Quelle  uaccess.c   Sprache: C

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/module.h>
#include <linux/uaccess.h>

unsigned long __generic_copy_from_user(void *to, const void __user *from,
           unsigned long n)
{
 unsigned long tmp, res;

 asm volatile ("\n"
  " tst.l %0\n"
  " jeq 2f\n"
  "1: "MOVES".l (%1)+,%3\n"
  " move.l %3,(%2)+\n"
  " subq.l #1,%0\n"
  " jne 1b\n"
  "2: btst #1,%5\n"
  " jeq 4f\n"
  "3: "MOVES".w (%1)+,%3\n"
  " move.w %3,(%2)+\n"
  "4: btst #0,%5\n"
  " jeq 6f\n"
  "5: "MOVES".b (%1)+,%3\n"
  " move.b %3,(%2)+\n"
  "6:\n"
  " .section .fixup,\"ax\"\n"
  " .even\n"
  "10: lsl.l #2,%0\n"
  " btst #1,%5\n"
  " jeq 8f\n"
  "30: addq.l #2,%0\n"
  "8: btst #0,%5\n"
  " jeq 6b\n"
  "50: addq.l #1,%0\n"
  " jra 6b\n"
  " .previous\n"
  "\n"
  " .section __ex_table,\"a\"\n"
  " .align 4\n"
  " .long 1b,10b\n"
  " .long 3b,30b\n"
  " .long 5b,50b\n"
  " .previous"
  : "=d" (res), "+a" (from), "+a" (to), "=&d" (tmp)
  : "0" (n / 4), "d" (n & 3));

 return res;
}
EXPORT_SYMBOL(__generic_copy_from_user);

unsigned long __generic_copy_to_user(void __user *to, const void *from,
         unsigned long n)
{
 unsigned long tmp, res;

 asm volatile ("\n"
  " tst.l %0\n"
  " jeq 4f\n"
  "1: move.l (%1)+,%3\n"
  "2: "MOVES".l %3,(%2)+\n"
  "3: subq.l #1,%0\n"
  " jne 1b\n"
  "4: btst #1,%5\n"
  " jeq 6f\n"
  " move.w (%1)+,%3\n"
  "5: "MOVES".w %3,(%2)+\n"
  "6: btst #0,%5\n"
  " jeq 8f\n"
  " move.b (%1)+,%3\n"
  "7: "MOVES".b %3,(%2)+\n"
  "8:\n"
  " .section .fixup,\"ax\"\n"
  " .even\n"
  "20: lsl.l #2,%0\n"
  "50: add.l %5,%0\n"
  " jra 8b\n"
  " .previous\n"
  "\n"
  " .section __ex_table,\"a\"\n"
  " .align 4\n"
  " .long 2b,20b\n"
  " .long 3b,20b\n"
  " .long 5b,50b\n"
  " .long 6b,50b\n"
  " .long 7b,50b\n"
  " .long 8b,50b\n"
  " .previous"
  : "=d" (res), "+a" (from), "+a" (to), "=&d" (tmp)
  : "0" (n / 4), "d" (n & 3));

 return res;
}
EXPORT_SYMBOL(__generic_copy_to_user);

/*
 * Zero Userspace
 */

unsigned long __clear_user(void __user *to, unsigned long n)
{
 unsigned long res;

 asm volatile ("\n"
  " tst.l %0\n"
  " jeq 3f\n"
  "1: "MOVES".l %2,(%1)+\n"
  "2: subq.l #1,%0\n"
  " jne 1b\n"
  "3: btst #1,%4\n"
  " jeq 5f\n"
  "4: "MOVES".w %2,(%1)+\n"
  "5: btst #0,%4\n"
  " jeq 7f\n"
  "6: "MOVES".b %2,(%1)\n"
  "7:\n"
  " .section .fixup,\"ax\"\n"
  " .even\n"
  "10: lsl.l #2,%0\n"
  "40: add.l %4,%0\n"
  " jra 7b\n"
  " .previous\n"
  "\n"
  " .section __ex_table,\"a\"\n"
  " .align 4\n"
  " .long 1b,10b\n"
  " .long 2b,10b\n"
  " .long 4b,40b\n"
  " .long 5b,40b\n"
  " .long 6b,40b\n"
  " .long 7b,40b\n"
  " .previous"
  : "=d" (res), "+a" (to)
  : "d" (0), "0" (n / 4), "d" (n & 3));

    return res;
}
EXPORT_SYMBOL(__clear_user);