AoS

Small playground bare-metal programming for raspberry pi 3+ (my own)

I have been inspired by https://github.com/bztsrc/raspi3-tutorial and https://github.com/rust-embedded/rust-raspi3-OS-tutorials

setup env`(macOS)

./setup.sh

compile and run

• to compile rust programs

make

• to run the kernel and programs

setup the tty to simulate the serial

socat pty,link=cu.serial-master,raw,echo=0 pty,link=cu.serial-slave,raw,echo=0

prepare the sender

pip install pyserial

python3 load.py cu.serial-slave

run arguments

./run.sh

show instructions and interruption

./run.sh -d in_asm,int

Run on real hardware

• wire the cable et setup the link

python3 load.py `ls /dev/cu.usb*`

• launch raspi (python will show the debug output)

copy on SD card and run on Raspi

Files to be found here : https://github.com/raspberrypi/firmware/tree/master/boot

• bootcode.bin
• start.elf
• fixup.dat

Schematics with my USB-to-serial

Troubleshooting

Exception Handling

Reference : SysReg_xml_v85A-2019-06.pdf (page 418)

ELR : The execption returns (where the exception occured if data fault or synchronous) ESR_ELx : Register holding exception information :

EC : Exception Class

Disassembling

• Disassemble stripped version

aarch64-none-elf-objdump -b binary -maarch64 -D program.img

• Disassemble version with symbol

aarch64-none-elf-objdump -g -D target/aarch64-unknown-none/release/aos-kernel