arch/frv/mm/extable.c

   1 /*
   2  * linux/arch/frv/mm/extable.c
   3  */
   4
   5 #include <linux/extable.h>
   6 #include <linux/spinlock.h>
   7 #include <linux/uaccess.h>
   8
   9 extern const void __memset_end, __memset_user_error_lr, __memset_user_error_handler;
  10 extern const void __memcpy_end, __memcpy_user_error_lr, __memcpy_user_error_handler;
  11 extern spinlock_t modlist_lock;
  12
  13
  14 /*****************************************************************************/
  15 /*
  16  * see if there's a fixup handler available to deal with a kernel fault
  17  */
  18 unsigned long search_exception_table(unsigned long pc)
  19 {
  20         const struct exception_table_entry *extab;
  21
  22         /* determine if the fault lay during a memcpy_user or a memset_user */
  23         if (__frame->lr == (unsigned long) &__memset_user_error_lr &&
  24             (unsigned long) &memset <= pc && pc < (unsigned long) &__memset_end
  25             ) {
  26                 /* the fault occurred in a protected memset
  27                  * - we search for the return address (in LR) instead of the program counter
  28                  * - it was probably during a clear_user()
  29                  */
  30                 return (unsigned long) &__memset_user_error_handler;
  31         }
  32
  33         if (__frame->lr == (unsigned long) &__memcpy_user_error_lr &&
  34             (unsigned long) &memcpy <= pc && pc < (unsigned long) &__memcpy_end
  35             ) {
  36                 /* the fault occurred in a protected memset
  37                  * - we search for the return address (in LR) instead of the program counter
  38                  * - it was probably during a copy_to/from_user()
  39                  */
  40                 return (unsigned long) &__memcpy_user_error_handler;
  41         }
  42
  43         extab = search_exception_tables(pc);
  44         if (extab)
  45                 return extab->fixup;
  46
  47         return 0;
  48
  49 } /* end search_exception_table() */