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Re: [PATCH] change GLIBC PPC64/ELF2 ABI default to 2.17
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: munroesj at us dot ibm dot com, libc-alpha at sourceware dot org
- Cc: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>, "Joseph S. Myers" <joseph at codesourcery dot com>, Jeff Law <law at redhat dot com>
- Date: Wed, 29 Jan 2014 11:38:20 -0500
- 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>
On 01/29/2014 10:18 AM, 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.
The new shlib-versions have never been publicly released, therefore
from a process perspective I see nothing wrong in changing them to
GLIBC_2.17 before 2.19 is released. My expectation is that IBM tested
these internally and found no problems.
Please note that any distributions that were using GLIBC_2.18 as the
default ABI baseline will need to rebuild all of userspace for the
symbol versioning to be correct.
I see nothing technically complicated about this change, it's purpose
is to allow the PPC64 LE work to be easily integrated into any and all
distributions based on glibc 2.17.
It also does not prevent any distribution from using a later version
of glibc as they see a need.
> 2014-01-29 Adhemerval Zanella <azanella@linux.vnet.ibm.com>
>
> * nptl/shlib-versions: Change powerpc*le start to 2.17.
> * shlib-versions: Likewise.
>
> ---
>
> diff --git a/nptl/shlib-versions b/nptl/shlib-versions
> index 495b240..f6b9b9a 100644
> --- a/nptl/shlib-versions
> +++ b/nptl/shlib-versions
> @@ -2,5 +2,5 @@
> sparc64.*-.*-linux.* libpthread=0 GLIBC_2.2
> sh.*-.*-linux.* libpthread=0 GLIBC_2.2
> s390x-.*-linux.* libpthread=0 GLIBC_2.2
> powerpc64-.*-linux.* libpthread=0 GLIBC_2.3
> -powerpc.*le-.*-linux.* libpthread=0 GLIBC_2.18
> +powerpc.*le-.*-linux.* libpthread=0 GLIBC_2.17
OK.
> .*-.*-linux.* libpthread=0
> diff --git a/shlib-versions b/shlib-versions
> index 51f5327..78b0ad7 100644
> --- a/shlib-versions
> +++ b/shlib-versions
> @@ -23,7 +23,7 @@
>
> s390x-.*-linux.* DEFAULT GLIBC_2.2
> powerpc64-.*-linux.* DEFAULT GLIBC_2.3
> -powerpc.*le-.*-linux.* DEFAULT GLIBC_2.18
> +powerpc.*le-.*-linux.* DEFAULT GLIBC_2.17
OK.
> .*-.*-gnu-gnu.* DEFAULT GLIBC_2.2.6
>
> # Configuration ABI Identifier for
> ABI data files
Looks good to me.
Thank you for expanding the scope of supported glibc versions
for PPC64 LE.
Let us all hope that the ELFv2 PPC64 LE ABI remains stable.
Not withstanding a double-double to IEEE binary128 transition which
the entire community would like to see happen as double-double is
very difficult to support and maintain.
Cheers,
Carlos.