src/hotspot/cpu/riscv/vm_version_riscv.cpp

/*
 * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2020, 2023, Huawei Technologies Co., Ltd. All rights reserved.
 * Copyright (c) 2023, Rivos Inc. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "classfile/vmIntrinsics.hpp"
#include "runtime/java.hpp"
#include "runtime/os.inline.hpp"
#include "runtime/vm_version.hpp"
#include "utilities/formatBuffer.hpp"
#include "utilities/macros.hpp"

#include <ctype.h>

uint32_t VM_Version::_initial_vector_length = 0;

#define DEF_RV_FEATURE(NAME, PRETTY, BIT, FSTRING, FLAGF)       \
VM_Version::NAME##RVFeatureValue VM_Version::NAME(PRETTY, BIT, FSTRING);
RV_FEATURE_FLAGS(DEF_RV_FEATURE)

#define ADD_RV_FEATURE_IN_LIST(NAME, PRETTY, BIT, FSTRING, FLAGF) \
    &VM_Version::NAME,
VM_Version::RVFeatureValue* VM_Version::_feature_list[] = {
RV_FEATURE_FLAGS(ADD_RV_FEATURE_IN_LIST)
  nullptr};

void VM_Version::useRVA20U64Profile() {
  RV_USE_RVA20U64;
}

void VM_Version::useRVA22U64Profile() {
  RV_USE_RVA22U64;
}

void VM_Version::useRVA23U64Profile() {
  RV_USE_RVA23U64;
}

void VM_Version::initialize() {
  common_initialize();
#ifdef COMPILER2
  c2_initialize();
#endif // COMPILER2
}

void VM_Version::common_initialize() {
  _supports_atomic_getset4 = true;
  _supports_atomic_getadd4 = true;
  _supports_atomic_getset8 = true;
  _supports_atomic_getadd8 = true;

  setup_cpu_available_features();

  // check if satp.mode is supported, currently supports up to SV48(RV64)
  if (satp_mode.value() > VM_SV48 || satp_mode.value() < VM_MBARE) {
    vm_exit_during_initialization(
      err_msg(
         "Unsupported satp mode: SV%d. Only satp modes up to sv48 are supported for now.",
         (int)satp_mode.value()));
  }

  if (UseRVA20U64) {
    useRVA20U64Profile();
  }
  if (UseRVA22U64) {
    useRVA22U64Profile();
  }
  if (UseRVA23U64) {
    useRVA23U64Profile();
  }

  // Enable vendor specific features

  if (mvendorid.enabled()) {
    // Rivos
    if (mvendorid.value() == RIVOS) {
      if (FLAG_IS_DEFAULT(UseConservativeFence)) {
        FLAG_SET_DEFAULT(UseConservativeFence, false);
      }
    }
  }

  if (UseZic64b) {
    if (CacheLineSize != 64) {
      assert(!FLAG_IS_DEFAULT(CacheLineSize), "default cache line size should be 64 bytes");
      warning("CacheLineSize is assumed to be 64 bytes because Zic64b is enabled");
      FLAG_SET_DEFAULT(CacheLineSize, 64);
    }
  } else {
    if (!FLAG_IS_DEFAULT(CacheLineSize) && !is_power_of_2(CacheLineSize)) {
      warning("CacheLineSize must be a power of 2");
      FLAG_SET_DEFAULT(CacheLineSize, DEFAULT_CACHE_LINE_SIZE);
    }
  }

  if (FLAG_IS_DEFAULT(UseFMA)) {
    FLAG_SET_DEFAULT(UseFMA, true);
  }

  if (FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
    FLAG_SET_DEFAULT(AllocatePrefetchDistance, 0);
  }

  if (UseVectorizedMismatchIntrinsic) {
    warning("VectorizedMismatch intrinsic is not available on this CPU.");
    FLAG_SET_DEFAULT(UseVectorizedMismatchIntrinsic, false);
  }

  if (FLAG_IS_DEFAULT(UseCopySignIntrinsic)) {
    FLAG_SET_DEFAULT(UseCopySignIntrinsic, true);
  }

  if (FLAG_IS_DEFAULT(UseSignumIntrinsic)) {
    FLAG_SET_DEFAULT(UseSignumIntrinsic, true);
  }

  if (UseRVC && !ext_C.enabled()) {
    warning("RVC is not supported on this CPU");
    FLAG_SET_DEFAULT(UseRVC, false);

    if (UseRVA20U64) {
      warning("UseRVA20U64 is not supported on this CPU");
      FLAG_SET_DEFAULT(UseRVA20U64, false);
    }
  }

  if (FLAG_IS_DEFAULT(AvoidUnalignedAccesses)) {
    FLAG_SET_DEFAULT(AvoidUnalignedAccesses,
      unaligned_scalar.value() != MISALIGNED_SCALAR_FAST);
  }

  if (!AvoidUnalignedAccesses) {
    if (FLAG_IS_DEFAULT(UsePoly1305Intrinsics)) {
      FLAG_SET_DEFAULT(UsePoly1305Intrinsics, true);
    }
  } else if (UsePoly1305Intrinsics) {
    warning("Intrinsics for Poly1305 crypto hash functions not available on this CPU.");
  }

  // See JDK-8026049
  // This machine has fast unaligned memory accesses
  if (FLAG_IS_DEFAULT(UseUnalignedAccesses)) {
    FLAG_SET_DEFAULT(UseUnalignedAccesses,
      (unaligned_scalar.value() == MISALIGNED_SCALAR_FAST));
  }

  if (FLAG_IS_DEFAULT(AlignVector)) {
    FLAG_SET_DEFAULT(AlignVector,
      unaligned_vector.value() != MISALIGNED_VECTOR_FAST);
  }

#ifdef __riscv_ztso
  // Hotspot is compiled with TSO support, it will only run on hardware which
  // supports Ztso
  if (FLAG_IS_DEFAULT(UseZtso)) {
    FLAG_SET_DEFAULT(UseZtso, true);
  }
#endif

  if (UseZbb) {
    if (FLAG_IS_DEFAULT(UsePopCountInstruction)) {
      FLAG_SET_DEFAULT(UsePopCountInstruction, true);
    }
  } else {
    FLAG_SET_DEFAULT(UsePopCountInstruction, false);
  }

  if (UseZicboz && zicboz_block_size.enabled() && zicboz_block_size.value() > 0) {
    assert(is_power_of_2(zicboz_block_size.value()), "Sanity");
    if (FLAG_IS_DEFAULT(UseBlockZeroing)) {
      FLAG_SET_DEFAULT(UseBlockZeroing, true);
    }
    if (FLAG_IS_DEFAULT(BlockZeroingLowLimit)) {
      FLAG_SET_DEFAULT(BlockZeroingLowLimit, 4 * zicboz_block_size.value());
    }
  } else if (UseBlockZeroing) {
    warning("Block zeroing is not available");
    FLAG_SET_DEFAULT(UseBlockZeroing, false);
  }

  if (UseRVV) {
    // read vector length from vector CSR vlenb
    _initial_vector_length = cpu_vector_length();
  }

  // Misc Intrinsics that could depend on RVV.

  if (!AvoidUnalignedAccesses && (UseZba || UseRVV)) {
    if (FLAG_IS_DEFAULT(UseCRC32Intrinsics)) {
      FLAG_SET_DEFAULT(UseCRC32Intrinsics, true);
    }
  } else {
    if (!FLAG_IS_DEFAULT(UseCRC32Intrinsics)) {
      warning("CRC32 intrinsic are not available on this CPU.");
    }
    FLAG_SET_DEFAULT(UseCRC32Intrinsics, false);
  }

  if (UseCRC32CIntrinsics) {
    warning("CRC32C intrinsics are not available on this CPU.");
    FLAG_SET_DEFAULT(UseCRC32CIntrinsics, false);
  }

  // UseZvbb (depends on RVV).
  if (UseZvbb && !UseRVV) {
    warning("Cannot enable UseZvbb on cpu without RVV support.");
    FLAG_SET_DEFAULT(UseZvbb, false);
  }

  // UseZvbc (depends on RVV).
  if (UseZvbc && !UseRVV) {
    warning("Cannot enable UseZvbc on cpu without RVV support.");
    FLAG_SET_DEFAULT(UseZvbc, false);
  }

