kOS doesn't use the Linux kernel code. It supports a few of the same syscalls:

clone, execve(!), epoll_create, epoll_ctl, epoll_wait, dup2, stat, rename, unlink, getcwd, chdir, fstat, getdents, open, close, read, write, ftruncate, mmap2, munmap, ioctl, gettimeofday, socket, bind, connect, listen, acccept, socketpair, setsockopt

execve just runs another k interpreter (regardless of what you tell it to do) though, so it can just be used to run more k programs.