Is it safe to use spinlock in FreeRTOS (SMP) tasks?

Kernel
1

I managed to port FreeRTOS SMP version onto my SoC, which has 8 ARM cores. I’m not sure whether it is safe to use spinlock directly in my FreeRTOS tasks. Is the following code within a task function safe to run without confusing the FreeRTOS scheduler?

 spinlock_t  lock = SPIN_LOCK_UNLOCKED;
 uint32_t msk;
 msk = spin_lock_irqsave(&lock); 
  //...Do something here
 spin_unlock_irqrestore(&lock, msk);

Because the spinlock API disables/restores interrupts, not sure if it will break the scheduler states.

Thanks in advance.

2

Spin lock is only good as long as all the cores try acquire it before entering the critical section. Is there a reason you do not want to use taskENTER_CRITICAL/taskEXIT_CRITICAL?

3

The major reason I’d like to use spinlock is performance. It looks like that taskENTER_CRITICAL does a lot of things. A minor reason is that we have some history code using spinlocks (but I can change it if I have to).

4

If at all the places where the data protected using spin lock is accessed , the SAME spin lock is acquired then I do not think there will be any problem.

In other words, wherever you want to access the shared data shown below, you must acquire the same spin lock -

 msk = spin_lock_irqsave(&lock); 
  //...Access shared data
 spin_unlock_irqrestore(&lock, msk);
5

Much appreciated, Gaurav.