Re: [PATCH] powerpc64: use a type for mcontext_t regs field

[David Edelsohn <dje.gcc@gmail.com>]

On Tue, Feb 12, 2019 at 1:36 PM A. Wilcox <awilfox@adelielinux.org> wrote:
>
> On 02/12/19 11:05, David Edelsohn wrote:
> > I presume that someone is trying to use GCCGo with Alpine Linux.  I
> > believe that Golang works with Alpine Linux.
> >
> > Thanks, David
>
>
> We're still here.  Adélie.  The distro that does big endian and ELFv2.
> The distro that *cares* about *quality*, not just hack-and-slashing.
>
> We can't use Golang because Golang doesn't work on half of our
> architectures - ppc32 will likely never be supported, and their ppc64
> support is unusable and written very poorly.  It assumes POWER8, not to
> mention the fact it likely has plenty of broken ELF ABI assumptions.
> (There's also very poor support for other architectures with musl, but I
> don't recall the specifics now.)
>
> I'm sure you're aware of all of this already.  In fact, it was probably
> your team that convinced Google that POWER7 is "old" when it is newer
> than Sandy Bridge:
>
> https://github.com/golang/go/issues/19074#issuecomment-436101375
>
> But I'm not sure if you work directly with Lynn or not, so I can't say
> that for certain.
>
> Anyway, GCC Go is definitely the best way forward for Adélie, which is
> why we're trying to make it work on ppc64.  It already works perfectly
> well on ppc32, x86*, and arm64.  And because it uses GCC's code
> generator, it won't be subject to ridiculously unportable ABI assumptions.

I didn't want to assume that this request was for support of Adelie.

IBM's product focus is systems running PPC64 Little Endian ELFv2
Linux.  The official ABI for PPC64 BE Linux is PPC64 ELFv1.  PPC64 BE
Linux with ELFv2 ABI is a niche within a niche.

If someone can offer patches to make it work, that's great.  The issue
with GCC Go and Musl Libc for PPC64 seems like a more general issue
than Adelie, but still a niche market.

- David