  // UseZvkn (depends on RVV).
  if (UseZvkn && !UseRVV) {
    warning("Cannot enable UseZvkn on cpu without RVV support.");
    FLAG_SET_DEFAULT(UseZvkn, false);
  }

  // UseZvfh (depends on RVV)
  if (UseZvfh) {
    if (!UseRVV) {
      warning("Cannot enable UseZvfh on cpu without RVV support.");
      FLAG_SET_DEFAULT(UseZvfh, false);
    }
    if (!UseZfh) {
      warning("Cannot enable UseZvfh on cpu without Zfh support.");
      FLAG_SET_DEFAULT(UseZvfh, false);
    }
  }
}

#ifdef COMPILER2
void VM_Version::c2_initialize() {
  if (!UseRVV) {
    FLAG_SET_DEFAULT(MaxVectorSize, 0);
  } else {
    if (!FLAG_IS_DEFAULT(MaxVectorSize) && MaxVectorSize != _initial_vector_length) {
      warning("Current system does not support RVV vector length for MaxVectorSize %d. Set MaxVectorSize to %d",
               (int)MaxVectorSize, _initial_vector_length);
    }
    MaxVectorSize = _initial_vector_length;
    if (MaxVectorSize < 16) {
      warning("RVV does not support vector length less than 16 bytes. Disabling RVV.");
      UseRVV = false;
      FLAG_SET_DEFAULT(MaxVectorSize, 0);
    }
  }

  // NOTE: Make sure codes dependent on UseRVV are put after MaxVectorSize initialize,
  //       as there are extra checks inside it which could disable UseRVV
  //       in some situations.

  // Base64
  if (FLAG_IS_DEFAULT(UseBASE64Intrinsics)) {
    FLAG_SET_DEFAULT(UseBASE64Intrinsics, true);
  }

  if (FLAG_IS_DEFAULT(UseVectorizedHashCodeIntrinsic)) {
    FLAG_SET_DEFAULT(UseVectorizedHashCodeIntrinsic, true);
  }

  if (!UseZicbop) {
    if (!FLAG_IS_DEFAULT(AllocatePrefetchStyle)) {
      warning("Zicbop is not available on this CPU");
    }
    FLAG_SET_DEFAULT(AllocatePrefetchStyle, 0);
  } else {
    // Limit AllocatePrefetchDistance so that it does not exceed the
    // static constraint of 512 defined in runtime/globals.hpp.
    if (FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
      FLAG_SET_DEFAULT(AllocatePrefetchDistance, MIN2(512, 3 * (int)CacheLineSize));
    }
    if (FLAG_IS_DEFAULT(AllocatePrefetchStepSize)) {
      FLAG_SET_DEFAULT(AllocatePrefetchStepSize, (int)CacheLineSize);
    }
    if (FLAG_IS_DEFAULT(PrefetchScanIntervalInBytes)) {
      FLAG_SET_DEFAULT(PrefetchScanIntervalInBytes, 3 * (int)CacheLineSize);
    }
    if (FLAG_IS_DEFAULT(PrefetchCopyIntervalInBytes)) {
      FLAG_SET_DEFAULT(PrefetchCopyIntervalInBytes, 3 * (int)CacheLineSize);
    }

    if (PrefetchCopyIntervalInBytes != -1 &&
        ((PrefetchCopyIntervalInBytes & 7) || (PrefetchCopyIntervalInBytes >= 32768))) {
      warning("PrefetchCopyIntervalInBytes must be -1, or a multiple of 8 and < 32768");
      PrefetchCopyIntervalInBytes &= ~7;
      if (PrefetchCopyIntervalInBytes >= 32768) {
        PrefetchCopyIntervalInBytes = 32760;
      }
    }
    if (AllocatePrefetchDistance !=-1 && (AllocatePrefetchDistance & 7)) {
      warning("AllocatePrefetchDistance must be multiple of 8");
      AllocatePrefetchDistance &= ~7;
    }
    if (AllocatePrefetchStepSize & 7) {
      warning("AllocatePrefetchStepSize must be multiple of 8");
      AllocatePrefetchStepSize &= ~7;
    }
  }

  if (FLAG_IS_DEFAULT(UseMulAddIntrinsic)) {
    FLAG_SET_DEFAULT(UseMulAddIntrinsic, true);
  }

