Re: [gentoo-dev] Introduce ppc64le architecture into gentoo ! please share your comments

["Anthony G. Basile" <blueness@gentoo.org>]

On 8/11/15 10:33 AM, Ian Stakenvicius wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> On 11/08/15 06:11 AM, Leno Hou wrote:
>> I think ppc64le would become popular,
>> https://en.wikipedia.org/wiki/Ppc64.
>>
>> 1. enable porting x86 Linux based application with minimal effort.
>>   2. Some PowerPC user, little endian apparently feels cheap, wrong,
>> and PCish. 3. Other distrbutions like Ubuntu, Redhat and SUSE
>> already support little endian in powerpc.
>>
>>
> In terms of the codepaths, what's different between ppc64le vs ppc64,
> and ppc64le vs amd64 ?  Obviously kernels will differ, but in terms of
> C/C++/other compiled source code what needs to change?
>
> If all this needs is its own profile for a CHOST/CBUILD specification
> and it can leverage an existing keyword, then this should be rather
> simple to implement yes?

We would leverage this on ppc64 keyword.  It is a bit dangerous to claim 
that a pkg stable on ppc64 is stable on ppc64le, but we would live with 
that risk.  Ideally you should test on both.  The situation is analogous 
to mips where there are many different ISAs and both be and le.  It is 
one of the reasons mips is hard to move back into stable.  But having 
stable keywords is really nice when it comes to building and maintaining 
stages and keeping base pkgs versions in sync with the other arches.  
For this reason, I would even been in favor of restoring stable mips 
with the understanding that "stable" carries something of a risk when 
crossing the be/le boundry, or the mips I vs mips III, or 32 vs 64, etc.

Having said that, what would break?  Assembly and other code that makes 
assumption about byte order.   There is some out there, but not much.  
We'll deal with it when we hit it.  Any of the heavy duty stuff, like 
syscall interfaces or setjmp/longjmp etc, should be relegated to the 
libc and kernel.

>
>
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v2
>
> iF4EAREIAAYFAlXKB7UACgkQAJxUfCtlWe1sbQD+KcbYpfo56GrLIVlFyw2iXbMB
> ZOWzuvyI8SVq/DY0SQMBAJgDIjCza8QyUgWEtq2/g5Yu+uWiCibf2ouMeNAOkQ33
> =YoUg
> -----END PGP SIGNATURE-----
>


-- 
Anthony G. Basile, Ph.D.
Gentoo Linux Developer [Hardened]
E-Mail    : blueness@gentoo.org
GnuPG FP  : 1FED FAD9 D82C 52A5 3BAB  DC79 9384 FA6E F52D 4BBA
GnuPG ID  : F52D4BBA