[parisc-linux] mcontext registers on parisc64

[Carlos O'Donell]

> 
> Inspecting the sigcontext that I get on a parisc64 machine gives
> register contents looking a bit like
>     [...]
>     0xffffffff, 0xdeadbeef, 0x0, 0xf00d, 0x0, 0xfaf00380, 0x0, 0x2097a, 0x0, 
>     0xfaf001a4, 0x0, 0x2096a, 0x0, 0x1, 0x0, 0x20972, 0x0, 0x1, 0x0, 0x0, 0x0, 
>     [...]
> 
> and the alternation of data, 0/-1 is what leads me to believe that
> 64-bit quantities are being delivered; userland only seems to know about
> 32-bits, though.
> 
> Please don't hesitate to get back to me with comments and/or criticisms,
> 
> Cheers,
> Christophe

This might be a kernel bug. We should always return 32-bit quantities to 
userspace (until we get a 64-bit userspace :).

Once we straighten out the sigcontext->mcontext_t issue in glibc, we can
take a look at this. I might just patch glibc on my box tonight... and go
forward with hacking on the kernel bits.

c.