TSMC has yet to ship a low power process 28nm HKMG part, although Nvidia Tegra 4 and Qualcomm Snapdragon S4 appear to be the first two.
On the Qualcomm side, only the Snapdragon 800 is on the HPM process, based on this article. Snapdragon 600 still uses the existing process node, which is the LP process without HKMG.