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x86: Refactor Intel init_cpu_features

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This patch should have no affect on existing functionality.

The current code, which has a single switch for model detection and
setting prefered features, is difficult to follow/extend. The cases
use magic numbers and many microarchitectures are missing. This makes
it difficult to reason about what is implemented so far and/or
how/where to add support for new features.

This patch splits the model detection and preference setting stages so
that CPU preferences can be set based on a complete list of available
microarchitectures, rather than based on model magic numbers.
Reviewed-by: DJ Delorie <dj@redhat.com>
This commit is contained in:
Noah Goldstein 2023-06-07 13:18:02 -05:00
parent af992e7abd
commit f193ea20ed
1 changed files with 309 additions and 81 deletions
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390
sysdeps/x86/cpu-features.c
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@ -417,6 +417,216 @@ _Static_assert (((index_arch_Fast_Unaligned_Load
== index_arch_Fast_Copy_Backward)),
"Incorrect index_arch_Fast_Unaligned_Load");
/* Intel Family-6 microarch list. */
enum
{
/* Atom processors. */
INTEL_ATOM_BONNELL,
INTEL_ATOM_SILVERMONT,
INTEL_ATOM_AIRMONT,
INTEL_ATOM_GOLDMONT,
INTEL_ATOM_GOLDMONT_PLUS,
INTEL_ATOM_SIERRAFOREST,
INTEL_ATOM_GRANDRIDGE,
INTEL_ATOM_TREMONT,
/* Bigcore processors. */
INTEL_BIGCORE_MEROM,
INTEL_BIGCORE_PENRYN,
INTEL_BIGCORE_DUNNINGTON,
INTEL_BIGCORE_NEHALEM,
INTEL_BIGCORE_WESTMERE,
INTEL_BIGCORE_SANDYBRIDGE,
INTEL_BIGCORE_IVYBRIDGE,
INTEL_BIGCORE_HASWELL,
INTEL_BIGCORE_BROADWELL,
INTEL_BIGCORE_SKYLAKE,
INTEL_BIGCORE_KABYLAKE,
INTEL_BIGCORE_COMETLAKE,
INTEL_BIGCORE_SKYLAKE_AVX512,
INTEL_BIGCORE_CANNONLAKE,
INTEL_BIGCORE_ICELAKE,
INTEL_BIGCORE_TIGERLAKE,
INTEL_BIGCORE_ROCKETLAKE,
INTEL_BIGCORE_SAPPHIRERAPIDS,
INTEL_BIGCORE_RAPTORLAKE,
INTEL_BIGCORE_EMERALDRAPIDS,
INTEL_BIGCORE_METEORLAKE,
INTEL_BIGCORE_LUNARLAKE,
INTEL_BIGCORE_ARROWLAKE,
INTEL_BIGCORE_GRANITERAPIDS,
/* Mixed (bigcore + atom SOC). */
INTEL_MIXED_LAKEFIELD,
INTEL_MIXED_ALDERLAKE,
/* KNL. */
INTEL_KNIGHTS_MILL,
INTEL_KNIGHTS_LANDING,
/* Unknown. */
INTEL_UNKNOWN,
};
static unsigned int
intel_get_fam6_microarch (unsigned int model,
__attribute__ ((unused)) unsigned int stepping)
{
switch (model)
{
case 0x1C:
case 0x26:
return INTEL_ATOM_BONNELL;
case 0x27:
case 0x35:
case 0x36:
/* Really Saltwell, but Saltwell is just a die shrink of Bonnell
(microarchitecturally identical). */
return INTEL_ATOM_BONNELL;
case 0x37:
case 0x4A:
case 0x4D:
case 0x5D:
return INTEL_ATOM_SILVERMONT;
case 0x4C:
case 0x5A:
case 0x75:
return INTEL_ATOM_AIRMONT;
case 0x5C:
case 0x5F:
return INTEL_ATOM_GOLDMONT;
case 0x7A:
