目录

 通过实验楼配置mykernel环境

 初始运行结果​

添加mypcb.h

 修改mymain.c与汇编语言分析

 修改myinterrupt.c与汇编语言分析

修改代码后运行结果

总结

 通过实验楼配置mykernel环境

# 注意路径是区分大小的
$ cd ~/LinuxKernel/linux-3.9.4

$ rm -rf mykernel

$ patch -p1 < ../mykernel_for_linux3.9.4sc.patch

$ make allnoconfig

# 编译内核请耐心等待
$ make

$ qemu -kernel arch/x86/boot/bzImage

 初始运行结果

添加mypcb.h

#define MAX_TASK_NUM        4
#define KERNEL_STACK_SIZE   1024*2

struct Thread {
        unsigned long       ip;
            unsigned long       sp;
};

typedef struct PCB{
        int pid;
            volatile long state;    
                unsigned long stack[KERNEL_STACK_SIZE];
                    
                    struct Thread thread;
                        unsigned long   task_entry;
                            struct PCB *next;
}tPCB;

void my_schedule(void);

 修改mymain.c与汇编语言分析

#include 
#include 
#include 
#include 
#include 


#include "mypcb.h"

tPCB task[MAX_TASK_NUM];
tPCB * my_current_task = NULL;
volatile int my_need_sched = 0;

void my_process(void);


void __init my_start_kernel(void)
{
    int pid = 0;
    int i;
    
    task[pid].pid = pid;
    task[pid].state = 0;
    task[pid].task_entry = task[pid].thread.ip = (unsigned long)my_process;
    task[pid].thread.sp = (unsigned long)&task[pid].stack[KERNEL_STACK_SIZE-1];
    task[pid].next = &task[pid];
    
    for(i=1;ipid);
            if(my_need_sched == 1)
            {
                my_need_sched = 0;
        	    my_schedule();
        	}
        	printk(KERN_NOTICE "this is process %d +n",my_current_task->pid);
        }     
    }
}

 修改myinterrupt.c与汇编语言分析

#include 
#include 
#include 
#include 
#include 

#include "mypcb.h"

extern tPCB task[MAX_TASK_NUM];
extern tPCB * my_current_task;
extern volatile int my_need_sched;
volatile int time_count = 0;

void my_timer_handler(void)
{
    if(time_count%1000 == 0 && my_need_sched != 1)
    {
        printk(KERN_NOTICE ">>>my_timer_handler here<<next == NULL)
    {
    	return;
    }
    printk(KERN_NOTICE ">>>my_schedule<<next;
    prev = my_current_task;
    if(next->state == 0)                  
    { 
        asm volatile(   
            "pushl %%ebpnt"          
            "movl %%esp,%0nt"    
            "movl %2,%%espnt"   
            "movl $1f,%1nt"           
            "pushl %3nt"               
            "retnt"                          
            "1:t"                              
            "popl %%ebpnt"           
            : "=m" (prev->thread.sp),"=m" (prev->thread.ip)
            : "m" (next->thread.sp),"m" (next->thread.ip)
        ); 
        my_current_task = next; 
        printk(KERN_NOTICE ">>>switch %d to %d<<pid,next->pid);      
    }
else                                        
    {
        next->state = 0;
        my_current_task = next;
        printk(KERN_NOTICE ">>>switch %d to %d<<pid,next->pid);
        
        asm volatile(   
            "pushl %%ebpnt"         
            "movl %%esp,%0nt"      
            "movl %2,%%espnt"      
            "movl %2,%%ebpnt"      
            "movl $1f,%1nt"             
            "pushl %3nt"                   
            "retnt"                             
            : "=m" (prev->thread.sp),"=m" (prev->thread.ip)
            : "m" (next->thread.sp),"m" (next->thread.ip)
        );          
    }   

    return;	
}

修改代码后运行结果

总结

操作系统的三大法宝是存储程序结构、函数调用、中断，本实验中点探究了操作系统实现终端的过程。