1 files changed, 88 insertions, 0 deletions
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
new file mode 100644
index 000000000..0a42327a5
--- /dev/null
+++ b/arch/x86/lib/usercopy_64.c
@@ -0,0 +1,88 @@
+/* 
+ * User address space access functions.
+ *
+ * Copyright 1997 Andi Kleen <ak@muc.de>
+ * Copyright 1997 Linus Torvalds
+ * Copyright 2002 Andi Kleen <ak@suse.de>
+ */
+#include <linux/module.h>
+#include <asm/uaccess.h>
+
+/*
+ * Zero Userspace
+ */
+
+unsigned long __clear_user(void __user *addr, unsigned long size)
+{
+	long __d0;
+	might_fault();
+	/* no memory constraint because it doesn't change any memory gcc knows
+	   about */
+	stac();
+	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"
+		_ASM_EXTABLE(0b,3b)
+		_ASM_EXTABLE(1b,2b)
+		: [size8] "=&c"(size), [dst] "=&D" (__d0)
+		: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
+		  [zero] "r" (0UL), [eight] "r" (8UL));
+	clac();
+	return size;
+}
+EXPORT_SYMBOL(__clear_user);
+
+unsigned long clear_user(void __user *to, unsigned long n)
+{
+	if (access_ok(VERIFY_WRITE, to, n))
+		return __clear_user(to, n);
+	return n;
+}
+EXPORT_SYMBOL(clear_user);
+
+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;		
+}
+EXPORT_SYMBOL(copy_in_user);
+
+/*
+ * Try to copy last bytes and clear the rest if needed.
+ * Since protection fault in copy_from/to_user is not a normal situation,
+ * it is not necessary to optimize tail handling.
+ */
+__visible unsigned long
+copy_user_handle_tail(char *to, char *from, unsigned len)
+{
+	for (; len; --len, to++) {
+		char c;
+
+		if (__get_user_nocheck(c, from++, sizeof(char)))
+			break;
+		if (__put_user_nocheck(c, to, sizeof(char)))
+			break;
+	}
+	clac();
+
+	/* If the destination is a kernel buffer, we always clear the end */
+	if (!__addr_ok(to))
+		memset(to, 0, len);
+	return len;
+}