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

#include <botan/cpuid.h>
#include <botan/types.h>
#include <botan/loadstor.h>
#include <botan/exceptn.h>
#include <botan/mem_ops.h>
#include <botan/parsing.h>
#include <botan/internal/os_utils.h>
#include <ostream>

#if defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)

/*
* On Darwin and OpenBSD ppc, use sysctl to detect AltiVec
*/
#if defined(BOTAN_TARGET_OS_IS_DARWIN)
  #include <sys/sysctl.h>
#elif defined(BOTAN_TARGET_OS_IS_OPENBSD)
  #include <sys/param.h>
  #include <sys/sysctl.h>
  #include <machine/cpu.h>
#endif

#elif defined(BOTAN_TARGET_CPU_IS_ARM_FAMILY)

/*
* On ARM, use getauxval if available, otherwise fall back to
* running probe functions with a SIGILL handler.
*/
#if defined(BOTAN_TARGET_OS_HAS_GETAUXVAL)
  #include <sys/auxv.h>
#endif

#elif defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)

/*
* On x86, use CPUID instruction
*/

#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 {

uint64_t CPUID::g_processor_features = 0;
size_t CPUID::g_cache_line_size = BOTAN_TARGET_CPU_DEFAULT_CACHE_LINE_SIZE;
CPUID::Endian_status CPUID::g_endian_status = ENDIAN_UNKNOWN;

namespace {

#if defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)

/*
* PowerPC specific block: check for AltiVec using either
* sysctl or by reading processor version number register.
*/
uint64_t detect_cpu_features(size_t* cache_line_size)
   {
#if defined(BOTAN_TARGET_OS_IS_DARWIN) || defined(BOTAN_TARGET_OS_IS_OPENBSD)
   // On Darwin/OS X and OpenBSD, use sysctl

   int sels[2] = {
#if defined(BOTAN_TARGET_OS_IS_OPENBSD)
      CTL_MACHDEP, CPU_ALTIVEC
#else
      CTL_HW, HW_VECTORUNIT
#endif
   };

   int vector_type = 0;
   size_t length = sizeof(vector_type);
   int error = sysctl(sels, 2, &vector_type, &length, NULL, 0);

   if(error == 0 && vector_type > 0)
      return CPUID::CPUID_ALTIVEC_BIT;

#else

   /*
   On PowerPC, MSR 287 is PVR, the Processor Version Number
   Normally it is only accessible to ring 0, but Linux and NetBSD
   (others, too, maybe?) will trap and emulate it for us.
   */

   int pvr = OS::run_cpu_instruction_probe([]() -> int {
      uint32_t pvr = 0;
      asm volatile("mfspr %0, 287" : "=r" (pvr));
      // Top 16 bits suffice to identify the model
      return static_cast<int>(pvr >> 16);
      });

   if(pvr > 0)
      {
      const uint16_t ALTIVEC_PVR[] = {
         0x003E, // IBM POWER6,
         0x003F, // IBM POWER7,
         0x004B, // IBM POWER8,
         0x000C, // G4-7400
         0x0039, // G5 970
         0x003C, // G5 970FX
         0x0044, // G5 970MP
         0x0070, // Cell PPU
         0, // end
      };

      for(size_t i = 0; ALTIVEC_PVR[i]; ++i)
         {
         if(pvr == ALTIVEC_PVR[i])
            return CPUID::CPUID_ALTIVEC_BIT;
         }

      return 0;
      }

   // TODO try direct instruction probing

#endif

   return 0;
   }

#elif defined(BOTAN_TARGET_CPU_IS_ARM_FAMILY)

uint64_t detect_cpu_features(size_t* cache_line_size)
   {
   uint64_t detected_features = 0;

#if defined(BOTAN_TARGET_OS_HAS_GETAUXVAL)
   /*
   * On systems with getauxval these bits should normally be defined
   * in bits/auxv.h but some buggy? glibc installs seem to miss them.
   * These following values are all fixed, for the Linux ELF format,
   * so we just hardcode them in ARM_hwcap_bit enum.
   */

   enum ARM_hwcap_bit {
#if defined(BOTAN_TARGET_ARCH_IS_ARM32)
      NEON_bit  = (1 << 12),
      AES_bit   = (1 << 0),
      PMULL_bit = (1 << 1),
      SHA1_bit  = (1 << 2),
      SHA2_bit  = (1 << 3),

      ARCH_hwcap_neon   = 16, // AT_HWCAP
      ARCH_hwcap_crypto = 26, // AT_HWCAP2
#elif defined(BOTAN_TARGET_ARCH_IS_ARM64)
      NEON_bit  = (1 << 1),
      AES_bit   = (1 << 3),
      PMULL_bit = (1 << 4),
      SHA1_bit  = (1 << 5),
      SHA2_bit  = (1 << 6),

      ARCH_hwcap_neon   = 16, // AT_HWCAP
      ARCH_hwcap_crypto = 16, // AT_HWCAP
#endif
   };

   const unsigned long hwcap_neon = ::getauxval(ARM_hwcap_bit::ARCH_hwcap_neon);
   if(hwcap_neon & ARM_hwcap_bit::NEON_bit)
      detected_features |= CPUID::CPUID_ARM_NEON_BIT;

