ARM announced a few days ago, on July 6th, that they posted a set of Linux kernel patches, implementing support for the AArch64 architecture, also known as the ARM 64-bit architecture.
The initial support for the ARMv8 64-bit architecture has been added by ARM in the Linux kernel via a set of 36 patches.
"The AArch64 Linux port follows the guidance for new architecture ports using generic headers (including unistd.h) and as much generic code as possible (some library functions may be later optimised, based on benchmarking results)."
"There is no hardware platform available at this point. From a kernel perspective, the aim is to minimise (or even completely remove) the platform code from the architecture specific directory. FDT is currently mandated and there are ongoing discussions for ACPI support," said Catalin Marinas in the announcement.
The necessary documentation regarding the ABI and instruction set was published earlier this year by ARM. Those of you interested in more details about the new AArch64 architecture can find the patches posted by ARM here.