Merge branch 'nmi' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

Pull NMI backtrace update from Russell King:
 "These changes convert the x86 NMI handling to be a library
  implementation which other architectures can make use of.  Thomas
  Gleixner has reviewed and tested these changes, and wishes me to send
  these rather than taking them through the tip tree.

  The final patch in the set adds an initial implementation using this
  infrastructure to ARM, even though it doesn't send the IPI at "NMI"
  level.  Patches are in progress to add the ARM equivalent of NMI, but
  we still need the IRQ-level fallback for systems where the "NMI" isn't
  available due to secure firmware denying access to it"

* 'nmi' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: add basic support for on-demand backtrace of other CPUs
  nmi: x86: convert to generic nmi handler
  nmi: create generic NMI backtrace implementation

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);
@@ -643,6 +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);
@@ -737,3 +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);
+}