Re: [PATCH] powerpc: allow cross-compilation of ppc64 kernel

Le 07/11/2015 00:12, Benjamin Herrenschmidt a écrit :

On Fri, 2015-11-06 at 15:09 -0600, Scott Wood wrote:

quoted

On Thu, 2015-11-05 at 12:47 +0100, Laurent Vivier wrote:

quoted

When I try to cross compile a ppc64 kernel, it generally
fails on the VDSO stage. This is true for powerpc64 cross-
compiler, but also when I try to build a ppc64le kernel
on a ppc64 host.

VDSO64L fails:

  VDSO64L arch/powerpc/kernel/vdso64/vdso64.so.dbg
/usr/bin/powerpc64-linux-gnu-ld:
arch/powerpc/kernel/vdso64/sigtramp.o:
file class ELFCLASS64 incompatible with ELFCLASS32
/usr/bin/powerpc64-linux-gnu-ld: final link failed: File in wrong
format

This fails because gcc calls "collect2" with
"--oformat elf32-powerpcle" with ppc64 objects, without the
"--oformat" ld works well because it use the format of the
first object as output format.

As this case is correctly managed to build the other kernel
objects, this patch replaces $(GCC) by $(LD) to generate the
VDSO objects.

This is LE ? I think that's a bug in binutils or gcc ... I remember we
fought that a while ago for the openpower builds. It might have been
fixed in upstream toolchain.

Yes, Segher has given me the commit id. It is just what I need.

Laurent