x86: kallsyms: disable absolute percpu symbols on !SMP

scripts/kallsyms.c has a special --absolute-percpu command line option
which deals with the zero based per cpu offsets that are used when
building for SMP on x86_64.  This means that the option should only be
passed in that case, so add a Kconfig symbol with the correct predicate,
and use that instead.

Signed-off-by: Ard Biesheuvel <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Tested-by: Kees Cook <[email protected]>
Acked-by: Rusty Russell <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Michal Marek <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

init/Kconfig

@@ -1420,6 +1420,10 @@ config KALLSYMS_ALL
 
 	   Say N unless you really need all symbols.
 
+config KALLSYMS_ABSOLUTE_PERCPU
+	bool
+	default X86_64 && SMP
+
 config PRINTK
 	default y
 	bool "Enable support for printk" if EXPERT

scripts/link-vmlinux.sh

@@ -86,7 +86,7 @@ kallsyms()
 		kallsymopt="${kallsymopt} --page-offset=$CONFIG_PAGE_OFFSET"
 	fi
 
-	if [ -n "${CONFIG_X86_64}" ]; then
+	if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
 		kallsymopt="${kallsymopt} --absolute-percpu"
 	fi