文档介绍：TrustZone API Specification
Version
Document number: PRD29-USGC-000089
Date of Issue: 20 February 2009
© Copyright ARM Limited 2005-2009. All rights reserved.
Abstract
This document provides the specification of the TrustZone® API, a software application programming interface
that enables application code running in a general purpose operating system to efficiently and robustly
communicate with a dedicated security environment.
This API originated as a mechanism to enable munications between a rich operating system and a
security middleware environment running on an ARM processor implementing the ARM Architecture Security
Extensions. Recognizing that development of security software has been hindered by the lack mon
standards for software development, ARM is releasing this API as a public specification that can be implemented
by any security platform vendor as an interface to their underlying security solution.
PRD29-USGC-000089 ARM Confidential Page 1 of 82
TrustZone API Specification
Contents
ABSTRACT 1 
CONTENTS 2 
1  PREFACE 5 
  Document confidentiality 5 
  TrustZone Software API license 5 
  Disclaimer 5 
2  DOCUMENT STATUS 6 
  Change history 6 
  References 6 
3  OVERVIEW 7 
  The TrustZone API 7 
  Client application 8 
  Service stub 9 
  Device 9 
  Service 9 
  Service manager 10 
  Login 10 
  Structured messages 10 
  Shared memory 10 
4  USER GUIDE 11 
  Device usage 11 
  Service usage 12 
  Identifying services 12 
  Opening a client session 12 
  Invoking mands 14 
  Closing a client session 16 
  Encoding and decoding structured messages 16 
  Encoding data 17 
  Decoding data 17 
  Empty and NULL arrays 17 
  Handling encoder and decoder errors 17 
  Shared memory blocks 18 
  Allocation of shared memory blocks 18