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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 694C5C43381 for ; Fri, 29 Mar 2019 10:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3EB6B206B8 for ; Fri, 29 Mar 2019 10:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729037AbfC2Kas (ORCPT ); Fri, 29 Mar 2019 06:30:48 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:57650 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728550AbfC2Kas (ORCPT ); Fri, 29 Mar 2019 06:30:48 -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 9F756A78; Fri, 29 Mar 2019 03:30:47 -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 817863F575; Fri, 29 Mar 2019 03:30:42 -0700 (PDT) Date: Fri, 29 Mar 2019 10:30:40 +0000 From: Catalin Marinas To: Steven Rostedt Cc: Andrey Konovalov , Will Deacon , Mark Rutland , Kees Cook , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Vincenzo Frascino , Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Peter Zijlstra , Arnaldo Carvalho de Melo , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , Linux ARM , Linux Memory Management List , linux-arch , LKML , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Ruben Ayrapetyan , Luc Van Oostenryck , Dave Martin , Kevin Brodsky , Szabolcs Nagy Subject: Re: [PATCH v13 04/20] mm, arm64: untag user pointers passed to memory syscalls Message-ID: <20190329103039.GA44339@arrakis.emea.arm.com> References: <44ad2d0c55dbad449edac23ae46d151a04102a1d.1553093421.git.andreyknvl@google.com> <20190322114357.GC13384@arrakis.emea.arm.com> <20190328141934.38960af0@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190328141934.38960af0@gandalf.local.home> 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 (I trimmed down the cc list a bit since it's always bouncing) On Thu, Mar 28, 2019 at 02:19:34PM -0400, Steven Rostedt wrote: > On Thu, 28 Mar 2019 19:10:07 +0100 > Andrey Konovalov wrote: > > > > > Signed-off-by: Andrey Konovalov > > > > --- > > > > ipc/shm.c | 2 ++ > > > > mm/madvise.c | 2 ++ > > > > mm/mempolicy.c | 5 +++++ > > > > mm/migrate.c | 1 + > > > > mm/mincore.c | 2 ++ > > > > mm/mlock.c | 5 +++++ > > > > mm/mmap.c | 7 +++++++ > > > > mm/mprotect.c | 1 + > > > > mm/mremap.c | 2 ++ > > > > mm/msync.c | 2 ++ > > > > 10 files changed, 29 insertions(+) > > > > > > I wonder whether it's better to keep these as wrappers in the arm64 > > > code. > > > > I don't think I understand what you propose, could you elaborate? > > I believe Catalin is saying that instead of placing things like: > > @@ -1593,6 +1593,7 @@ SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg) > unsigned long ret; > long err; > > + shmaddr = untagged_addr(shmaddr); > > To instead have the shmaddr set to the untagged_addr() before calling > the system call, and passing the untagged addr to the system call, as > that goes through the arm64 architecture specific code first. Indeed. For example, we already have a SYSCALL_DEFINE6(mmap, ...) in arch/arm64/kernel/sys.c, just add the untagging there. We could do something similar for the other syscalls. I don't mind doing this in the generic code but if it's only needed for arm64, I'd rather keep the generic changes to a minimum. (I had a hack overriding __SC_CAST to do this automatically for pointer arguments but this wouldn't work on mmap() and friends as the argument is unsigned long) -- Catalin