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
  13 asm(".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         );
  68 EXPORT_SYMBOL(__copy_from_user);
  69
  70 asm(
  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");
 130 EXPORT_SYMBOL(__copy_to_user);
 131
 132 long 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
 150 long 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 }