arch/i386/mm/extable.c

   1 /*
   2  * linux/arch/i386/mm/extable.c
   3  */
   4
   5 #include <linux/config.h>
   6 #include <linux/module.h>
   7 #include <asm/uaccess.h>
   8
   9 extern const struct exception_table_entry __start___ex_table[];
  10 extern const struct exception_table_entry __stop___ex_table[];
  11
  12 static inline unsigned long
  13 search_one_table(const struct exception_table_entry *first,
  14                  const struct exception_table_entry *last,
  15                  unsigned long value)
  16 {
  17         while (first <= last) {
  18                 const struct exception_table_entry *mid;
  19                 long diff;
  20
  21                 mid = (last - first) / 2 + first;
  22                 diff = mid->insn - value;
  23                 if (diff == 0)
  24                         return mid->fixup;
  25                 else if (diff < 0)
  26                         first = mid+1;
  27                 else
  28                         last = mid-1;
  29         }
  30         return 0;
  31 }
  32
  33 unsigned long
  34 search_exception_table(unsigned long addr)
  35 {
  36         unsigned long ret;
  37
  38 #ifndef CONFIG_MODULES
  39         /* There is only the kernel to search.  */
  40         ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
  41         if (ret) return ret;
  42 #else
  43         /* The kernel is the last "module" -- no need to treat it special.  */
  44         struct module *mp;
  45         for (mp = module_list; mp != NULL; mp = mp->next) {
  46                 if (mp->ex_table_start == NULL)
  47                         continue;
  48                 ret = search_one_table(mp->ex_table_start,
  49                                        mp->ex_table_end - 1, addr);
  50                 if (ret) return ret;
  51         }
  52 #endif
  53
  54         return 0;
  55 }