Beyond BIOS: Developing with the Unified Extensible Firmware Interface, Third Edition

by Vincent Zimmer, Michael Rothman, Suresh Marisetty

Overview

This book provides an overview of modern boot firmware, including the Unified Extensible Firmware Interface (UEFI) and its associated EFI Developer Kit II (EDKII) firmware. The authors have each made significant contributions to developments in these areas. The reader will learn to use the latest developments in UEFI on modern hardware, including open source firmware and open hardware designs. The book begins with an exploration of interfaces exposed to higher-level software and operating systems, and commences to the left of the boot timeline, describing the flow of typical systems, beginning with the machine restart event.

Software engineers working with UEFI will benefit greatly from this book, while specific sections of the book address topics relevant for a general audience: system architects, pre-operating-system application developers, operating system vendors (loader, kernel), independent hardware vendors (such as for plug-in adapters), and developers of end-user applications. As a secondary audience, project technical leaders or managers may be interested in this book to get a feel for what their engineers are doing.

The reader will find:

• An overview of UEFI and underlying Platform Initialization (PI) specifications
• How to create UEFI applications and drivers
• Workflow to design the firmware solution for a modern platform
• Advanced usages of UEFI firmware for security and manageability

Product Details

ISBN-13:	9781501505836
Publisher:	De G Press
Publication date:	01/23/2017
Sold by:	Barnes & Noble
Format:	eBook
Pages:	322
File size:	54 MB
Note:	This product may take a few minutes to download.
Age Range:	18 Years

About the Author

Vincent Zimmer Engineer, WA, USA, Suresh Marisetty Systems Architect, CA, USA, Michael Rothman Engineer,WA, USA

