From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.12] helo=sc8-sf-mx2.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1DDnZo-0005I7-Mm for user-mode-linux-devel@lists.sourceforge.net; Tue, 22 Mar 2005 09:54:00 -0800 Received: from smtp002.mail.ukl.yahoo.com ([217.12.11.33]) by sc8-sf-mx2.sourceforge.net with smtp (Exim 4.41) id 1DDnZn-0005SH-Pf for user-mode-linux-devel@lists.sourceforge.net; Tue, 22 Mar 2005 09:54:00 -0800 From: Blaisorblade Subject: Re: [uml-devel] Re: Supporting building on x86-64 host as 32-bit UML References: <200503191904.05870.blaisorblade@yahoo.it> <20050320150306.GA14594@bytesex> In-Reply-To: <20050320150306.GA14594@bytesex> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200503221853.20853.blaisorblade@yahoo.it> Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Tue, 22 Mar 2005 18:53:20 +0100 To: user-mode-linux-devel@lists.sourceforge.net Cc: Gerd Knorr On Sunday 20 March 2005 16:03, Gerd Knorr wrote: > > 1) how the user must choose what he wants (SUBARCH=i386 can be useful, > > maybe a Kconfig option would be nice - we need to choose the default > > depending on the host arch). > > That one is easy -- just use "linux32 make ...". That will switch the > personality and "uname" will return "i686" instead of "x86_64" then ;) linux32 is a SuSE specific alias like the "i386" for Fedora, right (they both alias setarch, IIRC)? > > 2) using the proper options for the tools (addressed partially by the > > patch below) > > Probably still needed. Maybe not any more with gcc4, I remember there > was some discussion among the gcc folks to make gcc default to -m64 / > -m32 depending on the current personalily. In that case the linux32 > thingy mentioned above should catch that one as well. Not sure that > actually happened. We're not going to wait gcc4, especially if it is still so memory hungry... > > 3) using the proper headers (asm-i386 instead of asm-x86_64)... Fedora > > linux32 should fix that one as well. > > > +AFLAGS += -m32 > > +CFLAGS += -m32 > > I think that can also be fixed on the make command line, with a small > wrapper script -- named make32 for example -- doing something like this: > > #!/bin/sh > exec linux32 make CC="gcc -m32" AS="as -m32" ... "$@" > > Last time I tried I ran into the problem that the glibc headers of the > x86_64 biarch compiler slightly different from the ones on a real i386 > machine, thus some #ifdefs in uml userspace code didn't work as expected > and broke the build. > > > +HOSTCFLAGS += -m32 > > +HOSTLDFLAGS += -m32 > > Not needed I think. Thats used for kconfig and other stuff which runs > on the _host_ machine (for cross compiles), thus it doesn't hurt if it > is 64 bit. I'm not sure, but that's probably needed for the userspace utilities that print out some headers (with offsets inside host proc. specific structs). -- Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------- This SF.net email is sponsored by: 2005 Windows Mobile Application Contest Submit applications for Windows Mobile(tm)-based Pocket PCs or Smartphones for the chance to win $25,000 and application distribution. Enter today at http://ads.osdn.com/?ad_id=6882&alloc_id=15148&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel