Add samsung specific changes

arch/um/kernel/Makefile

@@ -26,6 +26,7 @@ obj-$(CONFIG_OF) += dtb.o
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o
+obj-$(CONFIG_PLATFORM_MOCK)	+= io-mock.o
 
 USER_OBJS := config.o
 

arch/um/kernel/io-mock.c

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mock IO functions.
+ *
+ * Copyright (C) 2018, Google LLC.
+ * Author: Brendan Higgins <brendanhiggins@google.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <kunit/mock.h>
+
+DEFINE_FUNCTION_MOCK(readb,
+		     RETURNS(u8), PARAMS(const volatile void __iomem *));
+
+DEFINE_FUNCTION_MOCK(readw,
+		     RETURNS(u16), PARAMS(const volatile void __iomem *));
+
+DEFINE_FUNCTION_MOCK(readl,
+		     RETURNS(u32), PARAMS(const volatile void __iomem *));
+
+#ifdef CONFIG_64BIT
+DEFINE_FUNCTION_MOCK(readq,
+		     RETURNS(u64), PARAMS(const volatile void __iomem *));
+#endif /* CONFIG_64BIT */
+
+DEFINE_FUNCTION_MOCK_VOID_RETURN(writeb,
+				 PARAMS(u8, const volatile void __iomem *));
+
+DEFINE_FUNCTION_MOCK_VOID_RETURN(writew,
+				 PARAMS(u16, const volatile void __iomem *));
+
+DEFINE_FUNCTION_MOCK_VOID_RETURN(writel,
+				 PARAMS(u32, const volatile void __iomem *));
+
+#ifdef CONFIG_64BIT
+DEFINE_FUNCTION_MOCK_VOID_RETURN(writeq,
+				 PARAMS(u64, const volatile void __iomem *));
+#endif /* CONFIG_64BIT */