Table of Contents

Acknowledgements | v

Preface | vii

Chapter 1 – Introduction | 1

Terminology | 4

Short History of EFI | 5

EFI Becomes UEFI—The UEFI Forum | 6

PIWG and USWG | 8

Platform Trust/Security | 11

Embedded Systems: The New Challenge | 12

How the Boot Process Differs between a Normal Boot and an

Optimized/Embedded Boot | 13

Summary | 14

Chapter 2 – Basic UEFI Architecture | 15

Objects Managed by UEFI-based Firmware | 15

UEFI System Table | 16

Handle Database | 16

Protocols | 18

Working with Protocols | 21

Multiple Protocol Instances | 21

Tag GUID | 21

UEFI Images | 22

Applications | 25

OS Loader | 25

Drivers | 26

Events and Task Priority Levels | 27

Summary | 30

Chapter 3 – UEFI Driver Model | 31

Why a Driver Model Prior to OS Booting? | 31

Driver Initialization | 32

Host Bus Controllers | 33

Device Drivers | 35

Bus Drivers | 36

Platform Components | 38

Hot Plug Events | 38

Pseudo Code | 41

Device Driver | 41

Bus Driver that Creates All of Its Child Handles on the First Call to

Start() | 42

Bus Driver that Is Able to Create All or One of Its Child Handles on Each Call

to Start(): | 43

Additional Innovations | 47

Security | 47

Manageability | 48

Networking | 49

Summary | 52

Chapter 4 – Protocols You Should Know | 53

EFI OS Loaders | 55

Device Path and Image Information of the OS Loader | 56

Accessing Files in the Device Path of the OS Loader | 57

Finding the OS Partition | 58

Getting the Current System Configuration | 60

Getting the Current Memory Map | 61

Getting Environment Variables | 62

Transitioning to an OS Kernel | 63

Summary | 63

Chapter 5 – UEFI Runtime | 65

Isn’t There Only One Kind of Memory? | 66

How Are Runtime Services Exposed? | 69

Time Services | 70

Why Abstract Time? | 70

Get Time | 70

Set Time | 71

Get Wakeup Time | 72

Set Wakeup Time | 72

Virtual Memory Services | 72

Set Virtual Address Map | 73

ConvertPointer | 73

Variable Services | 74

GetVariable | 74

GetNextVariableName | 75

SetVariable | 75

Miscellaneous Services | 77

Reset System | 78

Get Next High Monotonic Count | 79

UpdateCapsule | 79

QueryCapsuleCapabilities | 80

Summary | 80

Chapter 6 – UEFI Console Services | 81

Simple Text Input Protocol | 83

Simple Text Input Ex Protocol | 86

Simple Text Output Protocol | 87

Remote Console Support | 89

Console Splitter | 92

Network Consoles | 93

Summary | 95

Chapter 7 – Different Types of Platforms | 97

Summary | 110

Chapter 8 – DXE Basics: Core, Dispatching, and Drivers | 111

DXE Core | 112

Hand-Off Block (HOB) List | 114

DXE Architectural Protocols | 115

EFI System Table | 117

EFI Boot Services Table | 118

EFI Runtime Services Table | 119

DXE Services Table | 119

Global Coherency Domain Services | 120

GCD Memory Resources | 120

GCD I/O Resources | 122

DXE Dispatcher | 123

The a priori File | 125

Dependency Grammar | 125

DXE Drivers | 126

Boot Device Selection (BDS) Phase | 127

Console Devices | 128

Boot Devices | 129

Boot Services Terminate | 129

Summary | 130

Chapter 9 – Some Common UEFI and PI Functions | 131

Architectural Protocol Examples | 132

CPU Architectural Protocol | 133

Real Time Clock Architectural Protocol | 135

Timer Architectural Protocol | 135

Reset Architectural Protocol | 136

Boot Device Selection Architectural Protocol | 137

Variable Architectural Protocol | 138

Watchdog Timer Architectural Protocol | 138

PCI Protocols | 139

PCI Host Bridge Resource Allocation Protocol | 139

PCI Root Bridge I/O | 143

PCI I/O | 145

Block I/O | 147

Disk I/O | 149

Simple File System | 150

EFI File Protocol | 151

Configuration Infrastructure | 152

Using the Configuration Infrastructure | 153

Driver Model Interactions | 154

Provisioning the Platform | 155

Summary | 156

Chapter 10 – Platform Security and Trust | 157

Trust Overview | 157

Trusted Platform Module (TPM) and Measured Boot | 160

What Is a Trusted Building Block (TBB)? | 163

What Is the Point of Measurements? | 168

UEFI Secure Boot | 169

UEFI Executable Verification | 170

UEFI Networking | 173

UEFI User Identification (UID) | 176

Hardware Evolution: SRTM-to-DRTM | 177

Platform Manufacturer | 178

Vulnerability Classification | 180

Roots of Trust/Guards | 180

Summary | 181

Chapter 11 – Boot Device Selection | 183

Firmware Boot Manager | 185

Related Definitions | 188

Globally-Defined Variables | 188

Default Behavior for Boot Option Variables | 191

Boot Mechanisms | 191

Boot via Simple File Protocol | 192

Boot via LOAD_FILE Protocol | 193

Summary | 194

Chapter 12 – Boot Flows | 195

Defined Boot Modes | 196

Priority of Boot Paths | 196

Reset Boot Paths | 198

Intel® Itanium® Processor Reset | 198

Non-Power-On Resets | 199

Normal Boot Paths | 199

Basic G0-to-S0 and S0 Variation Boot Paths | 200

S-State Boot Paths | 200

Recovery Paths | 201

Discovery | 201

General Recovery Architecture | 202

Special Boot Path Topics | 203

Special Boot Paths | 203

Special Intel Itanium® Architecture Boot Paths | 203

Intel Itanium® Architecture Access to the Boot Firmware Volume | 203

Architectural Boot Mode PPIs | 207

Recovery | 207

Discovery | 208

Summary | 208

Chapter 13 – Pre-EFI Initialization (PEI) | 209

Scope | 209

Rationale | 210

Overview | 210

Phase Prerequisites | 212

Temporary RAM | 212

Boot Firmware Volume | 212

Security Primitives | 213

Concepts | 213

PEI Foundation | 213

Pre-EFI Initialization Modules (PEIMs) | 214

PEI Services | 215

PEIM-to-PEIM Interfaces (PPIs) | 215

Simple Heap | 216

Hand-Off Blocks (HOBs) | 216

Operation | 217

Dependency Expressions | 218

Verification/Authentication | 219

PEIM Execution | 219

Memory Discovery | 219

Intel® Itanium® Processor MP Considerations | 220

Recovery | 220

S3 Resume | 221

The “Terse Executable” and Cache-as-RAM | 222

Example System | 223

Summary | 226

Chapter 14 – Putting It All Together—Firmware Emulation | 227

Virtual Platform | 228

Emulation Firmware Phases | 230

Hardware Pass-Through | 235

Summary | 236

Chapter 15 – Reducing Platform Boot Times | 237

Proof of Concept | 240

Marketing Requirements | 241

What Are the Design Goals? | 242

Platform Policy | 242

What Are the Supported OS Targets? | 243

Do We Have to Support Legacy Operating Systems? | 243

Do We Have to Support Legacy Option ROMs? | 243

Are We Required to Display an OEM Splash Screen? | 244

What Type of Boot Media Is Supported? | 244

What Is the BIOS Recovery/Update Strategy? | 245

When Processing Things Early | 245

Is There a Need for Pre-OS User Interaction? | 246

Additional Details | 246

Adjusting the BIOS to Avoid Unnecessary Drivers | 246

What Is the Boot Target? | 247

Steps Taken in a Normal and Optimized Boot | 247

Loading a Boot Target | 248

Organizing the Flash Effectively | 249

Minimize the Files Needed | 249

Summary | 250

The Primary Adjustments | 250

Suggested Next Steps | 251

Chapter 16 – Embedded Boot Solution | 253

CE Device Landscape | 253

CE Device Boot Challenges | 254

In-Vehicle Infotainment | 256

Other Embedded Platforms | 257

Generic Requirements | 258

Boot Strategies | 259

Power Management | 261

Boot Storage Devices | 261

Security | 263

Manageability | 267

Summary | 268

Chapter 17 – Manageability | 269

Overall Management Framework | 269

Dynamic In-Band | 271

Out-of-Band | 271

Distributed Management Task Force (DMTF) | 271

UEFI Error Format Standardization | 272

UEFI Error Format Overview | 276

Error Record Types | 276

Windows Hardware Error Architecture and the Role of UEFI | 277

Technology Intercepts: UEFI, IPMI, Intel® AMT, WS-MAN | 281

Intelligent Platform Management Interface (IPMI) | 281

Intel® Active Management Technology (Intel AMT) | 283

Web Services Management Protocol (WS-MAN) | 285

Other Industry Initiatives | 285

The UEFI/IPMI/Intel® AMT/WS-MAN Bridge | 286

IPMI Error Records to UEFI | 287

UEFI Error Records to IPMI | 287

Intel® AMT and IPMI | 287

Future Work | 288

Configuration Namespace | 288

Namespace Entries | 292

Summary | 293

Appendix A – Data Types | 295

Appendix B – Status Codes | 297

Index | 301