vm_version_linux_riscv.cpp

/*
 * Copyright (c) 2006, 2023, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2021, Huawei Technologies Co., Ltd. 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 "precompiled.hpp"
#include "asm/register.hpp"
#include "runtime/os.hpp"
#include "runtime/os.inline.hpp"
#include "runtime/vm_version.hpp"

#include <asm/hwcap.h>
#include <sys/auxv.h>

#ifndef HWCAP_ISA_I
#define HWCAP_ISA_I  (1 << ('I' - 'A'))
#endif

#ifndef HWCAP_ISA_M
#define HWCAP_ISA_M  (1 << ('M' - 'A'))
#endif

#ifndef HWCAP_ISA_A
#define HWCAP_ISA_A  (1 << ('A' - 'A'))
#endif

#ifndef HWCAP_ISA_F
#define HWCAP_ISA_F  (1 << ('F' - 'A'))
#endif

#ifndef HWCAP_ISA_D
#define HWCAP_ISA_D  (1 << ('D' - 'A'))
#endif

#ifndef HWCAP_ISA_C
#define HWCAP_ISA_C  (1 << ('C' - 'A'))
#endif

#ifndef HWCAP_ISA_V
#define HWCAP_ISA_V  (1 << ('V' - 'A'))
#endif

#define read_csr(csr)                                           \
({                                                              \
        register unsigned long __v;                             \
        __asm__ __volatile__ ("csrr %0, %1"                     \
                              : "=r" (__v)                      \
                              : "i" (csr)                       \
                              : "memory");                      \
        __v;                                                    \
})

uint32_t VM_Version::get_current_vector_length() {
  assert(_features & CPU_V, "should not call this");
  return (uint32_t)read_csr(CSR_VLENB);
}

VM_Version::VM_MODE VM_Version::get_satp_mode() {
  if (!strcmp(_vm_mode, "sv39")) {
    return VM_SV39;
  } else if (!strcmp(_vm_mode, "sv48")) {
    return VM_SV48;
  } else if (!strcmp(_vm_mode, "sv57")) {
    return VM_SV57;
  } else if (!strcmp(_vm_mode, "sv64")) {
    return VM_SV64;
  } else {
    return VM_MBARE;
  }
}

void VM_Version::get_os_cpu_info() {

  uint64_t auxv = getauxval(AT_HWCAP);

  static_assert(CPU_I == HWCAP_ISA_I, "Flag CPU_I must follow Linux HWCAP");
  static_assert(CPU_M == HWCAP_ISA_M, "Flag CPU_M must follow Linux HWCAP");
  static_assert(CPU_A == HWCAP_ISA_A, "Flag CPU_A must follow Linux HWCAP");
  static_assert(CPU_F == HWCAP_ISA_F, "Flag CPU_F must follow Linux HWCAP");
  static_assert(CPU_D == HWCAP_ISA_D, "Flag CPU_D must follow Linux HWCAP");
  static_assert(CPU_C == HWCAP_ISA_C, "Flag CPU_C must follow Linux HWCAP");
  static_assert(CPU_V == HWCAP_ISA_V, "Flag CPU_V must follow Linux HWCAP");

  // RISC-V has four bit-manipulation ISA-extensions: Zba/Zbb/Zbc/Zbs.
  // Availability for those extensions could not be queried from HWCAP.
  // TODO: Add proper detection for those extensions.
  _features = auxv & (
      HWCAP_ISA_I |
      HWCAP_ISA_M |
      HWCAP_ISA_A |
      HWCAP_ISA_F |
      HWCAP_ISA_D |
      HWCAP_ISA_C |
      HWCAP_ISA_V);

  if (FILE *f = fopen("/proc/cpuinfo", "r")) {
    char buf[512], *p;
    while (fgets(buf, sizeof (buf), f) != nullptr) {
      if ((p = strchr(buf, ':')) != nullptr) {
        if (strncmp(buf, "mmu", sizeof "mmu" - 1) == 0) {
          if (_vm_mode[0] != '\0') {
            continue;
          }
          char* vm_mode = os::strdup(p + 2);
          vm_mode[strcspn(vm_mode, "\n")] = '\0';
          _vm_mode = vm_mode;
        } else if (strncmp(buf, "uarch", sizeof "uarch" - 1) == 0) {
          char* uarch = os::strdup(p + 2);
          uarch[strcspn(uarch, "\n")] = '\0';
          _uarch = uarch;
          break;
        }
      }
    }
    fclose(f);
  }
}