lca14: lca14-102: adopting arm trusted firmware

1

Adopting ARM Trusted Firmware LCA14 – March 2014

Andrew Thoelke

Systems & Software, ARM

2

https://www.github.com/ARM-Software/arm-trusted-firmware

Standardized EL3 Runtime Firmware

For All 64-bit ARMv8-A systems

Reducing porting and integration work

For SoC and Trusted OS developers

Reusable, reference implementations

PSCI

SMC Calling Convention

Configuration of ARM hardware

Running on ARMv8-A FVP models

And now running on silicon

ARM Trusted Firmware for 64-bit ARMv8-A A recap

ARM Trusted FirmwareEL3

SoC/platform port

Normal World OSEL1/EL2

Trusted OSSecure-EL1

Trusted OS Dispatcher

TOS

spec

ific

p

roto

col a

nd

m

ech

anis

m

Trusted AppSecure-EL0

AppEL0

TOS driver

TOS library

TOS specific protocol via SMC

via

ioct

l

Porting interface between Trusted

Firmware and SoC/platform

Interface between Trusted Firmware and Trusted OS Dispatcher

ARM Trusted Firmware

Trusted OS supplier

SoC supplier

OS/hypervisor supplier

Trusted App supplier

Internal TOS interface








3


Reference boot flows

For 64-bit ARMv8-A systems

Open Source at GitHub

BSD License

Contributors welcome

Still to come…

Authenticated boot

Authenticated Firmware update

Firmware test suite

PSCI Conformance tests

ARM Trusted Firmware for 64-bit ARMv8-A A recap

EL3 Runtime Firmware - BL31SMC Interface

SMC Dispatcher

Other SMC Calls Interrupt Handler

Secure Monitor

PSCI

Power Control

Driver

EL3 Arch Context

Save/Restore

Normal World Trusted World

Interface Usage

External Interface

EL1 Execution

Secure EL1 Execution

EL2 Execution

KeyGlossaryBL - Boot Loader

EDK2 - EFI Development Kit 2

EL - Exception Level

NV - Non-Volatile

PSCI - Power State Control Interface

SMC - Secure Monitor Call

UEFI - Unified Enhanced Firmware Interface

EL3 Execution

Potential Interface

Non-secure

firmware - BL33

(EDK2, U-Boot)

Secure Boot

I/O Drivers

Boot ROM - BL1

Trusted Board

Boot 1

Trusted Boot

Firmware - BL2

Trusted Board

Boot 2

Cold/Warm

Boot Detection

NV Storage

Driver

Boot Time Arch

+ Platform Init

Temp SMC

Handler

Boot Time Arch

+ Platform Init

Test Secure EL1 Payload - BL32

PSCI

Test

Service Router

Other

Test

S-EL1 Arch

Context

Save/Restore

Interrupt

Handler

Runtime Arch +

Platform Init

Test Suite - BL33_ALT

PSCI

Tests

EL1 Arch Context

Save/Restore

EL2 Arch Context

Save/Restore

Other

Tests

Interrupt

Handler

Runtime Arch

+ Platform InitException Trapper

BL33

BL33

(Alternative)

BL32 BL2

BL1 BL31 RESET

2nd level

Boot Loader

(BL2) loads

all 3rd level

images

1st level Boot

Loader (BL1)

loads 2nd

level image

To

Hypervisor /

Linux Kernel








4


So ARM Trusted Firmware provides some great benefits:

Support for ARM standards like SMC Calling Convention and PSCI

Easier firmware integration by separation of SoC and Trusted OS software

Reducing the complexity of porting Monitor code to AArch64

Licensing that lets you use just the code you want with no obligation to publish what you have done

