[PATCH] x86_64: Fix the additional_cpus=.. option

It didn't set up the CPU possible map early enough, so the
option didn't actually work.

Noticed by Heiko Carstens

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index 9435ab7..5de7eaf 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -423,6 +423,12 @@
 		else if(!memcmp(from, "elfcorehdr=", 11))
 			elfcorehdr_addr = memparse(from+11, &from);
 #endif
+
+#ifdef CONFIG_SMP
+		else if (!memcmp(from, "additional_cpus=", 16))
+			setup_additional_cpus(from+16);
+#endif
+
 	next_char:
 		c = *(from++);
 		if (!c)