/* syscall-hello.c 
 *   A simple system call, printk and return hard coded into the
 *   kernel.
 * 
 *   We'll use an existing syscall entry (futex) and replace it
 *
 *   Include file locations
 *      <linux> is /usr/src/linux/include/linux
 *      <asm>   is /usr/src/linux/include/asm-i386
 *      <sys>   is part of standard gcc include for making a
 *              general syscall, see man syscall.
 *
 *   Source file locations
 *      sys_call_table[]    /usr/src/linux/arch/i386/kernel/entry.S
 *      system_call         /usr/src/linux/arch/i386/kernel/entry.S
 */


/* kernel programming */
#ifndef LINUX
#define LINUX
#endif

#ifndef __KERNEL__
#define __KERNEL__
#endif

#include <linux/kernel.h>   /* needed for KERN_ALERT */

/* Not used yet */
/* #include <sys/syscall.h>   the list of system calls and syscall function */
/* #include <asm/unistd.h>    pre-defined system call number constants */
/* #include <asm/uaccess.h>   user space memory access functions */


/* prototypes */
asmlinkage void my_syscall_hello(void);


/* My hello world system call */
asmlinkage void my_syscall_hello(void)
{ printk(KERN_ALERT "my_syscall_hello: entering.\n");
  printk(KERN_ALERT "my_syscall_hello: leaving.\n");
}