Based on the following commit, adjusted for glibc-2.28 in RHEL-8: commit 27f74636752d0c4438cf8346cf2a76b6fcf3be16 Author: H.J. Lu Date: Fri Mar 19 06:15:37 2021 -0700 x86: Properly disable XSAVE related features [BZ #27605] 1. Support GLIBC_TUNABLES=glibc.cpu.hwcaps=-XSAVE. 2. Disable all features which depend on XSAVE: a. If OSXSAVE is disabled by glibc tunables. Or b. If both XSAVE and XSAVEC aren't usable. diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 805d00a43309fc23..910425053d9e226f 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -654,6 +654,60 @@ no_cpuid: = TUNABLE_GET (x86_data_cache_size, long int, NULL); cpu_features->shared_cache_size = TUNABLE_GET (x86_shared_cache_size, long int, NULL); + + bool disable_xsave_features = false; + + if (!CPU_FEATURE_USABLE_P (cpu_features, OSXSAVE)) + { + /* These features are usable only if OSXSAVE is usable. */ + CPU_FEATURE_UNSET (cpu_features, XSAVE); + CPU_FEATURE_UNSET (cpu_features, XSAVEOPT); + CPU_FEATURE_UNSET (cpu_features, XSAVEC); + CPU_FEATURE_UNSET (cpu_features, XGETBV_ECX_1); + CPU_FEATURE_UNSET (cpu_features, XFD); + + disable_xsave_features = true; + } + + if (disable_xsave_features + || (!CPU_FEATURE_USABLE_P (cpu_features, XSAVE) + && !CPU_FEATURE_USABLE_P (cpu_features, XSAVEC))) + { + /* Clear xsave_state_size if both XSAVE and XSAVEC aren't usable. */ + cpu_features->xsave_state_size = 0; + + CPU_FEATURE_UNSET (cpu_features, AVX); + CPU_FEATURE_UNSET (cpu_features, AVX2); + CPU_FEATURE_UNSET (cpu_features, AVX_VNNI); + CPU_FEATURE_UNSET (cpu_features, FMA); + CPU_FEATURE_UNSET (cpu_features, VAES); + CPU_FEATURE_UNSET (cpu_features, VPCLMULQDQ); + CPU_FEATURE_UNSET (cpu_features, XOP); + CPU_FEATURE_UNSET (cpu_features, F16C); + CPU_FEATURE_UNSET (cpu_features, AVX512F); + CPU_FEATURE_UNSET (cpu_features, AVX512CD); + CPU_FEATURE_UNSET (cpu_features, AVX512ER); + CPU_FEATURE_UNSET (cpu_features, AVX512PF); + CPU_FEATURE_UNSET (cpu_features, AVX512VL); + CPU_FEATURE_UNSET (cpu_features, AVX512DQ); + CPU_FEATURE_UNSET (cpu_features, AVX512BW); + CPU_FEATURE_UNSET (cpu_features, AVX512_4FMAPS); + CPU_FEATURE_UNSET (cpu_features, AVX512_4VNNIW); + CPU_FEATURE_UNSET (cpu_features, AVX512_BITALG); + CPU_FEATURE_UNSET (cpu_features, AVX512_IFMA); + CPU_FEATURE_UNSET (cpu_features, AVX512_VBMI); + CPU_FEATURE_UNSET (cpu_features, AVX512_VBMI2); + CPU_FEATURE_UNSET (cpu_features, AVX512_VNNI); + CPU_FEATURE_UNSET (cpu_features, AVX512_VPOPCNTDQ); + CPU_FEATURE_UNSET (cpu_features, AVX512_VP2INTERSECT); + CPU_FEATURE_UNSET (cpu_features, AVX512_BF16); + CPU_FEATURE_UNSET (cpu_features, AVX512_FP16); + CPU_FEATURE_UNSET (cpu_features, AMX_BF16); + CPU_FEATURE_UNSET (cpu_features, AMX_TILE); + CPU_FEATURE_UNSET (cpu_features, AMX_INT8); + + CPU_FEATURE_UNSET (cpu_features, FMA4); + } #endif /* Reuse dl_platform, dl_hwcap and dl_hwcap_mask for x86. */ diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index 0728023007a0f423..3173b2b959ca88f9 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -168,6 +168,7 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, MOVBE, 5); CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SHSTK, 5); CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSSE3, 5); + CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, XSAVE, 5); } break; case 6: