Already mailed in for the Linux 4.3 kernel merge window this week were the numerous ARM SoC updates while being sent in over the night were the ARM64/AArch64 architectural changes for this next version of the Linux kernel.
Linux 4.3 will see support for new architectural features that were added to ARMv8.1, a minor update to the ARMv8 specification that brought 64-bit to the ARM world. Implemented from ARMv8.1 for Linux 4.3 is PAN, LSE, and DBM support. PAN is short for Privileged Access Never (PAN) and is an ARM way for catching user point dereferences in the kernel. LSE is the Large System Extension and is for building scalable atomics and locks. Lastly DBM of ARMv8.1 is Hardware Dirty Bit Management and is for updating clean PTEs automatically.