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glibc/sysdeps/x86/cpu-features.c
H.J. Lu 317f1c0a8a x86-64: Add glibc.cpu.prefer_map_32bit_exec [BZ #28656] 
Crossing 2GB boundaries with indirect calls and jumps can use more
branch prediction resources on Intel Golden Cove CPU (see the
"Misprediction for Branches >2GB" section in Intel 64 and IA-32
Architectures Optimization Reference Manual.)  There is visible
performance improvement on workloads with many PLT calls when executable
and shared libraries are mmapped below 2GB.  Add the Prefer_MAP_32BIT_EXEC
bit so that mmap will try to map executable or denywrite pages in shared
libraries with MAP_32BIT first.

NB: Prefer_MAP_32BIT_EXEC reduces bits available for address space
layout randomization (ASLR), which is always disabled for SUID programs
and can only be enabled by the tunable, glibc.cpu.prefer_map_32bit_exec,
or the environment variable, LD_PREFER_MAP_32BIT_EXEC.  This works only
between shared libraries or between shared libraries and executables with
addresses below 2GB.  PIEs are usually loaded at a random address above
4GB by the kernel.
2023-02-22 18:28:37 -08:00

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/* Initialize CPU feature data.
This file is part of the GNU C Library.
Copyright (C) 2008-2023 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 <dl-hwcap.h>
#include <libc-pointer-arith.h>
#include <get-isa-level.h>
#include <cacheinfo.h>
#include <dl-cacheinfo.h>
#include <dl-minsigstacksize.h>
#if HAVE_TUNABLES
extern void TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *)
attribute_hidden;
# ifdef __LP64__
static void
TUNABLE_CALLBACK (set_prefer_map_32bit_exec) (tunable_val_t *valp)
{
if (valp->numval)
GLRO(dl_x86_cpu_features).preferred[index_arch_Prefer_MAP_32BIT_EXEC]
|= bit_arch_Prefer_MAP_32BIT_EXEC;
}
# endif
# 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_active (struct cpu_features *cpu_features)
{
/* Copy the cpuid bits to active bits for CPU featuress whose usability
in user space can be detected without additonal OS support. */
CPU_FEATURE_SET_ACTIVE (cpu_features, SSE3);
CPU_FEATURE_SET_ACTIVE (cpu_features, PCLMULQDQ);
CPU_FEATURE_SET_ACTIVE (cpu_features, SSSE3);
CPU_FEATURE_SET_ACTIVE (cpu_features, CMPXCHG16B);
CPU_FEATURE_SET_ACTIVE (cpu_features, SSE4_1);
CPU_FEATURE_SET_ACTIVE (cpu_features, SSE4_2);
CPU_FEATURE_SET_ACTIVE (cpu_features, MOVBE);
CPU_FEATURE_SET_ACTIVE (cpu_features, POPCNT);
CPU_FEATURE_SET_ACTIVE (cpu_features, AES);
CPU_FEATURE_SET_ACTIVE (cpu_features, OSXSAVE);
CPU_FEATURE_SET_ACTIVE (cpu_features, TSC);
CPU_FEATURE_SET_ACTIVE (cpu_features, CX8);
CPU_FEATURE_SET_ACTIVE (cpu_features, CMOV);
CPU_FEATURE_SET_ACTIVE (cpu_features, CLFSH);
CPU_FEATURE_SET_ACTIVE (cpu_features, MMX);
CPU_FEATURE_SET_ACTIVE (cpu_features, FXSR);
CPU_FEATURE_SET_ACTIVE (cpu_features, SSE);
CPU_FEATURE_SET_ACTIVE (cpu_features, SSE2);
CPU_FEATURE_SET_ACTIVE (cpu_features, HTT);
CPU_FEATURE_SET_ACTIVE (cpu_features, BMI1);
CPU_FEATURE_SET_ACTIVE (cpu_features, HLE);
CPU_FEATURE_SET_ACTIVE (cpu_features, BMI2);
CPU_FEATURE_SET_ACTIVE (cpu_features, ERMS);
CPU_FEATURE_SET_ACTIVE (cpu_features, RDSEED);
CPU_FEATURE_SET_ACTIVE (cpu_features, ADX);
CPU_FEATURE_SET_ACTIVE (cpu_features, CLFLUSHOPT);
