linux-kernel - Re: [PATCH] Add non-zero module sections to sysfs

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Message-ID: <878v4tbqve.fsf@rustcorp.com.au>
Date:	Mon, 08 Apr 2013 13:44:45 +0930
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Philip Kranz <philip.kranz@...glemail.com>,
	James Bottomley <James.Bottomley@...senPartnership.com>
Cc:	Sebastian Wankerl <sisewank@....cs.fau.de>,
	linux-kernel@...r.kernel.org,
	Philip Kranz <philip.kranz@...glemail.com>,
	i4passt@...ts.informatik.uni-erlangen.de,
	linux-parisc@...r.kernel.org
Subject: Re: [PATCH] Add non-zero module sections to sysfs

Philip Kranz <philip.kranz@...glemail.com> writes:
> Hello.
>
> On Fri, Apr 05, 2013 at 12:07:15PM +0200, James Bottomley wrote:
>> Just so you know: this isn't a parisc specific problem.  Gcc produces
>> duplicate section names under various circumstances, but the one that
>> bites us is -ffunction-sections.  Note that there are proposals to use
>> -ffunction-sections on all architectures (so we can garbage collect
>> unused functions) in which case you'll induce the bug identified in
>> 35dead4235e2b67da7275b4122fed37099c2f462 on every architecture
>
> I am not able to produce an object file with duplicate section names
> using gcc on x86. Even with -ffunction-sections, every section gets a
> unique name. Is this architecture-specific behaviour of gcc?

Good point.  ld -r will collapse them into the same section (since gcc
produces them they have to have the same section attributes).

You can do it with --unique, but no arch uses that.  PARISC has a
platform-specific toolchain hack which does that for .text sections.
(Thanks to Alan Modra for that clue...)

Thanks,
Rusty.
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