+/*
+ * Add an extra bit as dictated by bios to the destination apicid of
+ * interrupts potentially passing through the UV HUB. This prevents
+ * a deadlock between interrupts and IO port operations.
+ */
+static void __init uv_set_apicid_hibit(void)
+{
+ union uvh_lb_target_physical_apic_id_mask_u apicid_mask;
+ unsigned long *mmr;
+
+ mmr = early_ioremap(UV_LOCAL_MMR_BASE |
+ UVH_LB_TARGET_PHYSICAL_APIC_ID_MASK, sizeof(*mmr));
+ apicid_mask.v = *mmr;
+ early_iounmap(mmr, sizeof(*mmr));
+ uv_apicid_hibits = apicid_mask.s.bit_enables & UV_APICID_HIBIT_MASK;
+}
+