1 files changed, 89 insertions, 0 deletions
diff --git a/arch/x86_64/lib/putuser.S b/arch/x86_64/lib/putuser.S
new file mode 100644
index 000000000000..0dee1fdcb162
--- /dev/null
+++ b/arch/x86_64/lib/putuser.S
@@ -0,0 +1,89 @@
+/*
+ * __put_user functions.
+ *
+ * (C) Copyright 1998 Linus Torvalds
+ * (C) Copyright 2005 Andi Kleen
+ *
+ * These functions have a non-standard call interface
+ * to make them more efficient, especially as they
+ * return an error value in addition to the "real"
+ * return value.
+ */
+
+/*
+ * __put_user_X
+ *
+ * Inputs:	%rcx contains the address
+ *		%rdx contains new value
+ *
+ * Outputs:	%rax is error code (0 or -EFAULT)
+ *
+ * %r8 is destroyed.
+ *
+ * These functions should not modify any other registers,
+ * as they get called from within inline assembly.
+ */
+
+#include <linux/linkage.h>
+#include <asm/page.h>
+#include <asm/errno.h>
+#include <asm/offset.h>
+#include <asm/thread_info.h>
+
+	.text
+	.p2align 4
+.globl __put_user_1
+__put_user_1:
+	GET_THREAD_INFO(%r8)
+	cmpq threadinfo_addr_limit(%r8),%rcx
+	jae bad_put_user
+1:	movb %dl,(%rcx)
+	xorl %eax,%eax
+	ret
+
+	.p2align 4
+.globl __put_user_2
+__put_user_2:
+	GET_THREAD_INFO(%r8)
+	addq $1,%rcx
+	jc bad_put_user
+	cmpq threadinfo_addr_limit(%r8),%rcx
+	jae	 bad_put_user
+2:	movw %dx,-1(%rcx)
+	xorl %eax,%eax
+	ret
+
+	.p2align 4
+.globl __put_user_4
+__put_user_4:
+	GET_THREAD_INFO(%r8)
+	addq $3,%rcx
+	jc bad_put_user
+	cmpq threadinfo_addr_limit(%r8),%rcx
+	jae bad_put_user
+3:	movl %edx,-3(%rcx)
+	xorl %eax,%eax
+	ret
+
+	.p2align 4
+.globl __put_user_8
+__put_user_8:
+	GET_THREAD_INFO(%r8)
+	addq $7,%rcx
+	jc bad_put_user
+	cmpq threadinfo_addr_limit(%r8),%rcx
+	jae	bad_put_user
+4:	movq %rdx,-7(%rcx)
+	xorl %eax,%eax
+	ret
+
+bad_put_user:
+	movq $(-EFAULT),%rax
+	ret
+
+.section __ex_table,"a"
+	.quad 1b,bad_put_user
+	.quad 2b,bad_put_user
+	.quad 3b,bad_put_user
+	.quad 4b,bad_put_user
+.previous