I have seen many drivers with a section named PAGE, but couldn't find good enough information on it, what is the role of this section?
That is, whatever gets stored in that section cannot be accessed at arbitrary IRQLs. Quote:
If the IRQL > APC_LEVEL, the PAGED_CODE macro causes the system to ASSERT.
Also see this for an entry point into the overall topic. But I reckon given the specific nature of your question you are aware of paged and nonpaged pool and so on.