powerpc/smp: Don't expose per-cpu "cpu_state" array

Instead, keep it static, expose an accessor and use that from
the PowerMac code. Avoids easy namespace collisions and will
make it easier to consolidate with other implementations.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/smp.h

@@ -45,7 +45,7 @@ extern void migrate_irqs(void);
 int generic_cpu_disable(void);
 void generic_cpu_die(unsigned int cpu);
 void generic_mach_cpu_die(void);
-DECLARE_PER_CPU(int, cpu_state);
+void generic_set_cpu_dead(unsigned int cpu);
 #endif
 
 #ifdef CONFIG_PPC64

arch/powerpc/kernel/smp.c

@@ -305,7 +305,7 @@ void __devinit smp_prepare_boot_cpu(void)
 
 #ifdef CONFIG_HOTPLUG_CPU
 /* State of each CPU during hotplug phases */
-DEFINE_PER_CPU(int, cpu_state) = { 0 };
+static DEFINE_PER_CPU(int, cpu_state) = { 0 };
 
 int generic_cpu_disable(void)
 {
@@ -348,6 +348,11 @@ void generic_mach_cpu_die(void)
 	while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 		cpu_relax();
 }
+
+void generic_set_cpu_dead(unsigned int cpu)
+{
+	per_cpu(cpu_state, cpu) = CPU_DEAD;
+}
 #endif
 
 int __cpuinit __cpu_up(unsigned int cpu)

arch/powerpc/platforms/powermac/smp.c

@@ -920,10 +920,12 @@ static int smp_core99_cpu_disable(void)
 
 static void pmac_cpu_die(void)
 {
+	int cpu = smp_processor_id();
+
 	local_irq_disable();
 	idle_task_exit();
-	printk(KERN_DEBUG "CPU%d offline\n", smp_processor_id());
-	__get_cpu_var(cpu_state) = CPU_DEAD;
+	pr_debug("CPU%d offline\n", cpu);
+	generic_set_cpu_dead(cpu);
 	smp_wmb();
 	mb();
 	low_cpu_die();
@@ -933,6 +935,8 @@ static void pmac_cpu_die(void)
 
 static void pmac_cpu_die(void)
 {
+	int cpu = smp_processor_id();
+
 	local_irq_disable();
 	idle_task_exit();
 
@@ -942,8 +946,8 @@ static void pmac_cpu_die(void)
 	 * on core99 platforms for now ...
 	 */
 
-	printk(KERN_INFO "CPU#%d offline\n", smp_processor_id());
-	__get_cpu_var(cpu_state) = CPU_DEAD;
+	printk(KERN_INFO "CPU#%d offline\n", cpu);
+	generic_set_cpu_dead(cpu);
 	smp_wmb();
 
 	/*