x86/percpu changes for v6.11: - Enable the named address spaces based percpu accessors optimization on all GCC versions that contain this feature, detected through a build-time testcase. This effectively enables the feature on GCC 6, GCC 7 and GCC 8 versions. - Fix operand constraint modifier in __raw_cpu_write() - Reorganize the per-CPU headers for better readability - Misc cleanups and fixes Signed-off-by: Ingo Molnar <mingo@kernel.org>