From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 02 Nov 2016 00:30:57 +0100 (CET) Received: from bh-25.webhostbox.net ([208.91.199.152]:47943 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23993269AbcKAXauDHNA1 (ORCPT ); Wed, 2 Nov 2016 00:30:50 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=roeck-us.net; s=default; h=In-Reply-To:Content-Type:MIME-Version:References :Message-ID:Subject:Cc:To:From:Date; bh=BD1hnzRE6R3Z+k4WrtSwYiTM46ZgFwYWLOJ0vycfuQs=; b=sQCbpqNAstyvLLrirQ866eFDwB /Q7X1HKNXz/F6H2EKb/leleeRQ4v+UD30flGHuz5bcDMGx+d3r3ylVRLrGP2OeSCGH1CApTCI5VQS ryPOpFUDNoPJvNyGBrStEoyGN8J5v1PJ59AAwrcNlSySdTIYEp5nX8+/mNOSHpXxCT7Dkd3UuFzyp dSAV+RoT1Az/7k1BdEtm7Cy+iBf4D5Dmzq5JmGfxDxLBsdMtVNkZLDi/ftNxtaYXjentsHP1i0rSL g0SEPcmFJL5JBtgF8QKoN1UUJj8d5alOyKKocw0xDwMxohsBGUQpBFwIcgyxvVPd+jeYAxxOBuHZp RHi9Yx1g==; Received: from 108-223-40-66.lightspeed.sntcca.sbcglobal.net ([108.223.40.66]:60312 helo=localhost) by bh-25.webhostbox.net with esmtpa (Exim 4.86_1) (envelope-from ) id 1c1iVo-002lP4-K3; Tue, 01 Nov 2016 23:30:37 +0000 Date: Tue, 1 Nov 2016 16:30:38 -0700 From: Guenter Roeck To: "Maciej W. Rozycki" Cc: Ralf Baechle , Alex Smith , linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, James Hogan Subject: Re: [PATCH] MIPS: VDSO: Always select -msoft-float Message-ID: <20161101233038.GA25472@roeck-us.net> References: <1477843551-21813-1-git-send-email-linux@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - linux-mips.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 55648 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: linux@roeck-us.net Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On Tue, Nov 01, 2016 at 10:40:24PM +0000, Maciej W. Rozycki wrote: > On Sun, 30 Oct 2016, Guenter Roeck wrote: > > > Some toolchains fail to build mips images with the following build error. > > > > arch/mips/vdso/gettimeofday.c:1:0: error: '-march=r3000' requires '-mfp32' > > > > This is seen, for example, with the 'mipsel-linux-gnu-gcc (Debian 6.1.1-9) > > 6.1.1 20160705' toolchain as used by the 0Day build robot when building > > decstation_defconfig. > > > > Comparison of compile flags suggests that the major difference is a missing > > '-soft-float', which is otherwise defined unconditionally. > > > > Reported-by: kbuild test robot > > Cc: James Hogan > > Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") > > Signed-off-by: Guenter Roeck > > --- > > Using `-msoft-float' changes the floating-point ABI with the result being > incompatible with the rest of the userland. I think the dynamic loader > may not be currently enforcing ABI compatibility here, but this may change > in the future. > > Using `-mno-float' in place of `-msoft-float' might be a safer option, > because even if we start enforcing floating-point ABI checks in dynamic > loading, then `-mno-float' DSOs will surely remain compatible with > everything else, because they guarantee no floating-point code or data > even to be ever produced by the compiler, be it using the software or the > hardware ABI. One problem with that option is however that it is > apparently not universally accepted, for reasons unclear to me offhand. > > That written not so long ago I actually explicitly tried the config file > sent by the build bot reporting this issue and I built a kernel thus > configured with current upstream top-of-tree toolchain components, which > went just fine. So what I suspect you've observied is just another sign > of a bug which has been already fixed, maybe even the very same binutils > bug I referred to recently. > > If you send me the generated assembly, i.e. `gettimeofday.s', that is > causing you trouble, then I'll see if I can figure out what is going on > here. We may decide to paper a particularly nasty toolchain bug over from The problem is seen in 0Day builds, with the toolchain mentioned above. I don't see the problem myself; I used to see it but switched toolchains instead of trying to nail down the problem. I don't think that generated assembly is going to help, though, since the compiler fails to compile the code in the first place because, as it says, it doesn't like '-march=r3000' without '-mfp32'. Guenter