chapter 8 内核代码

8.1.1中断处理程序

traps.c

#define get_seg_byte(seg,addr) ({ \ //取seg中addr处1byte
register char __res; \
__asm__("push %%fs;mov %%ax,%%fs;movb %%fs:%2,%%al;pop %%fs" \
    :"=a" (__res):"0" (seg),"m" (*(addr))); \
__res;})

#define get_seg_long(seg,addr) ({ \ //取seg中addr处4字节
register unsigned long __res; \
__asm__("push %%fs;mov %%ax,%%fs;movl %%fs:%2,%%eax;pop %%fs" \
    :"=a" (__res):"0" (seg),"m" (*(addr))); \
__res;})

#define _fs() ({ \ //取fs段的内容，段选择符
register unsigned short __res; \
__asm__("mov %%fs,%%ax":"=a" (__res):); \
__res;})

static void die(char * str,long esp_ptr,long nr)
{
    long * esp = (long *) esp_ptr;
    int i;

    printk("%s: %04x\n\r",str,nr&0xffff);
    printk("EIP:\t%04x:%p\nEFLAGS:\t%p\nESP:\t%04x:%p\n",
        esp[1],esp[0],esp[2],esp[4],esp[3]); //打印栈的相关信息
    printk("fs: %04x\n",_fs()); //段选择符
    printk("base: %p, limit: %p\n",get_base(current->ldt[1]),get_limit(0x17)); //基地址，段限长
    if (esp[4] == 0x17) { //esp[4]是ss(堆栈段寄存器)的值，0x17是用户栈
        printk("Stack: ");
        for (i=0;i<4;i++)
            printk("%p ",get_seg_long(0x17,i+(long *)esp[3]));
        printk("\n");
    }
    str(i); //这里是个sched.h里面的宏定义，但是又有相同的名字参数传进来，会不会有歧义？
    printk("Pid: %d, process nr: %d\n\r",current->pid,0xffff & i);
    for(i=0;i<10;i++)
        printk("%02x ",0xff & get_seg_byte(esp[1],(i+(char *)esp[0])));
    printk("\n\r");
    do_exit(11); //释放当前进程所占用的资源，结束进程        /* play segment exception */
}

void do_double_fault(long esp, long error_code) //都是调用die
{
    die("double fault",esp,error_code);
}

void do_general_protection(long esp, long error_code)
{
    die("general protection",esp,error_code);
}

void do_alignment_check(long esp, long error_code)
{
    die("alignment check",esp,error_code);
}

void do_divide_error(long esp, long error_code)
{
    die("divide error",esp,error_code);
}

void do_nmi(long esp, long error_code)
{
    die("nmi",esp,error_code);
}

void do_debug(long esp, long error_code)
{
    die("debug",esp,error_code);
}

void do_overflow(long esp, long error_code)
{
    die("overflow",esp,error_code);
}

void do_bounds(long esp, long error_code)
{
    die("bounds",esp,error_code);
}

void do_invalid_op(long esp, long error_code)
{
    die("invalid operand",esp,error_code);
}

void do_device_not_available(long esp, long error_code)
{
    die("device not available",esp,error_code);
}

void do_coprocessor_segment_overrun(long esp, long error_code)
{
    die("coprocessor segment overrun",esp,error_code);
}

void do_invalid_TSS(long esp,long error_code)
{
    die("invalid TSS",esp,error_code);
}

void do_segment_not_present(long esp,long error_code)
{
    die("segment not present",esp,error_code);
}

void do_stack_segment(long esp,long error_code)
{
    die("stack segment",esp,error_code);
}

void do_coprocessor_error(l