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kernel/linux-imx6_3.14.28/arch/frv/mm/extable.c 2.39 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * linux/arch/frv/mm/extable.c
   */
  
  #include <linux/module.h>
  #include <linux/spinlock.h>
  #include <asm/uaccess.h>
  
  extern const struct exception_table_entry __attribute__((aligned(8))) __start___ex_table[];
  extern const struct exception_table_entry __attribute__((aligned(8))) __stop___ex_table[];
  extern const void __memset_end, __memset_user_error_lr, __memset_user_error_handler;
  extern const void __memcpy_end, __memcpy_user_error_lr, __memcpy_user_error_handler;
  extern spinlock_t modlist_lock;
  
  /*****************************************************************************/
  /*
   *
   */
  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 __attribute__((aligned(8))) *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;
  } /* end search_one_table() */
  
  /*****************************************************************************/
  /*
   * see if there's a fixup handler available to deal with a kernel fault
   */
  unsigned long search_exception_table(unsigned long pc)
  {
  	const struct exception_table_entry *extab;
  
  	/* determine if the fault lay during a memcpy_user or a memset_user */
  	if (__frame->lr == (unsigned long) &__memset_user_error_lr &&
  	    (unsigned long) &memset <= pc && pc < (unsigned long) &__memset_end
  	    ) {
  		/* the fault occurred in a protected memset
  		 * - we search for the return address (in LR) instead of the program counter
  		 * - it was probably during a clear_user()
  		 */
  		return (unsigned long) &__memset_user_error_handler;
  	}
  
  	if (__frame->lr == (unsigned long) &__memcpy_user_error_lr &&
  	    (unsigned long) &memcpy <= pc && pc < (unsigned long) &__memcpy_end
  	    ) {
  		/* the fault occurred in a protected memset
  		 * - we search for the return address (in LR) instead of the program counter
  		 * - it was probably during a copy_to/from_user()
  		 */
  		return (unsigned long) &__memcpy_user_error_handler;
  	}
  
  	extab = search_exception_tables(pc);
  	if (extab)
  		return extab->fixup;
  
  	return 0;
  
  } /* end search_exception_table() */