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* [glibc] x86: Properly disable XSAVE related features [BZ #27605]
@ 2021-03-29 13:06 H.J. Lu
0 siblings, 0 replies; only message in thread
From: H.J. Lu @ 2021-03-29 13:06 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=27f74636752d0c4438cf8346cf2a76b6fcf3be16
commit 27f74636752d0c4438cf8346cf2a76b6fcf3be16
Author: H.J. Lu <hjl.tools@gmail.com>
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:
---
sysdeps/x86/cpu-features.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++
sysdeps/x86/cpu-tunables.c | 1 +
2 files changed, 56 insertions(+)
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index d7248cbb45..e99e67f34d 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -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
diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c
index 126896f41b..61b05e5b1d 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:
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