3 files changed, 24 insertions, 11 deletions
diff --git a/arch/x86/machine/boot.c b/arch/x86/machine/boot.c
index 58b675f9..f42f9bbf 100644
--- a/arch/x86/machine/boot.c
+++ b/arch/x86/machine/boot.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2012 Richard Braun.
+ * Copyright (c) 2010, 2012, 2013 Richard Braun.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -284,6 +284,7 @@ boot_main(void)
     vm_phys_info();
     pic_setup();
     pit_setup();
+    cpu_mp_setup();
     kernel_main();
 
     /* Never reached */
diff --git a/arch/x86/machine/cpu.c b/arch/x86/machine/cpu.c
index a5a62499..0d1a9f38 100644
--- a/arch/x86/machine/cpu.c
+++ b/arch/x86/machine/cpu.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2011, 2012 Richard Braun.
+ * Copyright (c) 2010, 2011, 2012, 2013 Richard Braun.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -79,6 +79,11 @@ static unsigned int cpu_boot_array_size __initdata;
 unsigned int cpu_array_size;
 
 /*
+ * Barrier for processor synchronization on kernel entry.
+ */
+static unsigned int cpu_mp_synced __initdata;
+
+/*
  * Interrupt descriptor table.
  */
 static struct cpu_gate_desc cpu_idt[CPU_IDT_SIZE] __aligned(8);
@@ -555,6 +560,12 @@ cpu_mp_setup(void)
 }
 
 void __init
+cpu_mp_sync(void)
+{
+    cpu_mp_synced = 1;
+}
+
+void __init
 cpu_ap_setup(void)
 {
     cpu_init(&cpu_array[boot_ap_id]);
@@ -565,7 +576,7 @@ cpu_ap_setup(void)
 void __init
 cpu_ap_sync(void)
 {
-    while (cpu_count() == 1)
+    while (!cpu_mp_synced)
         cpu_pause();
 }
 
diff --git a/arch/x86/machine/cpu.h b/arch/x86/machine/cpu.h
index 9e846e34..24d4ef48 100644
--- a/arch/x86/machine/cpu.h
+++ b/arch/x86/machine/cpu.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2011, 2012 Richard Braun.
+ * Copyright (c) 2010, 2011, 2012, 2013 Richard Braun.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -576,22 +576,23 @@ void cpu_mp_register_lapic(unsigned int apic_id, int is_bsp);
 
 /*
  * Probe application processors and start them.
+ *
+ * On return, cpu_count() gives the actual number of managed processors.
  */
 void cpu_mp_setup(void);
 
 /*
+ * Synchronize with APs on kernel entry.
+ */
+void cpu_mp_sync(void);
+
+/*
  * CPU initialization on APs.
  */
 void cpu_ap_setup(void);
 
 /*
- * Synchronize processors on kernel entry.
- *
- * Wait for all processors to reach a proper state when entering the kernel,
- * so that memory allocations can proceed and thread scheduling started.
- *
- * Once this function returns, cpu_count can be used reliably to know if there
- * are more than one processors, and how many.
+ * Synchronize with BSP on kernel entry.
  */
 void cpu_ap_sync(void);