Yes, something like this:

  static inline long read(int fd, void *buf, long count) {
    register long rax asm("rax") = __NR_read;
    register long rdi asm("rdi") = (long)fd;
    register long rsi asm("rsi") = (long)buf;
    register long rdx asm("rdx") = count;

    asm volatile(
        "syscall"
        : "+r"(rax)
        : "r"(rdi), "r"(rsi), "r"(rdx)
        : "rcx", "r11", "memory"
    );
    return rax;
  }

It's quite easy to get it to do syscalls directly, I even got Fable to do a simple standalone TLS implementation (in C). Not really useful since it hardcoded a set of supported algorithms etc., but it's fun to see how "simple" you can force it to go.