2.6.14-git1 (and -git2) build failure on AMD64

2.6.14-git1 (and -git2) build failure on AMD64

[Martin J. Bligh]

CC      arch/x86_64/pci/../../i386/pci/fixup.o
arch/x86_64/pci/../../i386/pci/fixup.c: In function `pci_fixup_i450nx':
arch/x86_64/pci/../../i386/pci/fixup.c:13: error: pci_fixup_i450nx causes a section type conflict
make[1]: *** [arch/x86_64/pci/../../i386/pci/fixup.o] Error 1
make: *** [arch/x86_64/pci] Error 2

Config: http://ftp.kernel.org/pub/linux/kernel/people/mbligh/config/abat/amd64

Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Roland Dreier]

Fixed by:
    http://lkml.org/lkml/2005/10/29/12

You .config breaks because it has
    # CONFIG_HOTPLUG is not set

 - R.

Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Andi Kleen]

On Sunday 30 October 2005 15:03, Martin J. Bligh wrote:
> CC      arch/x86_64/pci/../../i386/pci/fixup.o
> arch/x86_64/pci/../../i386/pci/fixup.c: In function `pci_fixup_i450nx':
> arch/x86_64/pci/../../i386/pci/fixup.c:13: error: pci_fixup_i450nx causes a section type conflict
> make[1]: *** [arch/x86_64/pci/../../i386/pci/fixup.o] Error 1
> make: *** [arch/x86_64/pci] Error 2
> 
> Config: http://ftp.kernel.org/pub/linux/kernel/people/mbligh/config/abat/amd64

What compiler do you use? I cannot make sense of the error - as far
as I can see the function only has a single section attribute.
But gcc 4.0.2 reports the same error for me on a different function.

-Andi 

Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Martin J. Bligh]

--Andi Kleen <ak@suse.de> wrote (on Sunday, October 30, 2005 16:28:29 +0100):

> On Sunday 30 October 2005 15:03, Martin J. Bligh wrote:
>> CC      arch/x86_64/pci/../../i386/pci/fixup.o
>> arch/x86_64/pci/../../i386/pci/fixup.c: In function `pci_fixup_i450nx':
>> arch/x86_64/pci/../../i386/pci/fixup.c:13: error: pci_fixup_i450nx causes a section type conflict
>> make[1]: *** [arch/x86_64/pci/../../i386/pci/fixup.o] Error 1
>> make: *** [arch/x86_64/pci] Error 2
>> 
>> Config: http://ftp.kernel.org/pub/linux/kernel/people/mbligh/config/abat/amd64
> 
> What compiler do you use? I cannot make sense of the error - as far
> as I can see the function only has a single section attribute.
> But gcc 4.0.2 reports the same error for me on a different function.

Looks like it's 3.4.0 on that box.

Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Roland Dreier]

    Andi> What compiler do you use? I cannot make sense of the error -
    Andi> as far as I can see the function only has a single section
    Andi> attribute.  But gcc 4.0.2 reports the same error for me on a
    Andi> different function.

Yes, the gcc error is very strange.  The underlying cause is that
(with CONFIG_HOTPLUG=n so __devinit is not just defined away to
nothing) having toshiba_ohci1394_dmi_table[] declared __devinit makes
gcc think it has to put the array in a section along with code.  But
instead of complaining about the array declaration, gcc complains
about some random function earlier in the file -- and which function
it picks to complain about seems to change depending on gcc version
and the phase of the moon.

 - R.

[PATCH] x86_64: Work around Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Andi Kleen]

On Sunday 30 October 2005 15:03, Martin J. Bligh wrote:
> CC      arch/x86_64/pci/../../i386/pci/fixup.o
> arch/x86_64/pci/../../i386/pci/fixup.c: In function `pci_fixup_i450nx':
> arch/x86_64/pci/../../i386/pci/fixup.c:13: error: pci_fixup_i450nx causes a section type conflict
> make[1]: *** [arch/x86_64/pci/../../i386/pci/fixup.o] Error 1
> make: *** [arch/x86_64/pci] Error 2
> 
> Config: http://ftp.kernel.org/pub/linux/kernel/people/mbligh/config/abat/amd64
> 

I think it's a gcc bug. Anyways, this should work around it.

Linus, can you please apply it?

