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glibc/sysdeps/x86/cpu-features.c
H.J. Lu 107e6a3c22 x86: Support usable check for all CPU features 
Support usable check for all CPU features with the following changes:

1. Change struct cpu_features to

struct cpuid_features
{
  struct cpuid_registers cpuid;
  struct cpuid_registers usable;
};

struct cpu_features
{
  struct cpu_features_basic basic;
  struct cpuid_features features[COMMON_CPUID_INDEX_MAX];
  unsigned int preferred[PREFERRED_FEATURE_INDEX_MAX];
...
};

so that there is a usable bit for each cpuid bit.
2. After the cpuid bits have been initialized, copy the known bits to the
usable bits.  EAX/EBX from INDEX_1 and EAX from INDEX_7 aren't used for
CPU feature detection.
3. Clear the usable bits which require OS support.
4. If the feature is supported by OS, copy its cpuid bit to its usable
bit.
5. Replace HAS_CPU_FEATURE and CPU_FEATURES_CPU_P with CPU_FEATURE_USABLE
and CPU_FEATURE_USABLE_P to check if a feature is usable.
6. Add DEPR_FPU_CS_DS for INDEX_7_EBX_13.
7. Unset MPX feature since it has been deprecated.

The results are

1. If the feature is known and doesn't requre OS support, its usable bit
is copied from the cpuid bit.
2. Otherwise, its usable bit is copied from the cpuid bit only if the
feature is known to supported by OS.
3. CPU_FEATURE_USABLE/CPU_FEATURE_USABLE_P are used to check if the
feature can be used.
4. HAS_CPU_FEATURE/CPU_FEATURE_CPU_P are used to check if CPU supports
the feature.
2020-07-13 06:05:16 -07:00

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/* Initialize CPU feature data.
This file is part of the GNU C Library.
Copyright (C) 2008-2020 Free Software Foundation, Inc.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <cpuid.h>
#include <cpu-features.h>
#include <dl-hwcap.h>
#include <libc-pointer-arith.h>
#if HAVE_TUNABLES
# define TUNABLE_NAMESPACE cpu
# include <unistd.h> /* Get STDOUT_FILENO for _dl_printf. */
# include <elf/dl-tunables.h>
extern void TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *)
attribute_hidden;
# if CET_ENABLED
extern void TUNABLE_CALLBACK (set_x86_ibt) (tunable_val_t *)
attribute_hidden;
extern void TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *)
attribute_hidden;
# endif
#endif
#if CET_ENABLED
# include <dl-cet.h>
#endif
static void
update_usable (struct cpu_features *cpu_features)
{
/* Before COMMON_CPUID_INDEX_80000001, copy the cpuid array elements to
the usable array. */
unsigned int i;
for (i = 0; i < COMMON_CPUID_INDEX_80000001; i++)
cpu_features->features[i].usable = cpu_features->features[i].cpuid;
/* Before COMMON_CPUID_INDEX_80000001, clear the unknown usable bits
and the always zero bits. */
CPU_FEATURE_UNSET (cpu_features, INDEX_1_ECX_16);
CPU_FEATURE_UNSET (cpu_features, INDEX_1_ECX_31);
CPU_FEATURE_UNSET (cpu_features, INDEX_1_EDX_10);
CPU_FEATURE_UNSET (cpu_features, INDEX_1_EDX_20);
