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Message-ID: <49FB8D27.3000305@linux.intel.com>
Date: Fri, 01 May 2009 17:00:39 -0700
From: "H. Peter Anvin" <hpa@linux.intel.com>
Organization: Intel Open Source Technology Center
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To: Sam Ravnborg <sam@ravnborg.org>
CC: Andreas Schwab <schwab@linux-m68k.org>,
       LKML <linux-kernel@vger.kernel.org>, linux-arch@vger.kernel.org
Subject: Re: "N" symbols and System.map
References: <49FB7692.2000508@linux.intel.com> <m2preso1wl.fsf@igel.home> <20090501232149.GA28888@uranus.ravnborg.org>
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Sam Ravnborg wrote:
> On Sat, May 02, 2009 at 01:10:18AM +0200, Andreas Schwab wrote:
>> "H. Peter Anvin" <hpa@linux.intel.com> writes:
>>
>>> right now, we filter out symbols that nm tag N, meaning "debugging
>>> symbols", from System.map.  However, at least on x86, the linker-generated
>>> symbol _end is tagged N, and in fact is the only N in the entire image.
>>>
>>> Are there other architectures which would suffer if N were included in
>>> System.map, or would that be a reasonable thing to do?
>> There should not be any N symbols unless you are using stabs debugging.
> 
> We have in vmlinux:
>         .end : AT(ADDR(.end) - LOAD_OFFSET) {
>                 _end = .;
>         }
> 
> 
> And I see:
> c1834000 N _end
> 
> This is the _only_ 'N' symbol in my vmlinux.
> 

Yup, this is what happens.  I don't know why the linker does this, and 
if there is a way around it.

	-hpa