4. Cross compiling DPDK for ARM64

This chapter describes how to cross compile DPDK for ARM64 from x86 build hosts.

Note

Whilst it is recommended to natively build DPDK on ARM64 (just like with x86), it is also possible to cross compile DPDK for ARM64. An ARM64 cross compiler GNU toolchain or an LLVM/clang toolchain may be used for cross-compilation.

4.1. Prerequisites

4.1.1. NUMA library

NUMA is required by most modern machines, not needed for non-NUMA architectures.

Note

For compiling the NUMA lib, run libtool –version to ensure the libtool version >= 2.2, otherwise the compilation will fail with errors.

git clone https://github.com/numactl/numactl.git
cd numactl
git checkout v2.0.13 -b v2.0.13
./autogen.sh
autoconf -i
./configure --host=aarch64-linux-gnu CC=<compiler> --prefix=<numa install dir>
make install

Note

The compiler above can be either aarch64-linux-gnu-gcc or clang. See below for information on how to get specific compilers.

The numa header files and lib file is generated in the include and lib folder respectively under <numa install dir>.

4.1.2. Meson prerequisites

Meson depends on pkgconfig to find the dependencies. The package pkg-config-aarch64-linux-gnu is required for aarch64. To install it in Ubuntu:

sudo apt install pkg-config-aarch64-linux-gnu

4.2. GNU toolchain

4.2.1. Obtain the cross toolchain

The latest GNU cross compiler toolchain can be downloaded from: https://developer.arm.com/open-source/gnu-toolchain/gnu-a/downloads.

It is always recommended to check and get the latest compiler tool from the page and use it to generate better code. As of this writing 9.2-2019.12 is the newest, the following description is an example of this version.

wget https://developer.arm.com/-/media/Files/downloads/gnu-a/9.2-2019.12/binrel/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu.tar.xz

4.2.2. Unzip and add into the PATH

tar -xvf gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu.tar.xz
export PATH=$PATH:<cross_install_dir>/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/bin

Note

For the host requirements and other info, refer to the release note section: https://releases.linaro.org/components/toolchain/binaries/

4.2.3. Augment the GNU toolchain with NUMA support

Note

This way is optional, an alternative is to use extra CFLAGS and LDFLAGS.

Copy the NUMA header files and lib to the cross compiler’s directories:

cp <numa_install_dir>/include/numa*.h <cross_install_dir>/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/aarch64-none-linux-gnu/libc/usr/include/
cp <numa_install_dir>/lib/libnuma.a <cross_install_dir>/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/lib/gcc/aarch64-none-linux-gnu/9.2.1/
cp <numa_install_dir>/lib/libnuma.so <cross_install_dir>/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/lib/gcc/aarch64-none-linux-gnu/9.2.1/

4.2.4. Cross Compiling DPDK with GNU toolchain using Meson

To cross-compile DPDK on a desired target machine we can use the following command:

meson cross-build --cross-file <target_machine_configuration>
ninja -C cross-build

For example if the target machine is aarch64 we can use the following command:

meson aarch64-build-gcc --cross-file config/arm/arm64_armv8_linux_gcc
ninja -C aarch64-build-gcc

4.3. LLVM/Clang toolchain

4.3.1. Obtain the cross tool chain

The latest LLVM/Clang cross compiler toolchain can be downloaded from: https://developer.arm.com/tools-and-software/open-source-software/developer-tools/llvm-toolchain.

# Ubuntu binaries
wget https://github.com/llvm/llvm-project/releases/download/llvmorg-10.0.0/clang+llvm-10.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz

The LLVM/Clang toolchain does not implement the standard c library. The GNU toolchain ships an implementation we can use. Refer to obtain_GNU_toolchain to get the GNU toolchain.

