Re: [patch, nios2] Update Linux parts for new syscall ABI

[Chung-Lin Tang <cltang at codesourcery dot com>]

On 13/12/2 3:44 PM, Joel Brobecker wrote:
>> Is Sandra not nios2 maintainer, or is she just not yet added to the
>> MAINTAINERS file?
> 
> She is not maintainer as far as I know (yet?).

Then I guess something was missed during the port submission? Is nios2
currently (technically) maintainer-less? ^^;;

>>>> 2013-12-01  Chung-Lin Tang  <cltang@codesourcery.com>
>>>>
>>>>         gdb/
>>>>         * nios2-linux-tdep.c (nios2_linux_sigreturn_init): Remove.
>>>>         (nios2_linux_sigreturn_tramp_frame): Remove.
>>>>         (nios2_linux_rt_sigreturn_tramp_frame): Update rt_sigreturn syscall
>>>>         number.
>>>>         (nios2_linux_syscall_next_pc): Likewise. Remove sigreturn case.
>>>>         (nios2_linux_init_abi):
>>>>         Remove registration of nios2_linux_sigreturn_tramp_frame.
>>>
>>> My concern with your patch is that it seems to eliminate support for
>>> the previous syscall ABI, which means a break in compatibility. Unless
>>> we really have no other choice, I don't think we would want that.
>>
>> This is a coordinated change, Altera will be using the new syscall ABI
>> when they upstream the kernel port.
> 
> I understand that. But is it conceivable that someone might be wanting
> to use the new GDB while still running on the old kernel, with the old
> software convention? How about the transition period? A break in
> compatibility is very unfriendly for the average user, and needs
> to be carefully considered.

nios2 support will only appear in the next 7.7 release. We're trying to
ensure only new-ABI support appears in formal FSF releases across all
toolchain components.

> I don't have any personal interest in this, other than trying to serve
> the interest of the potential users. If it's deemed too hard or useless
> by the nios community, then I won't object.

I can't personally judge what the community will react. However, our
work with Altera is to move everything towards the new syscall ABI. The
upstreamed ports of GCC and glibc will also be entirely new-ABI.

Thanks,
Chung-Lin