---

Work around gcc bug that causes build failures like
(exact function it is reported on varies with compiler version and optimization
level) 

> arch/x86_64/pci/../../i386/pci/fixup.c: In function `pci_fixup_i450nx':
> arch/x86_64/pci/../../i386/pci/fixup.c:13: error: pci_fixup_i450nx causes a section type conflict

with !CONFIG_HOTPLUG. It makes the !CONFIG_HOTPLUG case act
like CONFIG_HOTPLUG. This wastes a bit of memory, but is not
too bad.

The sections are legitimate, but gcc somehow gets confused.

Compiling with -O3 seems to also help at least with gcc 4, but I'm
not sure it'll help everything. Splitting up the file might
a different option.

Signed-off-by: Andi Kleen <ak@suse.de> 

diff -u linux-2.6.14-git2/arch/i386/pci/fixup.c-o linux-2.6.14-git2/arch/i386/pci/fixup.c
--- linux-2.6.14-git2/arch/i386/pci/fixup.c-o	2005-10-30 16:09:41.000000000 +0100
+++ linux-2.6.14-git2/arch/i386/pci/fixup.c	2005-10-30 16:42:32.000000000 +0100
@@ -8,6 +8,9 @@
 #include <linux/init.h>
 #include "pci.h"
 
+/* Works around a gcc bug which gets confused with so many section switches */
+#undef __devinit
+#define __devinit
 
 static void __devinit pci_fixup_i450nx(struct pci_dev *d)
 {

Re: [PATCH] x86_64: Work around Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Roland Dreier]

    Andi> Linus, can you please apply it?

No, please don't apply this.  The correct fix is to mark
toshiba_ohci1394_dmi_table[] as __devinitdata in that file, as in the
patch I posted here:

    http://lkml.org/lkml/2005/10/29/12

 - R.

Re: [PATCH] x86_64: Work around Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Andi Kleen]

On Sunday 30 October 2005 17:17, Roland Dreier wrote:
>     Andi> Linus, can you please apply it?
> 
> No, please don't apply this.  The correct fix is to mark
> toshiba_ohci1394_dmi_table[] as __devinitdata in that file, as in the
> patch I posted here:
> 
>     http://lkml.org/lkml/2005/10/29/12

While not correct I don't see how it should guarantee it will
work around that gcc bug on all possible gcc versions (which show
different behaviour) My patch is more conservative and safer.

-Andi

Re: [PATCH] x86_64: Work around Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Roland Dreier]

    Andi> While not correct I don't see how it should guarantee it
    Andi> will work around that gcc bug on all possible gcc versions
    Andi> (which show different behaviour) My patch is more
    Andi> conservative and safer.

What's the gcc bug?  The current fixup.c code is asking gcc to put
toshiba_ohci1394_dmi_table[] in the .init.text section.  This makes
gcc think that .init.text contains writable data.  Then some other
declaration in the file asks gcc to put a function in .init.text.  gcc
correctly complains that text and writable data can't share a section.

If we fix toshiba_ohci1394_dmi_table[] to go into .init.data as is
intended, then gcc is happy.

The only thing remotely like a gcc bug is that the diagnostic gcc
prints does not flag toshiba_ohci1394_dmi_table[] as the problem.

Admittedly I have only tested gcc 4.0 and gcc 3.4, but given that no
one reported this problem before toshiba_ohci1394_dmi_table[] was
added, and that the __devinit declaration of an array is obviously
wrong and would cause exactly this sort of section conflict, I think
we should at least try the correct fix.

 - R.

Re: [PATCH] x86_64: Work around Re: 2.6.14-git1 (and -git2) build failure on AMD64

[Martin J. Bligh]

--Roland Dreier <rolandd@cisco.com> wrote (on Sunday, October 30, 2005 08:17:39 -0800):

>     Andi> Linus, can you please apply it?
> 
> No, please don't apply this.  The correct fix is to mark
> toshiba_ohci1394_dmi_table[] as __devinitdata in that file, as in the
> patch I posted here:
> 
>     http://lkml.org/lkml/2005/10/29/12

Tested, fixes it for me. Linus - this is still broken in -git4, any chance
you could pick this one up? Makes nasty red marks across my shiny green
test matrix ;-)

Thanks,

M.