4.3.2. Unzip and add into the PATH

tar -xvf clang+llvm-10.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz
export PATH=$PATH:<cross_install_dir>/clang+llvm-10.0.0-x86_64-linux-gnu-ubuntu-18.04/bin

4.3.3. Cross Compiling DPDK with LLVM/Clang toolchain using Meson

Note

To use the NUMA library follow the same steps as for augment_the_gnu_toolchain_with_numa_support.

The paths to GNU stdlib must be specified in a cross file. Augmenting the default cross-file’s c_args and c_link_args config/arm/arm64_armv8_linux_clang_ubuntu1804 would look like this:

...
c_args = ['-target', 'aarch64-linux-gnu', '--sysroot', '<cross_install_dir>/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/aarch64-none-linux-gnu/libc']
c_link_args = ['-target', 'aarch64-linux-gnu', '-fuse-ld=lld', '--sysroot', '<cross_install_dir>/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu/aarch64-none-linux-gnu/libc', '--gcc-toolchain=<cross_install_dir>/gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu']

Assuming the file with augmented c_args and c_link_args is named arm64_armv8_linux_clang, use the following command to cross-compile DPDK for the target machine:

meson aarch64-build-clang --cross-file config/arm/arm64_armv8_linux_clang
ninja -C aarch64-build-clang

4.3.4. Cross Compiling DPDK with LLVM/Clang toolchain using Meson on Ubuntu 18.04

On most popular Linux distribution it is not necessary to download the toolchains, but rather use the packages provided by said distributions. On Ubuntu 18.04, these packages are needed:

sudo apt-get install pkg-config-aarch64-linux-gnu clang llvm llvm-dev lld
libc6-dev-arm64-cross libatomic1-arm64-cross libgcc-8-dev-arm64-cross

Use the following command to cross-compile DPDK for the target machine:

meson aarch64-build-clang --cross-file config/arm/arm64_armv8_linux_clang_ubuntu1804
ninja -C aarch64-build-clang

4.4. Building for an aarch64 SoC on an aarch64 build machine

If you wish to build on an aarch64 build machine for a different aarch64 SoC, you don’t need a separate cross toolchain, just a different set of configuration options. To build for an aarch64 SoC, use the -Dplatform meson option:

meson soc_build -Dplatform=<target_soc>

Substitute <target_soc> with one of the supported SoCs:

generic:     Generic un-optimized build for all aarch64 machines.
armada:      Marvell ARMADA
bluefield:   NVIDIA BlueField
dpaa:        NXP DPAA
emag:        Ampere eMAG
graviton2:   AWS Graviton2
n1sdp:       Arm Neoverse N1SDP
octeontx2:   Marvell OCTEON TX2
stingray:    Broadcom Stingray
thunderx2:   Marvell ThunderX2 T99
thunderxt88: Marvell ThunderX T88

These SoCs are also used in cross files, e.g.:

[properties]
# Generate binaries that are portable across all Armv8 machines
platform = 'generic'

4.5. Supported SoC configuration

The SoC configuration is a combination of implementer and CPU part number configuration and SoC-specific configuration:

soc_<name> = {
   'description': 'SoC Description',  # mandatory
   'implementer': <implementer_id>,   # mandatory
   'part_number': <part_number>,      # mandatory
   'numa': false,  # optional, specify for non-NUMA SoCs
   'enable_drivers': 'common/*,bus/*',  # optional, comma-separated list of
                           # drivers to build, wildcards are accepted
   'disable_drivers': 'crypto/*',       # optional, comma-separated list of
                           # drivers to disable, wildcards are accepted
   'flags': [
      ['RTE_MAX_LCORE', '16'],
      ['RTE_MAX_NUMA_NODES', '1']
   ]               # optional, list of DPDK options that will be added
                   # or overwritten
}

Where <implementer_id> is a key defined in the implementers dictionary in config/arm/meson.build (e.g. 0x41) and part_number is a key defined in implementers[<implementer_id>][‘part_number_config’] dictionary (i.e. the part number must be defined for the implementer, e.g. for 0x41, a valid value is 0xd49, which is the neoverse-n2 SoC).