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/* MN10300 Userspace accessor functions
*
* Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/uaccess.h>
/*
* Copy a null terminated string from userspace.
*/
#define __do_strncpy_from_user(dst, src, count, res) \
do { \
int w; \
asm volatile( \
" mov %1,%0\n" \
" cmp 0,%1\n" \
" beq 2f\n" \
"0:\n" \
" movbu (%5),%2\n" \
"1:\n" \
" movbu %2,(%6)\n" \
" inc %5\n" \
" inc %6\n" \
" cmp 0,%2\n" \
" beq 2f\n" \
" add -1,%1\n" \
" bne 0b\n" \
"2:\n" \
" sub %1,%0\n" \
"3:\n" \
" .section .fixup,\"ax\"\n" \
"4:\n" \
" mov %3,%0\n" \
" jmp 3b\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .balign 4\n" \
" .long 0b,4b\n" \
" .long 1b,4b\n" \
" .previous" \
:"=&r"(res), "=r"(count), "=&r"(w) \
:"i"(-EFAULT), "1"(count), "a"(src), "a"(dst) \
: "memory", "cc"); \
} while (0)
long
strncpy_from_user(char *dst, const char *src, long count)
{
long res = -EFAULT;
if (access_ok(VERIFY_READ, src, 1))
__do_strncpy_from_user(dst, src, count, res);
return res;
}
/*
* Clear a userspace memory
*/
#define __do_clear_user(addr, size) \
do { \
int w; \
asm volatile( \
" cmp 0,%0\n" \
" beq 1f\n" \
" clr %1\n" \
"0: movbu %1,(%3,%2)\n" \
" inc %3\n" \
" cmp %0,%3\n" \
" bne 0b\n" \
"1:\n" \
" sub %3,%0\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .balign 4\n" \
" .long 0b,3b\n" \
".previous\n" \
: "+r"(size), "=&r"(w) \
: "a"(addr), "d"(0) \
: "memory", "cc"); \
} while (0)
unsigned long
__clear_user(void *to, unsigned long n)
{
__do_clear_user(to, n);
return n;
}
unsigned long
clear_user(void *to, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
__do_clear_user(to, n);
return n;
}
/*
* Return the size of a string (including the ending 0)
*
* Return 0 on exception, a value greater than N if too long
*/
long strnlen_user(const char *s, long n)
{
unsigned long res, w;
if (!__addr_ok(s))
return 0;
if (n < 0 || n + (u_long) s > current_thread_info()->addr_limit.seg)
n = current_thread_info()->addr_limit.seg - (u_long)s;
asm volatile(
"0: cmp %4,%0\n"
" beq 2f\n"
"1: movbu (%0,%3),%1\n"
" inc %0\n"
" cmp 0,%1\n"
" beq 3f\n"
" bra 0b\n"
"2: clr %0\n"
"3:\n"
".section .fixup,\"ax\"\n"
"4: jmp 2b\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .balign 4\n"
" .long 1b,4b\n"
".previous\n"
:"=d"(res), "=&r"(w)
:"0"(0), "a"(s), "r"(n)
: "memory", "cc");
return res;
}
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