1 files changed, 49 insertions, 0 deletions
diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
index b4908789484e..c074799bddae 100644
--- a/arch/x86/lib/usercopy.c
+++ b/arch/x86/lib/usercopy.c
@@ -34,3 +34,52 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(copy_from_user_nmi);
+
+/**
+ * copy_to_user: - Copy a block of data into user space.
+ * @to:   Destination address, in user space.
+ * @from: Source address, in kernel space.
+ * @n:    Number of bytes to copy.
+ *
+ * Context: User context only. This function may sleep if pagefaults are
+ *          enabled.
+ *
+ * Copy data from kernel space to user space.
+ *
+ * Returns number of bytes that could not be copied.
+ * On success, this will be zero.
+ */
+unsigned long _copy_to_user(void __user *to, const void *from, unsigned n)
+{
+	if (access_ok(VERIFY_WRITE, to, n))
+		n = __copy_to_user(to, from, n);
+	return n;
+}
+EXPORT_SYMBOL(_copy_to_user);
+
+/**
+ * copy_from_user: - Copy a block of data from user space.
+ * @to:   Destination address, in kernel space.
+ * @from: Source address, in user space.
+ * @n:    Number of bytes to copy.
+ *
+ * Context: User context only. This function may sleep if pagefaults are
+ *          enabled.
+ *
+ * Copy data from user space to kernel space.
+ *
+ * Returns number of bytes that could not be copied.
+ * On success, this will be zero.
+ *
+ * If some data could not be copied, this function will pad the copied
+ * data to the requested size using zero bytes.
+ */
+unsigned long _copy_from_user(void *to, const void __user *from, unsigned n)
+{
+	if (access_ok(VERIFY_READ, from, n))
+		n = __copy_from_user(to, from, n);
+	else
+		memset(to, 0, n);
+	return n;
+}
+EXPORT_SYMBOL(_copy_from_user);