diff --git a/arch/ppc/syslib/cpm2_pic.c b/arch/ppc/syslib/cpm2_pic.c
index 954b07f..c867be6 100644
--- a/arch/ppc/syslib/cpm2_pic.c
+++ b/arch/ppc/syslib/cpm2_pic.c
@@ -107,6 +107,11 @@
 		simr = &(cpm2_immr->im_intctl.ic_simrh);
 		ppc_cached_irq_mask[word] |= 1 << bit;
 		simr[word] = ppc_cached_irq_mask[word];
+		/*
+		 * Work around large numbers of spurious IRQs on PowerPC 82xx
+		 * systems.
+		 */
+		mb();
 	}
 }