llext: provide an example of tristate Kconfig option

Add a tristate Kconfig option to the llext hello-world twister test.

Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>

tests/subsys/llext/Kconfig

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright (c) 2024 Intel Corporation.
+
+mainmenu "LLEXT functionality test"
+
+source "Kconfig.zephyr"
+
+config LLEXT_TEST_HELLO
+	tristate "llext hello test"
+	default n
+	help
+	  Set to "m" to test hello-world loading

tests/subsys/llext/hello_world/CMakeLists.txt

@@ -5,6 +5,8 @@ cmake_minimum_required(VERSION 3.20.0)
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 project(hello_world)
 
+if(NOT CONFIG_MODULES OR CONFIG_LLEXT_TEST_HELLO STREQUAL "m")
+
 # TODO check which architecture is being used
 if(CONFIG_ARM)
     set(CMAKE_C_FLAGS "-mlong-calls" "-mthumb")
@@ -34,3 +36,5 @@ endif()
 set(HELLO_WORLD_LLEXT ${PROJECT_BINARY_DIR}/hello_world.llext PARENT_SCOPE)
 
 add_custom_target(hello_world DEPENDS ${PROJECT_BINARY_DIR}/hello_world.llext)
+
+endif()

tests/subsys/llext/testcase.yaml

@@ -6,6 +6,8 @@ tests:
     arch_allow: arm
     extra_configs:
       - CONFIG_ARM_MPU=n
+      - CONFIG_MODULES=y
+      - CONFIG_LLEXT_TEST_HELLO=m
     # Broken platforms
     platform_exclude:
       - nuvoton_pfm_m487 # See #63167
@@ -13,6 +15,8 @@ tests:
     arch_allow: xtensa
     extra_configs:
       - CONFIG_LLEXT_STORAGE_WRITABLE=y
+      - CONFIG_MODULES=y
+      - CONFIG_LLEXT_TEST_HELLO=m
     # Broken platforms
     platform_exclude:
       - qemu_xtensa_mmu # ELF sections are read-only, and without peek() .text copy isn't executable