arch/frv/mm/extable.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/arch/frv/mm/extable.c
   4  */
   5
   6 #include <linux/extable.h>
   7 #include <linux/spinlock.h>
   8 #include <linux/uaccess.h>
   9
  10 extern const void __memset_end, __memset_user_error_lr, __memset_user_error_handler;
  11 extern const void __memcpy_end, __memcpy_user_error_lr, __memcpy_user_error_handler;
  12 extern spinlock_t modlist_lock;
  13
  14 int fixup_exception(struct pt_regs *regs)
  15 {
  16         const struct exception_table_entry *extab;
  17         unsigned long pc = regs->pc;
  18
  19         /* determine if the fault lay during a memcpy_user or a memset_user */
  20         if (regs->lr == (unsigned long) &__memset_user_error_lr &&
  21             (unsigned long) &memset <= pc && pc < (unsigned long) &__memset_end
  22             ) {
  23                 /* the fault occurred in a protected memset
  24                  * - we search for the return address (in LR) instead of the program counter
  25                  * - it was probably during a clear_user()
  26                  */
  27                 regs->pc = (unsigned long) &__memset_user_error_handler;
  28                 return 1;
  29         }
  30
  31         if (regs->lr == (unsigned long) &__memcpy_user_error_lr &&
  32             (unsigned long) &memcpy <= pc && pc < (unsigned long) &__memcpy_end
  33             ) {
  34                 /* the fault occurred in a protected memset
  35                  * - we search for the return address (in LR) instead of the program counter
  36                  * - it was probably during a copy_to/from_user()
  37                  */
  38                 regs->pc = (unsigned long) &__memcpy_user_error_handler;
  39                 return 1;
  40         }
  41
  42         extab = search_exception_tables(pc);
  43         if (extab) {
  44                 regs->pc = extab->fixup;
  45                 return 1;
  46         }
  47
  48         return 0;
  49 }