From: Blaisorblade <blaisorblade@yahoo.it>
To: user-mode-linux-devel@lists.sourceforge.net
Subject: Re: [uml-devel] Partial fix! - Was: Re: [BUG report] UML linux-2.6 latest BK doesn't compile
Date: Wed, 16 Feb 2005 19:27:03 +0100
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Cc: Anton Altaparmakov <aia21@cam.ac.uk>, Jeff Dike <jdike@addtoit.com>,
       lkml <linux-kernel@vger.kernel.org>
References: <1107857395.15872.2.camel@imp.csi.cam.ac.uk> <200502082223.j18MMxs0013724@ccure.user-mode-linux.org> <1108380903.22656.9.camel@imp.csi.cam.ac.uk>
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On Monday 14 February 2005 12:35, Anton Altaparmakov wrote:
> On Tue, 2005-02-08 at 17:22 -0500, Jeff Dike wrote:
> > blaisorblade@yahoo.it said:
> > > Why not simply disable CONFIG_GCOV for him, in this case?
> >
> > Anton presumably turned on CONFIG_GCOV because he wanted to do some
> > profiling...
>
> Yes.  I finally found a way to get it to compile.  Compiling without TT
> mode and WITHOUT static build it still fails with the same problem
> (__bb_init_func problem I already reported).  But compiling without TT
> but WITH static build the __bb_init_func problem goes away but instead I
> get a __gcov_init missing symbol in my modules.
>
> Note I have gcc-3.3.4-11 (SuSE 9.2) and it defines __gcov_init.  So I
> added this as an export symbol and lo and behold the kernel and modules
> compiled and I am now up an running with UML and NTFS as a module.  (-:

What do we do for previous GCC, which probably do not define _gcov_init (at 
least I guess, since things worked before)? We'll get a "unresolved symbol" 
in the kernel linking, I guess (unverified).

It is possible, even if ugly, to $(NM) the relevant libraries to choose what 
to do, by adding a -D__EXPORT_GCOV_INIT_ (or even, if we know well, to 
indicate the GCC version needed for this).

So, for now, I guess we must defer this to later than 2.6.11...

> Here is the patch that I used to fix this:
>
> --- ntfs-2.6-devel/arch/um/kernel/gmon_syms.c.old 2005-02-14
> 11:27:04.789474410 +0000 +++
> ntfs-2.6-devel/arch/um/kernel/gmon_syms.c 2005-02-14 11:26:49.191117739
> +0000 @@ -8,6 +8,9 @@
>  extern void __bb_init_func(void *);
>  EXPORT_SYMBOL(__bb_init_func);
>
> +extern void __gcov_init(void *);
> +EXPORT_SYMBOL(__gcov_init);
> +
>  /*
>   * Overrides for Emacs so that we follow Linus's tabbing style.
>   * Emacs will notice this stuff at the end of the file and automatically
>
> Best regards,
>
>         Anton

-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729
http://www.user-mode-linux.org/~blaisorblade

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