void ISR_auxTimer()
{
IRQstackOverflowCheck();
miosix::Scheduler::IRQfindNextThread();//If the kernel is running, preempt
if(miosix::kernel_running!=0) miosix::tick_skew=true;
TIM3->SR=0;
}
void ISR_yield()
{
#ifdef WITH_PROCESSES
// WARNING: Temporary fix. Rationale:
// This fix is intended to avoid kernel or process faulting due to
// another process actions. Consider the case in which a process statically
// allocates a big array such that there is no space left for saving
// context data. If the process issues a system call, in the following
// interrupt the context is saved, but since there is no memory available
// for all the context data, a mem manage interrupt is set to 'pending'. Then,
// a fake syscall is issued, based on the value read on the stack (which
// the process hasn't set due to the memory fault and is likely to be 0);
// this syscall is usually a yield (due to the value of 0 above),
// which can cause the scheduling of the kernel thread. At this point,
// the pending mem fault is issued from the kernel thread, causing the
// kernel fault and reboot. This is caused by the mem fault interrupt
// having less priority of the other interrupts.
// This fix checks if there is a mem fault interrupt pending, and, if so,
// it clears it and returns before calling the previously mentioned fake
// syscall.
if(SCB->SHCSR & (1<<13))
{
if(miosix::Thread::IRQreportFault(miosix_private::FaultData(
MP,0,0)))
{
SCB->SHCSR &= ~(1<<13); //Clear MEMFAULTPENDED bit
return;
}
}
#endif // WITH_PROCESSES
IRQstackOverflowCheck();
#ifdef WITH_PROCESSES
//If processes are enabled, check the content of r3. If zero then it
//it is a simple yield, otherwise handle the syscall
//Note that it is required to use ctxsave and not cur->ctxsave because
//at this time we do not know if the active context is user or kernel
unsigned int threadSp=ctxsave[0];
unsigned int *processStack=reinterpret_cast<unsigned int*>(threadSp);
if(processStack[3]!=miosix::SYS_YIELD)
miosix::Thread::IRQhandleSvc(processStack[3]);
else miosix::Scheduler::IRQfindNextThread();
#else //WITH_PROCESSES
miosix::Scheduler::IRQfindNextThread();
#endif //WITH_PROCESSES
}
void ISR_yield()
{
IRQstackOverflowCheck();
miosix::Scheduler::IRQfindNextThread();
}
