cpuid_x86.cpp

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/*
* Runtime CPU detection for x86
* (C) 2009,2010,2013,2017 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/cpuid.h>
#include <botan/mem_ops.h>
#include <botan/loadstor.h>

#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)

#if defined(BOTAN_BUILD_COMPILER_IS_MSVC)
  #include <intrin.h>
#elif defined(BOTAN_BUILD_COMPILER_IS_INTEL)
  #include <ia32intrin.h>
#elif defined(BOTAN_BUILD_COMPILER_IS_GCC) || defined(BOTAN_BUILD_COMPILER_IS_CLANG)
  #include <cpuid.h>
#endif

#endif

namespace Botan {

#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)

uint64_t CPUID::CPUID_Data::detect_cpu_features(size_t* cache_line_size)
   {
#if defined(BOTAN_BUILD_COMPILER_IS_MSVC)
  #define X86_CPUID(type, out) do { __cpuid((int*)out, type); } while(0)
  #define X86_CPUID_SUBLEVEL(type, level, out) do { __cpuidex((int*)out, type, level); } while(0)

#elif defined(BOTAN_BUILD_COMPILER_IS_INTEL)
  #define X86_CPUID(type, out) do { __cpuid(out, type); } while(0)
  #define X86_CPUID_SUBLEVEL(type, level, out) do { __cpuidex((int*)out, type, level); } while(0)

#elif defined(BOTAN_TARGET_ARCH_IS_X86_64) && defined(BOTAN_USE_GCC_INLINE_ASM)
  #define X86_CPUID(type, out)                                                    \
     asm("cpuid\n\t" : "=a" (out[0]), "=b" (out[1]), "=c" (out[2]), "=d" (out[3]) \
         : "0" (type))

  #define X86_CPUID_SUBLEVEL(type, level, out)                                    \
     asm("cpuid\n\t" : "=a" (out[0]), "=b" (out[1]), "=c" (out[2]), "=d" (out[3]) \
         : "0" (type), "2" (level))

#elif defined(BOTAN_BUILD_COMPILER_IS_GCC) || defined(BOTAN_BUILD_COMPILER_IS_CLANG)
  #define X86_CPUID(type, out) do { __get_cpuid(type, out, out+1, out+2, out+3); } while(0)

  #define X86_CPUID_SUBLEVEL(type, level, out) \
     do { __cpuid_count(type, level, out[0], out[1], out[2], out[3]); } while(0)
#else
  #warning "No way of calling x86 cpuid instruction for this compiler"
  #define X86_CPUID(type, out) do { clear_mem(out, 4); } while(0)
  #define X86_CPUID_SUBLEVEL(type, level, out) do { clear_mem(out, 4); } while(0)
#endif

   uint64_t features_detected = 0;
   uint32_t cpuid[4] = { 0 };

   // CPUID 0: vendor identification, max sublevel
   X86_CPUID(0, cpuid);

   const uint32_t max_supported_sublevel = cpuid[0];

   const uint32_t INTEL_CPUID[3] = { 0x756E6547, 0x6C65746E, 0x49656E69 };
   const uint32_t AMD_CPUID[3] = { 0x68747541, 0x444D4163, 0x69746E65 };
   const bool is_intel = same_mem(cpuid + 1, INTEL_CPUID, 3);
   const bool is_amd = same_mem(cpuid + 1, AMD_CPUID, 3);

   if(max_supported_sublevel >= 1)
      {
      // CPUID 1: feature bits
      X86_CPUID(1, cpuid);
      const uint64_t flags0 = (static_cast<uint64_t>(cpuid[2]) << 32) | cpuid[3];

      enum x86_CPUID_1_bits : uint64_t {
         RDTSC = (1ULL << 4),
         SSE2 = (1ULL << 26),
         CLMUL = (1ULL << 33),
         SSSE3 = (1ULL << 41),
         SSE41 = (1ULL << 51),
         SSE42 = (1ULL << 52),
         AESNI = (1ULL << 57),
         RDRAND = (1ULL << 62)
      };