…but using this software also raises some concerns

Some are valid, and need to be addressed

Many are based on misconceptions or misunderstandings

Maybe it is time for …

Adopting ARM Trusted Firmware








5


Busting ARM Trusted Firmware Myths








6


Myth: ARM Trusted Firmware only works with UEFI

So…

I won’t use it as I am using U-Boot

I can’t afford to switch to UEFI right now

UEFI is just wrong for my product








7


So…

I won’t use it as I am using U-Boot

I can’t afford to switch to UEFI right now

UEFI is just wrong for my product

Reality

Trusted Firmware is designed to work with

ANY non-secure firmware/software

e.g. U-Boot, UEFI, a test suite

Tianocore EDK2 is the UEFI firmware that

ARM is testing with ARM Trusted Firmware

Myth: ARM Trusted Firmware only works with UEFI Reality: ARM Trusted Firmware works with any non-secure firmware/software


SMC Dispatcher


Secure Monitor

PSCI

Power Control

Driver

EL3 Arch Context

Save/Restore


Interface Usage

External Interface

EL1 Execution


EL2 Execution




NV - Non-Volatile




EL3 Execution

Potential Interface

Non-secure

firmware - BL33

(EDK2, U-Boot)

Secure Boot

I/O Drivers

Boot ROM - BL1

Trusted Board

Boot 1

Trusted Boot

Firmware - BL2

Trusted Board

Boot 2

Cold/Warm

Boot Detection

NV Storage

Driver

Boot Time Arch

+ Platform Init

Temp SMC

Handler

Boot Time Arch

+ Platform Init


PSCI

Test

Service Router

Other

Test

S-EL1 Arch

Context

Save/Restore

Interrupt

Handler

Runtime Arch +

Platform Init


PSCI

Tests

EL1 Arch Context

Save/Restore

EL2 Arch Context

Save/Restore

Other

Tests

Interrupt

Handler

Runtime Arch


BL32 BL2

BL1 BL31

To

Hypervisor /

Linux Kernel








8


So…

I can’t use it for a product that doesn't

have a Trusted OS

It will be too big for a product that doesn't

need a Trusted OS

Myth: ARM Trusted Firmware requires a Trusted OS








9


So…

I can’t use it for a product that doesn't

have a Trusted OS

It will be too big for a product that doesn't

need a Trusted OS

Reality

Trusted Firmware can be built without a

Trusted OS or Secure Monitor

the default is to exclude it

and needs less RAM

Trusted Firmware still provides benefits

without a Trusted OS

Myth: ARM Trusted Firmware requires a Trusted OS Reality: ARM Trusted Firmware builds without a Trusted OS by default

ARM Trusted FirmwareEL3 AArch64

SoC/platform port

Normal WorldEL1/EL2 AArch64/AArch32

PSCI core framework No Secure Monitor

PSCI Implementation


Normal World Software

Platform Software

Trusted World Software








10


So...

I can’t run any Trusted OS

It can't work with my Trusted OS

Myth: ARM Trusted Firmware doesn’t have a Secure Monitor








11


So...

I can’t run any Trusted OS

It can't work with my Trusted OS

Reality

There is an example Secure Monitor that

works with the Test Secure-EL1 Payload

Trusted Firmware provides a framework to

build a Monitor specific to each Trusted OS

We'd like to help if your requirements

are not yet supported

More examples would make this easier

Linaro SWG is planning to do this

Myth: ARM Trusted Firmware doesn’t have a Secure Monitor Reality: ARM Trusted Firmware provides an example Secure Monitor


SoC/platform port

ARM Trusted Firmware Test SuiteEL1/EL2

Test Secure-EL1 Payload (TSP)Secure-EL1

Test Secure-EL1 PayloadDispatcher (TSPD)

AR

M T

F Te

st

spec

ific

pro

toco

l an

d m

ech

anis

m

ARM Trusted Firm

ware Test

specific protocol via SMC

World-switch support library

PSCI core framework

Secure Monitor

PSCI Implementation


ARM Trusted Firmware Test Suite

SoC supplier

Internal ARM Trusted Firmware Test interface








12


So…

I can't use my own one

I don't need to buy one

Doesn’t this undermine your partners?

Is this allowed?