CPU_FEATURE_UNSET (cpu_features, INDEX_1_EDX_30);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EBX_6);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EBX_22);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_13);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_15);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_16);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_23);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_24);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_ECX_26);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_0);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_1);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_5);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_6);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_7);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_9);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_11);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_12);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_13);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_17);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_19);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_21);
CPU_FEATURE_UNSET (cpu_features, INDEX_7_EDX_23);
/* EAX/EBX from COMMON_CPUID_INDEX_1 and EAX from COMMON_CPUID_INDEX_7
aren't used for CPU feature detection. */
cpu_features->features[COMMON_CPUID_INDEX_1].usable.eax = 0;
cpu_features->features[COMMON_CPUID_INDEX_1].usable.ebx = 0;
cpu_features->features[COMMON_CPUID_INDEX_7].usable.eax = 0;
/* Starting from COMMON_CPUID_INDEX_80000001, copy the cpuid bits to
usable bits. */
CPU_FEATURE_SET_USABLE (cpu_features, LAHF64_SAHF64);
CPU_FEATURE_SET_USABLE (cpu_features, SVM);
CPU_FEATURE_SET_USABLE (cpu_features, LZCNT);
CPU_FEATURE_SET_USABLE (cpu_features, SSE4A);
CPU_FEATURE_SET_USABLE (cpu_features, PREFETCHW);
CPU_FEATURE_SET_USABLE (cpu_features, XOP);
CPU_FEATURE_SET_USABLE (cpu_features, LWP);
CPU_FEATURE_SET_USABLE (cpu_features, FMA4);
CPU_FEATURE_SET_USABLE (cpu_features, TBM);
CPU_FEATURE_SET_USABLE (cpu_features, SYSCALL_SYSRET);
CPU_FEATURE_SET_USABLE (cpu_features, NX);
CPU_FEATURE_SET_USABLE (cpu_features, PAGE1GB);
CPU_FEATURE_SET_USABLE (cpu_features, RDTSCP);
CPU_FEATURE_SET_USABLE (cpu_features, LM);
CPU_FEATURE_SET_USABLE (cpu_features, XSAVEOPT);
CPU_FEATURE_SET_USABLE (cpu_features, XSAVEC);
CPU_FEATURE_SET_USABLE (cpu_features, XGETBV_ECX_1);
CPU_FEATURE_SET_USABLE (cpu_features, XSAVES);
CPU_FEATURE_SET_USABLE (cpu_features, XFD);
CPU_FEATURE_SET_USABLE (cpu_features, INVARIANT_TSC);
CPU_FEATURE_SET_USABLE (cpu_features, WBNOINVD);
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_BF16);
/* MPX has been deprecated. */
CPU_FEATURE_UNSET (cpu_features, MPX);
/* Clear the usable bits which require OS support. */
CPU_FEATURE_UNSET (cpu_features, FMA);
CPU_FEATURE_UNSET (cpu_features, AVX);
CPU_FEATURE_UNSET (cpu_features, F16C);
CPU_FEATURE_UNSET (cpu_features, AVX2);
CPU_FEATURE_UNSET (cpu_features, AVX512F);
CPU_FEATURE_UNSET (cpu_features, AVX512DQ);
CPU_FEATURE_UNSET (cpu_features, AVX512_IFMA);
CPU_FEATURE_UNSET (cpu_features, AVX512PF);
CPU_FEATURE_UNSET (cpu_features, AVX512ER);
CPU_FEATURE_UNSET (cpu_features, AVX512CD);
