1. Open sysproc.c file and add the two system calls.

//Add this where the other system calls are defined in syscall.c

extern int sys_cps(void);

extern int sys_chpr(void);

/*
	.
	.
	.
	*/
	//Add this inside static int (*syscalls[])(void)
	[SYS_cps] sys_cps,
	[SYS_chpr] sys_chpr,

2. Create a ps.c and nice.c file in which the cps and chpr functions will be called respectively.

#include "types.h"
	#include "stat.h"
	#include "user.h"
	#include "fcntl.h"
	int main(void){
	cps();
	exit();
	}

#include "types.h"
	#include "stat.h"
	#include "user.h"
	#include "fcntl.h"
	int
	main(int argc, char *argv[])
	{
	int priority, pid;
	if(argc < 3){
	printf(2,"Usage: nice pid priority ");
	exit();
	}
	pid = atoi(argv[1]);
	priority = atoi(argv[2]);
	if (priority < 0 || priority > 20){
	printf(2,"Invalid priority (0-20)! ");
	exit();
	}
	chpr(pid, priority);
	exit();
	}

Can someone help me to solve it using ubuntu, please? My laptop is broken please help me?