debug.c~

/*
 * =====================================================================================
 *
 *       Filename:  debug.c
 *
 *    Description:  调试相关的函数
 *
 *        Version:  1.0
 *        Created:  2013年11月06日 15时16分18秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Hurley (LiuHuan), liuhuan1992@gmail.com
 *        Company:  Class 1107 of Computer Science and Technology
 *
 * =====================================================================================
 */

#include "debug.h"

static void print_stack_trace();

static elf_t kernel_elf;

void init_debug()
{
	// 从 GRUB 提供的信息中获取到内核符号表和代码地址信息
	kernel_elf = elf_from_multiboot(glb_mboot_ptr);
}

void print_cur_status()
{
	static int round = 0;
	uint16_t reg1, reg2, reg3, reg4;

	asm volatile ( 	"mov %%cs, %0;"
			"mov %%ds, %1;"
			"mov %%es, %2;"
			"mov %%ss, %3;"
			: "=m"(reg1), "=m"(reg2), "=m"(reg3), "=m"(reg4));

	// 打印当前的运行级别
	printk("%d: @ring %d\n", round, reg1 & 0x3);
	printk("%d:  cs = %x\n", round, reg1);
	printk("%d:  ds = %x\n", round, reg2);
	printk("%d:  es = %x\n", round, reg3);
	printk("%d:  ss = %x\n", round, reg4);
	++round;
}

void panic(const char *msg)
{
	printk("*** System panic: %s\n", msg);
	print_stack_trace();
	printk("***\n");
	
	// 致命错误发生后打印栈信息后停止在这里
	while(1);
}

void print_stack_trace()
{
	uint32_t *ebp, *eip;

	asm volatile ("mov %%ebp, %0" : "=r" (ebp));
	while (ebp) {
		eip = ebp + 1;
		printk("   [0x%x] %s\n", *eip, elf_lookup_symbol(*eip, &kernel_elf));
		ebp = (uint32_t*)*ebp;
	}
}