LXR linux/arch/nios2/mm/uaccess.c

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 2009, Wind River Systems Inc
   7 * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
   8 */
   9
  10#include <linux/export.h>
  11#include <linux/uaccess.h>
  12
  13asm(".global    __copy_from_user\n"
  14        "   .type __copy_from_user, @function\n"
  15        "__copy_from_user:\n"
  16        "   movi  r2,7\n"
  17        "   mov   r3,r4\n"
  18        "   bge   r2,r6,1f\n"
  19        "   xor   r2,r4,r5\n"
  20        "   andi  r2,r2,3\n"
  21        "   movi  r7,3\n"
  22        "   beq   r2,zero,4f\n"
  23        "1: addi  r6,r6,-1\n"
  24        "   movi  r2,-1\n"
  25        "   beq   r6,r2,3f\n"
  26        "   mov   r7,r2\n"
  27        "2: ldbu  r2,0(r5)\n"
  28        "   addi  r6,r6,-1\n"
  29        "   addi  r5,r5,1\n"
  30        "   stb   r2,0(r3)\n"
  31        "   addi  r3,r3,1\n"
  32        "   bne   r6,r7,2b\n"
  33        "3:\n"
  34        "   addi  r2,r6,1\n"
  35        "   ret\n"
  36        "13:mov   r2,r6\n"
  37        "   ret\n"
  38        "4: andi  r2,r4,1\n"
  39        "   cmpeq r2,r2,zero\n"
  40        "   beq   r2,zero,7f\n"
  41        "5: andi  r2,r3,2\n"
  42        "   beq   r2,zero,6f\n"
  43        "9: ldhu  r2,0(r5)\n"
  44        "   addi  r6,r6,-2\n"
  45        "   addi  r5,r5,2\n"
  46        "   sth   r2,0(r3)\n"
  47        "   addi  r3,r3,2\n"
  48        "6: bge   r7,r6,1b\n"
  49        "10:ldw   r2,0(r5)\n"
  50        "   addi  r6,r6,-4\n"
  51        "   addi  r5,r5,4\n"
  52        "   stw   r2,0(r3)\n"
  53        "   addi  r3,r3,4\n"
  54        "   br    6b\n"
  55        "7: ldbu  r2,0(r5)\n"
  56        "   addi  r6,r6,-1\n"
  57        "   addi  r5,r5,1\n"
  58        "   addi  r3,r4,1\n"
  59        "   stb   r2,0(r4)\n"
  60        "   br    5b\n"
  61        ".section __ex_table,\"a\"\n"
  62        ".word 2b,3b\n"
  63        ".word 9b,13b\n"
  64        ".word 10b,13b\n"
  65        ".word 7b,13b\n"
  66        ".previous\n"
  67        );
  68EXPORT_SYMBOL(__copy_from_user);
  69
  70asm(
  71        "   .global __copy_to_user\n"
  72        "   .type __copy_to_user, @function\n"
  73        "__copy_to_user:\n"
  74        "   movi  r2,7\n"
  75        "   mov   r3,r4\n"
  76        "   bge   r2,r6,1f\n"
  77        "   xor   r2,r4,r5\n"
  78        "   andi  r2,r2,3\n"
  79        "   movi  r7,3\n"
  80        "   beq   r2,zero,4f\n"
  81        /* Bail if we try to copy zero bytes  */
  82        "1: addi  r6,r6,-1\n"
  83        "   movi  r2,-1\n"
  84        "   beq   r6,r2,3f\n"
  85        /* Copy byte by byte for small copies and if src^dst != 0 */
  86        "   mov   r7,r2\n"
  87        "2: ldbu  r2,0(r5)\n"
  88        "   addi  r5,r5,1\n"
  89        "9: stb   r2,0(r3)\n"
  90        "   addi  r6,r6,-1\n"
  91        "   addi  r3,r3,1\n"
  92        "   bne   r6,r7,2b\n"
  93        "3: addi  r2,r6,1\n"
  94        "   ret\n"
  95        "13:mov   r2,r6\n"
  96        "   ret\n"
  97        /*  If 'to' is an odd address byte copy */
  98        "4: andi  r2,r4,1\n"
  99        "   cmpeq r2,r2,zero\n"
 100        "   beq   r2,zero,7f\n"
 101        /* If 'to' is not divideable by four copy halfwords */
 102        "5: andi  r2,r3,2\n"
 103        "   beq   r2,zero,6f\n"
 104        "   ldhu  r2,0(r5)\n"
 105        "   addi  r5,r5,2\n"
 106        "10:sth   r2,0(r3)\n"
 107        "   addi  r6,r6,-2\n"
 108        "   addi  r3,r3,2\n"
 109        /* Copy words */
 110        "6: bge   r7,r6,1b\n"
 111        "   ldw   r2,0(r5)\n"
 112        "   addi  r5,r5,4\n"
 113        "11:stw   r2,0(r3)\n"
 114        "   addi  r6,r6,-4\n"
 115        "   addi  r3,r3,4\n"
 116        "   br    6b\n"
 117        /* Copy remaining bytes */
 118        "7: ldbu  r2,0(r5)\n"
 119        "   addi  r5,r5,1\n"
 120        "   addi  r3,r4,1\n"
 121        "12: stb  r2,0(r4)\n"
 122        "   addi  r6,r6,-1\n"
 123        "   br    5b\n"
 124        ".section __ex_table,\"a\"\n"
 125        ".word 9b,3b\n"
 126        ".word 10b,13b\n"
 127        ".word 11b,13b\n"
 128        ".word 12b,13b\n"
 129        ".previous\n");
 130EXPORT_SYMBOL(__copy_to_user);
 131
 132long strncpy_from_user(char *__to, const char __user *__from, long __len)
 133{
 134        int l = strnlen_user(__from, __len);
 135        int is_zt = 1;
 136
 137        if (l > __len) {
 138                is_zt = 0;
 139                l = __len;
 140        }
 141
 142        if (l == 0 || copy_from_user(__to, __from, l))
 143                return -EFAULT;
 144
 145        if (is_zt)
 146                l--;
 147        return l;
 148}
 149
 150long strnlen_user(const char __user *s, long n)
 151{
 152        long i;
 153
 154        for (i = 0; i < n; i++) {
 155                char c;
 156
 157                if (get_user(c, s + i) == -EFAULT)
 158                        return 0;
 159                if (c == 0)
 160                        return i + 1;
 161        }
 162        return n + 1;
 163}
 164