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/uaccess.h>
  13
  14 /*
  15  * Copy a null terminated string from userspace.
  16  */
  17 #define __do_strncpy_from_user(dst, src, count, res)            \
  18 do {                                                            \
  19         int w;                                                  \
  20         asm volatile(                                           \
  21                 "       mov     %1,%0\n"                        \
  22                 "       cmp     0,%1\n"                         \
  23                 "       beq     2f\n"                           \
  24                 "0:\n"                                          \
  25                 "       movbu   (%5),%2\n"                      \
  26                 "1:\n"                                          \
  27                 "       movbu   %2,(%6)\n"                      \
  28                 "       inc     %5\n"                           \
  29                 "       inc     %6\n"                           \
  30                 "       cmp     0,%2\n"                         \
  31                 "       beq     2f\n"                           \
  32                 "       add     -1,%1\n"                        \
  33                 "       bne     0b\n"                           \
  34                 "2:\n"                                          \
  35                 "       sub     %1,%0\n"                        \
  36                 "3:\n"                                          \
  37                 "       .section .fixup,\"ax\"\n"               \
  38                 "4:\n"                                          \
  39                 "       mov     %3,%0\n"                        \
  40                 "       jmp     3b\n"                           \
  41                 "       .previous\n"                            \
  42                 "       .section __ex_table,\"a\"\n"            \
  43                 "       .balign 4\n"                            \
  44                 "       .long 0b,4b\n"                          \
  45                 "       .long 1b,4b\n"                          \
  46                 "       .previous"                              \
  47                 :"=&r"(res), "=r"(count), "=&r"(w)              \
  48                 :"i"(-EFAULT), "1"(count), "a"(src), "a"(dst)   \
  49                 : "memory", "cc");                                      \
  50 } while (0)
  51
  52 long
  53 strncpy_from_user(char *dst, const char *src, long count)
  54 {
  55         long res = -EFAULT;
  56         if (access_ok(VERIFY_READ, src, 1))
  57                 __do_strncpy_from_user(dst, src, count, res);
  58         return res;
  59 }
  60
  61
  62 /*
  63  * Clear a userspace memory
  64  */
  65 #define __do_clear_user(addr, size)             \
  66 do {                                            \
  67         int w;                                  \
  68         asm volatile(                           \
  69                 "       cmp 0,%0\n"             \
  70                 "       beq 1f\n"               \
  71                 "       clr %1\n"               \
  72                 "0:     movbu %1,(%3,%2)\n"     \
  73                 "       inc %3\n"               \
  74                 "       cmp %0,%3\n"            \
  75                 "       bne 0b\n"               \
  76                 "1:\n"                          \
  77                 "       sub %3,%0\n"            \
  78                 "2:\n"                          \
  79                 ".section .fixup,\"ax\"\n"      \
  80                 "3:     jmp 2b\n"               \
  81                 ".previous\n"                   \
  82                 ".section __ex_table,\"a\"\n"   \
  83                 "       .balign 4\n"            \
  84                 "       .long 0b,3b\n"          \
  85                 ".previous\n"                   \
  86                 : "+r"(size), "=&r"(w)          \
  87                 : "a"(addr), "d"(0)             \
  88                 : "memory", "cc");              \
  89 } while (0)
  90
  91 unsigned long
  92 __clear_user(void *to, unsigned long n)
  93 {
  94         __do_clear_user(to, n);
  95         return n;
  96 }
  97
  98 unsigned long
  99 clear_user(void *to, unsigned long n)
 100 {
 101         if (access_ok(VERIFY_WRITE, to, n))
 102                 __do_clear_user(to, n);
 103         return n;
 104 }
 105
 106 /*
 107  * Return the size of a string (including the ending 0)
 108  *
 109  * Return 0 on exception, a value greater than N if too long
 110  */
 111 long strnlen_user(const char *s, long n)
 112 {
 113         unsigned long res, w;
 114
 115         if (!__addr_ok(s))
 116                 return 0;
 117
 118         if (n < 0 || n + (u_long) s > current_thread_info()->addr_limit.seg)
 119                 n = current_thread_info()->addr_limit.seg - (u_long)s;
 120
 121         asm volatile(
 122                 "0:     cmp %4,%0\n"
 123                 "       beq 2f\n"
 124                 "1:     movbu (%0,%3),%1\n"
 125                 "       inc %0\n"
 126                 "       cmp 0,%1\n"
 127                 "       beq 3f\n"
 128                 "       bra 0b\n"
 129                 "2:     clr %0\n"
 130                 "3:\n"
 131                 ".section .fixup,\"ax\"\n"
 132                 "4:     jmp 2b\n"
 133                 ".previous\n"
 134                 ".section __ex_table,\"a\"\n"
 135                 "       .balign 4\n"
 136                 "       .long 1b,4b\n"
 137                 ".previous\n"
 138                 :"=d"(res), "=&r"(w)
 139                 :"0"(0), "a"(s), "r"(n)
 140                 : "memory", "cc");
 141         return res;
 142 }