From owner-freebsd-amd64@FreeBSD.ORG Tue Jul 20 18:16:16 2010 Return-Path: Delivered-To: amd64@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 318E91065670; Tue, 20 Jul 2010 18:16:16 +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 012B38FC08; Tue, 20 Jul 2010 18:16:16 +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 A3EFB46B52; Tue, 20 Jul 2010 14:16:15 -0400 (EDT) Received: from jhbbsd.localnet (smtp.hudson-trading.com [209.249.190.9]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id D2F888A052; Tue, 20 Jul 2010 14:16:14 -0400 (EDT) From: John Baldwin To: Garrett Cooper Date: Tue, 20 Jul 2010 14:15:14 -0400 User-Agent: KMail/1.13.5 (FreeBSD/7.3-CBSD-20100217; KDE/4.4.5; amd64; ; ) References: <20100719213054.GB2381@deviant.kiev.zoral.com.ua> <201007200907.24715.jhb@freebsd.org> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201007201415.14497.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (bigwig.baldwin.cx); Tue, 20 Jul 2010 14:16:14 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.95.1 at bigwig.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-2.6 required=4.2 tests=AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on bigwig.baldwin.cx Cc: amd64@freebsd.org, freebsd-arch@freebsd.org Subject: Re: uname -m/-p for compat32 binaries X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Jul 2010 18:16:16 -0000 On Tuesday, July 20, 2010 1:51:27 pm Garrett Cooper wrote: > On Tue, Jul 20, 2010 at 6:07 AM, John Baldwin wrote: > > On Monday, July 19, 2010 5:30:54 pm Kostik Belousov wrote: > >> Hi, > >> I intend to commit the following change, that makes sysctls > >> hw.machine_arch and hw.machine to return "i386" for 32 bit > >> binaries run on amd64. In particular, 32 bit uname -m and uname -p > >> print "i386", that is good for i386 jails on amd64 kernels. > >> > >> I find the change very useful for me, but I wonder why such trivial > >> modification is not yet done. Can anybody note a possible fallout from > >> it ? > > > > Presumably ia64 and powerpc64 would need a similar change as well? It looks > > fine to me. I suspect Y! used the UNAME_* approach as it didn't add yet- > > another local diff to maintain in the kernel, and the uname fixes at Y! might > > have predated SCTL_MASK32. > > I thought amd64 was a special case because we run biarch, whereas ia64 > was always 64-bit... > > Wouldn't this change also create problems later on down the line when > we're no longer biarch? amd64 is not biarch, it just supports FreeBSD/i386 binaries similar to how FreeBSD/i386 supports Linux/i386 binaries. Kostik's patch makes a FreeBSD/i386 uname binary report that it is running under FreeBSD/i386 just as we currently make a Linux/i386 uname binary report that it is running under Linux/i386. ia64 and powerpc64 both support COMPAT_FREEBSD32 similar to amd64. COMPAT_FREEBSD32 for amd64 and ia64 supports FreeBSD/i386 binaries. COMPAT_FREEBSD32 for powerpc64 supports FreeBSD/powerpc binaries. -- John Baldwin