Linux init/main.c 初始化中硬件中断向量初始化 trap_init()

/init/main.c部分代码

void main(void)/* This really IS void, no error here. */{/* The startup routine assumes (well, ...) this *//* * Interrupts are still disabled. Do necessary setups, then * enable them */ ROOT_DEV = ORIG_ROOT_DEV; drive_info = DRIVE_INFO;memory_end = (1<<20) + (EXT_MEM_K<<10);memory_end &= 0xfffff000;if (memory_end > 16*1024*1024)memory_end = 16*1024*1024;if (memory_end > 12*1024*1024) buffer_memory_end = 4*1024*1024;else if (memory_end > 6*1024*1024)buffer_memory_end = 2*1024*1024;elsebuffer_memory_end = 1*1024*1024;main_memory_start = buffer_memory_end;#ifdef RAMDISKmain_memory_start += rd_init(main_memory_start, RAMDISK*1024);#endifmem_init(main_memory_start,memory_end);trap_init();blk_dev_init();chr_dev_init();tty_init();time_init();sched_init();buffer_init(buffer_memory_end);hd_init();floppy_init();sti();move_to_user_mode();if (!fork()) {/* we count on this going ok */init();} 

trap_init()函数位置  /kernel/traps.c

void trap_init(void){int i;//设置系统的硬件中断 中断位于kernel/asm.s 或 system_call.sset_trap_gate(0,÷_error);//0中断，位于/kernel/asm.s 19行set_trap_gate(1,&debug);set_trap_gate(2,&nmi);set_system_gate(3,&int3);/* int3-5 can be called from all */set_system_gate(4,&overflow);set_system_gate(5,&bounds);set_trap_gate(6,&invalid_op);set_trap_gate(7,&device_not_available);set_trap_gate(8,&double_fault);set_trap_gate(9,&coprocessor_segment_overrun);set_trap_gate(10,&invalid_TSS);set_trap_gate(11,&segment_not_present);set_trap_gate(12,&stack_segment);set_trap_gate(13,&general_protection);set_trap_gate(14,&page_fault);set_trap_gate(15,&reserved);set_trap_gate(16,&coprocessor_error);for (i=17;i<48;i++)set_trap_gate(i,&reserved);set_trap_gate(45,&irq13);outb_p(inb_p(0x21)&0xfb,0x21);outb(inb_p(0xA1)&0xdf,0xA1);set_trap_gate(39,¶llel_interrupt);} 

set_trap_gate()函数位于/include/asm/system.h

//n为中断向量号，addr中断程序的偏移地址//&idt[n]对应中断号在中断描述符表中的偏移值//中断描述符的类型是 14,特权级是 0。#define set_trap_gate(n,addr) /_set_gate(&idt[n],15,0,addr)//设置中断宏函数//参数:gate_addr -描述符地址;type -描述符中类型域值;dpl -描述符特权层值;addr -偏移地址// %0 - (由 dpl,type 组合成的类型标志字);%1 - (描述符低 4 字节地址);// %2 - (描述符高 4 字节地址);%3 - edx(程序偏移地址 addr);%4 - eax(高字中含有段选择符)。#define _set_gate(gate_addr,type,dpl,addr) /__asm__ ("movw %%dx,%%ax/n/t" /"movw %0,%%dx/n/t" /"movl %%eax,%1/n/t" /"movl %%edx,%2" /: /: "i" ((short) (0x8000+(dpl<<13)+(type<<8))), /"o" (*((char *) (gate_addr))), /"o" (*(4+(char *) (gate_addr))), /"d" ((char *) (addr)),"a" (0x00080000))