System Call Problem

[Hall, Luca]

Hello I have a small problem with a new sys call: 

Slackware 8 , Kernel 2.2.19
tring to add a system call i did:

/usr/src/linux/kernel/luca.c

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

asmlinkage int sys_luca(void){
        printk("my call in the kernel\n");
        return(555);

}

/usr/src/linux/include/linux/luca.h

#ifndef __LINUX_LUCA_H
#define __LINUX_LUCA_H

#include <linux/linkage.h>
#include <linux/unistd.h>

_syscall0(int,luca)

#endif

/usr/src/linux/include/asm-i386/unistd.h

added: #define __NR_luca               191

/usr/src/linux/arch/i386/kernel/entry.S

added: .long SYMBOL_NAME(sys_luca)
changed from 190: .rept NR_syscalls-191

compiled with make dep, make bzImage

The problem is now that when I boot i see the printk messages at the 
bottom. around 5 - 7 times.
When I log in I see the printk messages, and dmesg also. I checked many 
resources and cant seem too find what I'm doing wrong; why is my funct being
called at boot time and 
login ?

thanks alot
luca