Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965397AbcKDSd7 (ORCPT ); Fri, 4 Nov 2016 14:33:59 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:38433 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935018AbcKDSd6 (ORCPT ); Fri, 4 Nov 2016 14:33:58 -0400 Date: Fri, 4 Nov 2016 11:33:54 -0700 From: Guenter Roeck To: Matthew Fortune Cc: Maciej Rozycki , Ralf Baechle , "linux-mips@linux-mips.org" , "linux-kernel@vger.kernel.org" , James Hogan Subject: Re: [PATCH] MIPS: VDSO: Always select -msoft-float Message-ID: <20161104183354.GA16694@roeck-us.net> References: <1477843551-21813-1-git-send-email-linux@roeck-us.net> <20161101233038.GA25472@roeck-us.net> <6D39441BF12EF246A7ABCE6654B0235380AB79B7@HHMAIL01.hh.imgtec.org> <20161104152603.GB12009@roeck-us.net> <6D39441BF12EF246A7ABCE6654B0235380AB822B@HHMAIL01.hh.imgtec.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6D39441BF12EF246A7ABCE6654B0235380AB822B@HHMAIL01.hh.imgtec.org> 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 - vger.kernel.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: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1424 Lines: 31 On Fri, Nov 04, 2016 at 04:55:05PM +0000, Matthew Fortune wrote: > Maciej Rozycki writes: > > On Fri, 4 Nov 2016, Guenter Roeck wrote: > > > > > > As above, unless absolutely critical to have floating point code > > > > then the vDSO should just avoid all FP related issues and build > > soft-float. > ... > > > Anyway, isn't the kernel supposed to not use floating point operations > > > in the first place ? Is this different for vDSO ? > > > > This code is executed in the user mode so while floating-point code may > > not be needed there, not at least right now, there's actually nothing > > which should stop us from from adding some should such a need arise. > > Indeed. For now though the switch to -msoft-float is the simplest solution > isn't it? > One should think so, especially since 1) the code has to be built as part of the kernel build anyway, and 2) there would be other implications besides just adding floating point operations into the kernel (see the other e-mail). Overall I am glad that I don't have to maintain this code. Either case, it would be great if we can come up with a solution to avoid build failures due to toolchain configurations. If that means that vDSO won't be compilable with debian toolchains, so be it. After all, that would not be different to the current situation, only it would be official instead of causing build failures. Thanks, Guenter