From 5cb6edb6cd193d4b0462c718f4b6071f8b84ff90 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 23 Jun 2021 14:27:58 -0700 Subject: [PATCH] x86: Copy IBT and SHSTK usable only if CET is enabled IBT and SHSTK usable bits are copied from CPUID feature bits and later cleared if kernel doesn't support CET. Copy IBT and SHSTK usable only if CET is enabled so that they aren't set on CET capable processors with non-CET enabled glibc. (cherry picked from commit ea26ff03227d7cacef5de6036df57734373449b4) --- sysdeps/x86/cpu-features.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index dfad82f14ca..7a524dbae61 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -75,7 +75,6 @@ update_usable (struct cpu_features *cpu_features) CPU_FEATURE_SET_USABLE (cpu_features, PREFETCHWT1); CPU_FEATURE_SET_USABLE (cpu_features, OSPKE); CPU_FEATURE_SET_USABLE (cpu_features, WAITPKG); - CPU_FEATURE_SET_USABLE (cpu_features, SHSTK); CPU_FEATURE_SET_USABLE (cpu_features, GFNI); CPU_FEATURE_SET_USABLE (cpu_features, RDPID); CPU_FEATURE_SET_USABLE (cpu_features, RDRAND); @@ -85,7 +84,6 @@ update_usable (struct cpu_features *cpu_features) CPU_FEATURE_SET_USABLE (cpu_features, FSRM); CPU_FEATURE_SET_USABLE (cpu_features, SERIALIZE); CPU_FEATURE_SET_USABLE (cpu_features, TSXLDTRK); - CPU_FEATURE_SET_USABLE (cpu_features, IBT); CPU_FEATURE_SET_USABLE (cpu_features, LAHF64_SAHF64); CPU_FEATURE_SET_USABLE (cpu_features, LZCNT); CPU_FEATURE_SET_USABLE (cpu_features, SSE4A); @@ -97,6 +95,11 @@ update_usable (struct cpu_features *cpu_features) CPU_FEATURE_SET_USABLE (cpu_features, FSRS); CPU_FEATURE_SET_USABLE (cpu_features, FSRCS); +#if CET_ENABLED + CPU_FEATURE_SET_USABLE (cpu_features, IBT); + CPU_FEATURE_SET_USABLE (cpu_features, SHSTK); +#endif + /* Can we call xgetbv? */ if (CPU_FEATURES_CPU_P (cpu_features, OSXSAVE)) { -- 2.47.2