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Re: [PATCH] change GLIBC PPC64/ELF2 ABI default to 2.17
- From: Andreas Jaeger <aj at suse dot com>
- To: munroesj at us dot ibm dot com, Adam Conrad <adconrad at 0c3 dot net>, Carlos O'Donell <carlos at redhat dot com>
- Cc: libc-alpha at sourceware dot org, Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- Date: Thu, 30 Jan 2014 16:55:16 +0100
- Subject: Re: [PATCH] change GLIBC PPC64/ELF2 ABI default to 2.17
- Authentication-results: sourceware.org; auth=none
- References: <1391008726 dot 16702 dot 105 dot camel at spokane1 dot rchland dot ibm dot com> <52EA5D7A dot 9000903 at suse dot com> <1391095043 dot 16702 dot 200 dot camel at spokane1 dot rchland dot ibm dot com>
On 01/30/2014 04:17 PM, Steven Munroe wrote:
> On Thu, 2014-01-30 at 15:11 +0100, Andreas Jaeger wrote:
>> On 01/29/2014 04:18 PM, Steven Munroe wrote:
>>> Starting a new platform is always more complicated then we would like
>>> and we often find examples where the needs of the larger Linux community
>>> trumps our initial assumptions.
>>>
>>> Each distribution decides how it will support a new platform and we have
>>> requests to allow for back-ports of PPC64LE ELF2 to a GLIBC-2.17.
>>>
>>> To support the larger Linux community we need to insure forward
>>> compatibility across releases, and this implies setting the GLIBC
>>> powerpc.*le-.*-linux.* default back 2.17.
>>>
>>> We are not asking to apply this patch retroactively to the GLIBC-2.17
>>> source. But we like to get this patch accepted upstream to serve notice
>>> to all involved (in PPC64LE) that GLIBC-2.17 is the oldest symbol set,
>>> and promise this it final word on the topic.
>>>
>>> We also ask that all distributions apply this patch and ELF2 ABI patches
>>> if they planing to support the PPC64LE platform and doing a back port of
>>> the to GLIBC-2.17 or 2.18.
>>
>> I'm really surprised by this change at this point of time.
>>
> We are starting a new platform and building a new community around this
> new platform. The good news is the community is growing, but each new
> distro has it own set of policies and existing assumption.
>
> We are just trying to be inclusive. And it is not just about one distro.
>
>> Since there are apparently backported 2.17 and 2.18 versions out there,
>> let me ask a different question: Which ABI will be the one that you
>> promise stability for?
>>
> The GLIBC 2.19 will be the 2.19 ABI and the GLIBC-2.17 will be the 2.17
> ABI. We want to insure that PPC64LE ELF2 binary build on GLIBC-2.17 will
> run on a 2.18 or 2.19 or later GLIBC. We do not expect a binary build on
> 2.19 will run on GLIBC 2.18 or 2.17. But this the normal definition.
An ABI is more than just the default symbol version.
I'm asking for a stability promise of the ABI that will be in glibc.
What if the implemented 2.17 glibc used by Carlos is by accident
incompatible to the 2.19 ABI? Which ABI will then be broken to get those
compatible again.
>> My expectation is that the official glibc 2.19 release to be the
>> reference version and if there are any incompatibilities between the
>> backports and the glibc 2.19 release, the backports need to be fixed.
>>
> yes the 2.18 and 2.17 back ports must have forward compatible with
> GLIBC-2.19, which the normal requirement. I and not asking for change to
> the GLIBC-2.19 ABI. I am asking to change the GLIBC DEFAULT symbol for
> the new PPC64LE platform to be 2.17.
>
>> Can we all agree on using glibc 2.19 as the reference for ABI stabilitiy?
>>
> I agree. Adam, Carlos?
Thanks!
>> I'd like to see a signoff from the power maintainers on this one,
>>
> That would be Adhemerval and Myself.
Andreas
--
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