Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
In-Reply-To: <20190628002208.v6brs6b6hf7b6sth@treble>
References: <20190616231500.8572-1-mforney@mforney.org> <20190628002208.v6brs6b6hf7b6sth@treble>
From:   Michael Forney <mforney@mforney.org>
Date:   Thu, 27 Jun 2019 17:52:53 -0700
Message-ID: <CAGw6cBuaMoZQK-hV+Ztg5uFqPU3dY6L7um1bzsxVPQfaX4JA7g@mail.gmail.com>
Subject: Re: [PATCH 1/2] objtool: Rename elf_open to prevent conflict with
 libelf from elftoolchain
To:     Josh Poimboeuf <jpoimboe@redhat.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        linux-kernel@vger.kernel.org,
        elftoolchain-developers@lists.sourceforge.net
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2019-06-27, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> On Sun, Jun 16, 2019 at 04:14:59PM -0700, Michael Forney wrote:
>> Signed-off-by: Michael Forney <mforney@mforney.org>
>> ---
>>  tools/objtool/check.c | 2 +-
>>  tools/objtool/elf.c   | 2 +-
>>  tools/objtool/elf.h   | 2 +-
>>  3 files changed, 3 insertions(+), 3 deletions(-)
>
> Sorry for the delay, I was out for a bit and I'm still trying to get
> caught back up on email.

No worries :)

> These patches look fine.  I'll try to send them on to the -tip tree
> shortly.

Thanks!

> Just curious, have you done much testing with the elftoolchain version
> of libelf and objtool?  So far objtool has only been successfully used
> with the elfutils version, so I'm just curious how compatible your
> libelf is with the elfutils version.

I'm not affiliated with elftoolchain, I am just trying it out on my
system as an alternative to elfutils libelf for its clean codebase
that doesn't use many GNU C extensions.

I've done some basic testing to make sure that the .o files after
being processed with `objtool generate --no-fp --retpoline` match
between elfutils and elftoolchain. I noticed two differences, one of
which was due to a bug in elftoolchain that has since been fixed, and
the other is with the offset of SHT_NOBITS section after rewriting[0],
which I think doesn't matter.

[0] https://sourceforge.net/p/elftoolchain/tickets/571/