Add build scripts and continuous integration for ARM (#460)

* Scripts for ARM build

* Set permissions

* Fix ARM script bugs

* Fix typo

* Tweak ARM build

* Update README with ARM build instructions

.travis.yml

@@ -20,6 +20,19 @@ matrix:
         - graphviz
     before_install:
     - sh .travis/install-clang-format-linux.sh
+    script:
+    - .travis/all-tests.sh
+  - os: linux
+    compiler: arm-linux-gnueabi-gcc
+    addons:
+      apt:
+        packages:
+        - gcc-arm-linux-gnueabi
+        - libc6-dev-armel-cross
+        - qemu
+    script:
+    - scripts/arm-cross-compile.sh
+    - scripts/arm-run-tests-qemu.sh
   - os: linux
     compiler: gcc
     env:
@@ -35,6 +48,8 @@ matrix:
         - graphviz
     before_install:
     - sh .travis/install-clang-format-linux.sh
+    script:
+    - .travis/all-tests.sh
   - os: linux
     compiler: gcc
     env: CC_OVERRIDE=gcc-5
@@ -46,6 +61,8 @@ matrix:
         - gcc-5
         - doxygen
         - graphviz
+    script:
+    - .travis/all-tests.sh
   - os: linux
     compiler: gcc
     env:
@@ -60,6 +77,8 @@ matrix:
         - libssl-dev
         - doxygen
         - graphviz
+    script:
+    - .travis/all-tests.sh
   - os: osx
     compiler: clang
     env:
@@ -70,6 +89,8 @@ matrix:
     before_install:
     - brew update
     - brew install libsodium doxygen graphviz
+    script:
+    - .travis/all-tests.sh
   - os: osx
     compiler: clang
     env:
@@ -78,6 +99,5 @@ matrix:
     before_install:
     - brew update
     - brew install doxygen graphviz
-
-script:
-  - .travis/all-tests.sh
+    script:
+    - .travis/all-tests.sh

README.md

@@ -149,14 +149,21 @@ Builds are tested using the Appveyor continuous integration system on Windows Se
 
 The supported schemes are defined in the projects' `winconfig.h` file.
 
-Building on other platforms
+Building and running on ARM
 ---------------------------
 
-We do not yet fully support building liboqs on ARM platforms, but are working towards maintaining ARM support in a future release.
+Binaries for ARM can be cross-compiled from Ubuntu Linux.  Builds are tested using the Travis continuous integration system on Ubuntu 14.04.5 with QEMU target CPU Cortex-A8.
 
-At present, we have successfully built liboqs on a Raspberry Pi 3B (armv7l) with the following configure command:
+In order to cross compile, you need to have an appropriate toolchain installed, and to test you need QEMU installed.  On Ubuntu:
 
-    ./configure --disable-aes-ni --disable-sig-qtesla --disable-kem-frodokem
+	sudo apt install gcc-arm-linux-gnueabi libc6-dev-armel-cross qemu
+	
+Once the toolchain is installed, you can use the following scripts to build and test ARM builds from Ubuntu Linux:
+
+	scripts/arm-cross-compile.sh
+	scripts/arm-run-tests-qemu.sh
+
+At present there are still some quirks with our ARM build, including problems with the Picnic and qTESLA and the known answer tests causing build errors or segmentation faults.  See issues #461, #462, and #463.
 
 Documentation
 -------------

scripts/arm-cross-compile.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+# sudo apt-get install gcc-arm-linux-gnueabi libc6-dev-armel-cross
+
+set -e
+
+CBUILD="$(gcc -dumpmachine)"
+CHOST=arm-linux-gnueabi
+
+rm -rf build-arm
+mkdir build-arm
+PREFIX="$(pwd)/build-arm"
+
+if [ ! -f "openssl-1.1.1a.tar.gz" ]; then
+    wget https://www.openssl.org/source/openssl-1.1.1a.tar.gz
+fi
+rm -rf openssl-1.1.1a
+tar zxf openssl-1.1.1a.tar.gz
+cd openssl-1.1.1a
+CC="${CHOST}-gcc" ./Configure linux-armv4 no-shared no-dso no-hw no-engine no-tests -DOPENSSL_NO_SECURE_MEMORY --prefix="${PREFIX}"
+make -j
+make install_dev
+cd ..
+
+autoreconf -i
+hacks=(
+	gcc_cv_compiler=true	# Detecting at this phase isn't good for cross compilation
+	--disable-aes-ni	# This should be conditionalized on x86 host
+    --disable-sig-picnic
+	CFLAGS=-D_ARM_		# Several files aren't using the right define
+)
+
+./configure --disable-shared --enable-static --host="${CHOST}" --build="$CBUILD" CC="${CHOST}-gcc" --with-openssl-dir="${PREFIX}" "${hacks[@]}"
+make -j
+make -j check LDFLAGS="-L${PREFIX}/lib -static"

scripts/arm-run-tests-qemu.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+# sudo apt-get install qemu
+
+set -e
+
+CHOST=arm-linux-gnueabi
+
+qemu-arm -cpu cortex-a8 -L /usr/arm-linux-gnueabi tests/example_kem
+qemu-arm -cpu cortex-a8 -L /usr/arm-linux-gnueabi tests/test_kem
+
+# qemu-arm -cpu cortex-a8 -L /usr/arm-linux-gnueabi tests/example_sig
+# qemu-arm -cpu cortex-a8 -L /usr/arm-linux-gnueabi tests/test_sig