return INTEL_ATOM_GOLDMONT_PLUS;
case 0xAF:
return INTEL_ATOM_SIERRAFOREST;
case 0xB6:
return INTEL_ATOM_GRANDRIDGE;
case 0x86:
case 0x96:
case 0x9C:
return INTEL_ATOM_TREMONT;
case 0x0F:
case 0x16:
return INTEL_BIGCORE_MEROM;
case 0x17:
return INTEL_BIGCORE_PENRYN;
case 0x1D:
return INTEL_BIGCORE_DUNNINGTON;
case 0x1A:
case 0x1E:
case 0x1F:
case 0x2E:
return INTEL_BIGCORE_NEHALEM;
case 0x25:
case 0x2C:
case 0x2F:
return INTEL_BIGCORE_WESTMERE;
case 0x2A:
case 0x2D:
return INTEL_BIGCORE_SANDYBRIDGE;
case 0x3A:
case 0x3E:
return INTEL_BIGCORE_IVYBRIDGE;
case 0x3C:
case 0x3F:
case 0x45:
case 0x46:
return INTEL_BIGCORE_HASWELL;
case 0x3D:
case 0x47:
case 0x4F:
case 0x56:
return INTEL_BIGCORE_BROADWELL;
case 0x4E:
case 0x5E:
return INTEL_BIGCORE_SKYLAKE;
case 0x8E:
/*
Stepping = {9}
-> Amberlake
Stepping = {10}
-> Coffeelake
Stepping = {11, 12}
-> Whiskeylake
else
-> Kabylake
All of these are derivatives of Kabylake (Skylake client).
*/
return INTEL_BIGCORE_KABYLAKE;
case 0x9E:
/*
Stepping = {10, 11, 12, 13}
-> Coffeelake
else
-> Kabylake
Coffeelake is a derivatives of Kabylake (Skylake client).
*/
return INTEL_BIGCORE_KABYLAKE;
case 0xA5:
case 0xA6:
return INTEL_BIGCORE_COMETLAKE;
case 0x66:
return INTEL_BIGCORE_CANNONLAKE;
case 0x55:
/*
Stepping = {6, 7}
-> Cascadelake
Stepping = {11}
-> Cooperlake
else
-> Skylake-avx512
These are all microarchitecturally indentical, so use
Skylake-avx512 for all of them.
*/
return INTEL_BIGCORE_SKYLAKE_AVX512;
case 0x6A:
case 0x6C:
case 0x7D:
case 0x7E:
case 0x9D:
return INTEL_BIGCORE_ICELAKE;
case 0x8C:
case 0x8D:
return INTEL_BIGCORE_TIGERLAKE;
case 0xA7:
return INTEL_BIGCORE_ROCKETLAKE;
case 0x8F:
return INTEL_BIGCORE_SAPPHIRERAPIDS;
case 0xB7:
case 0xBA:
case 0xBF:
return INTEL_BIGCORE_RAPTORLAKE;
case 0xCF:
return INTEL_BIGCORE_EMERALDRAPIDS;
case 0xAA:
case 0xAC:
return INTEL_BIGCORE_METEORLAKE;
case 0xbd:
return INTEL_BIGCORE_LUNARLAKE;
case 0xc6:
return INTEL_BIGCORE_ARROWLAKE;
case 0xAD:
case 0xAE:
return INTEL_BIGCORE_GRANITERAPIDS;
case 0x8A:
return INTEL_MIXED_LAKEFIELD;
case 0x97:
case 0x9A:
case 0xBE:
return INTEL_MIXED_ALDERLAKE;
case 0x85:
return INTEL_KNIGHTS_MILL;
case 0x57:
return INTEL_KNIGHTS_LANDING;
default:
return INTEL_UNKNOWN;
}
}
static inline void
init_cpu_features (struct cpu_features *cpu_features)
{
@ -453,129 +663,147 @@ init_cpu_features (struct cpu_features *cpu_features)
if (family == 0x06)
{
model += extended_model;
switch (model)
unsigned int microarch
= intel_get_fam6_microarch (model, stepping);
switch (microarch)
{
case 0x1c:
case 0x26:
/* BSF is slow on Atom. */
/* Atom / KNL tuning. */
case INTEL_ATOM_BONNELL:
/* BSF is slow on Bonnell. */
cpu_features->preferred[index_arch_Slow_BSF]
|= bit_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. */
on Airmont, Silvermont, Goldmont, and Goldmont Plus. */
