1 files changed, 14 insertions, 3 deletions

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 344e52b16c8c..167e3cbe1f2f 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -318,9 +318,13 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
         smp_store_cpu_info(cpu);
 
         /*
-         * OK, now it's safe to let the boot CPU continue
+         * OK, now it's safe to let the boot CPU continue.  Wait for
+         * the CPU migration code to notice that the CPU is online
+         * before we continue.
          */
         set_cpu_online(cpu, true);
+        while (!cpu_active(cpu))
+                cpu_relax();
 
         /*
          * OK, it's off to the idle thread for us
@@ -361,8 +365,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
          */
         if (max_cpus > ncores)
                 max_cpus = ncores;
-
-        if (max_cpus > 1) {
+        if (ncores > 1 && max_cpus) {
                 /*
                  * Enable the local timer or broadcast device for the
                  * boot CPU, but only if we have more than one CPU.
@@ -370,6 +373,14 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
                 percpu_timer_setup();
 
                 /*
+                 * Initialise the present map, which describes the set of CPUs
+                 * actually populated at the present time. A platform should
+                 * re-initialize the map in platform_smp_prepare_cpus() if
+                 * present != possible (e.g. physical hotplug).
+                 */
+                init_cpu_present(&cpu_possible_map);
+
+                /*
                  * Initialise the SCU if there are more than one CPU
                  * and let them know where to start.
                  */