CPU_FEATURE_UNSET (cpu_features, AVX512BW);
CPU_FEATURE_UNSET (cpu_features, AVX512VL);
CPU_FEATURE_UNSET (cpu_features, AVX512_VBMI);
CPU_FEATURE_UNSET (cpu_features, PKU);
CPU_FEATURE_UNSET (cpu_features, AVX512_VBMI2);
CPU_FEATURE_UNSET (cpu_features, VAES);
CPU_FEATURE_UNSET (cpu_features, VPCLMULQDQ);
CPU_FEATURE_UNSET (cpu_features, AVX512_VNNI);
CPU_FEATURE_UNSET (cpu_features, AVX512_BITALG);
CPU_FEATURE_UNSET (cpu_features, AVX512_VPOPCNTDQ);
CPU_FEATURE_UNSET (cpu_features, AVX512_4VNNIW);
CPU_FEATURE_UNSET (cpu_features, AVX512_4FMAPS);
CPU_FEATURE_UNSET (cpu_features, AVX512_VP2INTERSECT);
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, XOP);
CPU_FEATURE_UNSET (cpu_features, FMA4);
CPU_FEATURE_UNSET (cpu_features, XSAVEC);
CPU_FEATURE_UNSET (cpu_features, XFD);
CPU_FEATURE_UNSET (cpu_features, AVX512_BF16);
/* Can we call xgetbv? */
if (CPU_FEATURES_CPU_P (cpu_features, OSXSAVE))
{
unsigned int xcrlow;
unsigned int xcrhigh;
asm ("xgetbv" : "=a" (xcrlow), "=d" (xcrhigh) : "c" (0));
/* Is YMM and XMM state usable? */
if ((xcrlow & (bit_YMM_state | bit_XMM_state))
== (bit_YMM_state | bit_XMM_state))
{
/* Determine if AVX is usable. */
if (CPU_FEATURES_CPU_P (cpu_features, AVX))
{
CPU_FEATURE_SET (cpu_features, AVX);
/* The following features depend on AVX being usable. */
/* Determine if AVX2 is usable. */
if (CPU_FEATURES_CPU_P (cpu_features, AVX2))
{
CPU_FEATURE_SET (cpu_features, AVX2);
/* Unaligned load with 256-bit AVX registers are faster
on Intel/AMD processors with AVX2. */
cpu_features->preferred[index_arch_AVX_Fast_Unaligned_Load]
|= bit_arch_AVX_Fast_Unaligned_Load;
}
/* Determine if FMA is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, FMA);
/* Determine if VAES is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, VAES);
/* Determine if VPCLMULQDQ is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, VPCLMULQDQ);
/* Determine if XOP is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, XOP);
/* Determine if F16C is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, F16C);
}
/* Check if OPMASK state, upper 256-bit of ZMM0-ZMM15 and
ZMM16-ZMM31 state are enabled. */
if ((xcrlow & (bit_Opmask_state | bit_ZMM0_15_state
| bit_ZMM16_31_state))
== (bit_Opmask_state | bit_ZMM0_15_state | bit_ZMM16_31_state))
{
/* Determine if AVX512F is usable. */
if (CPU_FEATURES_CPU_P (cpu_features, AVX512F))
{
CPU_FEATURE_SET (cpu_features, AVX512F);
/* Determine if AVX512CD is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512CD);
/* Determine if AVX512ER is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512ER);
/* Determine if AVX512PF is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512PF);
/* Determine if AVX512VL is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512VL);
/* Determine if AVX512DQ is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512DQ);
/* Determine if AVX512BW is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512BW);
/* Determine if AVX512_4FMAPS is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_4FMAPS);
