zhaojh329 / mykernel

mykernel 2.0: Develop your own OS kernel by reusing Linux infrastructure, based on x86-64/Linux Kernel 5.4.34.

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Welcome to the mykernel 2.0

Develop your own OS kernel by reusing Linux infrastructure, based on x86-64/Linux Kernel 5.4.34.

mykernel 1.0 based on IA32/Linux Kernel 3.9.4.

Set up mykernel 2.0 in Ubuntu 18.04

wget https://raw.github.com/mengning/mykernel/master/mykernel-2.0_for_linux-5.4.34.patch
sudo apt install axel
axel -n 20 https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/linux-5.4.34.tar.xz
xz -d linux-5.4.34.tar.xz
tar -xvf linux-5.4.34.tar
cd linux-5.4.34
patch -p1 < ../mykernel-2.0_for_linux-5.4.34.patch
sudo apt install build-essential libncurses-dev bison flex libssl-dev libelf-dev
make defconfig # Default configuration is based on 'x86_64_defconfig'
# 使用allnoconfig编译出来qemu无法加载启动,不知道为什么?有明白的告诉我,完整编译太慢了,消耗的资源也多。
make -j$(nproc) # 编译的时间比较久哦
sudo apt install qemu # install QEMU
qemu-system-x86_64 -kernel arch/x86/boot/bzImage

感谢meilihao 提交了pr #14 ,通过如下方法可以解决allnoconfig编译出来qemu无法加载启动的问题

$ make allnoconfig
$ make menuconfig
 General setup ---> Configure standard kernel features ---> Enable support for printk ---> yes
 64-bit kernel ---> yes # 如果不需要64bit支持, 这个也可不要
 Device Drivers ---> Character devices ---> Enable TTY ---> yes

从qemu窗口中您可以看到my_start_kernel在执行,同时my_timer_handler时钟中断处理程序周期性执行。

进入mykernel目录您可以看到qemu窗口输出的内容的代码mymain.c和myinterrupt.c。当前有一个CPU执行C代码的上下文环境,同时具有中断处理程序的上下文环境,我们通过Linux内核代码模拟了一个具有时钟中断和C代码执行环境的硬件平台。

您只要在mymain.c基础上继续写进程描述PCB和进程链表管理等代码,在myinterrupt.c的基础上完成进程切换代码,一个可运行的小OS kernel就完成了。start to write your own OS kernel, enjoy it!

  • mykernel-2.0 patch generated by this command:
    • diff -Naur linux-5.4.34 linux-5.4.34-mykernel > mykernel-2.0_for_linux-5.3.34.patch

your own OS kernel example code

  • mypcb.h、mymain.c和myinterrupt.c实现了一个简单的时间片轮转调度进程的精简内核,如下为进程上下文切换的关键代码(视频讲解):
    	printk(KERN_NOTICE ">>>switch %d to %d<<<\n",prev->pid,next->pid);  
    	/* switch to next process */
    	asm volatile(	
        	"pushq %%rbp\n\t" 	    /* save rbp of prev */
        	"movq %%rsp,%0\n\t" 	/* save rsp of prev */
        	"movq %2,%%rsp\n\t"     /* restore  rsp of next */
        	"movq $1f,%1\n\t"       /* save rip of prev */	
        	"pushq %3\n\t" 
        	"ret\n\t" 	            /* restore  rip of next */
        	"1:\t"                  /* next process start here */
        	"popq %%rbp\n\t"
        	: "=m" (prev->thread.sp),"=m" (prev->thread.ip)
        	: "m" (next->thread.sp),"m" (next->thread.ip)
    	); 

Comments

  • mykernel这样一个短小精悍的模拟内核,时常给我提供了看问题的角度和思路。当被庞杂的Linux内核代码弄得一头雾水时,我就去看看mykernel,很多复杂的问题就可以用简单的机制解释。——pianogirl

采用mykernel的课程和项目

Licensing

under GNU GPL v2, or Contact us 微信公众号互动二维码

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mykernel 2.0: Develop your own OS kernel by reusing Linux infrastructure, based on x86-64/Linux Kernel 5.4.34.


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