[Tutorial] Building lastest raspberry pi kernel for 64-bit Ubuntu (20.10)

One of the great parts about running Ubuntu is that just about all the Ubuntu-isms you’ve learned for other platforms work here too. Start with these links:

https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel
https://wiki.ubuntu.com/KernelTeam/ARMK … ossCompile
https://wiki.ubuntu.com/KernelTeam/Kern … k_failures
https://askubuntu.com/questions/500095/ … er-version
https://bugs.launchpad.net/ubuntu/+sour … ug/1701756

What follows isn’t very polished, since came out of my notebook verbatim. This is how I built the kernel.

First uncomment the relevant line int /etc/apt/sources.list:

deb-src http://ports.ubuntu.com/ubuntu-ports focal-updates main restricted

Update the package database:

apt update

Get the kernel source package, as root in some place where you want it. Alternatively replace $(uname -r) with the version you want. This is probably easiest to do on the target:

apt-get source linux-image-$(uname -r)

If this is on a target, copy it to a dev machine.

Over on the dev machine, hack up your kernel as you please. Then in debian.raspi/changelog, edit the first version number from something like this:

linux-raspi (5.4.0-1019.21) focal; urgency=medium

to something like this:

linux-raspi (5.4.0-1019.21+g34950~20200925) focal; urgency=medium

Note that CONFIG_LOCALVERSION will break the Ubuntu scripts, and EXTRAVERSION in the highest level makefile doesn’t do anything interesting.

Set some environment variables:

export $(dpkg-architecture -aarm64); export CROSS_COMPILE=aarch64-linux-gnu-

Now change into the root directory of the source tree and clean the build area:

fakeroot debian/rules clean

Kick off a menuconfig session with script:

fakeroot debian/rules editconfigs

menuconfig insists on running once each for 32 and 64 bit builds of kernel.

Now build the kernel and associated packages. We skip checks that are likely to break because of a changed list of modules:

fakeroot debian/rules binary skipmodule=true skipabi=true

This will result in the following .deb packages being created in the level ABOVE the kernel source tree:

linux-buildinfo-5.4.0-1019-raspi_5.4.0-1019.21+g34950~20200925_arm64.deb
linux-headers-5.4.0-1019-raspi_5.4.0-1019.21+g34950~20200925_arm64.deb
linux-image-5.4.0-1019-raspi_5.4.0-1019.21+g34950~20200925_arm64.deb
linux-modules-5.4.0-1019-raspi_5.4.0-1019.21+g34950~20200925_arm64.deb
linux-raspi-headers-5.4.0-1019_5.4.0-1019.21+g34950~20200925_arm64.deb

After copying to the target, each of the relevant packages may be installed there with dpkg:

dpkg -i linux-headers-5.4.0-1019-raspi_5.4.0-1019.21+g34950~20200925_arm64.deb
dpkg -i linux-image-5.4.0-1019-raspi_5.4.0-1019.21+g34950~20200925_arm64.deb
dpkg -i linux-modules-5.4.0-1019-raspi_5.4.0-1019.21+g34950~20200925_arm64.deb
dpkg -i linux-raspi-headers-5.4.0-1019_5.4.0-1019.21+g34950~20200925_arm64.deb

[Tutorial] Installing OpenCV on Raspberry Pi 4B with Ubuntu 20.04

This guide will show how to install OpenCV 4.5.0 (latest) on Raspberry Pi 4B running Ubuntu Server 20.04, where architecture is ARM64 (aarch64) – which is unusal part.

but installing procedure never changes – thanks to CMake. We can build own library within Raspberry Pi with following tutorials.

OpenCV-aarch64

This is a guide to natively install OpenCV on aarch64/arm64 devices (Updated 2020-12-13, by @LimeOrangePie)

Pre-requisites

Your aarch64 device should have Ubuntu/Debian/Armbian OS flashed on it.

