Problem for "insmod: unresolved symbol printk"

Problem for "insmod: unresolved symbol printk"

[Zhou Rui]

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Hi, all
    I'm a newbie for linuxppc. I've tried to write a simple hello.c as a kernel module.

/*hello.c*/
#ifndef MODULE
#define MODULE
#endif

#ifndef __KERNEL__
#define __KERNEL__
#endif

#include <linux/module.h>
#include <linux/kernel.h>

int init_module(void)
{
        printk("Hello world 1.\n");
        return 0;
}

void cleanup_module(void)
{
        printk("Goodbye world 1.\n");
}

I wrote the code on a machine with Slackware installed. There was a PowerPC405EP board connected to the machined with NFS used. On the PowerPC board, the kernel is linuxppc-2.4.25-rthal5 and can be logged in via telnet. On the machine, there was also a toolchain for PowerPC and there were a series of commands beginning with "powerpc-linux-" existing. I've tried to cross-compile the source file with "powerpc-linux-gcc -c hello.c" or "powerpc-linux-gcc -c -DMODVERSIONS -I/usr/src/linuxppc-2.4.25/include hello.c" for PowerPC. But when I telneted into the board and run "insmod hello.o" on the PowerPC board, there always was "insmod: unresolved symbol printk". So would anyone give me some advice about the problem? Thank you very much.

 		
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Re: Problem for "insmod: unresolved symbol printk"

[Olof Johansson]

On Thu, Jun 22, 2006 at 10:31:56PM +0800, Zhou Rui wrote:
> Hi, all
>     I'm a newbie for linuxppc. I've tried to write a simple hello.c as a kernel module.

Hi,

http://kernelnewbies.org/  should have information on kernel module
basics, and where to find help if you still have problems.


-Olof

Re: Problem for "insmod: unresolved symbol printk"

[Zhou Rui]

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Hi,
    My host machine kernel was 2.4.28 and the PowerPC board was 2.4.25-rthal5. I followed  the Standard Makefile for 2.4(<=) kernels on the page http://kernelnewbies.org/FAQ/LinuxKernelModuleCompile?highlight=%28insmod%29, and do some changes based on my situation:

TARGET := hello
INCLUDE := -I/lib/modules/2.4.25-rthal5/build/include
CFLAGS := -O2 -Wall -DMODULE -D__KERNEL__ -DLINUX
CC := powerpc-linux-gcc

${TARGET}.o: ${TARGET}.c
        $(CC) $(CFLAGS) ${INCLUDE} -c ${TARGET}.c

The problem is still "insmod: unresolved symbol printk". But when I logged in the PowerPC board, and # fgrep 'printk' /proc/ksyms, there was "c0015500 printk_Rdd132261".



Olof Johansson <olof@lixom.net> ： On Thu, Jun 22, 2006 at 10:31:56PM +0800, Zhou Rui wrote:
> Hi, all
>     I'm a newbie for linuxppc. I've tried to write a simple hello.c as a kernel module.

Hi,

http://kernelnewbies.org/  should have information on kernel module
basics, and where to find help if you still have problems.


-Olof



Zhou Rui
Distributed & Embedded System Lab
School of Information Science & Engineering
Lanzhou University, P. R. China
http://dslab.lzu.edu.cn/~zr/
 		
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