Changeset 7bcfbbc in mainline for kernel/arch/ia32xen/src/interrupt.c

Timestamp:

2007-04-07T23:30:59Z (18 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

ac88c93

Parents:

7e58979

Message:

support the possibility to send EOI or Interrupt Acknowledgement
prior to processing the interrupt
(this is essential on some architectures to prevent preemption deadlock)

File:

• kernel/arch/ia32xen/src/interrupt.c (modified) (3 diffs)

kernel/arch/ia32xen/src/interrupt.c

@@ -177 +177 @@
         
         int inum = n - IVT_IRQBASE;
+        bool ack = false;
         ASSERT(inum < IRQ_COUNT);
         ASSERT((inum != IRQ_PIC_SPUR) && (inum != IRQ_PIC1));
-
+        
         irq_t *irq = irq_dispatch_and_lock(inum);
         if (irq) {
@@ -185 +186 @@
                  * The IRQ handler was found.
                  */
+                 
+                if (irq->preack) {
+                        /* Send EOI before processing the interrupt */
+                        trap_virtual_eoi();
+                        ack = true;
+                }
                 irq->handler(irq, irq->arg);
                 spinlock_unlock(&irq->lock);
@@ -195 +202 @@
 #endif
         }
-        trap_virtual_eoi();
+        
+        if (!ack)
+                trap_virtual_eoi();
 }