/* Determine if AVX512_4VNNIW is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_4VNNIW);
/* Determine if AVX512_BITALG is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_BITALG);
/* Determine if AVX512_IFMA is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_IFMA);
/* Determine if AVX512_VBMI is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_VBMI);
/* Determine if AVX512_VBMI2 is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_VBMI2);
/* Determine if is AVX512_VNNI usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_VNNI);
/* Determine if AVX512_VPOPCNTDQ is usable. */
CPU_FEATURE_SET_USABLE (cpu_features,
AVX512_VPOPCNTDQ);
/* Determine if AVX512_VP2INTERSECT is usable. */
CPU_FEATURE_SET_USABLE (cpu_features,
AVX512_VP2INTERSECT);
/* Determine if AVX512_BF16 is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AVX512_BF16);
}
}
}
/* Are XTILECFG and XTILEDATA states usable? */
if ((xcrlow & (bit_XTILECFG_state | bit_XTILEDATA_state))
== (bit_XTILECFG_state | bit_XTILEDATA_state))
{
/* Determine if AMX_BF16 is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AMX_BF16);
/* Determine if AMX_TILE is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AMX_TILE);
/* Determine if AMX_INT8 is usable. */
CPU_FEATURE_SET_USABLE (cpu_features, AMX_INT8);
}
/* XFD is usable only when OSXSAVE is enabled. */
CPU_FEATURE_SET_USABLE (cpu_features, XFD);
/* For _dl_runtime_resolve, set xsave_state_size to xsave area
size + integer register save size and align it to 64 bytes. */
if (cpu_features->basic.max_cpuid >= 0xd)
{
unsigned int eax, ebx, ecx, edx;
__cpuid_count (0xd, 0, eax, ebx, ecx, edx);
if (ebx != 0)
{
unsigned int xsave_state_full_size
= ALIGN_UP (ebx + STATE_SAVE_OFFSET, 64);
cpu_features->xsave_state_size
= xsave_state_full_size;
cpu_features->xsave_state_full_size
= xsave_state_full_size;
/* Check if XSAVEC is available. */
if (CPU_FEATURES_CPU_P (cpu_features, XSAVEC))
{
unsigned int xstate_comp_offsets[32];
unsigned int xstate_comp_sizes[32];
unsigned int i;
xstate_comp_offsets[0] = 0;
xstate_comp_offsets[1] = 160;
xstate_comp_offsets[2] = 576;
xstate_comp_sizes[0] = 160;
xstate_comp_sizes[1] = 256;
for (i = 2; i < 32; i++)
{
if ((STATE_SAVE_MASK & (1 << i)) != 0)
{
__cpuid_count (0xd, i, eax, ebx, ecx, edx);
xstate_comp_sizes[i] = eax;
}
else
{
ecx = 0;
xstate_comp_sizes[i] = 0;
}
if (i > 2)
{
xstate_comp_offsets[i]
= (xstate_comp_offsets[i - 1]
+ xstate_comp_sizes[i -1]);
if ((ecx & (1 << 1)) != 0)
xstate_comp_offsets[i]
= ALIGN_UP (xstate_comp_offsets[i], 64);
}
}
/* Use XSAVEC. */
unsigned int size
= xstate_comp_offsets[31] + xstate_comp_sizes[31];
if (size)
{
cpu_features->xsave_state_size
= ALIGN_UP (size + STATE_SAVE_OFFSET, 64);
CPU_FEATURE_SET (cpu_features, XSAVEC);
}
}
}
}
}
/* Determine if PKU is usable. */
if (CPU_FEATURES_CPU_P (cpu_features, OSPKE))
CPU_FEATURE_SET (cpu_features, PKU);
}
static void
get_extended_indices (struct cpu_features *cpu_features)
{
unsigned int eax, ebx, ecx, edx;
__cpuid (0x80000000, eax, ebx, ecx, edx);
if (eax >= 0x80000001)