   /*
   On aarch64 this ends up calling getauxval twice with AT_HWCAP
   It doesn't seem worth optimizing this out, since getauxval is
   just reading a field in the ELF header.
   */
   const unsigned long hwcap_crypto = ::getauxval(ARM_hwcap_bit::ARCH_hwcap_crypto);
   if(hwcap_crypto & ARM_hwcap_bit::AES_bit)
      detected_features |= CPUID::CPUID_ARM_AES_BIT;
   if(hwcap_crypto & ARM_hwcap_bit::PMULL_bit)
      detected_features |= CPUID::CPUID_ARM_PMULL_BIT;
   if(hwcap_crypto & ARM_hwcap_bit::SHA1_bit)
      detected_features |= CPUID::CPUID_ARM_SHA1_BIT;
   if(hwcap_crypto & ARM_hwcap_bit::SHA2_bit)
      detected_features |= CPUID::CPUID_ARM_SHA2_BIT;

#if defined(AT_DCACHEBSIZE)
   const unsigned long dcache_line = ::getauxval(AT_DCACHEBSIZE);

   // plausibility check
   if(dcache_line == 32 || dcache_line == 64 || dcache_line == 128)
      *cache_line_size = static_cast<size_t>(dcache_line);
#endif

#else
   // No getauxval API available, fall back on probe functions

   // TODO: probe functions

#endif

   return detected_features;
   }

#elif defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)

uint64_t 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 {
         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::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

}

bool CPUID::has_simd_32()
   {
#if defined(BOTAN_TARGET_SUPPORTS_SSE2)
   return CPUID::has_sse2();
#elif defined(BOTAN_TARGET_SUPPORTS_ALTIVEC)
   return CPUID::has_altivec();
#elif defined(BOTAN_TARGET_SUPPORTS_NEON)
   return CPUID::has_neon();
#else
   return true;
#endif
   }

//static
std::string CPUID::to_string()
   {
   std::vector<std::string> flags;

#define CPUID_PRINT(flag) do { if(has_##flag()) { flags.push_back(#flag); } } while(0)

#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
   CPUID_PRINT(sse2);
   CPUID_PRINT(ssse3);
   CPUID_PRINT(sse41);
   CPUID_PRINT(sse42);
   CPUID_PRINT(avx2);
   CPUID_PRINT(avx512f);

   CPUID_PRINT(rdtsc);
   CPUID_PRINT(bmi2);
   CPUID_PRINT(adx);

   CPUID_PRINT(aes_ni);
   CPUID_PRINT(clmul);
   CPUID_PRINT(rdrand);
   CPUID_PRINT(rdseed);
   CPUID_PRINT(intel_sha);
#endif

#if defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY)
   CPUID_PRINT(altivec);
#endif

#if defined(BOTAN_TARGET_CPU_IS_ARM_FAMILY)
   CPUID_PRINT(neon);
   CPUID_PRINT(arm_sha1);
   CPUID_PRINT(arm_sha2);
   CPUID_PRINT(arm_aes);
   CPUID_PRINT(arm_pmull);
#endif

#undef CPUID_PRINT

   return string_join(flags, ' ');
   }

//static
void CPUID::print(std::ostream& o)
   {
   o << "CPUID flags: " << CPUID::to_string() << "\n";
   }

//static
void CPUID::initialize()
   {
   g_processor_features = 0;

#if defined(BOTAN_TARGET_CPU_IS_PPC_FAMILY) || \
    defined(BOTAN_TARGET_CPU_IS_ARM_FAMILY) || \
    defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)

   g_processor_features = detect_cpu_features(&g_cache_line_size);

#endif

   g_processor_features |= CPUID::CPUID_INITIALIZED_BIT;
   }

//static
CPUID::Endian_status CPUID::runtime_check_endian()
   {
   // Check runtime endian
   const uint32_t endian32 = 0x01234567;
   const uint8_t* e8 = reinterpret_cast<const uint8_t*>(&endian32);

   Endian_status endian = ENDIAN_UNKNOWN;

   if(e8[0] == 0x01 && e8[1] == 0x23 && e8[2] == 0x45 && e8[3] == 0x67)
      {
      endian = ENDIAN_BIG;
      }
   else if(e8[0] == 0x67 && e8[1] == 0x45 && e8[2] == 0x23 && e8[3] == 0x01)
      {
      endian = ENDIAN_LITTLE;
      }
   else
      {
      throw Internal_Error("Unexpected endian at runtime, neither big nor little");
      }

   // If we were compiled with a known endian, verify it matches at runtime
#if defined(BOTAN_TARGET_CPU_IS_LITTLE_ENDIAN)
   BOTAN_ASSERT(endian == ENDIAN_LITTLE, "Build and runtime endian match");
#elif defined(BOTAN_TARGET_CPU_IS_BIG_ENDIAN)
   BOTAN_ASSERT(endian == ENDIAN_BIG, "Build and runtime endian match");
#endif

   return endian;
   }

}