cpuid_ppc.cpp

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/*
* Runtime CPU detection for POWER/PowerPC
* (C) 2009,2010,2013,2017,2021,2024 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
 
#include <botan/internal/cpuid.h>
 
#include <botan/internal/target_info.h>
 
#if defined(BOTAN_HAS_OS_UTILS)
   #include <botan/internal/os_utils.h>
#endif
 
namespace Botan {
 
uint32_t CPUID::CPUID_Data::detect_cpu_features(uint32_t allowed) {
   uint32_t feat = 0;
 
#if defined(BOTAN_HAS_OS_UTILS)
 
   if(auto auxval = OS::get_auxval_hwcap()) {
      const auto [hwcap_altivec, hwcap_crypto] = *auxval;
 
      enum class PPC_hwcap_bit : uint64_t {
         ALTIVEC_bit = (1 << 28),
         CRYPTO_bit = (1 << 25),
         DARN_bit = (1 << 21),
      };
 
      feat |= if_set(hwcap_altivec, PPC_hwcap_bit::ALTIVEC_bit, CPUFeature::Bit::ALTIVEC, allowed);
 
   #if defined(BOTAN_TARGET_ARCH_IS_PPC64)
      if(feat & CPUFeature::Bit::ALTIVEC) {
         feat |= if_set(hwcap_crypto, PPC_hwcap_bit::CRYPTO_bit, CPUFeature::Bit::POWER_CRYPTO, allowed);
         feat |= if_set(hwcap_crypto, PPC_hwcap_bit::DARN_bit, CPUFeature::Bit::DARN, allowed);
      }
   #endif
 
      return feat;
   }
#endif
 
#if defined(BOTAN_USE_GCC_INLINE_ASM) && defined(BOTAN_HAS_OS_UTILS)
   auto vmx_probe = []() noexcept -> int {
      asm("vor 0, 0, 0");
      return 1;
   };
 
   if(allowed & CPUFeature::Bit::ALTIVEC) {
      if(OS::run_cpu_instruction_probe(vmx_probe) == 1) {
         feat |= CPUFeature::Bit::ALTIVEC;
      }
 
   #if defined(BOTAN_TARGET_CPU_IS_PPC64)
      auto vcipher_probe = []() noexcept -> int {
         asm("vcipher 0, 0, 0");
         return 1;
      };
 
      auto darn_probe = []() noexcept -> int {
         uint64_t output = 0;
         asm volatile("darn %0, 1" : "=r"(output));
         return (~output) != 0;
      };
 
      if(feat & CPUFeature::Bit::ALTIVEC) {
         if(OS::run_cpu_instruction_probe(vcipher_probe) == 1) {
            feat |= CPUFeature::Bit::POWER_CRYPTO & allowed;
         }
 
         if(OS::run_cpu_instruction_probe(darn_probe) == 1) {
            feat |= CPUFeature::Bit::DARN & allowed;
         }
      }
   #endif
   }
 
#endif
 
   return feat;
}
 
}  // namespace Botan