1、 What is? buildroot

	 Quote an official passage 		
	Buildroot is a simple, efficient and easy-to-use tool to generate  
embedded Linux systems through cross-compilation.

2、 Basic usage

	 When we download it from the official website buildroot After the source code of , There is nothing we want in it （ Kernel source code ,  
 programmatic C Code and so on , Don't panic at this time , We have no download errors . After doing the following , We can start learning   
 Drive developed .

3、 Download the source code

	 Find a place you like and execute the following commands , If not installed , Please install according to your own system wget Support 

wget https://buildroot.org/downloads/buildroot-2022.02.3.tar.xz && tar xf buildroot-2022.02.3.tar.xz

	 At this point we will buildroot The environment decompression of is completed .

4、 Generate configuration

	 By doing this , If there is no error , Description has been successfully decompressed buildroot Source code . Next, execute with  
 Issue the command to generate the configuration we need .

make qemu_arm_vexpress_defconfig

If your system has installed relevant commands , And there is no error , At this point, you can start compiling the kernel and related environment .

make

	 Be careful , The length of the above compilation time and the configuration of your computer , Related to network speed , If you encounter a software package that cannot be downloaded , build 
 It is recommended to use download software such as Xunlei , Download the file to the computer , Save to dl Execute again in the corresponding directory under the directory 
make

5、 Boot kernel

	 After successful compilation, there will be a prompt as follows 		
>>>   Executing post-image script board/qemu/post-image.sh		
 At this point, execute the following command to start ARM It's a virtual environment .

./output/images/start-qemu.sh --serial-only

	 The kernel source code directory is output/build/linux-5.xx.xx/ in .
	 Modify the kernel configuration command as follows 

make linux-menuconfig

After the modification , Execute the following command to update the kernel

make linux-rebuild && make

	 If there is no error , Start the virtual environment again , The kernel is the new configuration .
	 user name root, No password by default .

	 The default is vexpress-v2p-ca9.dts This device tree file . You can modify the experiment by yourself . After the modification   
 To be implemented make Relevant commands update the new configuration to the environment .