[PATCH] kexec: x86_64: factor out apic shutdown code

Factor out the apic and smp shutdown code from machine_restart so it can be
called by in the kexec reboot path as well.
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/reboot.c

@@ -66,41 +66,47 @@ static int __init reboot_setup(char *str)
 
 __setup("reboot=", reboot_setup);
 
-#ifdef CONFIG_SMP
-static void smp_halt(void)
+static inline void kb_wait(void)
 {
-	int cpuid = safe_smp_processor_id(); 
-	static int first_entry = 1;
+	int i;
 
-	if (reboot_force)
-		return;
+	for (i=0; i<0x10000; i++)
+		if ((inb_p(0x64) & 0x02) == 0)
+			break;
+}
 
-	if (first_entry) {
-		first_entry = 0;
-		smp_call_function((void *)machine_restart, NULL, 1, 0);
-	}
+void machine_shutdown(void)
+{
+	/* Stop the cpus and apics */
+#ifdef CONFIG_SMP
+	int reboot_cpu_id;
 
-	smp_stop_cpu(); 
+	/* The boot cpu is always logical cpu 0 */
+	reboot_cpu_id = 0;
 
-	/* AP calling this. Just halt */
-	if (cpuid != boot_cpu_id) { 
-		for (;;) 
-			asm("hlt");
+	/* Make certain the cpu I'm about to reboot on is online */
+	if (!cpu_isset(reboot_cpu_id, cpu_online_map)) {
+		reboot_cpu_id = smp_processor_id();
 	}
 
-	/* Wait for all other CPUs to have run smp_stop_cpu */
-	while (!cpus_empty(cpu_online_map))
-		rep_nop(); 
-}
+	/* Make certain I only run on the appropriate processor */
+	set_cpus_allowed(current, cpumask_of_cpu(reboot_cpu_id));
+
+	/* O.K Now that I'm on the appropriate processor,
+	 * stop all of the others.
+	 */
+	smp_send_stop();
 #endif
 
-static inline void kb_wait(void)
-{
-	int i;
+	local_irq_disable();
 
-	for (i=0; i<0x10000; i++)
-		if ((inb_p(0x64) & 0x02) == 0)
-			break;
+#ifndef CONFIG_SMP
+	disable_local_APIC();
+#endif
+
+	disable_IO_APIC();
+
+	local_irq_enable();
 }
 
 void machine_restart(char * __unused)
@@ -109,9 +115,7 @@ void machine_restart(char * __unused)
 
 	printk("machine restart\n");
 
-#ifdef CONFIG_SMP
-	smp_halt(); 
-#endif
+	machine_shutdown();
 
 	if (!reboot_force) {
 		local_irq_disable();