1/*
 2 * Copyright (C) 2015, He Kuang <hekuang@huawei.com>
 3 * Copyright (C) 2015, Huawei Inc.
 4 */
 5#ifndef __BPF_PROLOGUE_H
 6#define __BPF_PROLOGUE_H
 7
 8#include <linux/compiler.h>
 9#include <linux/filter.h>
10#include "probe-event.h"
11
12#define BPF_PROLOGUE_MAX_ARGS 3
13#define BPF_PROLOGUE_START_ARG_REG BPF_REG_3
14#define BPF_PROLOGUE_FETCH_RESULT_REG BPF_REG_2
15
16#ifdef HAVE_BPF_PROLOGUE
17int bpf__gen_prologue(struct probe_trace_arg *args, int nargs,
18		      struct bpf_insn *new_prog, size_t *new_cnt,
19		      size_t cnt_space);
20#else
21static inline int
22bpf__gen_prologue(struct probe_trace_arg *args __maybe_unused,
23		  int nargs __maybe_unused,
24		  struct bpf_insn *new_prog __maybe_unused,
25		  size_t *new_cnt,
26		  size_t cnt_space __maybe_unused)
27{
28	if (!new_cnt)
29		return -EINVAL;
30	*new_cnt = 0;
31	return -ENOTSUP;
32}
33#endif
34#endif /* __BPF_PROLOGUE_H */