  if (!AvoidUnalignedAccesses) {
    if (FLAG_IS_DEFAULT(UseMultiplyToLenIntrinsic)) {
      FLAG_SET_DEFAULT(UseMultiplyToLenIntrinsic, true);
    }
  } else if (UseMultiplyToLenIntrinsic) {
    warning("Intrinsics for BigInteger.multiplyToLen() not available on this CPU.");
    FLAG_SET_DEFAULT(UseMultiplyToLenIntrinsic, false);
  }

  if (!AvoidUnalignedAccesses) {
    if (FLAG_IS_DEFAULT(UseSquareToLenIntrinsic)) {
      FLAG_SET_DEFAULT(UseSquareToLenIntrinsic, true);
    }
  } else if (UseSquareToLenIntrinsic) {
    warning("Intrinsics for BigInteger.squareToLen() not available on this CPU.");
    FLAG_SET_DEFAULT(UseSquareToLenIntrinsic, false);
  }

  if (!AvoidUnalignedAccesses) {
    if (FLAG_IS_DEFAULT(UseMontgomeryMultiplyIntrinsic)) {
      FLAG_SET_DEFAULT(UseMontgomeryMultiplyIntrinsic, true);
    }
  } else if (UseMontgomeryMultiplyIntrinsic) {
    warning("Intrinsics for BigInteger.montgomeryMultiply() not available on this CPU.");
    FLAG_SET_DEFAULT(UseMontgomeryMultiplyIntrinsic, false);
  }

  if (!AvoidUnalignedAccesses) {
    if (FLAG_IS_DEFAULT(UseMontgomerySquareIntrinsic)) {
      FLAG_SET_DEFAULT(UseMontgomerySquareIntrinsic, true);
    }
  } else if (UseMontgomerySquareIntrinsic) {
    warning("Intrinsics for BigInteger.montgomerySquare() not available on this CPU.");
    FLAG_SET_DEFAULT(UseMontgomerySquareIntrinsic, false);
  }

  // Adler32
  if (UseRVV) {
    if (FLAG_IS_DEFAULT(UseAdler32Intrinsics)) {
      FLAG_SET_DEFAULT(UseAdler32Intrinsics, true);
    }
  } else if (UseAdler32Intrinsics) {
    if (!FLAG_IS_DEFAULT(UseAdler32Intrinsics)) {
      warning("Adler32 intrinsic requires RVV instructions (not available on this CPU).");
    }
    FLAG_SET_DEFAULT(UseAdler32Intrinsics, false);
  }

  // ChaCha20
  if (UseRVV && MaxVectorSize >= 32) {
    // performance tests on hardwares (MaxVectorSize == 16, 32) show that
    // it brings regression when MaxVectorSize == 16.
    if (FLAG_IS_DEFAULT(UseChaCha20Intrinsics)) {
      FLAG_SET_DEFAULT(UseChaCha20Intrinsics, true);
    }
  } else if (UseChaCha20Intrinsics) {
    if (!FLAG_IS_DEFAULT(UseChaCha20Intrinsics)) {
      warning("Chacha20 intrinsic requires RVV instructions (not available on this CPU)");
    }
    FLAG_SET_DEFAULT(UseChaCha20Intrinsics, false);
  }

  if (!AvoidUnalignedAccesses) {
    if (FLAG_IS_DEFAULT(UseMD5Intrinsics)) {
      FLAG_SET_DEFAULT(UseMD5Intrinsics, true);
    }
  } else if (UseMD5Intrinsics) {
    warning("Intrinsics for MD5 crypto hash functions not available on this CPU.");
    FLAG_SET_DEFAULT(UseMD5Intrinsics, false);
  }

  // SHA's
  if (FLAG_IS_DEFAULT(UseSHA)) {
    FLAG_SET_DEFAULT(UseSHA, true);
  }

  // SHA-1, no RVV required though.
  if (UseSHA && !AvoidUnalignedAccesses) {
    if (FLAG_IS_DEFAULT(UseSHA1Intrinsics)) {
      FLAG_SET_DEFAULT(UseSHA1Intrinsics, true);
    }
  } else if (UseSHA1Intrinsics) {
    warning("Intrinsics for SHA-1 crypto hash functions not available on this CPU.");
    FLAG_SET_DEFAULT(UseSHA1Intrinsics, false);
  }

