From: Suprateeka R Hegde <hegdesmailbox@gmail.com>
To: Roland McGrath <roland@hack.frob.com>
Cc: gnu-gabi@sourceware.org
Subject: Re: OSABI on Linux Distros
Date: Fri, 01 Jan 2016 00:00:00 -0000 [thread overview]
Message-ID: <a7ffb9cb-b876-4165-71ca-a76a13b3255f@gmail.com> (raw)
In-Reply-To: <20160610212256.D5A772C39F7@topped-with-meat.com>
On 11-Jun-2016 02:52 AM, Roland McGrath wrote:
>> What is the reason why we emit OSABI value as "UNIX - System V"
>> (ELFOSABI_SYSV) even on GNU/Linux systems? Shouldn't it be just "GNU"
>> (ELFOSABI_GNU)?
>
> In GNU systems the use of this field is specifically to indicate that
> certain GNU extensions to ELF are used in the particular object. In
> particular, if any .dynsym entries use STT_GNU_IFUNC o STB_GNU_UNIQUE,
> then e_ident[EI_OSABI] must be ELFOSABI_GNU.
OK. I understood this part. But then I did not know this set is partial.
I thought use of *any* GNU specific extension should mark it as GNU OSABI.
For instance, GNU_RELRO, GNU_EH_FRAME, GNU_STACK, etc. Even with all
these, it is still marked SYSV ABI.
So,
1. Do we have a documented list of GNU extensions that are necessary to
mark an ELF as GNU ABI?
2. Why the list is partial? Why not all GNU extensions?
--
Supra
Otherwise, it can be
> ELFOSABI_NONE (aka ELFOSABI_SYSV). In fact, it should be, and the
> tools (linkers) implement that distinction. This makes it possible
> for current tools (without special switches or whatnot) to produce
> binaries that are compatible with older dynamic linker implementations
> that did not support these GNU extensions to ELF.
>
> This is arguably a bad overloading of the original instead of
> EI_OSABI, but it's what's been done for GNU systems and so now it's an
> unchangeable part of the GNU ELF gABI.
>
next prev parent reply other threads:[~2016-06-11 6:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-01 0:00 Suprateeka R Hegde
2016-01-01 0:00 ` Roland McGrath
2016-01-01 0:00 ` Carlos O'Donell
2016-01-01 0:00 ` Suprateeka R Hegde
2016-01-01 0:00 ` Suprateeka R Hegde [this message]
2016-01-01 0:00 ` Carlos O'Donell
2016-01-01 0:00 ` Suprateeka R Hegde
2016-01-01 0:00 ` Carlos O'Donell
2016-01-01 0:00 ` Suprateeka R Hegde
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