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From: Ingo Molnar <mingo@elte.hu>
To: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Paul Mackerras <paulus@samba.org>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	emunson@mgebm.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf: Fix symbol resolution on old ppc64 ABI
Date: Mon, 25 Jul 2011 08:25:42 +0200	[thread overview]
Message-ID: <20110725062542.GA694@elte.hu> (raw)
In-Reply-To: <20110725142356.0c722c6b@kryten>


* Anton Blanchard <anton@samba.org> wrote:

> The synthetic symbol creation code has an issue with the old ppc64 
> ABI. We end up with duplicate symbols of different sizes that 
> overlap.
> 
> To fix this, walk all of the symbols and remove any duplicates that 
> are the length of a function descriptor.

> I'd prefer not to add a ppc64 specific hack here, but I'm not sure 
> how we can fix this in a simpler way.

Symbol space problems are common on other architectures as well.

We could use a heuristic: when symbols are overlapping then we could 
throw away the one that is smaller. This would implicitly cover the 
ppc64 case, right?

I'd also suggest we warn somewhere that a symbol has been thrown 
away, if verbosity is turned off. (i.e. don't warn by default.)

Thanks,

	Ingo

  reply	other threads:[~2011-07-25  6:26 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-25  4:23 [PATCH] perf: Fix symbol resolution on old ppc64 ABI Anton Blanchard
2011-07-25  6:25 ` Ingo Molnar [this message]
2011-07-25 10:48   ` Anton Blanchard
2011-07-25 10:50     ` Ingo Molnar
2011-07-25 12:32       ` Anton Blanchard
2011-07-25 12:36         ` Ingo Molnar

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