---
 arch/arm/Kconfig.debug         |    2 	1 +	1 -	0 !
 arch/arm/include/asm/hardirq.h |    2 	1 +	1 -	0 !
 arch/arm/include/asm/irq.h     |    3 	3 +	0 -	0 !
 arch/arm/include/asm/smp.h     |    2 	2 +	0 -	0 !
 arch/arm/kernel/process.c      |   15 	15 +	0 -	0 !
 arch/arm/kernel/smp.c          |   60 	60 +	0 -	0 !
 6 files changed, 82 insertions(+), 2 deletions(-)

Index: b/arch/arm/include/asm/irq.h
===================================================================
--- a/arch/arm/include/asm/irq.h
+++ b/arch/arm/include/asm/irq.h
@@ -25,6 +25,9 @@ extern void migrate_irqs(void);
 extern void asm_do_IRQ(unsigned int, struct pt_regs *);
 void init_IRQ(void);
 
+void arch_trigger_all_cpu_backtrace(void);
+#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
+
 #endif
 
 #endif
Index: b/arch/arm/kernel/process.c
===================================================================
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -62,6 +62,21 @@ static volatile int hlt_counter;
 
 #include <mach/system.h>
 
+#ifdef CONFIG_SMP
+
+void arch_trigger_all_cpu_backtrace(void)
+{
+	smp_send_all_cpu_backtrace();
+}
+
+#else
+
+void arch_trigger_all_cpu_backtrace(void)
+{
+}
+
+#endif
+
 void disable_hlt(void)
 {
 	hlt_counter++;
Index: b/arch/arm/include/asm/smp.h
===================================================================
--- a/arch/arm/include/asm/smp.h
+++ b/arch/arm/include/asm/smp.h
@@ -93,4 +93,6 @@ extern void arch_send_call_function_ipi_
  */
 extern void show_local_irqs(struct seq_file *, int);
 
+extern void smp_send_all_cpu_backtrace(void);
+
 #endif /* ifndef __ASM_ARM_SMP_H */
Index: b/arch/arm/kernel/smp.c
===================================================================
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -53,6 +53,7 @@ enum ipi_msg_type {
 	IPI_CALL_FUNC,
 	IPI_CALL_FUNC_SINGLE,
 	IPI_CPU_STOP,
+	IPI_ALL_CPU_BACKTRACE,
 };
 
 int __cpuinit __cpu_up(unsigned int cpu)
@@ -405,6 +406,7 @@ static const char *ipi_types[NR_IPI] = {
 	S(IPI_CALL_FUNC, "Function call interrupts"),
 	S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
 	S(IPI_CPU_STOP, "CPU stop interrupts"),
+	S(IPI_ALL_CPU_BACKTRACE, "All cpu backtrace"),
 };
 
 void show_ipi_list(struct seq_file *p, int prec)
@@ -555,6 +557,60 @@ static void ipi_cpu_stop(unsigned int cp
 		cpu_relax();
 }
 
+static cpumask_t backtrace_mask;
+
+/* "in progress" flag of arch_trigger_all_cpu_backtrace */
+static unsigned long backtrace_flag;
+
+void smp_send_all_cpu_backtrace(void)
+{
+	int i;
+	cpumask_t this_cpu_mask;
+
+	if (test_and_set_bit(0, &backtrace_flag))
+		/*
+		 * If there is already a trigger_all_cpu_backtrace() in progress
+		 * (backtrace_flag == 1), don't output double cpu dump infos.
+		 */
+		return;
+
+	backtrace_mask = cpu_online_map;
+	cpus_clear(this_cpu_mask);
+	cpu_set(smp_processor_id(), this_cpu_mask);
+
+	printk(KERN_INFO "sending IPI to all CPUs:\n");
+	smp_cross_call(&backtrace_mask, IPI_ALL_CPU_BACKTRACE);
+
+
+	/* Wait for up to 10 seconds for all other CPUs to do the backtrace */
+	for (i = 0; i < 10 * 1000; i++) {
+		if (cpus_equal(backtrace_mask, this_cpu_mask))
+			break;
+		mdelay(1);
+	}
+
+	clear_bit(0, &backtrace_flag);
+	smp_mb__after_clear_bit();
+}
+
+
+/*
+ * ipi_all_cpu_backtrace - handle IPI from smp_send_all_cpu_backtrace()
+ */
+static void ipi_all_cpu_backtrace(unsigned int cpu, struct pt_regs *regs)
+{
+	if (cpu_isset(cpu, backtrace_mask)) {
+		static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+		arch_spin_lock(&lock);
+		printk(KERN_WARNING "IPI backtrace for cpu %d\n", cpu);
+printk("regs 0x%p\n", regs);
+		show_regs(regs);
+		arch_spin_unlock(&lock);
+		cpu_clear(cpu, backtrace_mask);
+	}
+}
+
 /*
  * Main handler for inter-processor interrupts
  */
@@ -587,6 +643,10 @@ asmlinkage void __exception_irq_entry do
 		ipi_cpu_stop(cpu);
 		break;
 
+	case IPI_ALL_CPU_BACKTRACE:
+		ipi_all_cpu_backtrace(cpu, regs);
+		break;
+
 	default:
 		printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
 		       cpu, ipinr);
Index: b/arch/arm/Kconfig.debug
===================================================================
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -21,7 +21,7 @@ config STRICT_DEVMEM
 # traces, you can get a slightly smaller kernel by setting this option to
 # n, but then RMK will have to kill you ;).
 config FRAME_POINTER
-	bool
+	bool "frame pointer support"
 	depends on !THUMB2_KERNEL
 	default y if !ARM_UNWIND || FUNCTION_GRAPH_TRACER
 	help
Index: b/arch/arm/include/asm/hardirq.h
===================================================================
--- a/arch/arm/include/asm/hardirq.h
+++ b/arch/arm/include/asm/hardirq.h
@@ -5,7 +5,7 @@
 #include <linux/threads.h>
 #include <asm/irq.h>
 
-#define NR_IPI	5
+#define NR_IPI	6
 
 typedef struct {
 	unsigned int __softirq_pending;