南京大学操作系统实验-模拟读者优先和写者优先问题.zip

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ protect.c ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Forrest Yu, 2005 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/ #include "type.h" #include "const.h" #include "protect.h" #include "tty.h" #include "console.h" #include "proc.h" #include "global.h" #include "proto.h" /* 本文件内函数声明 */ PRIVATE void init_idt_desc(unsigned char vector, u8 desc_type, int_handler handler, unsigned char privilege); PRIVATE void init_descriptor(DESCRIPTOR * p_desc, u32 base, u32 limit, u16 attribute); /* 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(INT_VECTOR_SYS_CALL, DA_386IGate, sys_call, PRIVILEGE_USER); /* 填充 GDT 中 TSS 这个描述符 */ memset(&tss, 0, sizeof(tss)); tss.ss0 = SELECTOR_KERNEL_DS; init_descriptor(&gdt[INDEX_TSS], vir2phys(seg2phys(SELECTOR_KERNEL_DS), &tss), sizeof(tss) - 1, DA_386TSS); tss.iobase = sizeof(tss); /* 没有I/O许可位图 */ // 填充 GDT 中进程的 LDT 的描述符 int i; PROCESS* p_proc = proc_table; u16 selector_ldt = INDEX_LDT_FIRST << 3; for (i = 0; i < NR_TASKS+NR_PROCS; i++){ init_descriptor(&gdt[selector_ldt>>3], vir2phys(seg2phys(SELECTOR_KERNEL_DS), proc_table[i].ldts), LDT_SIZE * sizeof(DESCRIPTOR) - 1, DA_LDT); p_proc++; selector_ldt += 1 << 3; } } /*======================================================================* init_idt_desc *----------------------------------------------------------------------* 初始化 386 中断门 *======================================================================*/ PUBLIC void init_idt_desc(unsigned char vector, u8 desc_type, int_handler handler, unsigned char privilege) { GATE * p_gate = &idt[vector]; u32 base = (u32)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; } /*======================================================================* seg2phys *----------------------------------------------------------------------* 由段名求绝对地址 *======================================================================*/ PUBLIC u32 seg2phys(u16 seg) { DESCRIPTOR* p_dest = &gdt[seg >> 3]; return (p_dest->base_high << 24) | (p_dest->base_mid << 16) | (p_dest->base_low); } /*======================================================================* init_descriptor *----------------------------------------------------------------------* 初始化段描述符 *======================================================================*/ PRIVATE void init_descriptor(DESCRIPTOR * p_desc, u32 base, u32 limit, u16 attribute) { p_desc->limit_low = limit & 0x0FFFF; // 段界限 1 (2 字节) p_desc->base_low = base & 0x0FFFF; // 段基址 1 (2 字节) p_desc->base_mid = (base >> 16) & 0x0FF; // 段基址 2 (1 字节) p_desc->attr1 = attribute & 0xFF; // 属性 1 p_desc->limit_high_attr2 = ((limit >> 16) & 0x0F) | (attribute >> 8) & 0xF0;// 段界限 2 + 属性 2 p_desc->base_high = (base >> 24) & 0x0FF; // 段基址 3 (1 字节) } /*======================================================================* exception_handler *----------