Enabling dwarf unwinder for ppc64

[Mark Wielaard]

On Thu, Oct 20, 2011 at 04:36:35PM +0200, Mark Wielaard wrote:
> +FAIL: vma_vdso-m64
> +FAIL: vma_vdso.c compile -m32
> +UNTESTED: vma_vdso-m32
> 
> The vdso vma tracker is busted on powerpc, I haven't investigated yet
> why. The -m32 FAIL comes from not installing the 32bit devel packages of
> course.

For some reason some arches, including powerpc, use a differently named
field in mm->context for the vdso address. Fixed by:

commit 3b62d74b6a33a7c71c104d1b3e414044a5978cd5
Author: Mark Wielaard <mjw@redhat.com>
Date:   Thu Oct 20 20:42:34 2011 +0200

    Add runtime/autoconf-mm-context-vdso-base.c for vma.c vdso catching.
    
    Some architectures use an unsigned long vdso_base field in mm->context,
    instead of a void *vdso field. Detect either in _stp_vma_match_vdso().