Error in compiling Linux kernel after creating hello world system call

[Jackson Isaac]

Hi everyone,

I am trying to write hello world system call in linux but I am
encountering the following error when I run 'sudo make':

  ...
  AR      arch/x86/lib/lib.a
  LINK    vmlinux
  LD      vmlinux.o
ld: cannot find hello: File format not recognized
make: *** [vmlinux] Error 1

I have Linux 3.15.6 in my home directory and have created a hello
folder in it. I also made changes to makefile, syscalls.h, and
syscall_64.tbl

in make file I replaced

core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/
with
core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/ hello

Can anyone point out where I am going wrong. I have made the changes
first and then I am trying 'sudo make'.

I tried making some minor modifications and running it again 3 4 times
but getting the same error and also it takes 2-3 hours of time.

Jackson Isaac
S5 B.Tech CSE
Amrita Vishwa Vidyapeetham
Jackson Isaac's Blog
Github/JacksonIsaac