chore(ci): adding 2 dockerfiles to test ARM64 cross-compilation

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

docker/Dockerfile.base.ubuntu20.cross-arm64

+#/*
+# * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+# * contributor license agreements.  See the NOTICE file distributed with
+# * this work for additional information regarding copyright ownership.
+# * The OpenAirInterface Software Alliance licenses this file to You under
+# * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+# * except in compliance with the License.
+# * You may obtain a copy of the License at
+# *
+# *      http://www.openairinterface.org/?page_id=698
+# *
+# * Unless required by applicable law or agreed to in writing, software
+# * distributed under the License is distributed on an "AS IS" BASIS,
+# * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# * See the License for the specific language governing permissions and
+# * limitations under the License.
+# *-------------------------------------------------------------------------------
+# * For more information about the OpenAirInterface (OAI) Software Alliance:
+# *      contact@openairinterface.org
+# */
+#---------------------------------------------------------------------
+#
+# Dockerfile for the Open-Air-Interface BUILD service
+#   Valid for Ubuntu 20.04 to cross-compile for ARM64
+#
+#---------------------------------------------------------------------
+
+# Very important, the focal image shall not be using mirrors. A lot of them do NOT support ARM64.
+FROM ubuntu:focal AS ran-base
+ENV DEBIAN_FRONTEND=noninteractive
+ENV TZ=Europe/Paris
+
+#install developers pkg/repo
+RUN apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get upgrade --yes && \
+    #enabling arm64 architecture
+    dpkg --add-architecture arm64 && \
+    echo "deb [arch=arm64] http://ports.ubuntu.com/ focal main restricted\n" \
+         "deb [arch=arm64] http://ports.ubuntu.com/ focal-updates main restricted\n" \
+         "deb [arch=arm64] http://ports.ubuntu.com/ focal universe\n" \
+         "deb [arch=arm64] http://ports.ubuntu.com/ focal-updates universe\n" \
+         "deb [arch=arm64] http://ports.ubuntu.com/ focal multiverse\n" \
+         "deb [arch=arm64] http://ports.ubuntu.com/ focal-updates multiverse\n" \
+         "deb [arch=arm64] http://ports.ubuntu.com/ focal-backports main restricted universe multiverse" \
+         | tee /etc/apt/sources.list.d/arm-cross-compile-sources.list && \
+    cp /etc/apt/sources.list "/etc/apt/sources.list.`date`.backup" && \
+    sed -i -E "s/(deb)\ (http:.+)/\1\ [arch=amd64]\ \2/" /etc/apt/sources.list && \
+    apt-get update && \
+    DEBIAN_FRONTEND=noninteractive apt-get upgrade --yes && \
+    DEBIAN_FRONTEND=noninteractive apt-get install --yes \
+      build-essential \
+      psmisc \
+      git \
+      tzdata \
+      xxd \
+      # ARM64 packages
+      libatlas-base-dev:arm64 \
+      libblas-dev:arm64 \
+      liblapack-dev:arm64 \
+      liblapacke-dev:arm64 \
+      libreadline-dev:arm64 \
+      libgnutls28-dev:arm64 \
+      libconfig-dev:arm64 \
+      libsctp-dev:arm64 \
+      libssl-dev:arm64 \
+      libtool:arm64 \
+      zlib1g-dev:arm64 \
+      # cross build libs and compilers
+      libc6-dev-i386 \
+      gcc-9-aarch64-linux-gnu \
+      g++-9-aarch64-linux-gnu && \
+    apt-get clean
+
+# create the WORKDIR
+WORKDIR /oai-ran
+COPY . .
+
+#run build_oai -I to get the builder image
+RUN /bin/sh oaienv && \
+    cd cmake_targets && \
+    mkdir -p log && \
+    ./build_oai -I && \
+    apt-get clean

docker/Dockerfile.build.ubuntu20.cross-arm64

+#/*
+# * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+# * contributor license agreements.  See the NOTICE file distributed with
+# * this work for additional information regarding copyright ownership.
+# * The OpenAirInterface Software Alliance licenses this file to You under
+# * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+# * except in compliance with the License.
+# * You may obtain a copy of the License at
+# *
+# *      http://www.openairinterface.org/?page_id=698
+# *
+# * Unless required by applicable law or agreed to in writing, software
+# * distributed under the License is distributed on an "AS IS" BASIS,
+# * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# * See the License for the specific language governing permissions and
+# * limitations under the License.
+# *-------------------------------------------------------------------------------
+# * For more information about the OpenAirInterface (OAI) Software Alliance:
+# *      contact@openairinterface.org
+# */
+#---------------------------------------------------------------------
+#
+# Dockerfile for the Open-Air-Interface BUILD service
+#   Valid for Ubuntu 20.04 to cross-compile for ARM64
+#
+#---------------------------------------------------------------------
+
+FROM ran-base:latest as ran-build
+
+RUN rm -Rf /oai-ran
+WORKDIR /oai-ran
+COPY . .
+
+# build all targets so final targets can be created afterwards
+RUN /bin/sh oaienv && \
+    cd cmake_targets && \
+    mkdir -p ran_build/build ran_build/build-cross && \
+    cd ran_build/build && \
+    cmake ../../.. -GNinja && \
+    echo "====== Start of log for host-tools ======" && \
+    ninja ldpc_generators generate_T && \
+    echo "====== End of log for host-tools ======" && \
+    cd ../build-cross/ && \
+    cmake ../../.. -GNinja -DCMAKE_TOOLCHAIN_FILE=../../../cmake_targets/cross-arm.cmake -DNATIVE_DIR=../build && \
+    echo "====== Start of log for cross-build executables ======" && \
+    ninja dlsim ulsim ldpctest polartest smallblocktest nr_pbchsim nr_dlschsim nr_ulschsim nr_dlsim nr_ulsim nr_pucchsim nr_prachsim lte-softmodem nr-softmodem nr-cuup oairu lte-uesoftmodem nr-uesoftmodem params_libconfig coding rfsimulator && \
+    echo "====== End of log for cross-build executables ======"