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, 47 insertions, 0 deletions

diff --git a/arch/x86/xen/events.c b/arch/x86/xen/events.c
index dcf613e1758..0140981e93c 100644
--- a/arch/x86/xen/events.c
+++ b/arch/x86/xen/events.c
@@ -455,6 +455,53 @@ void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
         notify_remote_via_irq(irq);
 }
 
+irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
+{
+        struct shared_info *sh = HYPERVISOR_shared_info;
+        int cpu = smp_processor_id();
+        int i;
+        unsigned long flags;
+        static DEFINE_SPINLOCK(debug_lock);
+
+        spin_lock_irqsave(&debug_lock, flags);
+
+        printk("vcpu %d\n  ", cpu);
+
+        for_each_online_cpu(i) {
+                struct vcpu_info *v = per_cpu(xen_vcpu, i);
+                printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
+                        (get_irq_regs() && i == cpu) ? !(get_irq_regs()->flags & X86_EFLAGS_IF) : v->evtchn_upcall_mask,
+                        v->evtchn_upcall_pending,
+                        v->evtchn_pending_sel);
+        }
+        printk("pending:\n   ");
+        for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
+                printk("%08lx%s", sh->evtchn_pending[i],
+                        i % 8 == 0 ? "\n   " : " ");
+        printk("\nmasks:\n   ");
+        for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
+                printk("%08lx%s", sh->evtchn_mask[i],
+                        i % 8 == 0 ? "\n   " : " ");
+
+        printk("\nunmasked:\n   ");
+        for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
+                printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
+                        i % 8 == 0 ? "\n   " : " ");
+
+        printk("\npending list:\n");
+        for(i = 0; i < NR_EVENT_CHANNELS; i++) {
+                if (sync_test_bit(i, sh->evtchn_pending)) {
+                        printk("  %d: event %d -> irq %d\n",
+                                cpu_evtchn[i], i,
+                                evtchn_to_irq[i]);
+                }
+        }
+
+        spin_unlock_irqrestore(&debug_lock, flags);
+
+        return IRQ_HANDLED;
+}
+
 
 /*
  * Search the CPUs pending events bitmasks.  For each one found, map