From ebd3ad60a688131de7df1dd05fd2d7c57f542268 Mon Sep 17 00:00:00 2001 From: "Borislav Petkov (AMD)" Date: Wed, 25 Jan 2023 08:50:13 +0100 Subject: [PATCH] x86/cpu: Use cpu_feature_enabled() when checking global pages support X86_FEATURE_PGE determines whether the CPU has enabled global page translations support. Use the faster cpu_feature_enabled() check to shave off some more cycles when flushing all TLB entries, including the global ones. What this practically saves is: mov 0x82eb308(%rip),%rax # 0xffffffff8935bec8 test $0x20,%ah ... which test the bit. Not a lot, but TLB flushing is a timing-sensitive path, so anything to make it even faster. No functional changes. Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20230125075013.9292-1-bp@alien8.de --- arch/x86/mm/tlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index c1e31e9..92d73cc 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -1205,7 +1205,7 @@ void __flush_tlb_all(void) */ VM_WARN_ON_ONCE(preemptible()); - if (boot_cpu_has(X86_FEATURE_PGE)) { + if (cpu_feature_enabled(X86_FEATURE_PGE)) { __flush_tlb_global(); } else { /* -- 2.7.4