[PATCH 00/12] Fix various section mismatches and build errors.

[PATCH 00/12] Fix various section mismatches and build errors.

[Ralf Baechle]

I'm getting screen and screens full of section mismatches from my test
builds of the current kernel to the point where it's sometimes more
meaningful messages get hidden by the bulk of mismatches.  This is the
first round of fixes with more to come.

  Ralf

 drivers/gpu/drm/radeon/radeon_clocks.c |    4 ++--
 drivers/leds/leds-lp5521.c             |    4 ++--
 drivers/leds/leds-lp5523.c             |    4 ++--
 drivers/misc/ioc4.c                    |    2 +-
 drivers/net/3c509.c                    |    2 +-
 drivers/net/3c59x.c                    |    2 +-
 drivers/net/depca.c                    |   25 +++++++++++++------------
 drivers/net/hp100.c                    |    2 +-
 drivers/net/ne3210.c                   |   12 +++++++-----
 drivers/net/tulip/de4x5.c              |    2 +-
 drivers/scsi/sim710.c                  |    2 +-
 drivers/tty/serial/Kconfig             |    2 +-
 12 files changed, 33 insertions(+), 30 deletions(-)

[PATCH 01/12] SCSI: sim710: Fix section mismatch

[Ralf Baechle]

WARNING: drivers/scsi/sim710.o(.data+0x4c): Section mismatch in reference from the variable sim710_eisa_driver to the function .init.text:sim710_eisa_probe()
The variable sim710_eisa_driver references
the function __init sim710_eisa_probe()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: linux-scsi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
---
 drivers/scsi/sim710.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/sim710.c b/drivers/scsi/sim710.c
index 8ac6ce7..a128502 100644
--- a/drivers/scsi/sim710.c
+++ b/drivers/scsi/sim710.c
@@ -286,7 +286,7 @@ static struct eisa_device_id sim710_eisa_ids[] = {
 };
 MODULE_DEVICE_TABLE(eisa, sim710_eisa_ids);
 
-static __init int
+static __devinit int
 sim710_eisa_probe(struct device *dev)
 {
 	struct eisa_device *edev = to_eisa_device(dev);
-- 
1.7.4.4

Re: [PATCH 00/12] Fix various section mismatches and build errors.

[David Miller]

See commit:

commit 948252cb9e01d65a89ecadf67be5018351eee15e
Author: David S. Miller <davem@davemloft.net>
Date:   Tue May 31 19:27:48 2011 -0700

    Revert "net: fix section mismatches"
    
    This reverts commit e5cb966c0838e4da43a3b0751bdcac7fe719f7b4.
    
    It causes new build regressions with gcc-4.2 which is
    pretty common on non-x86 platforms.
    
    Reported-by: James Bottomley <James.Bottomley@HansenPartnership.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

and postings that led to this revert including:

http://marc.info/?l=linux-netdev&m=130653748205263&w=2

Re: [PATCH 00/12] Fix various section mismatches and build errors.

[Ralf Baechle]

On Mon, Jun 27, 2011 at 10:12:57PM -0700, David Miller wrote:

> commit 948252cb9e01d65a89ecadf67be5018351eee15e
> Author: David S. Miller <davem@davemloft.net>
> Date:   Tue May 31 19:27:48 2011 -0700
> 
>     Revert "net: fix section mismatches"
>     
>     This reverts commit e5cb966c0838e4da43a3b0751bdcac7fe719f7b4.
>     
>     It causes new build regressions with gcc-4.2 which is
>     pretty common on non-x86 platforms.
>     
>     Reported-by: James Bottomley <James.Bottomley@HansenPartnership.com>
>     Signed-off-by: David S. Miller <davem@davemloft.net>
> 
> and postings that led to this revert including:
> 
> http://marc.info/?l=linux-netdev&m=130653748205263&w=2

Thanks for the pointers; I looked into it a bit deeper and found that the
construct which hppa64-linux-gcc 4.2.4 doesn't like is the combination of
const and __devinitconst __devinitdata.

My patches are minimalistic and don't do any constification and seem to
work fine for PA-RISC.

A possible alternative to allow the use of Michał's reverted patch would
be to conditionalize the definition of __devinitconst.  There is no
user of __devexitconst so I left that unchanged.

  Ralf

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

 include/linux/init.h |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/include/linux/init.h b/include/linux/init.h
index 577671c..e12fd85 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -84,7 +84,15 @@
 /* Used for HOTPLUG */
 #define __devinit        __section(.devinit.text) __cold
 #define __devinitdata    __section(.devinit.data)
+#if defined __GNUC__ && (__GNUC__ == 4) && (__GNUC_MINOR__ == 2)
+/*
+ * GCC 4.2 will sometimes throw an error if the combination of const and
+ * __devinitconst is being used.  As a workaround make __devinitconst a noop
+ */
+#define __devinitconst
+#else
 #define __devinitconst   __section(.devinit.rodata)
+#endif
 #define __devexit        __section(.devexit.text) __exitused __cold
 #define __devexitdata    __section(.devexit.data)
 #define __devexitconst   __section(.devexit.rodata)

Re: [PATCH 00/12] Fix various section mismatches and build errors.

