12 could all just go > > > > via Andrew? I hope he agrees. :) > > > > > > I'll grab everything that has not yet appeared in linux-next. If more > > > of these patches appear in linux-next I'll drop those as well. > > > > > > The review discussion against " [PATCH v19 02/15] arm64: Introduce > > > prctl() options to control the tagged user addresses ABI" has petered > > > out inconclusively. prctl() vs arch_prctl(). > > > > I've always disliked arch_prctl() existing at all. Given that tagging is > > likely to be a multi-architectural feature, it seems like the controls > > should live in prctl() to me. > > It took a bit of grep'ing to figure out what Dave H meant by > arch_prctl(). It's an x86-specific syscall which we do not have on arm64 > (and possibly any other architecture). Actually, we don't have any arm64 > specific syscalls, only the generic unistd.h, hence the confusion. For > other arm64-specific prctls like SVE we used the generic sys_prctl() and > I can see x86 not being consistent either (PR_MPX_ENABLE_MANAGEMENT). > > In general I disagree with adding any arm64-specific syscalls but in > this instance it can't even be justified. I'd rather see some clean-up > similar to arch_ptrace/ptrace_request than introducing new syscall > numbers (but as I suggested in my reply to Dave, that's for another > patch series). I had a go at refactoring this a while ago, but it fell by the wayside. I can try to resurrect it if it's still considered worthwhile. Cheers ---Dave