Add sys_init

apps/sys_init/CMakeLists.txt

@@ -0,0 +1,7 @@
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+
+project(sys_init)
+
+target_sources(app PRIVATE src/main.c)

apps/sys_init/prj.conf

@@ -0,0 +1,16 @@
+# Set to -Og
+CONFIG_DEBUG_OPTIMIZATIONS=y
+
+# Thread awareness support
+CONFIG_DEBUG_THREAD_INFO=y
+
+# Generate stack usage per-function
+CONFIG_STACK_USAGE=y
+
+# Other options in case not set by default
+CONFIG_BUILD_OUTPUT_HEX=y
+CONFIG_BUILD_OUTPUT_META=y
+CONFIG_OUTPUT_SYMBOLS=y
+CONFIG_OUTPUT_STAT=y
+CONFIG_OUTPUT_DISASSEMBLY=y
+CONFIG_OUTPUT_PRINT_MEMORY_USAGE=y

apps/sys_init/src/main.c

@@ -0,0 +1,25 @@
+#include <zephyr/kernel.h>
+
+int post_kernel_cb(void) {
+	printk("[POST_KERNEL:10] Called automatically by the kernel\n");
+	return 0;
+}
+
+int post_kernel_cb2(void) {
+	printk("[POST_KERNEL:20] Called after priority 10\n");
+	return 0;
+}
+
+int application_cb(void) {
+	printk("[APPLICATION] Called automatically before main()\n");
+	return 0;
+}
+
+SYS_INIT(post_kernel_cb, POST_KERNEL, 10);
+SYS_INIT(post_kernel_cb2, POST_KERNEL, 20);
+SYS_INIT(application_cb, APPLICATION, 10);
+
+int main(void) {
+	printk("[main] running\n");
+	return 0;
+}