x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature

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

diff --git a/kernel/smp.c b/kernel/smp.c
index 3061483cb3ad3eac437046eda0634f8a152e07f2..3bece045f4a40c8375e867b818393fa97b53da2f 100644 (file)
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -498,6 +498,26 @@ EXPORT_SYMBOL(smp_call_function);
 unsigned int setup_max_cpus = NR_CPUS;
 EXPORT_SYMBOL(setup_max_cpus);
 
+#ifdef CONFIG_X86
+/*
+ * use IBRS
+ * bit 0 = indicate if ibrs is currently in use
+ * bit 1 = indicate if system supports ibrs
+ * bit 2 = indicate if admin disables ibrs
+*/
+
+int use_ibrs;
+EXPORT_SYMBOL(use_ibrs);
+
+/*
+ * use IBRS
+ * bit 0 = indicate if ibpb is currently in use
+ * bit 1 = indicate if system supports ibpb
+ * bit 2 = indicate if admin disables ibpb
+*/
+int use_ibpb;
+EXPORT_SYMBOL(use_ibpb);
+#endif
 
 /*
  * Setup routine for controlling SMP activation
@@ -522,6 +542,27 @@ static int __init nosmp(char *str)
 
 early_param("nosmp", nosmp);
 
+#ifdef CONFIG_X86
+static int __init noibrs(char *str)
+{
+       set_ibrs_disabled();
+
+       return 0;
+}
+
+early_param("noibrs", noibrs);
+
+static int __init noibpb(char *str)
+{
+       set_ibpb_disabled();
+
+       return 0;
+}
+
+early_param("noibpb", noibpb);
+#endif
+
+
 /* this is hard limit */
 static int __init nrcpus(char *str)
 {