Add toolchain for Raspberry Pi cross compilation (open-quantum-safe#618)

mraavi432 · Feb 17, 2020 · f8bfb1a · f8bfb1a
1 parent 410caa7
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diff --git a/.CMake/toolchain-rasppi.cmake b/.CMake/toolchain-rasppi.cmake
@@ -0,0 +1,12 @@
+# apt install gcc-8-arm-linux-gnueabihf
+# cmake -GNinja -DCMAKE_TOOLCHAIN_FILE=../.CMake/toolchain-rasppi.cmake -DUSE_OPENSSL=OFF ..
+
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR arm)
+
+set(CMAKE_C_COMPILER arm-linux-gnueabihf-gcc-8)
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
diff --git a/README.md b/README.md
@@ -122,6 +122,17 @@ If the build fails on macOS, you might have to run `cmake -GNinja -DCMAKE_BUILD_
 
 Binaries can be generated using Visual Studio 2019 with the [CMake Tools](https://marketplace.visualstudio.com/items?itemName=ms-vscode.cmake-tools) extension installed.
 
+### Cross compilation
+
+You can cross compile liboqs for various platform by supplying CMake with an appropriate [toolchain](https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html) file.  
+
+For example, to cross compile for a Raspberry Pi from Ubuntu Bionic:
+
+	apt install gcc-8-arm-linux-gnueabihf
+	mkdir build && cd build
+	cmake -GNinja -DCMAKE_TOOLCHAIN_FILE=../.CMake/toolchain-rasppi.cmake -DUSE_OPENSSL=OFF ..
+	ninja
+
 ## Documentation
 
 Further information can be found in the [wiki](https://github.com/open-quantum-safe/liboqs/wiki).