/*

 * Copyright (C) 2020 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <sys/ptrace.h>

#include <sys/uio.h>

#if defined(__BIONIC__)

#include <bionic/mte.h>

#else

#define mte_supported() false

#endif

#include "MemoryLocal.h"

#include "MemoryRemote.h"

namespace unwindstack {

long MemoryRemote::ReadTag(uint64_t addr) {

#if defined(PTRACE_PEEKMTETAGS) || defined(PT_PEEKMTETAGS)

  char tag;

  iovec iov = {&tag, 1};

  if (ptrace(PTRACE_PEEKMTETAGS, pid_, reinterpret_cast<void*>(addr), &iov) != 0 ||

      iov.iov_len != 1) {

    return -1;

  }

  return tag;

#else

  (void)addr;

  return -1;

#endif

}

long MemoryLocal::ReadTag(uint64_t addr) {

#if defined(__aarch64__)

  // Check that the memory is readable first. This is racy with the ldg but there's not much

  // we can do about it.

  char data;

  if (!mte_supported() || !Read(addr, &data, 1)) {

    return -1;

  }

  __asm__ __volatile__(".arch_extension mte; ldg %0, [%0]" : "+r"(addr) : : "memory");

  return (addr >> 56) & 0xf;

#else

  (void)addr;

  return -1;

#endif

}

}  // namespace unwindstack