x86/spec_ctrl: Add lock to serialize changes to ibrs and ibpb control

[mirror_ubuntu-artful-kernel.git] / kernel / smp.c

diff --git a/kernel/smp.c b/kernel/smp.c
index 3bece045f4a40c8375e867b818393fa97b53da2f..a224ec0c540c3062822dce97e14bf067cc9d28bb 100644 (file)
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -519,6 +519,10 @@ int use_ibpb;
 EXPORT_SYMBOL(use_ibpb);
 #endif
 
+/* mutex to serialize IBRS & IBPB control changes */
+DEFINE_MUTEX(spec_ctrl_mutex);
+EXPORT_SYMBOL(spec_ctrl_mutex);
+
 /*
  * Setup routine for controlling SMP activation
  *