__cpuid (0x80000001,
cpu_features->features[COMMON_CPUID_INDEX_80000001].cpuid.eax,
cpu_features->features[COMMON_CPUID_INDEX_80000001].cpuid.ebx,
cpu_features->features[COMMON_CPUID_INDEX_80000001].cpuid.ecx,
cpu_features->features[COMMON_CPUID_INDEX_80000001].cpuid.edx);
if (eax >= 0x80000007)
__cpuid (0x80000007,
cpu_features->features[COMMON_CPUID_INDEX_80000007].cpuid.eax,
cpu_features->features[COMMON_CPUID_INDEX_80000007].cpuid.ebx,
cpu_features->features[COMMON_CPUID_INDEX_80000007].cpuid.ecx,
cpu_features->features[COMMON_CPUID_INDEX_80000007].cpuid.edx);
if (eax >= 0x80000008)
__cpuid (0x80000008,
cpu_features->features[COMMON_CPUID_INDEX_80000008].cpuid.eax,
cpu_features->features[COMMON_CPUID_INDEX_80000008].cpuid.ebx,
cpu_features->features[COMMON_CPUID_INDEX_80000008].cpuid.ecx,
cpu_features->features[COMMON_CPUID_INDEX_80000008].cpuid.edx);
}
static void
get_common_indices (struct cpu_features *cpu_features,
unsigned int *family, unsigned int *model,
unsigned int *extended_model, unsigned int *stepping)
{
if (family)
{
unsigned int eax;
__cpuid (1, eax,
cpu_features->features[COMMON_CPUID_INDEX_1].cpuid.ebx,
cpu_features->features[COMMON_CPUID_INDEX_1].cpuid.ecx,
cpu_features->features[COMMON_CPUID_INDEX_1].cpuid.edx);
cpu_features->features[COMMON_CPUID_INDEX_1].cpuid.eax = eax;
*family = (eax >> 8) & 0x0f;
*model = (eax >> 4) & 0x0f;
*extended_model = (eax >> 12) & 0xf0;
*stepping = eax & 0x0f;
if (*family == 0x0f)
{
*family += (eax >> 20) & 0xff;
*model += *extended_model;
}
}
if (cpu_features->basic.max_cpuid >= 7)
{
__cpuid_count (7, 0,
cpu_features->features[COMMON_CPUID_INDEX_7].cpuid.eax,
cpu_features->features[COMMON_CPUID_INDEX_7].cpuid.ebx,
cpu_features->features[COMMON_CPUID_INDEX_7].cpuid.ecx,
cpu_features->features[COMMON_CPUID_INDEX_7].cpuid.edx);
__cpuid_count (7, 1,
cpu_features->features[COMMON_CPUID_INDEX_7_ECX_1].cpuid.eax,
cpu_features->features[COMMON_CPUID_INDEX_7_ECX_1].cpuid.ebx,
cpu_features->features[COMMON_CPUID_INDEX_7_ECX_1].cpuid.ecx,
cpu_features->features[COMMON_CPUID_INDEX_7_ECX_1].cpuid.edx);
}
if (cpu_features->basic.max_cpuid >= 0xd)
__cpuid_count (0xd, 1,
cpu_features->features[COMMON_CPUID_INDEX_D_ECX_1].cpuid.eax,
cpu_features->features[COMMON_CPUID_INDEX_D_ECX_1].cpuid.ebx,
cpu_features->features[COMMON_CPUID_INDEX_D_ECX_1].cpuid.ecx,
cpu_features->features[COMMON_CPUID_INDEX_D_ECX_1].cpuid.edx);
}
_Static_assert (((index_arch_Fast_Unaligned_Load
== index_arch_Fast_Unaligned_Copy)
&& (index_arch_Fast_Unaligned_Load
== index_arch_Prefer_PMINUB_for_stringop)
&& (index_arch_Fast_Unaligned_Load
== index_arch_Slow_SSE4_2)
&& (index_arch_Fast_Unaligned_Load
== index_arch_Fast_Rep_String)
&& (index_arch_Fast_Unaligned_Load
== index_arch_Fast_Copy_Backward)),
"Incorrect index_arch_Fast_Unaligned_Load");
static inline void
init_cpu_features (struct cpu_features *cpu_features)
{
unsigned int ebx, ecx, edx;
unsigned int family = 0;
unsigned int model = 0;
unsigned int stepping = 0;
enum cpu_features_kind kind;
#if !HAS_CPUID
if (__get_cpuid_max (0, 0) == 0)
{
kind = arch_kind_other;
goto no_cpuid;
