Commit-ID: 0bf17c102177d5da9363bf8b1e4704b9996d5079 Gitweb: https://git.kernel.org/tip/0bf17c102177d5da9363bf8b1e4704b9996d5079 Author: Tom Lendacky <thomas.lendacky@xxxxxxx> AuthorDate: Fri, 5 Jan 2018 10:07:56 -0600 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Sat, 6 Jan 2018 21:57:40 +0100 x86/cpu/AMD: Use LFENCE_RDTSC instead of MFENCE_RDTSC With LFENCE now a serializing instruction, set the LFENCE_RDTSC feature since the LFENCE instruction has less overhead than the MFENCE instruction. Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Borislav Petkov <bp@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxxx> Cc: David Woodhouse <dwmw@xxxxxxxxxxxx> Cc: Paul Turner <pjt@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20180105160756.23786.4220.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx --- arch/x86/kernel/cpu/amd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index fbd439e..b221fe5 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -838,8 +838,8 @@ static void init_amd(struct cpuinfo_x86 *c) msr_set_bit(MSR_F10H_DECFG, MSR_F10H_DECFG_LFENCE_SERIALIZE_BIT); - /* MFENCE stops RDTSC speculation */ - set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC); + /* A serializing LFENCE stops RDTSC speculation */ + set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC); } /* -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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