x86/percpu: Enable named address spaces with known compiler version

Enable named address spaces with known compiler versions
(GCC 12.1 and later) in order to avoid possible issues with named
address spaces with older compilers. Set CC_HAS_NAMED_AS when the
compiler satisfies version requirements and set USE_X86_SEG_SUPPORT
to signal when segment qualifiers could be used.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20231004145137.86537-3-ubizjak@gmail.com

Author: ubizjak

arch/x86/Kconfig

@@ -2388,6 +2388,13 @@ source "kernel/livepatch/Kconfig"
 
 endmenu
 
+config CC_HAS_NAMED_AS
+	def_bool CC_IS_GCC && GCC_VERSION >= 120100
+
+config USE_X86_SEG_SUPPORT
+	def_bool y
+	depends on CC_HAS_NAMED_AS && SMP
+
 config CC_HAS_SLS
 	def_bool $(cc-option,-mharden-sls=all)