From owner-svn-src-head@FreeBSD.ORG Wed Jan 5 14:38:41 2011 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C0A971065679; Wed, 5 Jan 2011 14:38:41 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 90EE48FC0C; Wed, 5 Jan 2011 14:38:41 +0000 (UTC) Received: from bigwig.baldwin.cx (66.111.2.69.static.nyinternet.net [66.111.2.69]) by cyrus.watson.org (Postfix) with ESMTPSA id 3083846B09; Wed, 5 Jan 2011 09:38:41 -0500 (EST) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 19EDC8A009; Wed, 5 Jan 2011 09:38:40 -0500 (EST) From: John Baldwin To: Dimitry Andric Date: Wed, 5 Jan 2011 09:28:30 -0500 User-Agent: KMail/1.13.5 (FreeBSD/7.3-CBSD-20101102; KDE/4.4.5; amd64; ; ) References: <201101042051.p04KpSGk054564@svn.freebsd.org> <201101050759.50877.jhb@freebsd.org> <4D2473C6.40102@FreeBSD.org> In-Reply-To: <4D2473C6.40102@FreeBSD.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <201101050928.30748.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.6 (bigwig.baldwin.cx); Wed, 05 Jan 2011 09:38:40 -0500 (EST) X-Virus-Scanned: clamav-milter 0.96.3 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-1.9 required=4.2 tests=BAYES_00 autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on bigwig.baldwin.cx Cc: svn-src-head@freebsd.org, Alexander Best , Gleb Kurtsou , src-committers@freebsd.org, svn-src-all@freebsd.org Subject: Re: svn commit: r216977 - in head/libexec/rtld-elf: amd64 i386 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Jan 2011 14:38:41 -0000 On Wednesday, January 05, 2011 8:36:06 am Dimitry Andric wrote: > On 2011-01-05 13:59, John Baldwin wrote: > >> Why not to add NO_HWFLOAT knob (or similar) into makefile > >> infrastructure. And set CFLAGS accordingly, depending on CC, arch, etc. > >> These flags are getting rather common in tree. > > > > It strikes me that we really want clang/gcc to have some sort of > > '-mno-hwfloat' so we don't keep having to add new flags in the future. > > This is not just about floats, clang can also use SSE/AVX instructions > for e.g. memset(), memcpy() and the like, or even for structure > assignments. Yes, but the thing that all these extensions have in common is that they use FPU state (i.e. subject to DNA traps, managed via *SAVE and *RSTOR, etc.) and that is the problem with using them in boot code or rtld. What I would want a -mno-hwfloat flag to do is to disable use of anything that would require working FPU state handling. -- John Baldwin