2.6.25.4-rt2 compile errors on ARM due to cmpxchg() problems.

2.6.25.4-rt2 compile errors on ARM due to cmpxchg() problems.

[Remy Bohmer]

Hello Steven,

I want to test 2.6.25.4-rt2 on ARM, but unfortunately I run into
several compile errors.
All errors seem to be related to cmpxchg routines -> duplicate
definitions or missing BUILD_BUG_ON() or typecheck() macros.
I already figured out the missing BUILD_BUG_ON() + typecheck() problem
which is caused by including a header
'include/asm-generic/cmpxchg-local.h' in linux/kernel.h before these
macros are defined in linux/kernel.h. See below for a piece/snippet of
the compiler output.

Looking deeper into this, things look quite messy around cmpxchg() on ARM...

Any ideas what has been changed here, and why these things can go
wrong so badly?


Kind Regards,

Remy

---- 8-< ----
In file included from include/linux/rt_lock.h:14,
                 from include/linux/spinlock.h:117,
                 from include/linux/mmzone.h:7,
                 from include/linux/gfp.h:4,
                 from include/linux/slab.h:14,
                 from include/linux/percpu.h:5,
                 from include/linux/kernel_stat.h:7,
                 from arch/arm/kernel/irq.c:24:
include/asm/atomic.h:241:1: warning: "cmpxchg" redefined
In file included from include/asm/system.h:378,
                 from include/asm/bitops.h:27,
                 from include/linux/bitops.h:17,
                 from include/linux/kernel.h:32,
                 from include/linux/cpumask.h:84,
                 from include/linux/smp.h:10,
                 from include/linux/kernel_stat.h:5,
                 from arch/arm/kernel/irq.c:24:
include/asm-generic/cmpxchg.h:19:1: warning: this is the location of
the previous definition
In file included from include/asm/system.h:366,
                 from include/linux/list.h:9,
                 from include/linux/module.h:9,
                 from arch/arm/kernel/process.c:13:
include/asm-generic/cmpxchg-local.h: In function '__cmpxchg_local_generic':
include/asm-generic/cmpxchg-local.h:23: error: implicit declaration of
function 'BUILD_BUG_ON'
include/asm-generic/cmpxchg-local.h:23: error: implicit declaration of
function 'typecheck'
include/asm-generic/cmpxchg-local.h:23: error: expected expression
before 'unsigned'
include/asm-generic/cmpxchg-local.h:44: error: expected expression
before 'unsigned'
include/asm-generic/cmpxchg-local.h: In function '__cmpxchg64_local_generic':
include/asm-generic/cmpxchg-local.h:57: error: expected expression
before 'unsigned'
include/asm-generic/cmpxchg-local.h:61: error: expected expression
before 'unsigned'
---- 8-< ----

Re: 2.6.25.4-rt2 compile errors on ARM due to cmpxchg() problems.

[Steven Rostedt]

On Tue, 20 May 2008, Remy Bohmer wrote:

> Hello Steven,
>
> I want to test 2.6.25.4-rt2 on ARM, but unfortunately I run into
> several compile errors.
> All errors seem to be related to cmpxchg routines -> duplicate
> definitions or missing BUILD_BUG_ON() or typecheck() macros.
> I already figured out the missing BUILD_BUG_ON() + typecheck() problem
> which is caused by including a header
> 'include/asm-generic/cmpxchg-local.h' in linux/kernel.h before these
> macros are defined in linux/kernel.h. See below for a piece/snippet of
> the compiler output.
>
> Looking deeper into this, things look quite messy around cmpxchg() on ARM...
>
> Any ideas what has been changed here, and why these things can go
> wrong so badly?
>

No idea right off the bat. But I may be needing to set up a ARM
crosscompiler. Unless Thomas would like to take a look into this.

Thomas?

-- Steve

Re: 2.6.25.4-rt2 compile errors on ARM due to cmpxchg() problems.

[Robert Schwebel]

Hi Steven,

On Tue, May 20, 2008 at 10:34:54AM -0400, Steven Rostedt wrote:
> No idea right off the bat. But I may be needing to set up a ARM
> crosscompiler. Unless Thomas would like to take a look into this.

If you need an ARM cross compiler, you can for example use ptxdist to
setup an OSELAS.Toolchain:

http://www.pengutronix.de/oselas/toolchain/index_en.html

The current well tested revisions are based on 4.1.2, but -trunk does
also contain (work-in-progress) top-of-tree versions.

rsc
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
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     Hannoversche Str. 2, 31134 Hildesheim, Germany
   Phone: +49-5121-206917-0 |  Fax: +49-5121-206917-9

Re: 2.6.25.4-rt2 compile errors on ARM due to cmpxchg() problems.

[Remy Bohmer]

Hello All,

2008/5/20, Robert Schwebel <r.schwebel@pengutronix.de>:
> Hi Steven,
>  On Tue, May 20, 2008 at 10:34:54AM -0400, Steven Rostedt wrote:
>  > No idea right off the bat. But I may be needing to set up a ARM
>  > crosscompiler. Unless Thomas would like to take a look into this.
>
> If you need an ARM cross compiler, you can for example use ptxdist to
>  setup an OSELAS.Toolchain:

In that case, here are my 2 cents ;-)))

If you do not want to bother building a compiler toolchain and just
want to have a compiler very quickly, you can also download the
precompiled Codesourcery compiler toolchain for ARM for free...
http://www.codesourcery.com/gnu_toolchains/arm/download.html

They provide toolchains for PowerPC and MIPS too...
(Always handy for cross compile checks)


Kind Regards,

Remy