}
#endif
__cpuid (0, cpu_features->basic.max_cpuid, ebx, ecx, edx);
/* This spells out "GenuineIntel". */
if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
{
unsigned int extended_model;
kind = arch_kind_intel;
get_common_indices (cpu_features, &family, &model, &extended_model,
&stepping);
get_extended_indices (cpu_features);
update_usable (cpu_features);
if (family == 0x06)
{
model += extended_model;
switch (model)
{
case 0x1c:
case 0x26:
/* BSF is slow on Atom. */
cpu_features->preferred[index_arch_Slow_BSF]
|= bit_arch_Slow_BSF;
break;
case 0x57:
/* Knights Landing. Enable Silvermont optimizations. */
case 0x7a:
/* Unaligned load versions are faster than SSSE3
on Goldmont Plus. */
case 0x5c:
case 0x5f:
/* Unaligned load versions are faster than SSSE3
on Goldmont. */
case 0x4c:
case 0x5a:
case 0x75:
/* Airmont is a die shrink of Silvermont. */
case 0x37:
case 0x4a:
case 0x4d:
case 0x5d:
/* Unaligned load versions are faster than SSSE3
on Silvermont. */
cpu_features->preferred[index_arch_Fast_Unaligned_Load]
|= (bit_arch_Fast_Unaligned_Load
| bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop
| bit_arch_Slow_SSE4_2);
break;
case 0x86:
case 0x96:
case 0x9c:
/* Enable rep string instructions, unaligned load, unaligned
copy, pminub and avoid SSE 4.2 on Tremont. */
cpu_features->preferred[index_arch_Fast_Rep_String]
|= (bit_arch_Fast_Rep_String
| bit_arch_Fast_Unaligned_Load
| bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop
| bit_arch_Slow_SSE4_2);
break;
default:
/* Unknown family 0x06 processors. Assuming this is one
of Core i3/i5/i7 processors if AVX is available. */
if (!CPU_FEATURES_CPU_P (cpu_features, AVX))
break;
/* Fall through. */
case 0x1a:
case 0x1e:
case 0x1f:
case 0x25:
case 0x2c:
case 0x2e:
case 0x2f:
/* Rep string instructions, unaligned load, unaligned copy,
and pminub are fast on Intel Core i3, i5 and i7. */
cpu_features->preferred[index_arch_Fast_Rep_String]
|= (bit_arch_Fast_Rep_String
| bit_arch_Fast_Unaligned_Load
| bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop);
break;
}
/* Disable TSX on some Haswell processors to avoid TSX on kernels that
weren't updated with the latest microcode package (which disables
broken feature by default). */
switch (model)
{
case 0x3f:
/* Xeon E7 v3 with stepping >= 4 has working TSX. */
if (stepping >= 4)
break;
/* Fall through. */
case 0x3c:
case 0x45:
case 0x46:
/* Disable Intel TSX on Haswell processors (except Xeon E7 v3
with stepping >= 4) to avoid TSX on kernels that weren't
updated with the latest microcode package (which disables
broken feature by default). */
CPU_FEATURE_UNSET (cpu_features, RTM);
break;
}
}
/* Since AVX512ER is unique to Xeon Phi, set Prefer_No_VZEROUPPER
if AVX512ER is available. Don't use AVX512 to avoid lower CPU
frequency if AVX512ER isn't available. */
if (CPU_FEATURES_CPU_P (cpu_features, AVX512ER))
cpu_features->preferred[index_arch_Prefer_No_VZEROUPPER]
|= bit_arch_Prefer_No_VZEROUPPER;
else
cpu_features->preferred[index_arch_Prefer_No_AVX512]
|= bit_arch_Prefer_No_AVX512;
}
