1 files changed, 17 insertions, 0 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index c421512ca5eb..98e24131ff3a 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2143,6 +2143,23 @@ int default_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
 }
 
 /*
+ * Override the generic EOI implementation with an optimized version.
+ * Only called during early boot when only one CPU is active and with
+ * interrupts disabled, so we know this does not race with actual APIC driver
+ * use.
+ */
+void __init apic_set_eoi_write(void (*eoi_write)(u32 reg, u32 v))
+{
+        struct apic **drv;
+
+        for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
+                /* Should happen once for each apic */
+                WARN_ON((*drv)->eoi_write == eoi_write);
+                (*drv)->eoi_write = eoi_write;
+        }
+}
+
+/*
  * Power management
  */
 #ifdef CONFIG_PM