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

$ 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

    	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)
    	);