From: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
arch/x86/include/asm/nospec-branch.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -6,6 +6,7 @@
#include <asm/alternative.h>
#include <asm/alternative-asm.h>
#include <asm/cpufeatures.h>
+#include <asm/msr.h>
/*
* Fill the CPU return stack buffer.
@@ -219,5 +220,16 @@ bool specctrl_force_enable_ibrs(void);
bool specctrl_cond_enable_ibrs(bool full_retpoline);
bool is_skylake_era(void);
+static inline void stop_indirect_branch_speculation(void)
+{
+ if (static_cpu_has(X86_FEATURE_IBRS))
+ native_wrmsrl(MSR_IA32_SPEC_CTRL, SPEC_CTRL_ENABLE_IBRS);
+}
+
+static inline void restart_indirect_branch_speculation(void)
+{
+ if (static_cpu_has(X86_FEATURE_IBRS))
+ native_wrmsrl(MSR_IA32_SPEC_CTRL, SPEC_CTRL_DISABLE_IBRS);
+}
#endif /* __ASSEMBLY__ */
#endif /* __NOSPEC_BRANCH_H__ */