  // SHA-2, depends on Zvkn.
  if (UseSHA) {
    if (UseZvkn) {
      if (FLAG_IS_DEFAULT(UseSHA256Intrinsics)) {
        FLAG_SET_DEFAULT(UseSHA256Intrinsics, true);
      }
      if (FLAG_IS_DEFAULT(UseSHA512Intrinsics)) {
        FLAG_SET_DEFAULT(UseSHA512Intrinsics, true);
      }
    } else {
      if (UseSHA256Intrinsics) {
        warning("Intrinsics for SHA-224 and SHA-256 crypto hash functions not available on this CPU, UseZvkn needed.");
        FLAG_SET_DEFAULT(UseSHA256Intrinsics, false);
      }
      if (UseSHA512Intrinsics) {
        warning("Intrinsics for SHA-384 and SHA-512 crypto hash functions not available on this CPU, UseZvkn needed.");
        FLAG_SET_DEFAULT(UseSHA512Intrinsics, false);
      }
    }
  } else {
    if (UseSHA256Intrinsics) {
      warning("Intrinsics for SHA-224 and SHA-256 crypto hash functions not available on this CPU, as UseSHA disabled.");
      FLAG_SET_DEFAULT(UseSHA256Intrinsics, false);
    }
    if (UseSHA512Intrinsics) {
      warning("Intrinsics for SHA-384 and SHA-512 crypto hash functions not available on this CPU, as UseSHA disabled.");
      FLAG_SET_DEFAULT(UseSHA512Intrinsics, false);
    }
  }

  // SHA-3
  if (UseSHA3Intrinsics) {
    warning("Intrinsics for SHA3-224, SHA3-256, SHA3-384 and SHA3-512 crypto hash functions not available on this CPU.");
    FLAG_SET_DEFAULT(UseSHA3Intrinsics, false);
  }

  // UseSHA
  if (!(UseSHA1Intrinsics || UseSHA256Intrinsics || UseSHA3Intrinsics || UseSHA512Intrinsics)) {
    FLAG_SET_DEFAULT(UseSHA, false);
  }

  // AES
  if (UseZvkn) {
    UseAES = UseAES || FLAG_IS_DEFAULT(UseAES);
    UseAESIntrinsics =
        UseAESIntrinsics || (UseAES && FLAG_IS_DEFAULT(UseAESIntrinsics));
    if (UseAESIntrinsics && !UseAES) {
      warning("UseAESIntrinsics enabled, but UseAES not, enabling");
      UseAES = true;
    }
  } else {
    if (UseAES) {
      warning("AES instructions are not available on this CPU");
      FLAG_SET_DEFAULT(UseAES, false);
    }
    if (UseAESIntrinsics) {
      warning("AES intrinsics are not available on this CPU");
      FLAG_SET_DEFAULT(UseAESIntrinsics, false);
    }
  }

  if (UseAESCTRIntrinsics) {
    warning("AES/CTR intrinsics are not available on this CPU");
    FLAG_SET_DEFAULT(UseAESCTRIntrinsics, false);
  }
}

#endif // COMPILER2

void VM_Version::initialize_cpu_information(void) {
  // do nothing if cpu info has been initialized
  if (_initialized) {
    return;
  }

  _no_of_cores  = os::processor_count();
  _no_of_threads = _no_of_cores;
  _no_of_sockets = _no_of_cores;
  snprintf(_cpu_name, CPU_TYPE_DESC_BUF_SIZE - 1, "RISCV64");
  snprintf(_cpu_desc, CPU_DETAILED_DESC_BUF_SIZE, "RISCV64 %s", cpu_info_string());
  _initialized = true;
}

bool VM_Version::is_intrinsic_supported(vmIntrinsicID id) {
  assert(id != vmIntrinsics::_none, "must be a VM intrinsic");
  switch (id) {
  case vmIntrinsics::_floatToFloat16:
  case vmIntrinsics::_float16ToFloat:
    if (!supports_float16_float_conversion()) {
      return false;
    }
    break;
  default:
    break;
  }
  return true;
}