[v3] x86: Properly disable XSAVE related features [BZ #27605]
Commit Message
On Fri, Mar 19, 2021 at 3:22 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Fri, Mar 19, 2021 at 2:42 PM DJ Delorie <dj@redhat.com> wrote:
> >
> > "H.J. Lu" <hjl.tools@gmail.com> writes:
> > > If OSXSAVE is disabled by glibc tunables, disable features which depend
> > > on OSXSAVE.
> >
> > This one seems to ignore -XSAVE, both on an 11th gen (-XSAVE,-XSAVEC ->
> > xsave()) and on 4th (just -XSAVE). Is this patch supposed to be used
> > with the previous patch, or standalone?
> >
>
> Fixed. Here is the v2 patch. OK for master?
>
Here is the v3 patch to disable all XSAVE related features if both
XSAVE and XSAVEC aren't usable.
Comments
On Mon, Mar 22, 2021 at 11:32 AM DJ Delorie <dj@redhat.com> wrote:
>
> "H.J. Lu" <hjl.tools@gmail.com> writes:
> > Here is the v3 patch to disable all XSAVE related features if both
> > XSAVE and XSAVEC aren't usable.
>
> This version passes all my tests, on both cpus. Thanks!
>
Are there any objections or comments?
On Mon, Mar 22, 2021 at 11:42 AM DJ Delorie <dj@redhat.com> wrote:
>
> "H.J. Lu" <hjl.tools@gmail.com> writes:
> > Are there any objections or comments?
>
> None from me.
>
If there are no objections, I will check this in on Thursday.
From 7ed30c76a7e20f77eb1b65f9b38c905819ad1880 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 19 Mar 2021 06:15:37 -0700
Subject: [PATCH v3] 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.
---
sysdeps/x86/cpu-features.c | 55 ++++++++++++++++++++++++++++++++++++++
sysdeps/x86/cpu-tunables.c | 1 +
2 files changed, 56 insertions(+)
@@ -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
@@ -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:
--
2.30.2