You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/rCore/kernel/src/arch/aarch64
    
    the code of the file until where you have to start completion: //! Entrance and initialization for aarch64.

use core::sync::atomic::{spin_loop_hint, AtomicBool, Ordering};

mod boot;
pub mod consts;
pub mod cpu;
pub mod fp;
pub mod interrupt;
pub mod io;
pub mod memory;
pub mod paging;
pub mod rand;
pub mod signal;
pub mod syscall;
pub mod timer;

#[cfg(feature = "board_raspi3")]
#[path = "board/raspi3/mod.rs"]
pub mod board;

static AP_CAN_INIT: AtomicBool = AtomicBool::new(false);

/// The entry 
    
pub extern "C" fn main_start() -> ! {
    // start up other CPUs
    unsafe { cpu::start_others() };

    crate::logging::init();
    unsafe {
        trapframe::init();
    }
    memory::init();

    board::early_init();
    println!("Hello {}! from CPU {}", board::BOARD_NAME, cpu::id());

    board::early_final();
    crate::lkm::manager::ModuleManager::init();
    board::init();

    crate::process::init();

    // wake up other CPUs
    AP_CAN_INIT.store(true, Ordering::Relaxed);

    crate::kmain();
}