---
title: Chapter 2 - Installing ThreadX support for ARMv8-M
description: This chapter explains how to install and use the ThreadX source code for the ARMv8-M architecture.
---

#  Chapter 2  Installing ThreadX support for ARMv8-M

There are additional ThreadX source code files to support the ARMv8-M architecture.

If ThreadX is to be run in *secure mode*, these additional files and APIs are not needed. To run ThreadX in secure mode, define the symbol **TX_SINGLE_MODE_SECURE** at the top of ***tx_port.h*** or on the command line or project settings. Ensure **TX_SINGLE_MODE_SECURE** is defined for all c and assembly files. ThreadX and the user application will execute in secure mode.

If ThreadX and the user application are to run only in *non-secure mode*, define the symbol **TX_SINGLE_MODE_NON_SECURE** at the top of ***tx_port.h*** or on the command line or project settings. Ensure **TX_SINGLE_MODE_NON_SECURE** is defined for all c and assembly files. ThreadX and the user application will execute in non-secure mode with no support for making secure function calls.

By default, ThreadX and the user application are designed to run in non-secure mode with support for non-secure callable secure functions.
To run ThreadX and the user application in non-secure mode and support non-secure callable secure functions, please do the following:

The file ***tx_thread_secure_stack.c*** must be added to the secure application.

The following files must be added to the ThreadX library:

- ***tx_secure_interface.h***
- ***txe_thread_secure_stack_allocate.c***
- ***txe_thread_secure_stack_free.c***
- ***tx_thread_secure_stack_allocate.s***
- ***tx_thread_secure_stack_free.s***

## Additional ThreadX Sources for ARMv8-M

The additional ThreadX files for the ARMv8-M TrustZone architecture are described below.

  | **File Name**                            | **Contents**                                                        |
  |------------------------------------------|---------------------------------------------------------------------|
  | ***tx_secure_interface.h***              | Include file that defines the ThreadX non-secure callable functions. |
  | ***txe_thread_secure_stack_allocate.c*** |  Error-checking file for the secure stack allocate API. |
  | ***txe_thread_secure_stack_free.c***     |  Error-checking file for the secure stack free API. |
  | ***tx_thread_secure_stack_initialize.s*** |  Initialize the secure stacks. |
  | ***tx_thread_secure_stack_allocate.s***  |  Non-secure veneer for the secure stack allocate service. |
  | ***tx_thread_secure_stack_free.s***      |  Non-secure veneer for the secure stack free service. |