Easy enough. Look for a sign at the doors that says no firearms, then you'll know.
Oh, and check this at an outside entrance to the mall area, not at a through-a-store entrance. Sometimes signs are posted at one and not the other.
There has been a lot of posts regarding carry in malls in the various states forums. Generally it seems most, if not all, shopping malls seem to prohibit firearms inside and possibly in any store located on the mall property even if outside the mall itself.