arch/mn10300/lib/usercopy.c

   1 /* MN10300 Userspace accessor functions
   2  *
   3  * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public Licence
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the Licence, or (at your option) any later version.
  11  */
  12 #include <linux/string.h>
  13 #include <linux/uaccess.h>
  14
  15 unsigned long
  16 __generic_copy_to_user(void *to, const void *from, unsigned long n)
  17 {
  18         if (access_ok(VERIFY_WRITE, to, n))
  19                 __copy_user(to, from, n);
  20         return n;
  21 }
  22
  23 unsigned long
  24 __generic_copy_from_user(void *to, const void *from, unsigned long n)
  25 {
  26         if (access_ok(VERIFY_READ, from, n))
  27                 __copy_user_zeroing(to, from, n);
  28         else
  29                 memset(to, 0, n);
  30         return n;
  31 }
  32
  33 /*
  34  * Copy a null terminated string from userspace.
  35  */
  36 #define __do_strncpy_from_user(dst, src, count, res)            \
  37 do {                                                            \
  38         int w;                                                  \
  39         asm volatile(                                           \
  40                 "       mov     %1,%0\n"                        \
  41                 "       cmp     0,%1\n"                         \
  42                 "       beq     2f\n"                           \
  43                 "0:\n"                                          \
  44                 "       movbu   (%5),%2\n"                      \
  45                 "1:\n"                                          \
  46                 "       movbu   %2,(%6)\n"                      \
  47                 "       inc     %5\n"                           \
  48                 "       inc     %6\n"                           \
  49                 "       cmp     0,%2\n"                         \
  50                 "       beq     2f\n"                           \
  51                 "       add     -1,%1\n"                        \
  52                 "       bne     0b\n"                           \
  53                 "2:\n"                                          \
  54                 "       sub     %1,%0\n"                        \
  55                 "3:\n"                                          \
  56                 "       .section .fixup,\"ax\"\n"               \
  57                 "4:\n"                                          \
  58                 "       mov     %3,%0\n"                        \
  59                 "       jmp     3b\n"                           \
  60                 "       .previous\n"                            \
  61                 "       .section __ex_table,\"a\"\n"            \
  62                 "       .balign 4\n"                            \
  63                 "       .long 0b,4b\n"                          \
  64                 "       .long 1b,4b\n"                          \
  65                 "       .previous"                              \
  66                 :"=&r"(res), "=r"(count), "=&r"(w)              \
  67                 :"i"(-EFAULT), "1"(count), "a"(src), "a"(dst)   \
  68                 : "memory", "cc");                                      \
  69 } while (0)
  70
  71 long
  72 __strncpy_from_user(char *dst, const char *src, long count)
  73 {
  74         long res;
  75         __do_strncpy_from_user(dst, src, count, res);
  76         return res;
  77 }
  78
  79 long
  80 strncpy_from_user(char *dst, const char *src, long count)
  81 {
  82         long res = -EFAULT;
  83         if (access_ok(VERIFY_READ, src, 1))
  84                 __do_strncpy_from_user(dst, src, count, res);
  85         return res;
  86 }
  87
  88
  89 /*
  90  * Clear a userspace memory
  91  */
  92 #define __do_clear_user(addr, size)             \
  93 do {                                            \
  94         int w;                                  \
  95         asm volatile(                           \
  96                 "       cmp 0,%0\n"             \
  97                 "       beq 1f\n"               \
  98                 "       clr %1\n"               \
  99                 "0:     movbu %1,(%3,%2)\n"     \
 100                 "       inc %3\n"               \
 101                 "       cmp %0,%3\n"            \
 102                 "       bne 0b\n"               \
 103                 "1:\n"                          \
 104                 "       sub %3,%0\n"            \
 105                 "2:\n"                          \
 106                 ".section .fixup,\"ax\"\n"      \
 107                 "3:     jmp 2b\n"               \
 108                 ".previous\n"                   \
 109                 ".section __ex_table,\"a\"\n"   \
 110                 "       .balign 4\n"            \
 111                 "       .long 0b,3b\n"          \
 112                 ".previous\n"                   \
 113                 : "+r"(size), "=&r"(w)          \
 114                 : "a"(addr), "d"(0)             \
 115                 : "memory", "cc");              \
 116 } while (0)
 117
 118 unsigned long
 119 __clear_user(void *to, unsigned long n)
 120 {
 121         __do_clear_user(to, n);
 122         return n;
 123 }
 124
 125 unsigned long
 126 clear_user(void *to, unsigned long n)
 127 {
 128         if (access_ok(VERIFY_WRITE, to, n))
 129                 __do_clear_user(to, n);
 130         return n;
 131 }
 132
 133 /*
 134  * Return the size of a string (including the ending 0)
 135  *
 136  * Return 0 on exception, a value greater than N if too long
 137  */
 138 long strnlen_user(const char *s, long n)
 139 {
 140         unsigned long res, w;
 141
 142         if (!__addr_ok(s))
 143                 return 0;
 144
 145         if (n < 0 || n + (u_long) s > current_thread_info()->addr_limit.seg)
 146                 n = current_thread_info()->addr_limit.seg - (u_long)s;
 147
 148         asm volatile(
 149                 "0:     cmp %4,%0\n"
 150                 "       beq 2f\n"
 151                 "1:     movbu (%0,%3),%1\n"
 152                 "       inc %0\n"
 153                 "       cmp 0,%1\n"
 154                 "       beq 3f\n"
 155                 "       bra 0b\n"
 156                 "2:     clr %0\n"
 157                 "3:\n"
 158                 ".section .fixup,\"ax\"\n"
 159                 "4:     jmp 2b\n"
 160                 ".previous\n"
 161                 ".section __ex_table,\"a\"\n"
 162                 "       .balign 4\n"
 163                 "       .long 1b,4b\n"
 164                 ".previous\n"
 165                 :"=d"(res), "=&r"(w)
 166                 :"0"(0), "a"(s), "r"(n)
 167                 : "memory", "cc");
 168         return res;
 169 }