Myth: ARM Trusted Firmware includes a Trusted OS








13


So…

I can't use my own one

I don't need to buy one

Doesn’t this undermine ARM partners?

Is this allowed?

Reality

ARM is not implementing a Trusted OS

Trusted Firmware provides test code that

runs in place of a Trusted OS

Trusted OS providers do need to write a

piece of code that allows their OS to work

with ARM Trusted Firmware

Myth: ARM Trusted Firmware includes a Trusted OS Reality: ARM is not implementing a Trusted OS


SoC/platform port

ARM Trusted Firmware Test SuiteEL1/EL2

Test Secure-EL1 Payload (TSP)Secure-EL1

Test Secure-EL1 PayloadDispatcher (TSPD)

AR

M T

F Te

st

spec

ific

pro

toco

l an

d m

ech

anis

m

ARM Trusted Firm

ware Test

specific protocol via SMC


PSCI core framework

Secure Monitor

PSCI Implementation


ARM Trusted Firmware Test Suite

SoC supplier

Internal ARM Trusted Firmware Test interface








14


So…

I have to port my Trusted OS to AArch64

I can’t run a 32-bit OS or hypervisor

It won’t work on ARMv7-A

Myth: ARM Trusted Firmware only supports AArch64








15


So…

I have to port my Trusted OS to AArch64

I can’t run a 32-bit OS or hypervisor

It won’t work on ARMv7-A

Reality

Initial products will use a 32-bit Trusted OS

an example Secure Monitor would help

Will support AArch32 non-secure software

but not in upstream code yet

There are no barriers to porting Trusted

Firmware to ARMv7-A

This depends on development priorities

Myth: ARM Trusted Firmware only supports AArch64 Reality: ARM Trusted Firmware is prioritising AArch64 without excluding Arch32


Normal World Software

Platform Software

Trusted World Software

ARM Trusted FirmwareEL3 AArch64

SoC/platform port

Normal WorldEL1/EL2 AArch64/AArch32

Secure-EL1 Payload (SP)Secure-EL1 AArch64/AArch32

Secure-EL1 PayloadDispatcher (SPD)


PSCI core framework

Secure Monitor

PSCI Implementation Secu

re-E

L1 P

aylo

ad

spec

ific

inte

rfac

e

via Secure Monitor Call (SM

C)








16


So…

It will be buggy, bloated and/or incomplete

I have to write my own firmware anyway

Myth: ARM Trusted Firmware isn't ready for products








17


So…

It will be buggy, bloated and/or incomplete

I have to write my own firmware anyway

Reality

It is being use by partners TODAY

It's open source, of course

take what you want, fix what you need

Hardening and fitness for use are priorities

for the EL3 Runtime Firmware in v0.4

We are continually improving the firmware

and welcome feedback and contributions

Myth: ARM Trusted Firmware isn't ready for products

Reality: ARM Trusted Firmware is in use today and product readiness is a priority for v0.4


SMC Dispatcher


Secure Monitor

PSCI

Power Control

Driver

EL3 Arch Context

Save/Restore


Interface Usage

External Interface

EL1 Execution


EL2 Execution




NV - Non-Volatile




EL3 Execution

Potential Interface

Non-secure

firmware - BL33

(U-Boot, EDK2)

