Linux0.11 copy_process()详解

今天主要解决几个操作系统学习过程中的问题。

1. get_free_page()的代码
2. copy_page_table()的代码
   上个星期杨老师已经详细讲解了copy_process()这个函数，它是一个重要的函数，所以我们先来复习一下。
   由于我们现在要练基本功，我就直接粘贴linux0.11所有的代码，一定要严谨，以便串联起所有的内容。

int copy_process(int nr,long ebp,long edi,long esi,long gs,long none,
		long ebx,long ecx,long edx,
		long fs,long es,long ds,
		long eip,long cs,long eflags,long esp,long ss)
{
   
	struct task_struct *p;      
	int i;
	struct file *f;

	p = (struct task_struct *) get_free_page();//这里是第一次调用get_free_page
	if (!p)
		return -EAGAIN;
	task[nr] = p;   //先从大事开始做
	*p = *current;	/* NOTE! this doesn't copy the supervisor stack */
	p->state = TASK_UNINTERRUPTIBLE;//强制挂起
	p->pid = last_pid;
	p->father = current->pid;
	p->counter = p->priority;
	p->signal = 0;
	p->alarm = 0;
	p->leader = 0;		/* process leadership doesn't inherit */
	p->utime = p->stime = 0;
	p->cutime = p->cstime = 0;
	p->start_time = jiffies;
	p->tss.back_link = 0;
	p->tss.esp0 = PAGE_SIZE + (long) p;
	p->tss.ss0 = 0x10;
	p->tss.eip = eip;
	p->tss.eflags = eflags;
	p->tss.eax = 0;
	p->tss.ecx = ecx;
	p->tss.edx = edx;
	p->tss.ebx = ebx;
	p->tss.esp = esp;
	p->tss.ebp = ebp;
	p->tss.esi = esi;
	p->tss.edi = edi;
	p