/* This spells out "AuthenticAMD" or "HygonGenuine". */
else if ((ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65)
|| (ebx == 0x6f677948 && ecx == 0x656e6975 && edx == 0x6e65476e))
{
unsigned int extended_model;
kind = arch_kind_amd;
get_common_indices (cpu_features, &family, &model, &extended_model,
&stepping);
get_extended_indices (cpu_features);
update_usable (cpu_features);
ecx = cpu_features->features[COMMON_CPUID_INDEX_1].cpuid.ecx;
if (CPU_FEATURE_USABLE_P (cpu_features, AVX))
{
/* Since the FMA4 bit is in COMMON_CPUID_INDEX_80000001 and
FMA4 requires AVX, determine if FMA4 is usable here. */
CPU_FEATURE_SET_USABLE (cpu_features, FMA4);
}
if (family == 0x15)
{
/* "Excavator" */
if (model >= 0x60 && model <= 0x7f)
{
cpu_features->preferred[index_arch_Fast_Unaligned_Load]
|= (bit_arch_Fast_Unaligned_Load
| bit_arch_Fast_Copy_Backward);
/* Unaligned AVX loads are slower.*/
cpu_features->preferred[index_arch_AVX_Fast_Unaligned_Load]
&= ~bit_arch_AVX_Fast_Unaligned_Load;
}
}
}
/* This spells out "CentaurHauls" or " Shanghai ". */
else if ((ebx == 0x746e6543 && ecx == 0x736c7561 && edx == 0x48727561)
|| (ebx == 0x68532020 && ecx == 0x20206961 && edx == 0x68676e61))
{
unsigned int extended_model, stepping;
kind = arch_kind_zhaoxin;
get_common_indices (cpu_features, &family, &model, &extended_model,
&stepping);
get_extended_indices (cpu_features);
update_usable (cpu_features);
model += extended_model;
if (family == 0x6)
{
if (model == 0xf || model == 0x19)
{
CPU_FEATURE_UNSET (cpu_features, AVX);
CPU_FEATURE_UNSET (cpu_features, AVX2);
cpu_features->preferred[index_arch_Slow_SSE4_2]
|= bit_arch_Slow_SSE4_2;
cpu_features->preferred[index_arch_AVX_Fast_Unaligned_Load]
&= ~bit_arch_AVX_Fast_Unaligned_Load;
}
}
else if (family == 0x7)
{
if (model == 0x1b)
{
CPU_FEATURE_UNSET (cpu_features, AVX);
CPU_FEATURE_UNSET (cpu_features, AVX2);
cpu_features->preferred[index_arch_Slow_SSE4_2]
|= bit_arch_Slow_SSE4_2;
cpu_features->preferred[index_arch_AVX_Fast_Unaligned_Load]
&= ~bit_arch_AVX_Fast_Unaligned_Load;
}
else if (model == 0x3b)
{
CPU_FEATURE_UNSET (cpu_features, AVX);
CPU_FEATURE_UNSET (cpu_features, AVX2);
cpu_features->preferred[index_arch_AVX_Fast_Unaligned_Load]
&= ~bit_arch_AVX_Fast_Unaligned_Load;
}
}
}
else
{
kind = arch_kind_other;
get_common_indices (cpu_features, NULL, NULL, NULL, NULL);
update_usable (cpu_features);
}
/* Support i586 if CX8 is available. */
if (CPU_FEATURES_CPU_P (cpu_features, CX8))
cpu_features->preferred[index_arch_I586] |= bit_arch_I586;
/* Support i686 if CMOV is available. */
if (CPU_FEATURES_CPU_P (cpu_features, CMOV))
cpu_features->preferred[index_arch_I686] |= bit_arch_I686;
#if !HAS_CPUID
no_cpuid:
#endif
cpu_features->basic.kind = kind;
cpu_features->basic.family = family;
cpu_features->basic.model = model;
cpu_features->basic.stepping = stepping;
#if HAVE_TUNABLES
TUNABLE_GET (hwcaps, tunable_val_t *, TUNABLE_CALLBACK (set_hwcaps));
cpu_features->non_temporal_threshold
= TUNABLE_GET (x86_non_temporal_threshold, long int, NULL);
cpu_features->rep_movsb_threshold
= TUNABLE_GET (x86_rep_movsb_threshold, long int, NULL);
