Displaying Hello World after the boot loader process [closed]

Question

I have my odroid-s that uses u-boot. After the u-boot do the processes, u-boot will jump to the kernel entry point.

What I'm trying to do here is, I am trying to modify the Linux kernel.

asmlinkage void __init start_kernel(void){
   ...
}

I found out that display comes out after console_init() finishes. I want to change my kernel just to print "Hello world" but do nothing else (like initializing memory manager or scheduler...).