System call service routine and interrupt context

Hi, My question is, do all the code of interrupt handler in system call gets executed in interrupt context? System calls generate software interrupts. So when I do open() syscall it we call do_sys_open() handler which will eventually call file system specific open function call. Will all this happen in interrupt context until I get open file descriptor in user land? If not when does context change? Thanks and regards, Pritam Bankar