Took a time compiling linux kernel. I don't know why, but somehow version 4.11 does not boot properly. It's forever rebooting itself. I tried to fix it but later just used latest version. Now everything's fine. 6.7.2 is very stable and was able to boot it successfully.

I was quite astonished by the strict organization of system in linux kernel. It felt like everything is possible in that state of operating system. It was true technological marvel.. Anyways, while I was tweaking things in kernel, I figured out that linux governs system call with some kind of external script. Basically, there's a '.tbl' file that has all the name for handlers corresponding to each system calls. It's very interesting structure, and now I have to figure out how to modify that structure.