Re: [Qemu-devel] [PATCH] Make the ELF loader aware of backwards compatibility

[Blue Swirl]

On 2/28/09, Andreas Färber <address@hidden> wrote:
>
>  Am 28.02.2009 um 16:30 schrieb Blue Swirl:
>
>
> > On 2/28/09, Alexander Graf <address@hidden> wrote:
> >
> > > Most 64 bit architectures I'm aware of support running 32 bit code
> > > of the same architecture as well.
> > >
> >
> > For Sparc64 this is only true for userland, kernel level code is not
> > compatible at all. Sparc64 kernel can run Sparc64 and Sparc32
> > binaries, but a Sparc32 kernel will crash on Sparc64.
> >
>
>  Same for ppc. To install Linux, you need to type "install64" at the prompt,
> the default "install" crashes on a G5.

Not exactly. I guess it's possible to construct a dual PPC32/PPC64
kernel for 32 bit mode because even though the MMUs are not
compatible, instruction sets are. But Sparc32 supervisor instructions
do wildly different things on a Sparc64.