Steps

  1. Install dependencies
sudo apt-get install python3-dev python3-pip python3-numpy

sudo apt-get install build-essential cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev  libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libdc1394-22-dev protobuf-compiler libgflags-dev libgoogle-glog-dev libblas-dev libhdf5-serial-dev liblmdb-dev libleveldb-dev liblapack-dev libsnappy-dev libprotobuf-dev libopenblas-dev libgtk2.0-dev libboost-dev libboost-all-dev libeigen3-dev libatlas-base-dev libne10-10 libne10-dev

pip3 install neon

sudo apt-get install libneon27-dev

sudo apt-get install libneon27-gnutls-dev
  1. Download Source
cd ~/

git clone https://github.com/opencv/opencv.git -b 4.5.0 --single-branch

git clone https://github.com/opencv/opencv_contrib.git -b 4.5.0 --single-branch
  1. Configuring OpenCV using cmake:

Put your username in place of [username] below for the path to opencv_contrib/modules

mkdir opencv_build

cd opencv_build

cmake -D CMAKE_BUILD_TYPE=RELEASE -D ENABLE_NEON=ON -D ENABLE_TBB=ON -D ENABLE_IPP=ON -D ENABLE_VFVP3=ON -D WITH_OPENMP=ON -D WITH_CSTRIPES=ON -D WITH_OPENCL=ON -D CMAKE_INSTALL_PREFIX=/usr/local -D OPENCV_EXTRA_MODULES_PATH=../opencv_contrib/modules/ ../opencv
  1. Compilation:
make -j${nproc}

sudo make install
  1. Testing:
python3
>>import cv2
>>

Repository: https://github.com/jungin500/OpenCV-aarch64

Original Repository: https://github.com/huzz/OpenCV-aarch64

(Reference) Build 64-bit kernel for Raspberry Pi 3, using native tools

Reference

Guide on how to build a 64-bit kernel for the Raspberry Pi 3 & 3+ boards, on device, using native 64-bit cross-compilation tools. Using kernel branch 4.14 at time of writing.

The SoC on the Raspberry Pi 3 & 3+ supports 64-bit ARM mode, unfortunately raspbian and the foundation does not provide 64-bit support or userland even if they are advertising the Pi 3 as a 64-bit platform.

There are 3 ways to get a 64-bit kernel compiled:

  1. Native build on another 64-bit ARM platform
  2. Cross-compilation on another platform
  3. Cross-compilation on the Pi 3 itself

This tutorial will explain how to do option number 3. (And will actually work just fine for option number 2 as they are pretty much the same).

Note: The tools should work just fine for building a 64-bit kernel for the Raspberry Pi 4 too. Unfortunately the author does not have Pi 4 at this time so kernel configuration, building and booting has not been tested and therefor has been omitted for now.

Note: You will need plenty of space when building as the sources and build results for both the tools and kernel takes quite a lot of space. Also a heat sink is highly recommended if building in parallel.

Time: Speed is relative. The Raspberry Pi 3 is fast or slow, depending on what you compare it to. Even so, it will take a while to build everything, for example C-compiler only gcc will about 85 minutes to build using non-parallel make on a Pi 3.

Install essential build tools and development packages

As we need to build the tools we need, that is aarch64 binutils and gcc, we need to install the required build tools first. Start by first installing required dependencies for compilation of these tools:

sudo apt-get install build-essential libgmp-dev libmpfr-dev libmpc-dev libisl-dev libncurses5-dev bc git-core bison flex

Build the cross compilation tools

To be able to cross-compile we need to build a couple of tools ourselves as they are not provided. These are aarch64 versions of binutils (assembler, linker) and gcc (C compiler). We will install these tools in their own prefix or path,

/opt/aarch64

We will also use out-of-source build directories to keep the sources clean. This is handy if you need to re-configure, re-build or start over without needing to clean the source tree.

Build and install Binutils

We will start with building the low-level tool, binutils. Binutils is basically an assembler and linker.