case INTEL_ATOM_AIRMONT:
case INTEL_ATOM_SILVERMONT:
case INTEL_ATOM_GOLDMONT:
case INTEL_ATOM_GOLDMONT_PLUS:
case 0x5c:
case 0x5f:
/* Unaligned load versions are faster than SSSE3
on Goldmont. */
/* Knights Landing. Enable Silvermont optimizations. */
case INTEL_KNIGHTS_LANDING:
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);
|= (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:
case INTEL_ATOM_TREMONT:
/* Enable rep string instructions, unaligned load, unaligned
copy, pminub and avoid SSE 4.2 on Tremont. */
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);
|= (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 tuned Knights microarch.
case INTEL_KNIGHTS_MILL:
*/
/*
Default tuned atom microarch.
case INTEL_ATOM_SIERRAFOREST:
case INTEL_ATOM_GRANDRIDGE:
*/
/* Bigcore/Default Tuning. */
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:
case INTEL_BIGCORE_NEHALEM:
case INTEL_BIGCORE_WESTMERE:
/* 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);
|= (bit_arch_Fast_Rep_String
| bit_arch_Fast_Unaligned_Load
| bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop);
break;
/*
Default tuned Bigcore microarch.
case INTEL_BIGCORE_SANDYBRIDGE:
case INTEL_BIGCORE_IVYBRIDGE:
case INTEL_BIGCORE_HASWELL:
case INTEL_BIGCORE_BROADWELL:
case INTEL_BIGCORE_SKYLAKE:
case INTEL_BIGCORE_KABYLAKE:
case INTEL_BIGCORE_COMETLAKE:
case INTEL_BIGCORE_SKYLAKE_AVX512:
case INTEL_BIGCORE_CANNONLAKE:
case INTEL_BIGCORE_ICELAKE:
case INTEL_BIGCORE_TIGERLAKE:
case INTEL_BIGCORE_ROCKETLAKE:
case INTEL_BIGCORE_RAPTORLAKE:
case INTEL_BIGCORE_METEORLAKE:
case INTEL_BIGCORE_LUNARLAKE:
case INTEL_BIGCORE_ARROWLAKE:
case INTEL_BIGCORE_SAPPHIRERAPIDS:
case INTEL_BIGCORE_EMERALDRAPIDS:
case INTEL_BIGCORE_GRANITERAPIDS:
*/
/*
Default tuned Mixed (bigcore + atom SOC).
case INTEL_MIXED_LAKEFIELD:
case INTEL_MIXED_ALDERLAKE:
*/
}
/* 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)
/* 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 (microarch)
{
case 0x55:
case INTEL_BIGCORE_SKYLAKE_AVX512:
/* 0x55 (Skylake-avx512) && stepping <= 5 disable TSX. */
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:
case INTEL_BIGCORE_KABYLAKE:
/* NB: Although the errata documents that for model == 0x8e
(kabylake skylake client), 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. */
if (stepping > 0xc)
break;
/* Fall through. */
case 0x4e:
case 0x5e:
{
case INTEL_BIGCORE_SKYLAKE:
/* 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:
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;
case INTEL_BIGCORE_HASWELL:
/* Xeon E7 v3 (model == 0x3f) with stepping >= 4 has working
TSX. Haswell also include other model numbers that have
working TSX. */
if (model == 0x3f && stepping >= 4)
break;
CPU_FEATURE_UNSET (cpu_features, RTM);
break;
}
}