Merge "Switch to new kernel ptrace interface for reading tags." am: 58429281

#if defined(ANDROID_EXPERIMENTAL_MTE)

#include <sys/ptrace.h>

#include <sys/uio.h>

#include <bionic/mte.h>

#include <bionic/mte_kernel.h>

long MemoryRemote::ReadTag(uint64_t addr) {

#if defined(__aarch64__)

  return ptrace(PTRACE_PEEKTAG, pid_, (void*)addr, nullptr);

  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;