cpu_features->rep_stosb_threshold
= TUNABLE_GET (x86_rep_stosb_threshold, long int, NULL);
cpu_features->data_cache_size
= TUNABLE_GET (x86_data_cache_size, long int, NULL);
cpu_features->shared_cache_size
= TUNABLE_GET (x86_shared_cache_size, long int, NULL);
#endif
/* Reuse dl_platform, dl_hwcap and dl_hwcap_mask for x86. */
#if !HAVE_TUNABLES && defined SHARED
/* The glibc.cpu.hwcap_mask tunable is initialized already, so no need to do
this. */
GLRO(dl_hwcap_mask) = HWCAP_IMPORTANT;
#endif
#ifdef __x86_64__
GLRO(dl_hwcap) = HWCAP_X86_64;
if (cpu_features->basic.kind == arch_kind_intel)
{
const char *platform = NULL;
if (CPU_FEATURE_USABLE_P (cpu_features, AVX512CD))
{
if (CPU_FEATURE_USABLE_P (cpu_features, AVX512ER))
{
if (CPU_FEATURE_USABLE_P (cpu_features, AVX512PF))
platform = "xeon_phi";
}
else
{
if (CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
&& CPU_FEATURE_USABLE_P (cpu_features, AVX512DQ)
&& CPU_FEATURE_USABLE_P (cpu_features, AVX512VL))
GLRO(dl_hwcap) |= HWCAP_X86_AVX512_1;
}
}
if (platform == NULL
&& CPU_FEATURE_USABLE_P (cpu_features, AVX2)
&& CPU_FEATURE_USABLE_P (cpu_features, FMA)
&& CPU_FEATURE_USABLE_P (cpu_features, BMI1)
&& CPU_FEATURE_USABLE_P (cpu_features, BMI2)
&& CPU_FEATURE_USABLE_P (cpu_features, LZCNT)
&& CPU_FEATURE_USABLE_P (cpu_features, MOVBE)
&& CPU_FEATURE_USABLE_P (cpu_features, POPCNT))
platform = "haswell";
if (platform != NULL)
GLRO(dl_platform) = platform;
}
#else
GLRO(dl_hwcap) = 0;
if (CPU_FEATURE_USABLE_P (cpu_features, SSE2))
GLRO(dl_hwcap) |= HWCAP_X86_SSE2;
if (CPU_FEATURES_ARCH_P (cpu_features, I686))
GLRO(dl_platform) = "i686";
else if (CPU_FEATURES_ARCH_P (cpu_features, I586))
GLRO(dl_platform) = "i586";
#endif
#if CET_ENABLED
# if HAVE_TUNABLES
TUNABLE_GET (x86_ibt, tunable_val_t *,
TUNABLE_CALLBACK (set_x86_ibt));
TUNABLE_GET (x86_shstk, tunable_val_t *,
TUNABLE_CALLBACK (set_x86_shstk));
# endif
/* Check CET status. */
unsigned int cet_status = get_cet_status ();
if (cet_status)
{
GL(dl_x86_feature_1) = cet_status;
# ifndef SHARED
/* Check if IBT and SHSTK are enabled by kernel. */
if ((cet_status & GNU_PROPERTY_X86_FEATURE_1_IBT)
|| (cet_status & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
{
/* Disable IBT and/or SHSTK if they are enabled by kernel, but
disabled by environment variable:
GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK
*/
unsigned int cet_feature = 0;
if (!CPU_FEATURE_USABLE (IBT))
cet_feature |= GNU_PROPERTY_X86_FEATURE_1_IBT;
if (!CPU_FEATURE_USABLE (SHSTK))
cet_feature |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
if (cet_feature)
{
int res = dl_cet_disable_cet (cet_feature);
/* Clear the disabled bits in dl_x86_feature_1. */
if (res == 0)
GL(dl_x86_feature_1) &= ~cet_feature;
}
/* Lock CET if IBT or SHSTK is enabled in executable. Don't
lock CET if IBT or SHSTK is enabled permissively. */
if (GL(dl_x86_feature_control).ibt != cet_permissive
&& GL(dl_x86_feature_control).shstk != cet_permissive)
dl_cet_lock_cet ();
}
# endif
}
#endif
}
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