Linux-内核编译

一、下载源码

执行以下命令下载kernel源码

wget https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.5.6.tar.xz

然后解压压缩包，接着cd到kernel目录中

二、编译配置环境

编译kernel需要很多库，所以请执行以下命令安装库

sudo apt-get install libncurses* build-essential openssl zlibc minizip libidn11-dev libidn11 libssl-dev flex libelf-dev

三、Kernel编译配置

接下来开始配置kernel编译参数

make menuconfig

配置好了,保存为.config即可

四、开始编译

make
如果想要编译的更快可以用以下指令
make -j8

五、制作启动程序和文件系统

将下面的c代码静态编译，如果不静态编译的话，由于我们的文件系统中没有lib环境会导致程序没有对应的ld和libc无法启动。

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
void init(){
	setbuf(stdin,0);
	setbuf(stdout,0);
	setbuf(stderr,0);
}
int main(){
	init();
	printf("Hello World(Kernel init)");
	return 0;
}

制作rootfs

echo c程序的名字 | cpio -o --format=newc > rootfs

编译好了之后进入arch目录在x86_64文件夹内找到bzImage，将其单独取出来，然后放到自己的目录里，接下来开始启动kernel

qemu-system-x86_64   \
        -kernel ./bzImage_x86_64 \
        -initrd ./rootfs  \
        -append "root=/dev/ram rdinit=/c程序的名字 console=ttyS0"   \
        -nographic

当然为了方便起见，可以将上述代码写入到shell脚本中，便于下次的启动。

运行之后你会在log中发现输出Hello World(Kernel init)

六、将Kernel放置到/lib/modules下

由于我们可能需要开发ko文件，需要将内核放到/lib/modules下

cd 编译好的kernel目录
make modules_instal

拓展指令

cd /xxxx/linux-4.18.8	//切换到你解压源码的文件夹
make mrproper 		//清除编译过程中产生的所有中间文件
make clean 	 	//清除上一次产生的编译中间文件
make menuconfig	//图形化界面，方便选择一些功能

[本文章可能存在出现的问题]

make menuconfig可能出现的问题

问题1: 3.14.38内核
root@simon-virtual-machine:/home/simon/FeiLing/src/linux-3.14.38# make menuconfig
*** Unable to find the ncurses libraries or the
*** required header files.
*** 'make menuconfig' requires the ncurses libraries.
*** 
*** Install ncurses (ncurses-devel) and try again.
*** 
/home/simon/FeiLing/src/linux-3.14.38/scripts/kconfig/Makefile:199: recipe for target 'scripts/kconfig/dochecklxdialog' failed
make[1]: *** [scripts/kconfig/dochecklxdialog] Error 1
Makefile:512: recipe for target 'menuconfig' failed
make: *** [menuconfig] Error 2

答案1: sudo apt-get install ncurses-devel

 

问题2: 4.17.2内核
root@simon-virtual-machine:/home/simon/Src/linux-4.17.2# make menuconfig
YACC scripts/kconfig/zconf.tab.c
/bin/sh: 1: bison: not found
scripts/Makefile.lib:196: recipe for target 'scripts/kconfig/zconf.tab.c' failed
make[1]: *** [scripts/kconfig/zconf.tab.c] Error 127
Makefile:528: recipe for target 'menuconfig' failed
make: *** [menuconfig] Error 2

答案2：apt-get install bison -y


问题3:
root@simon-virtual-machine:/home/simon/Src/linux-4.17.2# make menuconfig
YACC scripts/kconfig/zconf.tab.c
LEX scripts/kconfig/zconf.lex.c
/bin/sh: 1: flex: not found
scripts/Makefile.lib:188: recipe for target 'scripts/kconfig/zconf.lex.c' failed
make[1]: *** [scripts/kconfig/zconf.lex.c] Error 127
Makefile:528: recipe for target

答案3: sudo apt-get install flex


问题4: 5.5.6内核
root@ubuntu:/home/robye/Kernel/linux-5.5.6# make menuconfig
*
* Unable to find the ncurses package.
* Install ncurses (ncurses-devel or libncurses-dev
* depending on your distribution).
*
* You may also need to install pkg-config to find the
* ncurses installed in a non-default location.
*
scripts/kconfig/Makefile:212: recipe for target 'scripts/kconfig/mconf-cfg' failed
make[1]: *** [scripts/kconfig/mconf-cfg] Error 1
Makefile:568: recipe for target 'menuconfig' failed
make: *** [menuconfig] Error 2

答案4: sudo apt-get install libncurses5-dev


问题4: 
root@ubuntu:/home/robye/Kernel/linux-5.5.6# make
"CANNOT GENERATE ORC METADATA FOR CONFIG_UNWINDER_ORC=Y, PLEASE INSTALL LIBELF-DEV, LIBELF-DEVEL OR ELFUTILS-LIBELF-DEVEL". STOP.
答案4: 
Ubuntu:
	sudo apt install libelf-dev
CentOS:
	yum install elfutils-libelf-devel