GNU Toolchain Begins Adding ARMv8.7-A Support
While all of the ARMv8 cores to date remain with older versions of the architecture and even cases like ARMv8.2-A with the Cortex-A78 and X1, Arm continues working on new ARMv8 revisions and getting that software support in place well ahead of hardware availability.
After outlining some of the ARMv8.7-A register changes in September, the GNU toolchain bits began appearing on Tuesday but still are a work in progress.
The GNU Assembler saw -march=armv8.7-a support added. That was followed up by enabling DSB and WFET so far as two new instructions with ARMv8.7-A. The DSB nXS variant is extending the memory barrier behavior with new capabilities. The WFET instruction is to "Wait For Event with Timeout" where specified is a general purpose source register.
That's it so far but expect more soon along with the GCC compiler bring-up and on the LLVM/Clang side too.