diff --git a/Makefile.umbrella.tmk b/Makefile.umbrella.tmk
index 744c6c05c..049ea98ce 100644
--- a/Makefile.umbrella.tmk
+++ b/Makefile.umbrella.tmk
@@ -24,6 +24,7 @@ NV_REPOSITORY_COMPONENTS := drivers/gpu/nvgpu
 NV_REPOSITORY_COMPONENTS += userspace
 NV_REPOSITORY_COMPONENTS += userspace/units/posix-bitops
 NV_REPOSITORY_COMPONENTS += userspace/units/posix-env
+NV_REPOSITORY_COMPONENTS += userspace/units/posix-mockio
 endif
 
 # Local Variables:
diff --git a/drivers/gpu/nvgpu/libnvgpu-drv.export b/drivers/gpu/nvgpu/libnvgpu-drv.export
index b42443896..dc5d088f1 100644
--- a/drivers/gpu/nvgpu/libnvgpu-drv.export
+++ b/drivers/gpu/nvgpu/libnvgpu-drv.export
@@ -15,3 +15,19 @@ test_and_clear_bit
 test_and_set_bit
 bitmap_clear
 bitmap_set
+nvgpu_readl
+nvgpu_writel
+nvgpu_writel_check
+nvgpu_bar1_writel
+nvgpu_usermode_writel
+__nvgpu_readl
+nvgpu_bar1_readl
+nvgpu_posix_register_io
+nvgpu_posix_io_writel_reg_space
+nvgpu_posix_io_record_access
+nvgpu_posix_io_readl_reg_space
+nvgpu_posix_io_init_reg_space
+nvgpu_posix_io_start_recorder
+nvgpu_posix_io_add_reg_space
+nvgpu_posix_io_get_error_code
+nvgpu_posix_io_check_sequence
diff --git a/userspace/units/posix-mockio/Makefile.interface.tmk b/userspace/units/posix-mockio/Makefile.interface.tmk
new file mode 100644
index 000000000..87b47398b
--- /dev/null
+++ b/userspace/units/posix-mockio/Makefile.interface.tmk
@@ -0,0 +1,25 @@
+################################### tell Emacs this is a -*- makefile-gmake -*-
+#
+# Copyright (c) 2018, NVIDIA CORPORATION.  All Rights Reserved.
+#
+# NVIDIA CORPORATION and its licensors retain all intellectual property
+# and proprietary rights in and to this software, related documentation
+# and any modifications thereto.  Any use, reproduction, disclosure or
+# distribution of this software and related documentation without an express
+# license agreement from NVIDIA CORPORATION is strictly prohibited.
+#
+# tmake for SW Mobile component makefile
+#
+###############################################################################
+
+ifdef NV_INTERFACE_FLAG_SHARED_LIBRARY_SECTION
+NV_INTERFACE_NAME             := posix-mockio
+NV_INTERFACE_EXPORTS          := posix-mockio
+NV_INTERFACE_PUBLIC_INCLUDES  := . include
+endif
+
+# Local Variables:
+# indent-tabs-mode: t
+# tab-width: 8
+# End:
+# vi: set tabstop=8 noexpandtab:
diff --git a/userspace/units/posix-mockio/Makefile.tmk b/userspace/units/posix-mockio/Makefile.tmk
new file mode 100644
index 000000000..fbc31351d
--- /dev/null
+++ b/userspace/units/posix-mockio/Makefile.tmk
@@ -0,0 +1,40 @@
+################################### tell Emacs this is a -*- makefile-gmake -*-
+#
+# Copyright (c) 2018 NVIDIA CORPORATION.  All Rights Reserved.
+#
+# NVIDIA CORPORATION and its licensors retain all intellectual property
+# and proprietary rights in and to this software, related documentation
+# and any modifications thereto.  Any use, reproduction, disclosure or
+# distribution of this software and related documentation without an express
+# license agreement from NVIDIA CORPORATION is strictly prohibited.
+#
+# tmake for SW Mobile component makefile
+#
+###############################################################################
+
+ifdef NV_COMPONENT_FLAG_SHARED_LIBRARY_SECTION
+include $(NV_BUILD_START_COMPONENT)
+
+NV_COMPONENT_NAME		:= posix-mockio
+NV_COMPONENT_SOURCES		:= posix-mockio.c
+NV_COMPONENT_OWN_INTERFACE_DIR	:= .
+NV_COMPONENT_CFLAGS		+= -D__NVGPU_POSIX__
+
+NV_COMPONENT_NEEDED_INTERFACE_DIRS := \
+                                $(NV_SOURCE)/kernel/nvgpu/drivers/gpu/nvgpu \
+                                $(NV_SOURCE)/kernel/nvgpu/userspace
+
+NV_COMPONENT_SYSTEMIMAGE_DIR    := $(NV_SYSTEMIMAGE_TEST_EXECUTABLE_DIR)/nvgpu_unit/units
+systemimage:: $(NV_COMPONENT_SYSTEMIMAGE_DIR)
+$(NV_COMPONENT_SYSTEMIMAGE_DIR) : $(NV_SYSTEMIMAGE_TEST_EXECUTABLE_DIR)
+	$(MKDIR_P) $@
+
+include $(NV_BUILD_SHARED_LIBRARY)
+
+endif
+
+# Local Variables:
+# indent-tabs-mode: t
+# tab-width: 8
+# End:
+# vi: set tabstop=8 noexpandtab:
diff --git a/userspace/units/posix-mockio/posix-mockio.export b/userspace/units/posix-mockio/posix-mockio.export
new file mode 100644
index 000000000..b039dd364
--- /dev/null
+++ b/userspace/units/posix-mockio/posix-mockio.export
@@ -0,0 +1,3 @@
+# Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+
+__unit_module__