Linux操作系统下糟糕的异常处理方式

extern const struct exception_table_entry __start___ex_table[]; 
extern const struct exception_table_entry __stop___ex_table[]; 

unsigned long search_exception_table(unsigned long addr) 
{ 
unsigned long ret; 

#ifndef CONFIG_MODULES 
/* There is only the kernel to search. */ 
ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr); 
if (ret) return ret; 
#else 
/* The kernel is the last "module" -- no need to treat it special. */ 
struct module *mp; 
for (mp = module_list; mp != NULL; mp = mp->next) { 
if (mp->ex_table_start == NULL) 
continue; 
ret = search_one_table(mp->ex_table_start, 
mp->ex_table_end - 1, addr); 
if (ret) return ret; 
} 
#endif 

return 0; 
} 

static inline unsigned long 
search_one_table(const struct exception_table_entry *first, 
const struct exception_table_entry *last, 
unsigned long value) 
{ 
while (first <= last) { 
const struct exception_table_entry *mid; 
long diff; 

mid = (last - first) / 2 + first; 
diff = mid->insn - value; 
if (diff == 0) 
return mid->fixup; 
else if (diff < 0) 
first = mid+1; 
else 
last = mid-1; 
} 
return 0; 
}