ARM: CPU hotplug: move cpu_killed completion to core code

We always need to wait for the dying CPU to reach a safe state before
taking it down, irrespective of the requirements of the platform.
Move the completion code into the ARM SMP hotplug code rather than
having each platform re-implement this.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 13 insertions, 1 deletions

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index a30c4094db3a..8c81ff9b3732 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -24,6 +24,7 @@
 #include <linux/irq.h>
 #include <linux/percpu.h>
 #include <linux/clockchips.h>
+#include <linux/completion.h>
 
 #include <asm/atomic.h>
 #include <asm/cacheflush.h>
@@ -238,12 +239,20 @@ int __cpu_disable(void)
         return 0;
 }
 
+static DECLARE_COMPLETION(cpu_died);
+
 /*
  * called on the thread which is asking for a CPU to be shutdown -
  * waits until shutdown has completed, or it is timed out.
  */
 void __cpu_die(unsigned int cpu)
 {
+        if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
+                pr_err("CPU%u: cpu didn't die\n", cpu);
+                return;
+        }
+        printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
+
         if (!platform_cpu_kill(cpu))
                 printk("CPU%u: unable to kill\n", cpu);
 }
@@ -263,9 +272,12 @@ void __ref cpu_die(void)
         local_irq_disable();
         idle_task_exit();
 
+        /* Tell __cpu_die() that this CPU is now safe to dispose of */
+        complete(&cpu_died);
+
         /*
          * actual CPU shutdown procedure is at least platform (if not
-         * CPU) specific
+         * CPU) specific.
          */
         platform_cpu_die(cpu);