| Date | Thu, 18 Jan 2018 14:48:25 +0100 | From | Peter Zijlstra <> | From | Peter Zijlstra <> | Subject | [PATCH 25/35] x86/speculation: Add inlines to control Indirect Branch Speculation |
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From: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@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__ */
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