protect.c

这是《自己动手写操作系统》的原文件和代码

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                              protect.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                                                    Forrest Yu, 2005
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

#include "type.h"
#include "const.h"
#include "protect.h"
#include "global.h"


/* 本文件内函数声明 */
PRIVATE void init_idt_desc(unsigned char vector, t_8 desc_type, t_pf_int_handler handler, unsigned char privilege);


/* 中断处理函数 */
void	divide_error();
void	single_step_exception();
void	nmi();
void	breakpoint_exception();
void	overflow();
void	bounds_check();
void	inval_opcode();
void	copr_not_available();
void	double_fault();
void	copr_seg_overrun();
void	inval_tss();
void	segment_not_present();
void	stack_exception();
void	general_protection();
void	page_fault();
void	copr_error();
void	hwint00();
void	hwint01();
void	hwint02();
void	hwint03();
void	hwint04();
void	hwint05();
void	hwint06();
void	hwint07();
void	hwint08();
void	hwint09();
void	hwint10();
void	hwint11();
void	hwint12();
void	hwint13();
void	hwint14();
void	hwint15();


/*======================================================================*
                            init_prot
 *----------------------------------------------------------------------*
 初始化 IDT
 *======================================================================*/
PUBLIC void init_prot()
{
	init_8259A();

	// 全部初始化成中断门(没有陷阱门)
	init_idt_desc(INT_VECTOR_DIVIDE,	DA_386IGate, divide_error,		PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_DEBUG,		DA_386IGate, single_step_exception,	PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_NMI,		DA_386IGate, nmi,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_BREAKPOINT,	DA_386IGate, breakpoint_exception,	PRIVILEGE_USER);
	init_idt_desc(INT_VECTOR_OVERFLOW,	DA_386IGate, overflow,			PRIVILEGE_USER);
	init_idt_desc(INT_VECTOR_BOUNDS,	DA_386IGate, bounds_check,		PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_INVAL_OP,	DA_386IGate, inval_opcode,		PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_COPROC_NOT,	DA_386IGate, copr_not_available,	PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_DOUBLE_FAULT,	DA_386IGate, double_fault,		PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_COPROC_SEG,	DA_386IGate, copr_seg_overrun,		PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_INVAL_TSS,	DA_386IGate, inval_tss,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_SEG_NOT,	DA_386IGate, segment_not_present,	PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_STACK_FAULT,	DA_386IGate, stack_exception,		PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_PROTECTION,	DA_386IGate, general_protection,	PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_PAGE_FAULT,	DA_386IGate, page_fault,		PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_COPROC_ERR,	DA_386IGate, copr_error,		PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 0,	DA_386IGate, hwint00,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 1,	DA_386IGate, hwint01,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 2,	DA_386IGate, hwint02,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 3,	DA_386IGate, hwint03,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 4,	DA_386IGate, hwint04,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 5,	DA_386IGate, hwint05,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 6,	DA_386IGate, hwint06,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ0 + 7,	DA_386IGate, hwint07,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 0,	DA_386IGate, hwint08,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 1,	DA_386IGate, hwint09,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 2,	DA_386IGate, hwint10,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 3,	DA_386IGate, hwint11,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 4,	DA_386IGate, hwint12,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 5,	DA_386IGate, hwint13,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 6,	DA_386IGate, hwint14,			PRIVILEGE_KRNL);
	init_idt_desc(INT_VECTOR_IRQ8 + 7,	DA_386IGate, hwint15,			PRIVILEGE_KRNL);
}


/*======================================================================*
                             init_idt_desc
 *----------------------------------------------------------------------*
 初始化 386 中断门
 *======================================================================*/
PUBLIC void init_idt_desc(unsigned char vector, t_8 desc_type, t_pf_int_handler handler, unsigned char privilege)
{
	GATE *	p_gate	= &idt[vector];
	t_32	base	= (t_32)handler;
	p_gate->offset_low	= base & 0xFFFF;
	p_gate->selector	= SELECTOR_KERNEL_CS;
	p_gate->dcount		= 0;
	p_gate->attr		= desc_type | (privilege << 5);
	p_gate->offset_high	= (base >> 16) & 0xFFFF;
}


/*======================================================================*
                            exception_handler
 *----------------------------------------------------------------------*
 异常处理
 *======================================================================*/
PUBLIC void exception_handler(int vec_no, int err_code, int eip, int cs, int eflags)
{
	int i;
	int text_color = 0x74; /* 灰底红字 */
	char err_description[][64] = {	"#DE Divide Error",
					"#DB RESERVED",
					"—  NMI Interrupt",
					"#BP Breakpoint",
					"#OF Overflow",
					"#BR BOUND Range Exceeded",
					"#UD Invalid Opcode (Undefined Opcode)",
					"#NM Device Not Available (No Math Coprocessor)",
					"#DF Double Fault",
					"    Coprocessor Segment Overrun (reserved)",
					"#TS Invalid TSS",
					"#NP Segment Not Present",
					"#SS Stack-Segment Fault",
					"#GP General Protection",
					"#PF Page Fault",
					"—  (Intel reserved. Do not use.)",
					"#MF x87 FPU Floating-Point Error (Math Fault)",
					"#AC Alignment Check",
					"#MC Machine Check",
					"#XF SIMD Floating-Point Exception"
				};

	/* 通过打印空格的方式清空屏幕的前五行，并把 disp_pos 清零 */
	disp_pos = 0;
	for(i=0;i<80*5;i++){
		disp_str(" ");
	}
	disp_pos = 0;

	disp_color_str("Exception! --> ", text_color);
	disp_color_str(err_description[vec_no], text_color);
	disp_color_str("\n\n", text_color);
	disp_color_str("EFLAGS:", text_color);
	disp_int(eflags);
	disp_color_str("CS:", text_color);
	disp_int(cs);
	disp_color_str("EIP:", text_color);
	disp_int(eip);

	if(err_code != 0xFFFFFFFF){
		disp_color_str("Error code:", text_color);
		disp_int(err_code);
	}
}