Re: Removing architectures without upstream gcc support

[Richard Kuo]

On Wed, Feb 28, 2018 at 09:37:09AM +0100, Arnd Bergmann wrote:
> On Wed, Feb 28, 2018 at 3:06 AM, Richard Kuo <rkuo@xxxxxxxxxxxxxx> wrote:
> > On Thu, Feb 22, 2018 at 11:43:10PM +0100, Arnd Bergmann wrote:
> >> - How do I build an llvm based toolchain for Hexagon? Do I need patches
> >>   on top of the llvm-6 release branch? Where can I find the corresponding
> >>   binutils-2.30 sources?
> >
> > Just to follow up on this, the closest thing right now to compile the kernel
> > for Hexagon is the toolchain included with the Hexagon SDK.  However, the
> > linker will fail because of something in the kernel build process that
> > I think produces empty sections, which that linker can't handle.  A newer
> > linker can handle it, but that's not scheduled to be released until much later
> > this year.
> >
> > That's actually the closest option currently.  I tried the upstream source
> > but it seems to lack some specific patches to support kernel compilation,
> > so I will need to chase those down.
> 
> Thanks for trying it out. Can you point me to the sources? I tried downloading
> a Hexagon SDK when I first looked at it, but only got a huge chunk of binary
> java files and gave up before finding the llvm patches.


I don't think the SDK patches are available externally.

The good news is I think we're now one patch away from the upstream LLVM
compiling a functional kernel for Hexagon (a few fixes to LLVM/clang have
been committed already).  It technically compiles but produces an abort (from
a null deref) which the linker doesn't like.

The linker itself unfortunately is going to be a different matter.


Thanks,
Richard Kuo


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