mm.c

用于汇编领域的,运用于OS的MAIN函数.基于硬件基础的源代码

#include "../hos.h"
void init_mm(){
   int i;
   // do some preparation for mm
   init_mem_map();
   // we assume 1st Mega (first 256 frames) is already occupied by kernel
   for(i=0;i<256;i++)
      mem_map[i].count=1;
}

void set_page_table(struct task_struct *p, unsigned long sloc){
// process p is located physically at sloc. set page directory
// and page table properly. we assume all processes is less than 1 page
   unsigned long * dir0;
   dir0 = (unsigned long *)get_free_pgframe(); 
                              // location of free page frame. use this frame
                              // as dir 0 for current process
   // copy swapper_dir0 to dir0 to represent kernel
   mymemcpy(dir0, swapper_dir0, PGSIZE);
   p->mm.pgdir[0]=(unsigned long)dir0 | 0x03;
   printk("in set page table. pid %d, pgdir[0] is %x\n",p->pid, p->mm.pgdir[0]);
   dir0[USER_PAGE]=sloc | 0x03; 
   printk("aft modifying dir0. pid %d, pgdir[0] is %x\n",p->pid, p->mm.pgdir[0]);
   // we have changed page table. need to flush TLB
   __flush_tlb();
      // also we assume all process locates at 0x200000 which is page 512
   //dump_directory_table(p->mm.pgdir);
}

void init_directory_table(struct task_struct *p){
   int i;
   printk("init dir table for pid %d\n",p->pid);
   printk("i is at %x \n",&i);
   printk("p is at %x \n", p);
   printk("pgdir is at %x \n", p->mm.pgdir);
   for(i=0;i<MAXDIR;i++){
	  p->mm.pgdir[i]=0;
   }
   printk("done\n");
}
void init_directory(unsigned long *dir){
   int i;
   printk("in init dir\n");
   for(i=0;i<MAXFRAME;i++){
	  dir[i]=0;
   }
}

void dump_directory(unsigned long *dir){
   int i;
   printk("dumping directory at %x\n", dir);
   for(i=0;i<MAXFRAME;i++){
      if ((i % 25)==0) wait_for_anykey();
      if (dir[i]!=0) 
	     printk("page %d is at %x\n", i, dir[i]);
   }
}

void dump_directory_table(unsigned long *pgdir){
   int i;
   printk("dumping directory table at %x\n",pgdir);
   wait_for_anykey();
   for(i=0;i<MAXDIR;i++){
      if (mloc(pgdir[i])!=0){ // pgdir[i] is pointing to a directory
	     printk("dumping %d th directory which is at %x\n",i,pgdir[i]);
		 wait_for_anykey();
	     dump_directory(mloc(pgdir[i]));
	  }
   }
}


void dump_mm(struct task_struct *p){
// dump mm of p. dump page table only for now
   printk("dumping mm for pid %d\n", p->pid);
   wait_for_anykey();
   dump_directory_table(p->mm.pgdir);
}

void copy_mm(struct task_struct *src, struct task_struct *dest){
   int i;
   printk("copying directory table\n");
   // allocate directory table first
   dest->mm.pgdir = (unsigned long *)get_free_pgframe();
   init_directory_table(dest);
   // now copy
   for(i=0;i<MAXDIR;i++){
      dest->mm.pgdir[i]=src->mm.pgdir[i];
   }
}