[PATCH] x86 topology: don;t create a control file for BSP that cannot be removed

Don't create "online" control file for BSP (i386/x86_64) since its
not removable.

We originally added this to support ppc64 if the kernel has support but
BIOS indicated no offline support, we just didnt create online files for
them.

We used the same method in ia64 as well, if we have a cpu taking platform
interrupts but cannot be removed if those interrupts cannot be re-targeted
to another cpu.
Signed-off-by: NAshok Raj <ashok.raj@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/i386/kernel/topology.c

@@ -41,6 +41,15 @@ int arch_register_cpu(int num){
 		parent = &node_devices[node].node;
 #endif /* CONFIG_NUMA */
 
+	/*
+	 * CPU0 cannot be offlined due to several
+	 * restrictions and assumptions in kernel. This basically
+	 * doesnt add a control file, one cannot attempt to offline
+	 * BSP.
+	 */
+	if (!num)
+		cpu_devices[num].cpu.no_control = 1;
+
 	return register_cpu(&cpu_devices[num].cpu, num, parent);
 }