usbarmory/

README

TamaGo - bare metal Go for ARM SoCs - USB armory support

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

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

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 usbarmory package provides support for the USB armory Single Board Computer.

Documentation

For more information about TamaGo see its repository and project wiki.

For the underlying driver support for this board see package imx6.

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

Supported hardware

SoC	Board	SoC package	Board package
NXP i.MX6ULZ	USB armory Mk II	imx6	usbarmory/mark-two

Compiling

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

import (
	_ "github.com/f-secure-foundry/tamago/board/f-secure/usbarmory/mark-two"
)

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

wget https://github.com/f-secure-foundry/tamago-go/archive/refs/tags/latest.zip
unzip latest.zip
cd tamago-go-latest/src && ./all.bash
cd ../bin && export TAMAGO=`pwd`/go

Go applications can be compiled as usual, using the compiler built in the previous step, but with the addition of the following flags/variables and ensuring that the required SoC and board packages are available in GOPATH:

GO_EXTLINK_ENABLED=0 CGO_ENABLED=0 GOOS=tamago GOARM=7 GOARCH=arm \
  ${TAMAGO} build -ldflags "-T 0x80010000  -E _rt0_arm_tamago -R 0x1000"

An example application, targeting the USB armory Mk II platform, is available.

Executing and debugging

The example application provides reference usage and a Makefile target for automatic creation of an ELF as well as imx image for flashing.

Native hardware: imx image

Follow these instructions using built imx images.

Native hardware: existing bootloader

Copy the built ELF binary on an external microSD card (replace $dev with 0) or the internal eMMC (replace $dev with 1), then launch it from the U-Boot console as follows:

ext2load mmc $dev:1 0x90000000 example
bootelf -p 0x90000000

For non-interactive execution modify the U-Boot configuration accordingly.

Standard output

The standard output can be accessed through the debug accessory and the following picocom configuration:

picocom -b 115200 -eb /dev/ttyUSB2 --imap lfcrlf

Debugging

The application can be debugged with GDB over JTAG using openocd (version > 0.11.0) and the gdbinit debugging helper published here.

# start openocd daemon
openocd -f interface/ftdi/jtagkey.cfg -f target/imx6ul.cfg -c "adapter speed 1000"

# connect to the OpenOCD command line
telnet localhost 4444

# debug with GDB
arm-none-eabi-gdb -x gdbinit example

Hardware breakpoints can be set in the usual way:

hb ecdsa.Verify
continue

QEMU

The target can be executed under emulation as follows:

qemu-system-arm \
	-machine mcimx6ul-evk -cpu cortex-a7 -m 512M
	\ -nographic -monitor none -serial null -serial stdio -net none
	\ -kernel example -semihosting -d unimp

The emulated target can be debugged with GDB by adding the -S -s flags to the previous execution command, this will make qemu waiting for a GDB connection that can be launched as follows:

arm-none-eabi-gdb -ex "target remote 127.0.0.1:1234" example

Breakpoints can be set in the usual way:

b ecdsa.Verify
continue

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.