x86: I/O APIC: Add a 64-bit variation of replace_pin_at_irq()

When an interrupt is rerouted to a different I/O APIC pin the relevant
entry of the irq_2_pin list should get updated accordingly so that
operations are performed on the correct redirection entry.

This is already done by the 32-bit variation of the code and here is a
complementing 64-bit implementation.  Should make someone's decision less
tough when merging the two. ;)

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 21 insertions, 1 deletions

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index f930885ac667..848411753c7c 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -373,6 +373,26 @@ static void add_pin_to_irq(unsigned int irq, int apic, int pin)
         entry->pin = pin;
 }
 
+/*
+ * Reroute an IRQ to a different pin.
+ */
+static void __init replace_pin_at_irq(unsigned int irq,
+                                      int oldapic, int oldpin,
+                                      int newapic, int newpin)
+{
+        struct irq_pin_list *entry = irq_2_pin + irq;
+
+        while (1) {
+                if (entry->apic == oldapic && entry->pin == oldpin) {
+                        entry->apic = newapic;
+                        entry->pin = newpin;
+                }
+                if (!entry->next)
+                        break;
+                entry = irq_2_pin + entry->next;
+        }
+}
+
 
 #define DO_ACTION(name,R,ACTION, FINAL)                                 \
                                                                         \
@@ -1735,7 +1755,7 @@ static inline void __init check_timer(void)
                 /*
                  * legacy devices should be connected to IO APIC #0
                  */
-                /* replace_pin_at_irq(0, apic1, pin1, apic2, pin2); */
+                replace_pin_at_irq(0, apic1, pin1, apic2, pin2);
                 setup_timer_IRQ0_pin(apic2, pin2, cfg->vector);
                 unmask_IO_APIC_irq(0);
                 enable_8259A_irq(0);