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 int fixup_exception(struct pt_regs *regs)
  14 {
  15         const struct exception_table_entry *extab;
  16         unsigned long pc = regs->pc;
  17
  18         /* determine if the fault lay during a memcpy_user or a memset_user */
  19         if (regs->lr == (unsigned long) &__memset_user_error_lr &&
  20             (unsigned long) &memset <= pc && pc < (unsigned long) &__memset_end
  21             ) {
  22                 /* the fault occurred in a protected memset
  23                  * - we search for the return address (in LR) instead of the program counter
  24                  * - it was probably during a clear_user()
  25                  */
  26                 regs->pc = (unsigned long) &__memset_user_error_handler;
  27                 return 1;
  28         }
  29
  30         if (regs->lr == (unsigned long) &__memcpy_user_error_lr &&
  31             (unsigned long) &memcpy <= pc && pc < (unsigned long) &__memcpy_end
  32             ) {
  33                 /* the fault occurred in a protected memset
  34                  * - we search for the return address (in LR) instead of the program counter
  35                  * - it was probably during a copy_to/from_user()
  36                  */
  37                 regs->pc = (unsigned long) &__memcpy_user_error_handler;
  38                 return 1;
  39         }
  40
  41         extab = search_exception_tables(pc);
  42         if (extab) {
  43                 regs->pc = extab->fixup;
  44                 return 1;
  45         }
  46
  47         return 0;
  48 }