IopAcquirePassiveInterruptBlockLock

void __fastcall IopAcquirePassiveInterruptBlockLock(__int64 a1, unsigned __int8 *a2){
  unsigned __int8 CurrentIrql; 
  CurrentIrql = KeGetCurrentIrql();
  __writecr8(0xCui64);
  *a2 = CurrentIrql;
  KxAcquireSpinLock((UINT64 *)(a1 + 56));
}

Referenced by:

IoProcessPassiveInterrupts
IopDereferencePassiveInterruptBlock
IopPassiveInterruptWorker