diff --git a/arch/x86/kernel/smpboot_32.c b/arch/x86/kernel/smpboot_32.c
index 4e5416eb42b09877a0799765e22ce28daf4c1fa0..a232f4d1f7a5ad96cfc37b3b2f0e4f4af23eef43 100644
--- a/arch/x86/kernel/smpboot_32.c
+++ b/arch/x86/kernel/smpboot_32.c
@@ -180,6 +180,9 @@ static void __cpuinit start_secondary(void *unused)
 	smp_callin();
 	while (!cpu_isset(smp_processor_id(), smp_commenced_mask))
 		cpu_relax();
+
+	/* otherwise gcc will move up smp_processor_id before the cpu_init */
+	barrier();
 	/*
 	 * Check TSC synchronization with the BP:
 	 */
@@ -432,6 +435,7 @@ wakeup_secondary_cpu(int phys_apicid, unsigned long start_eip)
 	Dprintk("Waiting for send to finish...\n");
 	send_status = safe_apic_wait_icr_idle();
 
+	mb();
 	atomic_set(&init_deasserted, 1);
 
 	/*
diff --git a/arch/x86/kernel/smpboot_64.c b/arch/x86/kernel/smpboot_64.c
index d7b59d6c6963275baaefe65b59a0f9f5006d7b8f..a9cc91127b9111946a0ebee8f631d64fedf13e1b 100644
--- a/arch/x86/kernel/smpboot_64.c
+++ b/arch/x86/kernel/smpboot_64.c
@@ -239,6 +239,7 @@ void __cpuinit start_secondary(void)
 
 	setup_secondary_clock();
 
+	wmb();
 	cpu_idle();
 }