ppc64: allow iSeries to use IRQSTACKS again

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

1 files changed, 17 insertions, 1 deletions

diff --git a/arch/powerpc/platforms/iseries/irq.c b/arch/powerpc/platforms/iseries/irq.c
index a06603d84a45..a0ff7d95fdf3 100644
--- a/arch/powerpc/platforms/iseries/irq.c
+++ b/arch/powerpc/platforms/iseries/irq.c
@@ -103,6 +103,9 @@ static void intReceived(struct XmPciLpEvent *eventParm,
                 struct pt_regs *regsParm)
 {
         int irq;
+#ifdef CONFIG_IRQSTACKS
+        struct thread_info *curtp, *irqtp;
+#endif
 
         ++Pci_Interrupt_Count;
 
@@ -110,7 +113,20 @@ static void intReceived(struct XmPciLpEvent *eventParm,
         case XmPciLpEvent_SlotInterrupt:
                 irq = eventParm->hvLpEvent.xCorrelationToken;
                 /* Dispatch the interrupt handlers for this irq */
-                ppc_irq_dispatch_handler(regsParm, irq);
+#ifdef CONFIG_IRQSTACKS
+                /* Switch to the irq stack to handle this */
+                curtp = current_thread_info();
+                irqtp = hardirq_ctx[smp_processor_id()];
+                if (curtp != irqtp) {
+                        irqtp->task = curtp->task;
+                        irqtp->flags = 0;
+                        call_ppc_irq_dispatch_handler(regsParm, irq, irqtp);
+                        irqtp->task = NULL;
+                        if (irqtp->flags)
+                                set_bits(irqtp->flags, &curtp->flags);
+                } else
+#endif
+                        ppc_irq_dispatch_handler(regsParm, irq);
                 HvCallPci_eoi(eventParm->eventData.slotInterrupt.busNumber,
                         eventParm->eventData.slotInterrupt.subBusNumber,
                         eventParm->eventData.slotInterrupt.deviceId);