      if(flags0 & x86_CPUID_1_bits::RDTSC)
         features_detected |= CPUID::CPUID_RDTSC_BIT;
      if(flags0 & x86_CPUID_1_bits::SSE2)
         features_detected |= CPUID::CPUID_SSE2_BIT;
      if(flags0 & x86_CPUID_1_bits::CLMUL)
         features_detected |= CPUID::CPUID_CLMUL_BIT;
      if(flags0 & x86_CPUID_1_bits::SSSE3)
         features_detected |= CPUID::CPUID_SSSE3_BIT;
      if(flags0 & x86_CPUID_1_bits::SSE41)
         features_detected |= CPUID::CPUID_SSE41_BIT;
      if(flags0 & x86_CPUID_1_bits::SSE42)
         features_detected |= CPUID::CPUID_SSE42_BIT;
      if(flags0 & x86_CPUID_1_bits::AESNI)
         features_detected |= CPUID::CPUID_AESNI_BIT;
      if(flags0 & x86_CPUID_1_bits::RDRAND)
         features_detected |= CPUID::CPUID_RDRAND_BIT;
      }

   if(is_intel)
      {
      // Intel cache line size is in cpuid(1) output
      *cache_line_size = 8 * get_byte(2, cpuid[1]);
      }
   else if(is_amd)
      {
      // AMD puts it in vendor zone
      X86_CPUID(0x80000005, cpuid);
      *cache_line_size = get_byte(3, cpuid[2]);
      }

   if(max_supported_sublevel >= 7)
      {
      clear_mem(cpuid, 4);
      X86_CPUID_SUBLEVEL(7, 0, cpuid);

      enum x86_CPUID_7_bits : uint64_t {
         BMI1 = (1ULL << 3),
         AVX2 = (1ULL << 5),
         BMI2 = (1ULL << 8),
         AVX512F = (1ULL << 16),
         RDSEED = (1ULL << 18),
         ADX = (1ULL << 19),
         SHA = (1ULL << 29),
      };
      uint64_t flags7 = (static_cast<uint64_t>(cpuid[2]) << 32) | cpuid[1];

      if(flags7 & x86_CPUID_7_bits::AVX2)
         features_detected |= CPUID::CPUID_AVX2_BIT;
      if(flags7 & x86_CPUID_7_bits::BMI1)
         {
         features_detected |= CPUID::CPUID_BMI1_BIT;
         /*
         We only set the BMI2 bit if BMI1 is also supported, so BMI2
         code can safely use both extensions. No known processor
         implements BMI2 but not BMI1.
         */
         if(flags7 & x86_CPUID_7_bits::BMI2)
            features_detected |= CPUID::CPUID_BMI2_BIT;
         }

      if(flags7 & x86_CPUID_7_bits::AVX512F)
         features_detected |= CPUID::CPUID_AVX512F_BIT;
      if(flags7 & x86_CPUID_7_bits::RDSEED)
         features_detected |= CPUID::CPUID_RDSEED_BIT;
      if(flags7 & x86_CPUID_7_bits::ADX)
         features_detected |= CPUID::CPUID_ADX_BIT;
      if(flags7 & x86_CPUID_7_bits::SHA)
         features_detected |= CPUID::CPUID_SHA_BIT;
      }

#undef X86_CPUID
#undef X86_CPUID_SUBLEVEL

   /*
   * If we don't have access to CPUID, we can still safely assume that
   * any x86-64 processor has SSE2 and RDTSC
   */
#if defined(BOTAN_TARGET_ARCH_IS_X86_64)
   if(features_detected == 0)
      {
      features_detected |= CPUID::CPUID_SSE2_BIT;
      features_detected |= CPUID::CPUID_RDTSC_BIT;
      }
#endif

   return features_detected;
   }

#endif

}