Function syscall_1_nr 

pub unsafe extern "C" fn syscall_1_nr(
    syscall: usize,
    syscall_name: SyscallName,
    from_host: *mut u32,
    from_host_words: usize,
    a3: u32,
) -> Return

Invoke a raw system call

Safety

from_host must be aligned and dereferenceable.