CPU_FEATURE_SET_ACTIVE (cpu_features, CLWB);
CPU_FEATURE_SET_ACTIVE (cpu_features, SHA);
CPU_FEATURE_SET_ACTIVE (cpu_features, PREFETCHWT1);
CPU_FEATURE_SET_ACTIVE (cpu_features, OSPKE);
CPU_FEATURE_SET_ACTIVE (cpu_features, WAITPKG);
CPU_FEATURE_SET_ACTIVE (cpu_features, GFNI);
CPU_FEATURE_SET_ACTIVE (cpu_features, RDPID);
CPU_FEATURE_SET_ACTIVE (cpu_features, RDRAND);
CPU_FEATURE_SET_ACTIVE (cpu_features, CLDEMOTE);
CPU_FEATURE_SET_ACTIVE (cpu_features, MOVDIRI);
CPU_FEATURE_SET_ACTIVE (cpu_features, MOVDIR64B);
CPU_FEATURE_SET_ACTIVE (cpu_features, FSRM);
CPU_FEATURE_SET_ACTIVE (cpu_features, RTM_ALWAYS_ABORT);
CPU_FEATURE_SET_ACTIVE (cpu_features, SERIALIZE);
CPU_FEATURE_SET_ACTIVE (cpu_features, TSXLDTRK);
CPU_FEATURE_SET_ACTIVE (cpu_features, LAHF64_SAHF64);
CPU_FEATURE_SET_ACTIVE (cpu_features, LZCNT);
CPU_FEATURE_SET_ACTIVE (cpu_features, SSE4A);
CPU_FEATURE_SET_ACTIVE (cpu_features, PREFETCHW);
CPU_FEATURE_SET_ACTIVE (cpu_features, TBM);
CPU_FEATURE_SET_ACTIVE (cpu_features, RDTSCP);
CPU_FEATURE_SET_ACTIVE (cpu_features, WBNOINVD);
CPU_FEATURE_SET_ACTIVE (cpu_features, FZLRM);
CPU_FEATURE_SET_ACTIVE (cpu_features, FSRS);
CPU_FEATURE_SET_ACTIVE (cpu_features, FSRCS);
CPU_FEATURE_SET_ACTIVE (cpu_features, PTWRITE);
if (!CPU_FEATURES_CPU_P (cpu_features, RTM_ALWAYS_ABORT))
CPU_FEATURE_SET_ACTIVE (cpu_features, RTM);
#if CET_ENABLED
CPU_FEATURE_SET_ACTIVE (cpu_features, IBT);
CPU_FEATURE_SET_ACTIVE (cpu_features, SHSTK);
#endif
/* 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 AVX-VNNI is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX_VNNI);
/* Determine if FMA is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, FMA);
/* Determine if VAES is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, VAES);
/* Determine if VPCLMULQDQ is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, VPCLMULQDQ);
/* Determine if XOP is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, XOP);
/* Determine if F16C is usable. */
CPU_FEATURE_SET_ACTIVE (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_ACTIVE (cpu_features, AVX512CD);
/* Determine if AVX512ER is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512ER);
/* Determine if AVX512PF is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512PF);
/* Determine if AVX512VL is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512VL);
/* Determine if AVX512DQ is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512DQ);
/* Determine if AVX512BW is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512BW);
/* Determine if AVX512_4FMAPS is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_4FMAPS);
/* Determine if AVX512_4VNNIW is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_4VNNIW);
/* Determine if AVX512_BITALG is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_BITALG);
/* Determine if AVX512_IFMA is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_IFMA);
/* Determine if AVX512_VBMI is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_VBMI);
/* Determine if AVX512_VBMI2 is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_VBMI2);
/* Determine if is AVX512_VNNI usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_VNNI);
/* Determine if AVX512_VPOPCNTDQ is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features,
