How can I build a 2.4 kernel on a 2.6 System

How can I build a 2.4 kernel on a 2.6 System

[j.d.-linux-kernel]

Hello list

I will build some 2.4 kernel modules on a system with a running 2.6 kernel.

Is it possible and how can I do this?

Thanks for reply

Re: How can I build a 2.4 kernel on a 2.6 System

[Willy Tarreau]

Hi,

On Fri, Oct 24, 2008 at 02:16:40PM +0200, j.d.-linux-kernel@arcor.de wrote:
> Hello list
> 
> I will build some 2.4 kernel modules on a system with a running 2.6 kernel.
> 
> Is it possible and how can I do this?

Not sure what you really mean. If you mean build 2.4 modules for 2.4 on
a machine running 2.6, that's OK as there's no dependency between the
running kernel and the one you're building. However, you should be
careful about two things :
  - gcc: it tends to be too recent for 2.4. gcc 4.1 is the highest version
    supported.
  - modutils: most recent distros only ship module-init-tools without the
    old depmod. If you intend to "make modules_install INSTALL_MOD_PATH=..."
    then get prepared to see some errors from depmod at the end. The easiest
    solution consists in getting a depmod from an old machine an installing
    it in /tmp for instance.

Hoping this helps,
Willy

Re: How can I build a 2.4 kernel on a 2.6 System

[Jörg Dohle]

Hello Willy

Thanks for answering, but I have a problem with the compiling.
When I try to compile the 2.4 kernel with the following commands:

# make clean && make mrproper
then I restore the .config file
# make oldconfig
# make dep && make bzImage respectively make modules


 I get the following error message:

make[1]: Leaving directory 
`/fileserver/99_Frei/kernel-build-tree/linux-2.4.21-57.EL'
gcc -D__KERNEL__ -I/fileserver/99_Frei/kernel-build-tree/linux-2.4.21-57.EL/include 
 -Wall -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common 
  -Wno-unused -fomit-frame-pointer -pipe -freorder-blocks  -march=i386   -DKBUILD_BASENAME=main 
 -c -o init/main.o init/main.c
init/main.c:1: Fehler: Die ausgewählte CPU unterstützt nicht den x86-64 
Befehlssatz

English translation (by google)
init / main.c: 1: Error: The selected CPU does not support x86-64 
instruction


I use a x86_64 system with a 2.6.16.60-0.31-smp kernel for compiling 2.4 
kernel modules.

I think some compiler information are missing for make.

Could you help me?


----- Original Message ----- 
From: "Willy Tarreau" <w@1wt.eu>
To: <j.d.-linux-kernel@arcor.de>
Cc: <linux-kernel@vger.kernel.org>
Sent: Friday, October 24, 2008 9:29 PM
Subject: Re: How can I build a 2.4 kernel on a 2.6 System


> Hi,
>
> On Fri, Oct 24, 2008 at 02:16:40PM +0200, j.d.-linux-kernel@arcor.de 
> wrote:
>> Hello list
>>
>> I will build some 2.4 kernel modules on a system with a running 2.6 
>> kernel.
>>
>> Is it possible and how can I do this?
>
> Not sure what you really mean. If you mean build 2.4 modules for 2.4 on
> a machine running 2.6, that's OK as there's no dependency between the
> running kernel and the one you're building. However, you should be
> careful about two things :
>  - gcc: it tends to be too recent for 2.4. gcc 4.1 is the highest version
>    supported.
>  - modutils: most recent distros only ship module-init-tools without the
>    old depmod. If you intend to "make modules_install 
> INSTALL_MOD_PATH=..."
>    then get prepared to see some errors from depmod at the end. The 
> easiest
>    solution consists in getting a depmod from an old machine an installing
>    it in /tmp for instance.
>
> Hoping this helps,
> Willy
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> 

Re: How can I build a 2.4 kernel on a 2.6 System

[Willy Tarreau]

On Sun, Oct 26, 2008 at 11:32:17AM +0100, Jörg Dohle wrote:
> Hello Willy
> 
> Thanks for answering, but I have a problem with the compiling.
> When I try to compile the 2.4 kernel with the following commands:
> 
> # make clean && make mrproper
> then I restore the .config file
> # make oldconfig
> # make dep && make bzImage respectively make modules
> 
> 
> I get the following error message:
> 
> make[1]: Leaving directory 
> `/fileserver/99_Frei/kernel-build-tree/linux-2.4.21-57.EL'

OK, first it's an RHEL3 kernel, not a mainline one. The difference can
sometimes be important.

> gcc -D__KERNEL__ 
> -I/fileserver/99_Frei/kernel-build-tree/linux-2.4.21-57.EL/include -Wall 
> -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common 
>  -Wno-unused -fomit-frame-pointer -pipe -freorder-blocks  -march=i386   
>  -DKBUILD_BASENAME=main -c -o init/main.o init/main.c
> init/main.c:1: Fehler: Die ausgewählte CPU unterstützt nicht den x86-64 
> Befehlssatz
> 
> English translation (by google)
> init / main.c: 1: Error: The selected CPU does not support x86-64 
> instruction

You might get native error messages by doing "export LANG=C" before
building. I think that the problem you're encountering is simply
because by default you're trying to build for a different architecture.

You should try appending "ARCH=i386" to all your make commands :

# make oldconfig ARCH=i386
# make dep ARCH=i386 && make bzImage ARCH=i386
# make modules ARCH=i386

It should theorically work, but since this is not used very often, it is
possible that you still get minor trouble.

Regards,
Willy