xen: implement a debug-interrupt handler

Xen supports the notion of a debug interrupt which can be triggered
from the console.  For now this is implemented to show pending events,
masks and each CPU's pending event set.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 14 insertions, 5 deletions

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index d61e4f8b07c7..92dd3dbf3ffb 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -36,8 +36,9 @@
 #include "mmu.h"
 
 static cpumask_t xen_cpu_initialized_map;
-static DEFINE_PER_CPU(int, resched_irq);
-static DEFINE_PER_CPU(int, callfunc_irq);
+static DEFINE_PER_CPU(int, resched_irq) = -1;
+static DEFINE_PER_CPU(int, callfunc_irq) = -1;
+static DEFINE_PER_CPU(int, debug_irq) = -1;
 
 /*
  * Structure and data for smp_call_function(). This is designed to minimise
@@ -89,9 +90,7 @@ static __cpuinit void cpu_bringup_and_idle(void)
 static int xen_smp_intr_init(unsigned int cpu)
 {
         int rc;
-        const char *resched_name, *callfunc_name;
-
-        per_cpu(resched_irq, cpu) = per_cpu(callfunc_irq, cpu) = -1;
+        const char *resched_name, *callfunc_name, *debug_name;
 
         resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
         rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
@@ -115,6 +114,14 @@ static int xen_smp_intr_init(unsigned int cpu)
                 goto fail;
         per_cpu(callfunc_irq, cpu) = rc;
 
+        debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
+        rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
+                                     IRQF_DISABLED | IRQF_PERCPU | IRQF_NOBALANCING,
+                                     debug_name, NULL);
+        if (rc < 0)
+                goto fail;
+        per_cpu(debug_irq, cpu) = rc;
+
         return 0;
 
  fail:
@@ -122,6 +129,8 @@ static int xen_smp_intr_init(unsigned int cpu)
                 unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL);
         if (per_cpu(callfunc_irq, cpu) >= 0)
                 unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL);
+        if (per_cpu(debug_irq, cpu) >= 0)
+                unbind_from_irqhandler(per_cpu(debug_irq, cpu), NULL);
         return rc;
 }