i upgraded to the new ios on my 4s and i no longer have siri. what gives?

I presume that it was working prior to the upgrade, yes? Check Settings -> General and make sure Siri is still turned on. If you don't seen an option for Siri there, check the Restrictions to see if perhaps Siri has inadvertently been turned off there.

If that doesn't help, post back with details as to what happens when you try to use Siri and someone may have additional suggestions.

Regards.