uaccess.c

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/*
 * 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 <asm/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:    move.l  %0,%3\n"
        "7: clr.l   (%2)+\n"
        "   subq.l  #1,%3\n"
        "   jne 7b\n"
        "   lsl.l   #2,%0\n"
        "   btst    #1,%5\n"
        "   jeq 8f\n"
        "30:    clr.w   (%2)+\n"
        "   addq.l  #2,%0\n"
        "8: btst    #0,%5\n"
        "   jeq 6b\n"
        "50:    clr.b   (%2)+\n"
        "   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), "=&r" (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), "=&r" (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)
        : "r" (0), "0" (n / 4), "d" (n & 3));

    return res;
}
EXPORT_SYMBOL(__clear_user);