swarren / rpi-3-aarch64-demo

Simplest possible code to demonstrate RPi 3 running AArch64 code

This repository contains a simple AArch64 test for the Raspberry Pi 3. It relies on the VideoCore firmware providing a suitable 64-bit ARM stub. As of 20160406, the released version doesn't, but a pre-release is available at raspberrypi/firmware#579 (comment).

If you want to experiment with changes to the ARM stub code, find the source at: https://github.com/raspberrypi/tools/tree/master/armstubs. You can copy armstub8.bin to the boot partition on the SD card, and the FW will use that file rather than the built-in version.

Some of the application code is stolen from U-Boot, including some from my recently upstreamed AArch32 port of U-Boot to the Raspberry Pi 3:

• git://git.denx.de/u-boot.git
• git://github.com/swarren/u-boot.git

To build, simply run ./build.sh. This was tested on Ubuntu 16.04. You will need an aarch64-linux-gnu-gcc binary (i.e. gcc-aarch64-linux-gnu package) or equivalent.

To make a bootable SD card, start with a recent Raspbian image, update all the firmware files to a version that includes the 64-bit ARM stub, and:

• Copy config.txt to the boot partition.
• Delete armstub*.bin from the boot partition.
• Delete kernel*.img from the boot partition.
• Copy app.bin to the boot partition as kernel8.img.

You'll need a serial console running at 115200 baud to observe the code running.

If you want to use the PL011 UART instead of the mini UART, you'll need to perform at least the following steps:

• Modify app.c's UART IO routines.
• run mkknlimg on app.bin rather than using it raw. This tells the VC FW to process DT overlays, and doing so is required to switch between UARTs.
• Add "dtoverlay=pi3-miniuart-bt" to config.txt.

rpi-3-aarch64-demo's Issues

Compilation error in main.c

I fixed (sukantoghosh@03d941e) the following compilation error in main.c when compiled with Linaro gcc 4.8.2 ($ aarch64-linux-gnu-gcc --version
aarch64-linux-gnu-gcc (crosstool-NG linaro-1.13.1-4.8-2013.08 - Linaro GCC 2013.08) 4.8.2 20130805 (prerelease))

+ aarch64-linux-gnu-gcc -c -o main.o main.c
main.c: In function ‘dbg_puthex32’:
main.c:77:2: error: ‘for’ loop initial declarations are only allowed in C99 mode
  for (int i = 28; i >= 0; i -= 4)
  ^
main.c:77:2: note: use option -std=c99 or -std=gnu99 to compile your code

test.bin or test to kernel7.img?

Hi, thank you for your work!

The readme says:

Copy test.bin to the boot partition as kernel7.img

Is it really be test.bin, not the file test? Reason: test.bin is not recognized as aarch64, but test is:

sander@haring:~/git/rpi-3-aarch64-demo$ file test
test: ELF 64-bit LSB  executable, ARM aarch64, version 1 (SYSV), statically linked, not stripped

sander@haring:~/git/rpi-3-aarch64-demo$ file test.bin
test.bin: data

I have no Raspi3 at hand to test it, so I'm asking here.

FWIW: build process on my Ubuntu 14.04:

sander@haring:~/git/rpi-3-aarch64-demo$ ./build.sh 
./build.sh: line 7: aarch64-linux-gnu-gcc: command not found

sander@haring:~/git/rpi-3-aarch64-demo$ sudo apt-get install gcc-aarch64-linux-gnu

sander@haring:~/git/rpi-3-aarch64-demo$ ./build.sh