diff --git a/xen/arch/x86/include/asm/traps.h b/xen/arch/x86/include/asm/traps.h
index 7414420e57..6ae451d3fc 100644
--- a/xen/arch/x86/include/asm/traps.h
+++ b/xen/arch/x86/include/asm/traps.h
@@ -9,6 +9,7 @@
 
 void bsp_early_traps_init(void);
 void traps_init(void);
+void bsp_traps_reinit(void);
 void percpu_traps_init(void);
 
 extern unsigned int ler_msr;
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 64f02699e1..c8c408e024 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -902,11 +902,7 @@ static void __init noreturn reinit_bsp_stack(void)
     unsigned long *stack = (void*)(get_stack_bottom() & ~(STACK_SIZE - 1));
     int rc;
 
-    /* Update TSS and ISTs */
-    load_system_tables();
-
-    /* Update SYSCALL trampolines */
-    percpu_traps_init();
+    bsp_traps_reinit();
 
     stack_base[0] = stack;
 
diff --git a/xen/arch/x86/traps-setup.c b/xen/arch/x86/traps-setup.c
index 7713f427d3..99257bbb16 100644
--- a/xen/arch/x86/traps-setup.c
+++ b/xen/arch/x86/traps-setup.c
@@ -107,6 +107,15 @@ void __init traps_init(void)
     percpu_traps_init();
 }
 
+/*
+ * Re-initialise all state referencing the early-boot stack.
+ */
+void __init bsp_traps_reinit(void)
+{
+    load_system_tables();
+    percpu_traps_init();
+}
+
 /*
  * Set up per-CPU linkage registers for exception, interrupt and syscall
  * handling.