1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2015, He Kuang <hekuang@huawei.com>
4 * Copyright (C) 2015, Huawei Inc.
5 */
6#ifndef __BPF_PROLOGUE_H
7#define __BPF_PROLOGUE_H
8
9struct probe_trace_arg;
10struct bpf_insn;
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
21#include <linux/compiler.h>
22#include <errno.h>
23
24static inline int
25bpf__gen_prologue(struct probe_trace_arg *args __maybe_unused,
26		  int nargs __maybe_unused,
27		  struct bpf_insn *new_prog __maybe_unused,
28		  size_t *new_cnt,
29		  size_t cnt_space __maybe_unused)
30{
31	if (!new_cnt)
32		return -EINVAL;
33	*new_cnt = 0;
34	return -ENOTSUP;
35}
36#endif
37#endif /* __BPF_PROLOGUE_H */
38