CPU loops in while(1) in single threaded environment

[vikash-singh-rawat]

Dear Community Members,

CPU keep looping in while(1) with irq_lock() after calling and returning from the main() function in case single threaded environment (CONFIG_MULTITHREADING=n). However CPU will be in WFI in case of multithreading in idle thread.

https://github.com/zephyrproject-rtos/zephyr/blob/main/kernel/init.c#L694C1-L702C4

bg_thread_main(NULL, NULL, NULL);

/* LCOV_EXCL_START
 * We've already dumped coverage data at this point.
 */
irq_lock();
while (true) {
}

https://github.com/zephyrproject-rtos/zephyr/blob/main/arch/riscv/core/thread.c#L223C1-L227C1

/* infinite loop */
irq_lock();
while (true) {
}

It keeps the CPU busy without doing any significant task. Moreover CPU doesn’t serve any external interrupt as irq_lock() is called before while(1) which disable the external interrupt (in case of RISC V).

Is there any specific reason for it ?
Can we keep the CPU in WFI with irq_unlock() after calling main() for single threaded environment ?

while (1) {
	__asm__ volatile("wfi");
}