Re: kbuild: Section mismatch warnings

From: Nicholas Miell <nmiell@comcast.net>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Adrian Bunk <bunk@stusta.de>, LKML <linux-kernel@vger.kernel.org>,
	len.brown@intel.com, Paul Bristow <paul@paulbristow.net>,
	mpm@selenic.com, B.Zolnierkiewicz@elka.pw.edu.pl,
	dtor_core@ameritech.net, kkeil@suse.de,
	linux-dvb-maintainer@linuxtv.org, philb@gnu.org, gregkh@suse.de,
	dwmw2@infradead.org
Subject: Re: kbuild: Section mismatch warnings
Date: Fri, 17 Feb 2006 16:14:59 -0800	[thread overview]
Message-ID: <1140221699.2907.5.camel@entropy> (raw)
In-Reply-To: <20060217233848.GA26630@mars.ravnborg.org>

On Sat, 2006-02-18 at 00:38 +0100, Sam Ravnborg wrote:
> Hi Adrian
> 
> > > I did not find a way to look up the offending symbol but maybe some elf
> > > expert can help?
> > >...
> >  
> > I'm not an ELF expert, but simply checking all __init functions in this 
> > files finds that this seems to be the following:
> > 
> > <--  snip  -->
> > 
> > ...
> > static struct acpi_driver asus_hotk_driver = {
> >         .name = ACPI_HOTK_NAME,
> >         .class = ACPI_HOTK_CLASS,
> >         .ids = ACPI_HOTK_HID,
> >         .ops = {
> >                 .add = asus_hotk_add,
> >                 .remove = asus_hotk_remove,
> >                 },
> > };
> > ...
> > static int __init asus_hotk_add(struct acpi_device *device)
> > ...
> > 
> Correct.
> What I wanted was modpost to tell that the symbol being referenced in
> the .data section was 'asus_hotk_add' and not just an offset after
> asus_hotk_driver.
> 
> What is needed is a link from the RELOCATION RECORD to the symbol table.

The r_info field of Elf{32,64}_Rel{,a} contains an index into the symbol
table which can be extracted using the ELF{32,64}_R_SYM() macro.

-- 
Nicholas Miell <nmiell@comcast.net>