Download the latest binutils, (Tested with 2.29.1 at time of writing, feel free to try any later versions (2.30 is reported not to work!) when available)

wget https://ftp.gnu.org/gnu/binutils/binutils-2.29.1.tar.bz2

Untar the binutils archive

tar xf binutils-2.29.1.tar.bz2

Configure build and install

mkdir binutils-obj
cd binutils-obj
../binutils-2.29.1/configure --prefix=/opt/aarch64 --target=aarch64-linux-gnu --disable-nls
make -j4
sudo make install

Binutils is now installed, to be able to use it directly, add “/opt/aarch64/bin/” to your path:

export PATH=$PATH:/opt/aarch64/bin/

Build and install GCC

Next up is gcc, the C compiler. We will build a minimal compiler for C only and no userland support. This is enough to get a aarch64 kernel compiled.

Download latest stable gcc (Tested with 6.4.0 at time of writing, feel free to try any later version when available):

wget https://ftp.gnu.org/gnu/gcc/gcc-6.4.0/gcc-6.4.0.tar.xz

Untar the gcc archive

tar xf gcc-6.4.0.tar.xz

Next configure gcc and build gcc. We will configure the build for only a minimal C compiler, that is enough for building a kernel.

mkdir gcc-out
cd gcc-out
../gcc-6.4.0/configure --prefix=/opt/aarch64 --target=aarch64-linux-gnu --with-newlib --without-headers \
 --disable-nls --disable-shared --disable-threads --disable-libssp --disable-decimal-float \
 --disable-libquadmath --disable-libvtv --disable-libgomp --disable-libatomic \
 --enable-languages=c
make all-gcc -j4
sudo make install-gcc

Test that the cross gcc runs ok, run:

aarch64-linux-gnu-gcc -v

It should report something close to this is everything is ok:

Using built-in specs.

COLLECT_GCC=aarch64-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/opt/aarch64/libexec/gcc/aarch64-linux-gnu/6.4.0/lto-wrapper
Target: aarch64-linux-gnu
Configured with: ../gcc-6.4.0/configure --prefix=/opt/aarch64 --target=aarch64-linux-gnu --with-newlib --without-headers --disable-shared --enable-languages=c
Thread model: posix
gcc version 6.4.0 (GCC)

If all is well, then you can continue to building the kernel itself!

Optional: libgcc

The C-only compiler we built above is enough for building a Linux kernel and is enough for this guide. But, if you would like to for example build and use u-boot, then you will need to build libgcc, a static library that contains shared code and various helper functions. Building and installing libgcc is fortunately easy, just do the following after building gcc:

make all-target-libgcc
make install-target-libgcc

Build the Linux kernel

Now you have a toolchain that is able to build 64-bit ARM kernels. So the next step is to download the Raspberry Pi kernel sources, configure them and build a 64-bit kernel and modules.

Download Linux kernel sources

Get the most up to date stable branch kernel sources (4.14 branch at time of writing) directly from the Raspberry Pi GitHub repository with

git clone --depth=1 -b rpi-4.14.y https://github.com/raspberrypi/linux.git
Keeping sources fresh

The Linux kernel is a moving target and evolves almost daily. To keep updated with latest changes, run the following command in the directory you checked out above:

git pull

Configure Linux kernel for 64-bit Raspberry Pi 3

We use output directory for kernel build so we can use the same source tree for other configuration (32-bit for example)

mkdir kernel-out
cd linux
make O=../kernel-out/ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-  bcmrpi3_defconfig

The kernel build is now configured with a default configuration for a 64-bit Raspberry Pi kernel.

In case you need to customize the configuration (Add support for some specific hardware, trim out things you don't need or otherwise mess around with the configuration) run

make O=../kernel-out/ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig

and adjust the configuration for your needs.

Build the kernel and modules

Next build the kernel and modules with:

make -j4 O=../kernel-out/ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-

If all goes well, as it should, you should now have a 64-bit kernel, modules and device tree built.

Keep up with kernel development

The Linux kernel evolves and so does the Raspberry Pi kernel too. To keep up with development changes you can ask git to download changes to your kernel source tree. To do that run the following command in the kernel source locations:

git pull

This will download any changes made to the kernel source.

Update kernel configuration

After pulling in changes I personally like to always run, just in case:

make -j4 O=../kernel-out/ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- oldconfig

Next step:

Booting 64-bit kernel on Raspberry Pi 3

Changelog:

11/04/2018 – 13:15

  • Update to 4.14