AVX512_VPOPCNTDQ);
/* Determine if AVX512_VP2INTERSECT is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features,
AVX512_VP2INTERSECT);
/* Determine if AVX512_BF16 is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_BF16);
/* Determine if AVX512_FP16 is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AVX512_FP16);
}
}
}
/* 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_ACTIVE (cpu_features, AMX_BF16);
/* Determine if AMX_TILE is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AMX_TILE);
/* Determine if AMX_INT8 is usable. */
CPU_FEATURE_SET_ACTIVE (cpu_features, AMX_INT8);
}
/* These features are usable only when OSXSAVE is enabled. */
CPU_FEATURE_SET (cpu_features, XSAVE);
CPU_FEATURE_SET_ACTIVE (cpu_features, XSAVEOPT);
CPU_FEATURE_SET_ACTIVE (cpu_features, XSAVEC);
CPU_FEATURE_SET_ACTIVE (cpu_features, XGETBV_ECX_1);
CPU_FEATURE_SET_ACTIVE (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);
/* Determine if Key Locker instructions are usable. */
if (CPU_FEATURES_CPU_P (cpu_features, AESKLE))
{
CPU_FEATURE_SET (cpu_features, AESKLE);
CPU_FEATURE_SET_ACTIVE (cpu_features, KL);
CPU_FEATURE_SET_ACTIVE (cpu_features, WIDE_KL);
}
cpu_features->isa_1 = get_isa_level (cpu_features);
}
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[CPUID_INDEX_80000001].cpuid.eax,
cpu_features->features[CPUID_INDEX_80000001].cpuid.ebx,
cpu_features->features[CPUID_INDEX_80000001].cpuid.ecx,
cpu_features->features[CPUID_INDEX_80000001].cpuid.edx);
if (eax >= 0x80000007)
__cpuid (0x80000007,
cpu_features->features[CPUID_INDEX_80000007].cpuid.eax,
cpu_features->features[CPUID_INDEX_80000007].cpuid.ebx,
cpu_features->features[CPUID_INDEX_80000007].cpuid.ecx,
cpu_features->features[CPUID_INDEX_80000007].cpuid.edx);
if (eax >= 0x80000008)
__cpuid (0x80000008,
cpu_features->features[CPUID_INDEX_80000008].cpuid.eax,
cpu_features->features[CPUID_INDEX_80000008].cpuid.ebx,
cpu_features->features[CPUID_INDEX_80000008].cpuid.ecx,
cpu_features->features[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[CPUID_INDEX_1].cpuid.ebx,
cpu_features->features[CPUID_INDEX_1].cpuid.ecx,
cpu_features->features[CPUID_INDEX_1].cpuid.edx);
cpu_features->features[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[CPUID_INDEX_7].cpuid.eax,
cpu_features->features[CPUID_INDEX_7].cpuid.ebx,
cpu_features->features[CPUID_INDEX_7].cpuid.ecx,
cpu_features->features[CPUID_INDEX_7].cpuid.edx);
__cpuid_count (7, 1,
cpu_features->features[CPUID_INDEX_7_ECX_1].cpuid.eax,
cpu_features->features[CPUID_INDEX_7_ECX_1].cpuid.ebx,
cpu_features->features[CPUID_INDEX_7_ECX_1].cpuid.ecx,
cpu_features->features[CPUID_INDEX_7_ECX_1].cpuid.edx);
}
if (cpu_features->basic.max_cpuid >= 0xd)
__cpuid_count (0xd, 1,
cpu_features->features[CPUID_INDEX_D_ECX_1].cpuid.eax,
cpu_features->features[CPUID_INDEX_D_ECX_1].cpuid.ebx,
cpu_features->features[CPUID_INDEX_D_ECX_1].cpuid.ecx,
cpu_features->features[CPUID_INDEX_D_ECX_1].cpuid.edx);
if (cpu_features->basic.max_cpuid >= 0x14)
__cpuid_count (0x14, 0,
cpu_features->features[CPUID_INDEX_14_ECX_0].cpuid.eax,
cpu_features->features[CPUID_INDEX_14_ECX_0].cpuid.ebx,
cpu_features->features[CPUID_INDEX_14_ECX_0].cpuid.ecx,
cpu_features->features[CPUID_INDEX_14_ECX_0].cpuid.edx);
if (cpu_features->basic.max_cpuid >= 0x19)
