/*
   * Copyright (C) 2015, He Kuang <hekuang@huawei.com>
   * Copyright (C) 2015, Huawei Inc.
   */
  #ifndef __BPF_PROLOGUE_H
  #define __BPF_PROLOGUE_H
  
  #include <linux/compiler.h>
  #include <linux/filter.h>
  #include "probe-event.h"
  
  #define BPF_PROLOGUE_MAX_ARGS 3
  #define BPF_PROLOGUE_START_ARG_REG BPF_REG_3
  #define BPF_PROLOGUE_FETCH_RESULT_REG BPF_REG_2
  
  #ifdef HAVE_BPF_PROLOGUE
  int bpf__gen_prologue(struct probe_trace_arg *args, int nargs,
  		      struct bpf_insn *new_prog, size_t *new_cnt,
  		      size_t cnt_space);
  #else

  #include <errno.h>

  static inline int
  bpf__gen_prologue(struct probe_trace_arg *args __maybe_unused,
  		  int nargs __maybe_unused,
  		  struct bpf_insn *new_prog __maybe_unused,
  		  size_t *new_cnt,
  		  size_t cnt_space __maybe_unused)
  {
  	if (!new_cnt)
  		return -EINVAL;
  	*new_cnt = 0;
  	return -ENOTSUP;
  }
  #endif
  #endif /* __BPF_PROLOGUE_H */