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Re: [PATCHv3] powerpc: ABI change - add HWCAP/HWCAP2/platform info to TCB
- From: Carlos Eduardo Seo <cseo at linux dot vnet dot ibm dot com>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>, Tulio Machado <tuliom at linux dot vnet dot ibm dot com>, "Steven J. Munroe" <sjmunroe at us dot ibm dot com>, "Carlos O'Donell" <carlos at redhat dot com>
- Date: Wed, 23 Sep 2015 18:30:05 -0300
- Subject: Re: [PATCHv3] powerpc: ABI change - add HWCAP/HWCAP2/platform info to TCB
- Authentication-results: sourceware.org; auth=none
- References: <4BE991CB-F601-4D63-A416-5991FE870FC4 at linux dot vnet dot ibm dot com> <alpine dot DEB dot 2 dot 10 dot 1509232114070 dot 10585 at digraph dot polyomino dot org dot uk>
OâDonell suggested we used a versioned symbol to track this change, so it doesnât break applications when running against an old glibc:
> > I have only a few substantive technical issues with the patch. Given
> > that the ABI allocates a large block of tp+offset data, I think it is
> > OK for IBM to use the data in this way. For example I think it is much
> > much more serious that such a built application will likely just crash
> > when run with an older glibc. This is a distribution maintenance issue
> > that I can't ignore and I'd like to see it solved by a dependency on a
> > versioned dummy symbol.
See: https://sourceware.org/ml/libc-alpha/2015-07/msg00196.html
Thanks,
--
Carlos Eduardo Seo
Software Engineer - Linux on Power Toolchain
cseo@linux.vnet.ibm.com
> On Sep 23, 2015, at 6:15 PM, Joseph Myers <joseph@codesourcery.com> wrote:
>
> Why do you need a public symbol init_hwcapinfo? If this function is
> called from outside the library that defines it, I'd have expected a
> private, implementation-namespace symbol __init_hwcapinfo, at version
> GLIBC_PRIVATE. A public symbol should only be needed if it's a documented
> API for users to call.
>
> --
> Joseph S. Myers
> joseph@codesourcery.com
>