1 files changed, 18 insertions, 11 deletions

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index e4ab2b42bd6f..426cfedefd04 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1266,6 +1266,19 @@ static void dbg_restore_debug_regs(void)
 #define dbg_restore_debug_regs()
 #endif /* ! CONFIG_KGDB */
 
+static void wait_for_master_cpu(int cpu)
+{
+#ifdef CONFIG_SMP
+        /*
+         * wait for ACK from master CPU before continuing
+         * with AP initialization
+         */
+        WARN_ON(cpumask_test_and_set_cpu(cpu, cpu_initialized_mask));
+        while (!cpumask_test_cpu(cpu, cpu_callout_mask))
+                cpu_relax();
+#endif
+}
+
 /*
  * cpu_init() initializes state that is per-CPU. Some data is already
  * initialized (naturally) in the bootstrap process, such as the GDT
@@ -1281,16 +1294,17 @@ void cpu_init(void)
         struct task_struct *me;
         struct tss_struct *t;
         unsigned long v;
-        int cpu;
+        int cpu = stack_smp_processor_id();
         int i;
 
+        wait_for_master_cpu(cpu);
+
         /*
          * Load microcode on this cpu if a valid microcode is available.
          * This is early microcode loading procedure.
          */
         load_ucode_ap();
 
-        cpu = stack_smp_processor_id();
         t = &per_cpu(init_tss, cpu);
         oist = &per_cpu(orig_ist, cpu);
 
@@ -1302,9 +1316,6 @@ void cpu_init(void)
 
         me = current;
 
-        if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask))
-                panic("CPU#%d already initialized!\n", cpu);
-
         pr_debug("Initializing CPU#%d\n", cpu);
 
         clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
@@ -1381,13 +1392,9 @@ void cpu_init(void)
         struct tss_struct *t = &per_cpu(init_tss, cpu);
         struct thread_struct *thread = &curr->thread;
 
-        show_ucode_info_early();
+        wait_for_master_cpu(cpu);
 
-        if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask)) {
-                printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
-                for (;;)
-                        local_irq_enable();
-        }
+        show_ucode_info_early();
 
         printk(KERN_INFO "Initializing CPU#%d\n", cpu);