__cpuid_count (0x19, 0,
cpu_features->features[CPUID_INDEX_19].cpuid.eax,
cpu_features->features[CPUID_INDEX_19].cpuid.ebx,
cpu_features->features[CPUID_INDEX_19].cpuid.ecx,
cpu_features->features[CPUID_INDEX_19].cpuid.edx);
dl_check_minsigstacksize (cpu_features);
}
_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_active (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 processors to avoid TSX on kernels that
weren't updated with the latest microcode package (which
disables broken feature by default). */
switch (model)
{
case 0x55:
if (stepping <= 5)
goto disable_tsx;
break;
case 0x8e:
/* NB: Although the errata documents that for model == 0x8e,
only 0xb stepping or lower are impacted, the intention of
the errata was to disable TSX on all client processors on
all steppings. Include 0xc stepping which is an Intel
Core i7-8665U, a client mobile processor. */
case 0x9e:
if (stepping > 0xc)
break;
/* Fall through. */
case 0x4e:
case 0x5e:
{
/* Disable Intel TSX and enable RTM_ALWAYS_ABORT for
processors listed in:
https://www.intel.com/content/www/us/en/support/articles/000059422/processors.html
*/
disable_tsx:
CPU_FEATURE_UNSET (cpu_features, HLE);
CPU_FEATURE_UNSET (cpu_features, RTM);
CPU_FEATURE_SET (cpu_features, RTM_ALWAYS_ABORT);
}
break;
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
{
/* Processors with AVX512 and AVX-VNNI won't lower CPU frequency
when ZMM load and store instructions are used. */
if (!CPU_FEATURES_CPU_P (cpu_features, AVX_VNNI))
cpu_features->preferred[index_arch_Prefer_No_AVX512]
|= bit_arch_Prefer_No_AVX512;
/* Avoid RTM abort triggered by VZEROUPPER inside a
transactionally executing RTM region. */
if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
cpu_features->preferred[index_arch_Prefer_No_VZEROUPPER]
|= bit_arch_Prefer_No_VZEROUPPER;
}
/* Avoid avoid short distance REP MOVSB on processor with FSRM. */
if (CPU_FEATURES_CPU_P (cpu_features, FSRM))
cpu_features->preferred[index_arch_Avoid_Short_Distance_REP_MOVSB]
|= bit_arch_Avoid_Short_Distance_REP_MOVSB;
}
/* 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_active (cpu_features);
ecx = cpu_features->features[CPUID_INDEX_1].cpuid.ecx;
if (CPU_FEATURE_USABLE_P (cpu_features, AVX))
{
/* Since the FMA4 bit is in CPUID_INDEX_80000001 and
FMA4 requires AVX, determine if FMA4 is usable here. */
CPU_FEATURE_SET_ACTIVE (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_active (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_active (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;
dl_init_cacheinfo (cpu_features);
#if HAVE_TUNABLES
TUNABLE_GET (hwcaps, tunable_val_t *, TUNABLE_CALLBACK (set_hwcaps));
# ifdef __LP64__
TUNABLE_GET (prefer_map_32bit_exec, tunable_val_t *,
TUNABLE_CALLBACK (set_prefer_map_32bit_exec));
# endif
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
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 & GNU_PROPERTY_X86_FEATURE_1_IBT) == 0)
CPU_FEATURE_UNSET (cpu_features, IBT)
if ((cet_status & GNU_PROPERTY_X86_FEATURE_1_SHSTK) == 0)
CPU_FEATURE_UNSET (cpu_features, SHSTK)
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
#ifndef SHARED
/* NB: In libc.a, call init_cacheinfo. */
init_cacheinfo ();
#endif
}
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