Add support for compiling modules into kernel side

Define __KERNEL__ macro during compilation and place the module in separate library

Remove default library linking to m or libc on NuttX. Add these in platform layer instead, since
they are different on kernel and user side

Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>

CMakeLists.txt

@@ -125,6 +125,11 @@ define_property(GLOBAL PROPERTY PX4_MODULE_LIBRARIES
                  FULL_DOCS "List of all PX4 module libraries"
                  )
 
+define_property(GLOBAL PROPERTY PX4_KERNEL_MODULE_LIBRARIES
+                 BRIEF_DOCS "PX4 kernel side module libs"
+                 FULL_DOCS "List of all PX4 kernel module libraries"
+                 )
+
 define_property(GLOBAL PROPERTY PX4_MODULE_PATHS
                  BRIEF_DOCS "PX4 module paths"
                  FULL_DOCS "List of paths to all PX4 modules"
@@ -142,6 +147,7 @@ set(CONFIG "px4_sitl_default" CACHE STRING "desired configuration")
 
 include(px4_add_module)
 set(config_module_list)
+set(config_kernel_list)
 
 include(px4_config)
 include(px4_add_board)

cmake/px4_add_board.cmake

@@ -147,6 +147,9 @@ function(px4_add_board)
 			CRYPTO
 			KEYSTORE
 		MULTI_VALUE
+			KERNEL_DRIVERS
+			KERNEL_MODULES
+			KERNEL_SYSTEMCMDS
 			DRIVERS
 			MODULES
 			SYSTEMCMDS
@@ -296,6 +299,28 @@ function(px4_add_board)
 	###########################################################################
 	# Modules (includes drivers, examples, modules, systemcmds)
 	set(config_module_list)
+        set(config_kernel_list)
+
+	if(KERNEL_DRIVERS)
+		foreach(driver ${KERNEL_DRIVERS})
+			list(APPEND config_module_list drivers/${driver})
+			list(APPEND config_kernel_list drivers/${driver})
+		endforeach()
+	endif()
+
+	if(KERNEL_MODULES)
+		foreach(module ${KERNEL_MODULES})
+			list(APPEND config_module_list modules/${module})
+			list(APPEND config_kernel_list modules/${module})
+		endforeach()
+	endif()
+
+	if(KERNEL_SYSTEMCMDS)
+		foreach(systemcmd ${KERNEL_SYSTEMCMDS})
+			list(APPEND config_module_list systemcmds/${systemcmd})
+			list(APPEND config_kernel_list systemcmds/${systemcmd})
+		endforeach()
+	endif()
 
 	if(DRIVERS)
 		foreach(driver ${DRIVERS})
@@ -326,5 +351,6 @@ function(px4_add_board)
 	list(APPEND config_module_list ${board_support_src_rel}/src)
 
 	set(config_module_list ${config_module_list} PARENT_SCOPE)
+	set(config_kernel_list ${config_kernel_list} PARENT_SCOPE)
 
 endfunction()

cmake/px4_add_library.cmake

@@ -43,14 +43,10 @@ function(px4_add_library target)
 
 	target_compile_definitions(${target} PRIVATE MODULE_NAME="${target}")
 
-	# all PX4 libraries have access to parameters and uORB
+	add_dependencies(${target} uorb_headers parameters)
-	add_dependencies(${target} uorb_headers)
-	target_link_libraries(${target} PRIVATE prebuild_targets parameters_interface px4_platform uorb_msgs)
 
-	# TODO: move to platform layer
+	# all PX4 libraries have access to uORB
-	if ("${PX4_PLATFORM}" MATCHES "nuttx")
+	target_link_libraries(${target} PRIVATE prebuild_targets uorb_msgs)
-		target_link_libraries(${target} PRIVATE m nuttx_c)
-	endif()
 
 	set_property(GLOBAL APPEND PROPERTY PX4_MODULE_PATHS ${CMAKE_CURRENT_SOURCE_DIR})
 	px4_list_make_absolute(ABS_SRCS ${CMAKE_CURRENT_SOURCE_DIR} ${ARGN})

cmake/px4_add_module.cmake

@@ -153,9 +153,26 @@ function(px4_add_module)
 	# all modules can potentially use parameters and uORB
 	add_dependencies(${MODULE} uorb_headers)
 
+	# Check if the modules source dir exists in config_kernel_list
+	# in this case, treat is as a kernel side component for
+	# protected build
+	get_target_property(MODULE_SOURCE_DIR ${MODULE} SOURCE_DIR)
+	file(RELATIVE_PATH module ${PROJECT_SOURCE_DIR}/src ${MODULE_SOURCE_DIR})
+
+	list (FIND config_kernel_list ${module} _index)
+	if (${_index} GREATER -1)
+		set (KERNEL TRUE)
+	endif()
+
 	if(NOT DYNAMIC)
-		target_link_libraries(${MODULE} PRIVATE prebuild_targets parameters_interface px4_layer px4_platform systemlib)
+		target_link_libraries(${MODULE} PRIVATE prebuild_targets parameters_interface px4_platform systemlib perf)
+		if (${PX4_PLATFORM} STREQUAL "nuttx" AND NOT CONFIG_BUILD_FLAT AND KERNEL)
+			target_link_libraries(${MODULE} PRIVATE px4_kernel_layer uORB_kernel)
+			set_property(GLOBAL APPEND PROPERTY PX4_KERNEL_MODULE_LIBRARIES ${MODULE})
+		else()
+			target_link_libraries(${MODULE} PRIVATE px4_layer uORB)
 			set_property(GLOBAL APPEND PROPERTY PX4_MODULE_LIBRARIES ${MODULE})
+		endif()
 		set_property(GLOBAL APPEND PROPERTY PX4_MODULE_PATHS ${CMAKE_CURRENT_SOURCE_DIR})
 		px4_list_make_absolute(ABS_SRCS ${CMAKE_CURRENT_SOURCE_DIR} ${SRCS})
 		set_property(GLOBAL APPEND PROPERTY PX4_SRC_FILES ${ABS_SRCS})
@@ -195,6 +212,10 @@ function(px4_add_module)
 		target_compile_options(${MODULE} PRIVATE ${COMPILE_FLAGS})
 	endif()
 
+	if (KERNEL)
+		target_compile_options(${MODULE} PRIVATE -D__KERNEL__)
+	endif()
+
 	if(INCLUDES)
 		target_include_directories(${MODULE} PRIVATE ${INCLUDES})
 	endif()