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=-2.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_PASS 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 30F4EC5ACD3 for ; Fri, 18 Jan 2019 19:53:46 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E83A7208E4 for ; Fri, 18 Jan 2019 19:53:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="WExeNrd0"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="oXZuN8bp" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E83A7208E4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=x0utoDw8lFyByOklCZ+86WYKN0+e4EVOIOtbqtGHi9I=; b=WExeNrd0G++H4s JdRF8/RVWDY4Jwlu24qLgrMhx4dYPjTZ3PFKv7qM9UQ/Ru+olMhdg2PchekjKLR5RWu8Wwxbl1DKb TzBr6+ePZg4u43mNTgHOCHQkebASO4gZr5ftxocWCccJcCBTzI/teQaWj/ZKNur9rWJr/VXhLHlkt TFYqPlF8+E7H8O7GEvUeBnl6S5AkjVGABXskXrfb1D0e8xBQMHndNgwHCEWvJNLDU8MmLO2Lh23xE LsF6gUylVo/8lc7XcB4uSyhikj+09xrNP6cIPmJCnKctTIwE6O+xyBu7upiKE9KzqWcBFEBnFEiBr gTj/7qJ/fhL+5BHADWxA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gkaD2-0003RW-Ej; Fri, 18 Jan 2019 19:53:44 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gkaCz-0003Qd-BC for linux-arm-kernel@lists.infradead.org; Fri, 18 Jan 2019 19:53:42 +0000 Received: from mail-wr1-f47.google.com (mail-wr1-f47.google.com [209.85.221.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4B29C21855 for ; Fri, 18 Jan 2019 19:53:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547841220; bh=Y+Mkku2hpjHuuxfJcSbx0NCmyP047W00KgMfbKQs2v4=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=oXZuN8bpl7JO1HHlyJ0rBP27+NxU97vc4K2YMPp9tpjDP7ZyAS4VPhg0sKzkGrhGL gl4esmhhdnMv2qRY42CYbfQHSvoACOAC08eP/XECCjAIzpA5m4vNdJ+SUeYIQSuS11 xyOSBpsZ78Xd0zbQ1oayf1Vw47DpmCpYwWsy1J9k= Received: by mail-wr1-f47.google.com with SMTP id p4so16507861wrt.7 for ; Fri, 18 Jan 2019 11:53:40 -0800 (PST) X-Gm-Message-State: AJcUukeMxZQHM4WXTJWhUOsgjHEZaDUTaa9+Vqcot5yAcN9v+vgsMl/r 1wdNyFV/XJkFsCTqhMwGJeipZJ+M+Hr6RyxrAeK1cQ== X-Google-Smtp-Source: ALg8bN53XBFm0k52gttkiOitsF79fQNn3QWHfyq1eUU45COG9ndt1TzlVHWhAbvhM0sXfa6/3VThsSvvBz3zraeomxM= X-Received: by 2002:a5d:550f:: with SMTP id b15mr18669734wrv.330.1547841216670; Fri, 18 Jan 2019 11:53:36 -0800 (PST) MIME-Version: 1.0 References: <20190118161835.2259170-1-arnd@arndb.de> <20190118161835.2259170-30-arnd@arndb.de> In-Reply-To: From: Andy Lutomirski Date: Fri, 18 Jan 2019 11:53:25 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 29/29] y2038: add 64-bit time_t syscalls to all 32-bit architectures To: Arnd Bergmann X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190118_115341_435470_1A6325CB X-CRM114-Status: GOOD ( 20.08 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rich Felker , linux-ia64@vger.kernel.org, Linux-sh list , Benjamin Herrenschmidt , Heiko Carstens , linux-mips@vger.kernel.org, Max Filippov , Network Development , Deepa Dinamani , "H. Peter Anvin" , sparclinux , linux-arch , linux-s390 , y2038 Mailman List , Michael Ellerman , Helge Deller , X86 ML , Russell King , Ingo Molnar , Geert Uytterhoeven , Catalin Marinas , Firoz Khan , Matt Turner , Fenghua Yu , Will Deacon , Linux FS Devel , linux-m68k , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel , Michal Simek , Tony Luck , Parisc List , Linux API , LKML , Paul Burton , "Eric W. Biederman" , alpha , Martin Schwidefsky , Andrew Morton , linuxppc-dev , "David S. Miller" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jan 18, 2019 at 11:33 AM Arnd Bergmann wrote: > > On Fri, Jan 18, 2019 at 7:50 PM Andy Lutomirski wrote: > > On Fri, Jan 18, 2019 at 8:25 AM Arnd Bergmann wrote: > > > - Once we get to 512, we clash with the x32 numbers (unless > > > we remove x32 support first), and probably have to skip > > > a few more. I also considered using the 512..547 space > > > for 32-bit-only calls (which never clash with x32), but > > > that also seems to add a bit of complexity. > > > > I have a patch that I'll send soon to make x32 use its own table. As > > far as I'm concerned, 547 is *it*. 548 is just a normal number and is > > not special. But let's please not reuse 512..547 for other purposes > > on x86 variants -- that way lies even more confusion, IMO. > > Fair enough, the space for those numbers is cheap enough here. > I take it you mean we also should not reuse that number space if > we were to decide to remove x32 soon, but you are not worried > about clashing with arch/alpha when everything else uses consistent > numbers? > I think we have two issues if we reuse those numbers for new syscalls. First, I'd really like to see new syscalls be numbered consistently everywhere, or at least on all x86 variants, and we can't on x32 because they mean something else. Perhaps more importantly, due to what is arguably a rather severe bug, issuing a native x86_64 syscall (x32 bit clear) with nr in the range 512..547 does *not* return -ENOSYS on a kernel with x32 enabled. Instead it does something that is somewhat arbitrary. With my patch applied, it will return -ENOSYS, but old kernels will still exist, and this will break syscall probing. Can we perhaps just start the consistent numbers above 547 or maybe block out 512..547 in the new regime? --Andy _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel