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x86: Properly disable XSAVE related features [BZ #27605]

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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.
This commit is contained in:
H.J. Lu 2021-03-19 06:15:37 -07:00
parent cb882b21b6
commit 27f7463675
2 changed files with 56 additions and 0 deletions
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55
sysdeps/x86/cpu-features.c
View File

@ -654,6 +654,61 @@ no_cpuid:
#if HAVE_TUNABLES
TUNABLE_GET (hwcaps, tunable_val_t *, TUNABLE_CALLBACK (set_hwcaps));
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);
}
#elif defined SHARED
/* Reuse dl_platform, dl_hwcap and dl_hwcap_mask for x86. The
glibc.cpu.hwcap_mask tunable is initialized already, so no

1
sysdeps/x86/cpu-tunables.c
View File

@ -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: