src/cpuinfo_x86.c

// Copyright 2017 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "cpuinfo_x86.h"
#include "internal/bit_utils.h"
#include "internal/cpuid_x86.h"

#include <stdbool.h>
#include <string.h>

static const Leaf kEmptyLeaf;

static Leaf SafeCpuId(uint32_t max_cpuid_leaf, uint32_t leaf_id) {
  if (leaf_id <= max_cpuid_leaf) {
    return CpuId(leaf_id);
  } else {
    return kEmptyLeaf;
  }
}

#define MASK_XMM 0x2
#define MASK_YMM 0x4
#define MASK_MASKREG 0x20
#define MASK_ZMM0_15 0x40
#define MASK_ZMM16_31 0x80

static bool HasMask(uint32_t value, uint32_t mask) {
  return (value & mask) == mask;
}

// Checks that operating system saves and restores xmm registers during context
// switches.
static bool HasXmmOsXSave(uint32_t xcr0_eax) {
  return HasMask(xcr0_eax, MASK_XMM);
}

// Checks that operating system saves and restores ymm registers during context
// switches.
static bool HasYmmOsXSave(uint32_t xcr0_eax) {
  return HasMask(xcr0_eax, MASK_XMM | MASK_YMM);
}

// Checks that operating system saves and restores zmm registers during context
// switches.
static bool HasZmmOsXSave(uint32_t xcr0_eax) {
  return HasMask(xcr0_eax, MASK_XMM | MASK_YMM | MASK_MASKREG | MASK_ZMM0_15 |
                               MASK_ZMM16_31);
}

static void SetVendor(const Leaf leaf, char* const vendor) {
  *(uint32_t*)(vendor) = leaf.ebx;
  *(uint32_t*)(vendor + 4) = leaf.edx;
  *(uint32_t*)(vendor + 8) = leaf.ecx;
  vendor[12] = '\0';
}

static int IsVendor(const Leaf leaf, const char* const name) {
  const uint32_t ebx = *(const uint32_t*)(name);
  const uint32_t edx = *(const uint32_t*)(name + 4);
  const uint32_t ecx = *(const uint32_t*)(name + 8);
  return leaf.ebx == ebx && leaf.ecx == ecx && leaf.edx == edx;
}

// Reference https://en.wikipedia.org/wiki/CPUID.
static void ParseCpuId(const uint32_t max_cpuid_leaf, X86Info* info) {
  const Leaf leaf_1 = SafeCpuId(max_cpuid_leaf, 1);
  const Leaf leaf_7 = SafeCpuId(max_cpuid_leaf, 7);

  const bool have_xsave = IsBitSet(leaf_1.ecx, 26);
  const bool have_osxsave = IsBitSet(leaf_1.ecx, 27);
  const uint32_t xcr0_eax = (have_xsave && have_osxsave) ? GetXCR0Eax() : 0;
  const bool have_sse_os_support = HasXmmOsXSave(xcr0_eax);
  const bool have_avx_os_support = HasYmmOsXSave(xcr0_eax);
  const bool have_avx512_os_support = HasZmmOsXSave(xcr0_eax);

  const uint32_t family = ExtractBitRange(leaf_1.eax, 11, 8);
  const uint32_t extended_family = ExtractBitRange(leaf_1.eax, 27, 20);
  const uint32_t model = ExtractBitRange(leaf_1.eax, 7, 4);
  const uint32_t extended_model = ExtractBitRange(leaf_1.eax, 19, 16);

  X86Features* const features = &info->features;

  info->family = extended_family + family;
  info->model = (extended_model << 4) + model;
  info->stepping = ExtractBitRange(leaf_1.eax, 3, 0);

  features->smx = IsBitSet(leaf_1.ecx, 6);
  features->aes = IsBitSet(leaf_1.ecx, 25);
  features->f16c = IsBitSet(leaf_1.ecx, 29);
  features->sgx = IsBitSet(leaf_7.ebx, 2);
  features->bmi1 = IsBitSet(leaf_7.ebx, 3);
  features->bmi2 = IsBitSet(leaf_7.ebx, 8);
  features->erms = IsBitSet(leaf_7.ebx, 9);
  features->vpclmulqdq = IsBitSet(leaf_7.ecx, 10);

  if (have_sse_os_support) {
    features->ssse3 = IsBitSet(leaf_1.ecx, 9);
    features->sse4_1 = IsBitSet(leaf_1.ecx, 19);
    features->sse4_2 = IsBitSet(leaf_1.ecx, 20);
  }

  if (have_avx_os_support) {
    features->fma3 = IsBitSet(leaf_1.ecx, 12);
    features->avx = IsBitSet(leaf_1.ecx, 28);
    features->avx2 = IsBitSet(leaf_7.ebx, 5);
  }

  if (have_avx512_os_support) {
    features->avx512f = IsBitSet(leaf_7.ebx, 16);
    features->avx512cd = IsBitSet(leaf_7.ebx, 28);
    features->avx512er = IsBitSet(leaf_7.ebx, 27);
    features->avx512pf = IsBitSet(leaf_7.ebx, 26);
    features->avx512bw = IsBitSet(leaf_7.ebx, 30);
    features->avx512dq = IsBitSet(leaf_7.ebx, 17);
    features->avx512vl = IsBitSet(leaf_7.ebx, 31);
    features->avx512ifma = IsBitSet(leaf_7.ebx, 21);
    features->avx512vbmi = IsBitSet(leaf_7.ecx, 1);
    features->avx512vbmi2 = IsBitSet(leaf_7.ecx, 6);
    features->avx512vnni = IsBitSet(leaf_7.ecx, 11);
    features->avx512bitalg = IsBitSet(leaf_7.ecx, 12);
    features->avx512vpopcntdq = IsBitSet(leaf_7.ecx, 14);
    features->avx512_4vnniw = IsBitSet(leaf_7.edx, 2);
    features->avx512_4vbmi2 = IsBitSet(leaf_7.edx, 3);
  }
}

static const X86Info kEmptyX86Info;

X86Info GetX86Info(void) {
  X86Info info = kEmptyX86Info;
  const Leaf leaf_0 = CpuId(0);
  const uint32_t max_cpuid_leaf = leaf_0.eax;
  SetVendor(leaf_0, info.vendor);
  if (IsVendor(leaf_0, "GenuineIntel") || IsVendor(leaf_0, "AuthenticAMD")) {
    ParseCpuId(max_cpuid_leaf, &info);
  }
  return info;
}

#define CPUID(FAMILY, MODEL) (((FAMILY & 0xFF) << 8) | (MODEL & 0xFF))

X86Microarchitecture GetX86Microarchitecture(const X86Info* info) {
  if (memcmp(info->vendor, "GenuineIntel", sizeof(info->vendor)) == 0) {
    switch (CPUID(info->family, info->model)) {
      case CPUID(0x06, 0x35):
      case CPUID(0x06, 0x36):
        // https://en.wikipedia.org/wiki/Bonnell_(microarchitecture)
        return INTEL_ATOM_BNL;
      case CPUID(0x06, 0x37):
      case CPUID(0x06, 0x4C):
        // https://en.wikipedia.org/wiki/Silvermont
        return INTEL_ATOM_SMT;
      case CPUID(0x06, 0x5C):
        // https://en.wikipedia.org/wiki/Goldmont
        return INTEL_ATOM_GMT;
      case CPUID(0x06, 0x0F):
      case CPUID(0x06, 0x16):
        // https://en.wikipedia.org/wiki/Intel_Core_(microarchitecture)
        return INTEL_CORE;
      case CPUID(0x06, 0x17):
      case CPUID(0x06, 0x1D):
        // https://en.wikipedia.org/wiki/Penryn_(microarchitecture)
        return INTEL_PNR;
      case CPUID(0x06, 0x1A):
      case CPUID(0x06, 0x1E):
      case CPUID(0x06, 0x1F):
      case CPUID(0x06, 0x2E):
        // https://en.wikipedia.org/wiki/Nehalem_(microarchitecture)
        return INTEL_NHM;
      case CPUID(0x06, 0x25):
      case CPUID(0x06, 0x2C):
      case CPUID(0x06, 0x2F):
        // https://en.wikipedia.org/wiki/Westmere_(microarchitecture)
        return INTEL_WSM;
      case CPUID(0x06, 0x2A):
      case CPUID(0x06, 0x2D):
        // https://en.wikipedia.org/wiki/Sandy_Bridge#Models_and_steppings
        return INTEL_SNB;
      case CPUID(0x06, 0x3A):
      case CPUID(0x06, 0x3E):
        // https://en.wikipedia.org/wiki/Ivy_Bridge_(microarchitecture)#Models_and_steppings
        return INTEL_IVB;
      case CPUID(0x06, 0x3C):
      case CPUID(0x06, 0x3F):
      case CPUID(0x06, 0x45):
      case CPUID(0x06, 0x46):
        // https://en.wikipedia.org/wiki/Haswell_(microarchitecture)
        return INTEL_HSW;
      case CPUID(0x06, 0x3D):
      case CPUID(0x06, 0x47):
      case CPUID(0x06, 0x4F):
      case CPUID(0x06, 0x56):
        // https://en.wikipedia.org/wiki/Broadwell_(microarchitecture)
        return INTEL_BDW;
      case CPUID(0x06, 0x4E):
      case CPUID(0x06, 0x55):
      case CPUID(0x06, 0x5E):
        // https://en.wikipedia.org/wiki/Skylake_(microarchitecture)
        return INTEL_SKL;
      case CPUID(0x06, 0x8E):
      case CPUID(0x06, 0x9E):
        // https://en.wikipedia.org/wiki/Kaby_Lake
        return INTEL_KBL;
      default:
        return X86_UNKNOWN;
    }
  }
  if (memcmp(info->vendor, "AuthenticAMD", sizeof(info->vendor)) == 0) {
    switch (info->family) {
        // https://en.wikipedia.org/wiki/List_of_AMD_CPU_microarchitectures
      case 0x0F:
        return AMD_HAMMER;
      case 0x10:
        return AMD_K10;
      case 0x14:
        return AMD_BOBCAT;
      case 0x15:
        return AMD_BULLDOZER;
      case 0x16:
        return AMD_JAGUAR;
      case 0x17:
        return AMD_ZEN;
      default:
        return X86_UNKNOWN;
    }
  }
  return X86_UNKNOWN;
}

static void SetString(const uint32_t max_cpuid_ext_leaf, const uint32_t leaf_id,
                      char* buffer) {
  const Leaf leaf = SafeCpuId(max_cpuid_ext_leaf, leaf_id);
  // We allow calling memcpy from SetString which is only called when requesting
  // X86BrandString.
  memcpy(buffer, &leaf, sizeof(Leaf));
}

void FillX86BrandString(char brand_string[49]) {
  const Leaf leaf_ext_0 = CpuId(0x80000000);
  const uint32_t max_cpuid_leaf_ext = leaf_ext_0.eax;
  SetString(max_cpuid_leaf_ext, 0x80000002, brand_string);
  SetString(max_cpuid_leaf_ext, 0x80000003, brand_string + 16);
  SetString(max_cpuid_leaf_ext, 0x80000004, brand_string + 32);
  brand_string[48] = '\0';
}

////////////////////////////////////////////////////////////////////////////////
// Introspection functions

int GetX86FeaturesEnumValue(const X86Features* features,
                            X86FeaturesEnum value) {
  switch (value) {
    case X86_AES:
      return features->aes;
    case X86_ERMS:
      return features->erms;
    case X86_F16C:
      return features->f16c;
    case X86_FMA3:
      return features->fma3;
    case X86_VPCLMULQDQ:
      return features->vpclmulqdq;
    case X86_BMI1:
      return features->bmi1;
    case X86_BMI2:
      return features->bmi2;
    case X86_SSSE3:
      return features->ssse3;
    case X86_SSE4_1:
      return features->sse4_1;
    case X86_SSE4_2:
      return features->sse4_2;
    case X86_AVX:
      return features->avx;
    case X86_AVX2:
      return features->avx2;
    case X86_AVX512F:
      return features->avx512f;
    case X86_AVX512CD:
      return features->avx512cd;
    case X86_AVX512ER:
      return features->avx512er;
    case X86_AVX512PF:
      return features->avx512pf;
    case X86_AVX512BW:
      return features->avx512bw;
    case X86_AVX512DQ:
      return features->avx512dq;
    case X86_AVX512VL:
      return features->avx512vl;
    case X86_AVX512IFMA:
      return features->avx512ifma;
    case X86_AVX512VBMI:
      return features->avx512vbmi;
    case X86_AVX512VBMI2:
      return features->avx512vbmi2;
    case X86_AVX512VNNI:
      return features->avx512vnni;
    case X86_AVX512BITALG:
      return features->avx512bitalg;
    case X86_AVX512VPOPCNTDQ:
      return features->avx512vpopcntdq;
    case X86_AVX512_4VNNIW:
      return features->avx512_4vnniw;
    case X86_AVX512_4VBMI2:
      return features->avx512_4vbmi2;
    case X86_SMX:
      return features->smx;
    case X86_SGX:
      return features->sgx;
    case X86_LAST_:
      break;
  }
  return false;
}

const char* GetX86FeaturesEnumName(X86FeaturesEnum value) {
  switch (value) {
    case X86_AES:
      return "aes";
    case X86_ERMS:
      return "erms";
    case X86_F16C:
      return "f16c";
    case X86_FMA3:
      return "fma3";
    case X86_VPCLMULQDQ:
      return "vpclmulqdq";
    case X86_BMI1:
      return "bmi1";
    case X86_BMI2:
      return "bmi2";
    case X86_SSSE3:
      return "ssse3";
    case X86_SSE4_1:
      return "sse4_1";
    case X86_SSE4_2:
      return "sse4_2";
    case X86_AVX:
      return "avx";
    case X86_AVX2:
      return "avx2";
    case X86_AVX512F:
      return "avx512f";
    case X86_AVX512CD:
      return "avx512cd";
    case X86_AVX512ER:
      return "avx512er";
    case X86_AVX512PF:
      return "avx512pf";
    case X86_AVX512BW:
      return "avx512bw";
    case X86_AVX512DQ:
      return "avx512dq";
    case X86_AVX512VL:
      return "avx512vl";
    case X86_AVX512IFMA:
      return "avx512ifma";
    case X86_AVX512VBMI:
      return "avx512vbmi";
    case X86_AVX512VBMI2:
      return "avx512vbmi2";
    case X86_AVX512VNNI:
      return "avx512vnni";
    case X86_AVX512BITALG:
      return "avx512bitalg";
    case X86_AVX512VPOPCNTDQ:
      return "avx512vpopcntdq";
    case X86_AVX512_4VNNIW:
      return "avx512_4vnniw";
    case X86_AVX512_4VBMI2:
      return "avx512_4vbmi2";
    case X86_SMX:
      return "smx";
    case X86_SGX:
      return "sgx";
    case X86_LAST_:
      break;
  }
  return "unknown_feature";
}

const char* GetX86MicroarchitectureName(X86Microarchitecture uarch) {
  switch (uarch) {
    case X86_UNKNOWN:
      return "X86_UNKNOWN";
    case INTEL_CORE:
      return "INTEL_CORE";
    case INTEL_PNR:
      return "INTEL_PNR";
    case INTEL_NHM:
      return "INTEL_NHM";
    case INTEL_ATOM_BNL:
      return "INTEL_ATOM_BNL";
    case INTEL_WSM:
      return "INTEL_WSM";
    case INTEL_SNB:
      return "INTEL_SNB";
    case INTEL_IVB:
      return "INTEL_IVB";
    case INTEL_ATOM_SMT:
      return "INTEL_ATOM_SMT";
    case INTEL_HSW:
      return "INTEL_HSW";
    case INTEL_BDW:
      return "INTEL_BDW";
    case INTEL_SKL:
      return "INTEL_SKL";
    case INTEL_ATOM_GMT:
      return "INTEL_ATOM_GMT";
    case INTEL_KBL:
      return "INTEL_KBL";
    case INTEL_CFL:
      return "INTEL_CFL";
    case INTEL_CNL:
      return "INTEL_CNL";
    case AMD_HAMMER:
      return "AMD_HAMMER";
    case AMD_K10:
      return "AMD_K10";
    case AMD_BOBCAT:
      return "AMD_BOBCAT";
    case AMD_BULLDOZER:
      return "AMD_BULLDOZER";
    case AMD_JAGUAR:
      return "AMD_JAGUAR";
    case AMD_ZEN:
      return "AMD_ZEN";
  }
  return "unknown microarchitecture";
}