Adding System Call

Hi

These are the steps to add system call to the linux kernel 2.6.39.4

1. Download source code http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.39.4.tar.bz2

2. Open file linux-2.6.39/arch/x86/kernel/syscall_table_32.S

add line

.long sys_add2

3. Open linux-2.6.39/arch/x86/include/asm/unistd_32.h

After Line

#define __NR_syncfs 344

Add line

#define __NR_add2 345

and also change NR_syscalls to

#define NR_syscalls 346

4. Now edit linux-2.6.39/arch/x86/include/asm/unistd_64.h

   Find Lines

   #define __NR_syncfs 306

   __SYSCALL(__NR_syncfs, sys_syncfs)

   Add Line

   #define __NR_add2 307

   __SYSCALL(__NR_add2,sys_add2)

5. open file linux-2.6.39/include/linux/syscalls.h

   before #endif add

   asmlinkage long sys_add2(int i,int j);

6. Now create add2.c

   linux-2.6.39/kernel/add2.c

   #include

   asmlinkage long sys_add2(int i,int j)

   {

   return i+j;

   }

7. Now open the Makefile in this folder(linux-2.6.39/kernel/Makefile) and find out

   obj-y += groups.o

   Add a new line before this line :

   obj-y += add2.o

8. Now its Time to compile kernel

   Go to linux-2.6.39/

   $make

9. Start compiling to kernel modules:

$make modules

10. Install kernel modules

    su -

    $make modules_install

11. It is time to install kernel itself

    $make install

12. $update-grub