Secure Boot

I/O Drivers

Boot ROM - BL1

Trusted Board

Boot 1

Trusted Boot

Firmware - BL2

Trusted Board

Boot 2

Cold/Warm

Boot Detection

NV Storage

Driver

Boot Time Arch

+ Platform Init

Temp SMC

Handler

Boot Time Arch

+ Platform Init


PSCI

Test

Service Router

Other

Test

S-EL1 Arch

Context

Save/Restore

Interrupt

Handler

Runtime Arch +

Platform Init


PSCI

Tests

EL1 Arch Context

Save/Restore

EL2 Arch Context

Save/Restore

Other

Tests

Interrupt

Handler

Runtime Arch


Not Yet in v0.3

Partially in v0.3








18


So…

I can’t use it as Trusted Boot isn’t ready

I can’t use my existing Trusted Boot

code

Myth: ARM Trusted Firmware requires using its Trusted Boot








19


So…

I can’t use it as Trusted Boot isn’t ready

I can’t use my existing Trusted Boot

code

Reality

Partners are using Trusted Firmware

with their own Trusted Boot code

TODAY

The EL3 Runtime Firmware provides

significant benefits on its own

This component will have a stable

interface for Trusted Boot components

Myth: ARM Trusted Firmware requires using its Trusted Boot Reality: ARM Trusted Firmware can work with any Trusted Boot solution


SMC Dispatcher


Secure Monitor

PSCI

Power Control

Driver

EL3 Arch Context

Save/Restore


Interface Usage

External Interface

EL1 Execution


EL2 Execution




NV - Non-Volatile




EL3 Execution

Potential Interface

Non-secure

firmware - BL33

(EDK2, U-Boot)

Secure Boot

I/O Drivers

Boot ROM - BL1

Trusted Board

Boot 1

Trusted Boot

Firmware - BL2

Trusted Board

Boot 2

Cold/Warm

Boot Detection

NV Storage

Driver

Boot Time Arch

+ Platform Init

Temp SMC

Handler

Boot Time Arch

+ Platform Init


PSCI

Test

Service Router

Other

Test

S-EL1 Arch

Context

Save/Restore

Interrupt

Handler

Runtime Arch +

Platform Init


PSCI

Tests

EL1 Arch Context

Save/Restore

EL2 Arch Context

Save/Restore

Other

Tests

Interrupt

Handler

Runtime Arch


BL33

BL33

(Alternative)

BL32 BL2

BL1 BL31

To

Hypervisor /

Linux Kernel








20


So…

I can’t use it for my Server SoC

I can’t use it for my Client SoC

It doesn’t work with a SCP/BMC

Myth: ARM Trusted Firmware is not for my kind of SoC








21


So…

I can’t use it for my Server SoC

I can’t use it for my Client SoC

It doesn’t work with a SCP/BMC

Reality

Trusted Firmware is focussed on ARMv8-A

Upstream examples need a platform to run

the Base FVPs came first

other examples will follow

Trusted Boot flow with a control/

management processor is different, but not

incompatible with ARM Trusted Firmware

Myth: ARM Trusted Firmware is for my kind of SoC Reality: ARM Trusted Firmware is focussed on ARMv8-A

Base Platform

Cortex-A53, A57

ARMv8

Dual Cluster

big.LITTLE

Power Management

OpenGLES

Foundation

Platform

ARMv8

AEM








22


ARM Trusted Firmware Reality Check

ARM Trusted Firmware Myths

Only works with UEFI

Requires a Trusted OS

No Secure Monitor

Includes a Trusted OS

Only supports AArch64

Isn’t ready

Requires ARM’s Trusted Boot code

Not for Client/Network/Server SoCs








23


ARM Trusted Firmware Reality Check

ARM Trusted Firmware Myths

Only works with UEFI

Requires a Trusted OS

No Secure Monitor

Includes a Trusted OS

Only supports AArch64

Isn’t ready

Requires ARM’s Trusted Boot code

Not for Client/Network/Server SoCs

ARM Trusted Firmware Reality

Works with any non-secure firmware

Trusted OS is optional

Example Monitor code included

Not a Trusted OS

AArch32 examples coming later

Is ready enough

Works with other Trusted Boot code

Designed for all ARMv8-A SoCs








24

ARM Trusted Firmware is for every ARMv8-A system

… but doesn’t yet cover every configuration

… so please get involved

…and help us fill the gaps


Adopt ARM Trusted Firmware









25


Thank you








lca14: lca14-102: adopting arm trusted firmware

Technology

uefi firmware

silicon arm trusted

secure firmware bl33

rom bl1 trusted board

uboot secure boot io

armtrusted firmware

level boot loader bl1

level boot loader bl2