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

[mirror_ubuntu-artful-kernel.git] / include / linux / smp.h

diff --git a/include/linux/smp.h b/include/linux/smp.h
index 68123c1fe54918c051292eb5ba3427df09f31c2f..e2935c0a1bb4448d1e1dcb1c53b83fa2841cc1a4 100644 (file)
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -50,6 +50,93 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
 
 int smp_call_function_single_async(int cpu, struct call_single_data *csd);
 
+#ifdef CONFIG_X86
+/* indicate usage of IBRS to control execution speculation */
+extern int use_ibrs;
+extern u32 sysctl_ibrs_enabled;
+extern struct mutex spec_ctrl_mutex;
+#define ibrs_supported         (use_ibrs & 0x2)
+#define ibrs_disabled          (use_ibrs & 0x4)
+static inline void set_ibrs_inuse(void)
+{
+       if (ibrs_supported)
+               use_ibrs |= 0x1;
+}
+static inline void clear_ibrs_inuse(void)
+{
+       use_ibrs &= ~0x1;
+}
+static inline int check_ibrs_inuse(void)
+{
+       if (use_ibrs & 0x1)
+               return 1;
+       else
+               /* rmb to prevent wrong speculation for security */
+               rmb();
+       return 0;
+}
+static inline void set_ibrs_supported(void)
+{
+       use_ibrs |= 0x2;
+       if (!ibrs_disabled)
+               set_ibrs_inuse();
+}
+static inline void set_ibrs_disabled(void)
+{
+       use_ibrs |= 0x4;
+       if (check_ibrs_inuse())
+               clear_ibrs_inuse();
+}
+static inline void clear_ibrs_disabled(void)
+{
+       use_ibrs &= ~0x4;
+       set_ibrs_inuse();
+}
+#define ibrs_inuse             (check_ibrs_inuse())
+
+/* indicate usage of IBPB to control execution speculation */
+extern int use_ibpb;
+extern u32 sysctl_ibpb_enabled;
+#define ibpb_supported         (use_ibpb & 0x2)
+#define ibpb_disabled          (use_ibpb & 0x4)
+static inline void set_ibpb_inuse(void)
+{
+       if (ibpb_supported)
+               use_ibpb |= 0x1;
+}
+static inline void clear_ibpb_inuse(void)
+{
+       use_ibpb &= ~0x1;
+}
+static inline int check_ibpb_inuse(void)
+{
+       if (use_ibpb & 0x1)
+               return 1;
+       else
+               /* rmb to prevent wrong speculation for security */
+               rmb();
+       return 0;
+}
+static inline void set_ibpb_supported(void)
+{
+       use_ibpb |= 0x2;
+       if (!ibpb_disabled)
+               set_ibpb_inuse();
+}
+static inline void set_ibpb_disabled(void)
+{
+       use_ibpb |= 0x4;
+       if (check_ibpb_inuse())
+               clear_ibpb_inuse();
+}
+static inline void clear_ibpb_disabled(void)
+{
+       use_ibpb &= ~0x4;
+       set_ibpb_inuse();
+}
+#define ibpb_inuse             (check_ibpb_inuse())
+#endif
+
 #ifdef CONFIG_SMP
 
 #include <linux/preempt.h>