--- /dev/null
+/*
+ * User address space access functions.
+ *
+ * Copyright 1997 Andi Kleen <ak@muc.de>
+ * Copyright 1997 Linus Torvalds
+ * Copyright 2002 Andi Kleen <ak@suse.de>
+ */
+#include <arch/uaccess.h>
+
+/*
+ * Copy a null terminated string from userspace.
+ */
+
+#define __do_strncpy_from_user(dst,src,count,res) \
+do { \
+ long __d0, __d1, __d2; \
+ __asm__ __volatile__( \
+ " testq %1,%1\n" \
+ " jz 2f\n" \
+ "0: lodsb\n" \
+ " stosb\n" \
+ " testb %%al,%%al\n" \
+ " jz 1f\n" \
+ " decq %1\n" \
+ " jnz 0b\n" \
+ "1: subq %1,%0\n" \
+ "2:\n" \
+ ".section .fixup,\"ax\"\n" \
+ "3: movq %5,%0\n" \
+ " jmp 2b\n" \
+ ".previous\n" \
+ ".section __ex_table,\"a\"\n" \
+ " .align 8\n" \
+ " .quad 0b,3b\n" \
+ ".previous" \
+ : "=r"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1), \
+ "=&D" (__d2) \
+ : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
+ : "memory"); \
+} while (0)
+
+long
+__strncpy_from_user(char *dst, const char __user *src, long count)
+{
+ long res;
+ __do_strncpy_from_user(dst, src, count, res);
+ return res;
+}
+
+long
+strncpy_from_user(char *dst, const char __user *src, long count)
+{
+ long res = -EFAULT;
+ if (access_ok(VERIFY_READ, src, 1))
+ return __strncpy_from_user(dst, src, count);
+ return res;
+}
+
+/*
+ * Zero Userspace
+ */
+
+unsigned long __clear_user(void __user *addr, unsigned long size)
+{
+ long __d0;
+ /* no memory constraint because it doesn't change any memory gcc knows
+ about */
+ asm volatile(
+ " testq %[size8],%[size8]\n"
+ " jz 4f\n"
+ "0: movq %[zero],(%[dst])\n"
+ " addq %[eight],%[dst]\n"
+ " decl %%ecx ; jnz 0b\n"
+ "4: movq %[size1],%%rcx\n"
+ " testl %%ecx,%%ecx\n"
+ " jz 2f\n"
+ "1: movb %b[zero],(%[dst])\n"
+ " incq %[dst]\n"
+ " decl %%ecx ; jnz 1b\n"
+ "2:\n"
+ ".section .fixup,\"ax\"\n"
+ "3: lea 0(%[size1],%[size8],8),%[size8]\n"
+ " jmp 2b\n"
+ ".previous\n"
+ ".section __ex_table,\"a\"\n"
+ " .align 8\n"
+ " .quad 0b,3b\n"
+ " .quad 1b,2b\n"
+ ".previous"
+ : [size8] "=c"(size), [dst] "=&D" (__d0)
+ : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
+ [zero] "r" (0UL), [eight] "r" (8UL));
+ return size;
+}
+
+unsigned long clear_user(void __user *to, unsigned long n)
+{
+ if (access_ok(VERIFY_WRITE, to, n))
+ return __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 __user *s, long n)
+{
+ long res = 0;
+ char c;
+
+ while (1) {
+ if (res>n)
+ return n+1;
+ if (__get_user(c, s))
+ return 0;
+ if (!c)
+ return res+1;
+ res++;
+ s++;
+ }
+}
+
+long strnlen_user(const char __user *s, long n)
+{
+ if (!access_ok(VERIFY_READ, s, n))
+ return 0;
+ return __strnlen_user(s, n);
+}
+
+long strlen_user(const char __user *s)
+{
+ long res = 0;
+ char c;
+
+ for (;;) {
+ if (get_user(c, s))
+ return 0;
+ if (!c)
+ return res+1;
+ res++;
+ s++;
+ }
+}
+
+unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
+{
+ if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) {
+ return copy_user_generic((__force void *)to, (__force void *)from, len);
+ }
+ return len;
+}
+