[James Bottomley]

On Wed, 2011-06-29 at 14:07 +0100, Ralf Baechle wrote:
> On Mon, Jun 27, 2011 at 10:12:57PM -0700, David Miller wrote:
> 
> > commit 948252cb9e01d65a89ecadf67be5018351eee15e
> > Author: David S. Miller <davem@davemloft.net>
> > Date:   Tue May 31 19:27:48 2011 -0700
> > 
> >     Revert "net: fix section mismatches"
> >     
> >     This reverts commit e5cb966c0838e4da43a3b0751bdcac7fe719f7b4.
> >     
> >     It causes new build regressions with gcc-4.2 which is
> >     pretty common on non-x86 platforms.
> >     
> >     Reported-by: James Bottomley <James.Bottomley@HansenPartnership.com>
> >     Signed-off-by: David S. Miller <davem@davemloft.net>
> > 
> > and postings that led to this revert including:
> > 
> > http://marc.info/?l=linux-netdev&m=130653748205263&w=2
> 
> Thanks for the pointers; I looked into it a bit deeper and found that the
> construct which hppa64-linux-gcc 4.2.4 doesn't like is the combination of
> const and __devinitconst __devinitdata.
> 
> My patches are minimalistic and don't do any constification and seem to
> work fine for PA-RISC.
> 
> A possible alternative to allow the use of Michał's reverted patch would
> be to conditionalize the definition of __devinitconst.  There is no
> user of __devexitconst so I left that unchanged.

To be honest, my own take on this is that, apart from the compiler
cockups trying to do read only annotations, which affect various
versions of gcc not just the parisc ones, the _devX annotations are
pretty pointless.  They only really do something in the non-hotplug
case, so since 95% of the world seems to use hotplug now and the other
5% doesn't care that much about the odd page of memory (which you rarely
get, since modules sections are accumulated per module, not aggregate),
I'd just favour stripping __init and __exit where there's a problem.

I think we should simply concentrate on __init and __exit; that's where
most of the discard value lies and stop expending huge efforts on the
__devX stuff which adds huge complexity for no real gain.

James

Re: [PATCH 00/12] Fix various section mismatches and build errors.

[Greg KH]

On Wed, Jun 29, 2011 at 08:58:19AM -0500, James Bottomley wrote:
> I think we should simply concentrate on __init and __exit; that's where
> most of the discard value lies and stop expending huge efforts on the
> __devX stuff which adds huge complexity for no real gain.

I have long felt that those __devX markings should just go away as they
cause nothing but problems and have no real gain as you point out.

greg k-h

Re: [PATCH 00/12] Fix various section mismatches and build errors.

[Ralf Baechle]

On Wed, Jun 29, 2011 at 08:14:24AM -0700, Greg KH wrote:

> 
> On Wed, Jun 29, 2011 at 08:58:19AM -0500, James Bottomley wrote:
> > I think we should simply concentrate on __init and __exit; that's where
> > most of the discard value lies and stop expending huge efforts on the
> > __devX stuff which adds huge complexity for no real gain.
> 
> I have long felt that those __devX markings should just go away as they
> cause nothing but problems and have no real gain as you point out.

The suggestion to do that has been floated around before but seems to
have missed sufficient thrust.  I'm all for it; the manual tagging with
__devX has not been very efficient on developer time.  I just want to see
meaningful warnings again over all that noise the current mechanisn may
produce.

  Ralf

Re: [PATCH 00/12] Fix various section mismatches and build errors.

[James Bottomley]

On Wed, 2011-06-29 at 17:19 +0100, Ralf Baechle wrote:
> On Wed, Jun 29, 2011 at 08:14:24AM -0700, Greg KH wrote:
> 
> > 
> > On Wed, Jun 29, 2011 at 08:58:19AM -0500, James Bottomley wrote:
> > > I think we should simply concentrate on __init and __exit; that's where
> > > most of the discard value lies and stop expending huge efforts on the
> > > __devX stuff which adds huge complexity for no real gain.
> > 
> > I have long felt that those __devX markings should just go away as they
> > cause nothing but problems and have no real gain as you point out.
> 
> The suggestion to do that has been floated around before but seems to
> have missed sufficient thrust.  I'm all for it; the manual tagging with
> __devX has not been very efficient on developer time.  I just want to see
> meaningful warnings again over all that noise the current mechanisn may
> produce.

For me, just go ahead and fix the actual problems: so _init sections and
_exit sections that are used from the main body, just strip the
annotations, don't try to change them for _devX ones.

Thanks,

James