[Buildroot] problems compiling uclibc for Geode (i386)

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Le Wed, 29 Jun 2011 14:29:34 +0200,
Sven Neumann <s.neumann@raumfeld.com> a ?crit :

> >   LD libuClibc-0.9.32.so
> > libc/libc_so.a(err.os):(.text.vwarn_work+0x127): undefined
> > reference to `__lll_unlock_wake_private'
> > collect2: ld returned 1 exit status
> > make[1]: *** [lib/libc.so] Error 1
> > make[1]: Leaving directory
> > `/home/sven/git/buildroot/output/toolchain/uClibc-0.9.32'
> 
> Looks like NPTL support is broken for the generic 386 target. I've
> changed the uclibc configuration to i586 now (in the hope that this
> will work for a Geode processor) and that has fixed above problem for
> me.

This function is implemented in
libpthread/nptl/sysdeps/unix/sysv/linux/i386/i486/lowlevellock.S, so
presumably, i386 does not work, but i486 should.

My understanding is that the futex mechanism uses the cmpxchgl
instruction, which is only available on 486+ processors.

Maybe someone should send a patch to the uClibc configuration system to
make sure that NPTL cannot be selected on i386.

Regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com