* Kirill A. Shutemov <kir...@shutemov.name> wrote:
> On Tue, Apr 11, 2017 at 07:09:07AM -0700, Andi Kleen wrote:
> > > I'll look closer (building proccess it's rather complicated), but my
> > > understanding is that VDSO is stand-alone binary and doesn't really links
> > > with the rest of the kernel, rather included as blob, no?
> > >
> > > Andy, may be you have an idea?
> >
> > There isn't any way I know of to directly link them together. The ELF
> > format wasn't designed for that. You would need to merge blobs and then use
> > manual jump vectors, like the 16bit startup code does. It would be likely
> > complicated and ugly.
>
> Ingo, can we proceed without coverting this assembly to C?
>
> I'm committed to convert it to C later if we'll find reasonable solution
> to the issue.
So one way to do it would be to build it standalone as a .o, then add it not to
the regular kernel objects link target (as you found out it's not possible to
link
32-bit and 64-bit objects), but to link it in a manual fashion, as part of
vmlinux.bin.all-y in arch/x86/boot/compressed/Makefile.
But there would be other complications with this approach, such as we'd have to
add a size field and there might be symbol linking problems ...
Another, pretty hacky way would be to generate a .S from the .c, then
post-process
the .S and essentially generate today's 32-bit .S from it.
Probably not worth the trouble.
Thanks,
Ingo
