static bool solaris_mprotect(char* addr, size_t bytes, int prot) {

  {- -------------------------------------------
  (1) mprotect() を呼び出すだけ.
      ---------------------------------------- -}

      assert(addr == (char*)align_size_down((uintptr_t)addr, os::vm_page_size()),
             "addr must be page aligned");
      int retVal = mprotect(addr, bytes, prot);
      return retVal == 0;
    }