TamaGo - bare metal Go for ARM SoCs

tamago | https://github.com/f-secure-foundry/tamago

Authors

Andrea Barisani
andrea.barisani@f-secure.com | andrea@inversepath.com

Andrej Rosano
andrej.rosano@f-secure.com | andrej@inversepath.com

Introduction

TamaGo is a framework that enables compilation and execution of unencumbered Go applications on bare metal ARM System-on-Chip (SoC) components.

The projects spawns from the desire of reducing the attack surface of embedded systems firmware by removing any runtime dependency on C code and Operating Systems.

The TamaGo framework consists of the following components:

A modified Go distribution which extends GOOS support to the tamago target, allowing bare metal execution.
Go packages for SoC driver support.
Go packages for board support.

The modifications are meant to be minimal for both the Go distribution (< ~4000 LOC changed) and the target application (one import required), with a clean separation from other architectures.

Strong emphasis is placed on code re-use from existing architectures already included within the standard Go runtime, see Internals.

Both aspects are motivated by the desire of providing a framework that allows secure Go firmware development on embedded systems.

Current release level

The current release for the TamaGo modified Go distribution is tamago1.15.5, which adds GOOS=tamago support to go1.15.5.

Binary releases for amd64 and armv7l Linux hosts are available.

Documentation

The main documentation can be found on the project wiki.

The package API documentation can be found on pkg.go.dev.

Supported hardware

The following table summarizes currently supported SoCs and boards.

SoC	Board	SoC package	Board package
NXP i.MX6ULZ	USB armory Mk II	imx6	usbarmory/mark-two
NXP i.MX6ULL	MCIMX6ULL-EVK	imx6	mx6ullevk
BCM2835	Raspberry Pi Zero	bcm2835	pi/pizero
BCM2835	Raspberry Pi 1 Model A+	bcm2835	pi/pi1
BCM2835	Raspberry Pi 1 Model B+	bcm2835	pi/pi1
BCM2836	Raspberry Pi 2 Model B	bcm2835	pi/pi2

Compiling

Go applications are simply required to import, the relevant board package to ensure that hardware initialization and runtime support takes place:

import (
	// Example for USB armory Mk II
	_ "github.com/f-secure-foundry/tamago/board/f-secure/usbarmory/mark-two"
)

Build the TamaGo compiler (or use the latest binary release):

git clone https://github.com/f-secure-foundry/tamago-go -b latest
cd tamago-go/src && ./all.bash
cd ../bin && export TAMAGO=`pwd`/go

Go applications can be compiled with the compiler built in the previous step, with the addition of a few flags/variables:

# Example for USB armory Mk II
GO_EXTLINK_ENABLED=0 CGO_ENABLED=0 GOOS=tamago GOARM=7 GOARCH=arm \
  ${TAMAGO} build -ldflags "-T 0x80010000  -E _rt0_arm_tamago -R 0x1000"

See the respective board package README file for compilation information for each specific target.

Executing and debugging

See the respective board package README file for execution and debugging information for each specific target (real or emulated).

The example application provides sample driver usage and instructions for native as well as emulated execution.

License

tamago | https://github.com/f-secure-foundry/tamago
Copyright (c) F-Secure Corporation

These source files are distributed under the BSD-style license found in the LICENSE file.

The TamaGo logo is adapted from the Go gopher designed by Renee French and licensed under the Creative Commons 3.0 Attributions license. Go Gopher vector illustration by Hugo Arganda.

AlCutter/tamago