1 files changed, 33 insertions, 2 deletions

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 3d6b7821cff8..48185a773852 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -21,6 +21,7 @@
 #include <linux/cpu.h>
 #include <linux/seq_file.h>
 #include <linux/irq.h>
+#include <linux/nmi.h>
 #include <linux/percpu.h>
 #include <linux/clockchips.h>
 #include <linux/completion.h>
@@ -72,6 +73,7 @@ enum ipi_msg_type {
 	IPI_CPU_STOP,
 	IPI_IRQ_WORK,
 	IPI_COMPLETION,
+	IPI_CPU_BACKTRACE = 15,
 };
 
 static DECLARE_COMPLETION(cpu_running);
@@ -175,13 +177,26 @@ static int platform_cpu_disable(unsigned int cpu)
 	if (smp_ops.cpu_disable)
 		return smp_ops.cpu_disable(cpu);
 
+	return 0;
+}
+
+int platform_can_hotplug_cpu(unsigned int cpu)
+{
+	/* cpu_die must be specified to support hotplug */
+	if (!smp_ops.cpu_die)
+		return 0;
+
+	if (smp_ops.cpu_can_disable)
+		return smp_ops.cpu_can_disable(cpu);
+
 	/*
 	 * By default, allow disabling all CPUs except the first one,
 	 * since this is special on a lot of platforms, e.g. because
 	 * of clock tick interrupts.
 	 */
-	return cpu == 0 ? -EPERM : 0;
+	return cpu != 0;
 }
+
 /*
  * __cpu_disable runs on the processor to be shutdown.
  */
@@ -253,7 +268,7 @@ void __cpu_die(unsigned int cpu)
  * of the other hotplug-cpu capable cores, so presumably coming
  * out of idle fixes this.
  */
-void __ref cpu_die(void)
+void arch_cpu_idle_dead(void)
 {
 	unsigned int cpu = smp_processor_id();
 
@@ -630,6 +645,12 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 		irq_exit();
 		break;
 
+	case IPI_CPU_BACKTRACE:
+		irq_enter();
+		nmi_cpu_backtrace(regs);
+		irq_exit();
+		break;
+
 	default:
 		pr_crit("CPU%u: Unknown IPI message 0x%x\n",
 		        cpu, ipinr);
@@ -724,3 +745,13 @@ static int __init register_cpufreq_notifier(void)
 core_initcall(register_cpufreq_notifier);
 
 #endif
+
+static void raise_nmi(cpumask_t *mask)
+{
+	smp_cross_call(mask, IPI_CPU_BACKTRACE);
+}
+
+void arch_trigger_all_cpu_backtrace(bool include_self)
+{
+	nmi_trigger_all_cpu_backtrace(include_self, raise_nmi);
+}