一、安裝工具：
$ sudo apt-get install vim openssh-server net-tools nfs-kernel-server git qemu crash \
build-essential libncurses-dev libssl-dev gcc-arm-linux-gnueabi gcc-aarch64-linux-gnu systemtap
二、下載源碼：
linux-4.15.10
busybox-1.28.1
三、製作根文件系統：
$ cd busybox-1.28.1
$ export ARCH=arm
$ export CROSS_COMPILE=arm-linux-gnueabi-
$ make menuconfig
$ make -j8
$ make install
注意：make menuconfig時,
- Settings ---> [*] Build BusyBox as a static binary (no shared libs)
- Settings ---> (../linux-4.15.10/rootfs_arm32) Destination path for 'make install'
$ cd ../linux-4.15.10/rootfs_arm32
$ mkdir dev sys proc etc tmp var mnt root
$ cd dev
$ sudo mknod console c 5 1
$ sudo mknod tty1 c 4 1
$ sudo mknod tty2 c 4 2
$ sudo mknod tty3 c 4 3
$ sudo mknod tty4 c 4 4
$ sudo mknod null c 1 3
$ cd ../etc
$ mkdir init.d
$ cd init.d
$ vim rcS
$ chmod 0755 rcS
注意：rcS的內容爲
#!/bin/sh
mount -t proc proc /proc
mount -t sysfs sysfs /sys
/sbin/mdev -s
四、編譯ARM32內核：
$ export ARCH=arm
$ export CROSS_COMPILE=arm-linux-gnueabi-
$ make vexpress_defconfig
$ make menuconfig
$ make bzImage -j8
$ make dtbs
注意：make menuconfig時，
- General setup ---> (rootfs_arm32) Initramfs source file(s)
即，CONFIG_INITRAMFS_SOURCE=“rootfs_arm32"
五、運行ARM32內核：
$ qemu-system-arm -M vexpress-a9 -smp 2 -m 1024M -kernel arch/arm/boot/zImage -append "rdinit=/linuxrc console=ttyAMA0 loglevel=8” -dtb arch/arm/boot/dts/vexpress-v2p-ca9.dtb -nographic
六、製作ARM64根文件系統：
$ cd busybox-1.28.1
$ export ARCH=arm64
$ export CROSS_COMPILE=aarch64-linux-gnu-
$ make menuconfig
$ make -j8
$ make install
注意：make menuconfig時,
- Settings ---> [*] Build BusyBox as a static binary (no shared libs)
- Settings ---> (../linux-4.15.10/rootfs_arm64) Destination path for 'make install'
$ cd ../linux-4.15.10/rootfs_arm64
$ mkdir dev sys proc etc tmp var mnt root
$ sudo cp -r ../rootfs_arm32/dev/* rootfs_arm64/dev/
$ sudo cp -r ../rootfs_arm32/etc/* rootfs_arm64/etc/
七、編譯ARM64內核：
$ export ARCH=arm64
$ export CROSS_COMPILE=aarch64-linux-gnu-
$ make defconfig
$ make menuconfig
$ make -j8
注意：make menuconfig時，
- General setup ---> (rootfs_arm64) Initramfs source file(s)
即，CONFIG_INITRAMFS_SOURCE="rootfs_arm64”
八、運行ARM64內核：
$ qemu-system-aarch64 -M virt -cpu cortex-a57 -nographic -m 2048M -smp 2 -kernel arch/arm64/boot/Image -append "rdinit=/linuxrc console=ttyAMA0 loglevel=8" -nographic
九、配置nfs:
$ sudo mkdir /nfsroot
$ sudo chmod 0777 /nfsroot
$ sudo vim /etc/exports
$ /etc/init.d/nfs-kernel-server restart
在/etc/exports尾部加一行:
/nfsroot *(rw,sync,no_root_squash,no_subtree_check)