Re: [uml-devel] Re: Supporting building on x86-64 host as 32-bit UML

[Blaisorblade <blaisorblade@yahoo.it>]

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