LXR linux/tools/testing/selftests/bpf/progs/tailcall1.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/bpf.h>
   3
   4#include <bpf/bpf_helpers.h>
   5
   6struct {
   7        __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
   8        __uint(max_entries, 3);
   9        __uint(key_size, sizeof(__u32));
  10        __uint(value_size, sizeof(__u32));
  11} jmp_table SEC(".maps");
  12
  13#define TAIL_FUNC(x)                            \
  14        SEC("classifier/" #x)                   \
  15        int bpf_func_##x(struct __sk_buff *skb) \
  16        {                                       \
  17                return x;                       \
  18        }
  19TAIL_FUNC(0)
  20TAIL_FUNC(1)
  21TAIL_FUNC(2)
  22
  23SEC("classifier")
  24int entry(struct __sk_buff *skb)
  25{
  26        /* Multiple locations to make sure we patch
  27         * all of them.
  28         */
  29        bpf_tail_call_static(skb, &jmp_table, 0);
  30        bpf_tail_call_static(skb, &jmp_table, 0);
  31        bpf_tail_call_static(skb, &jmp_table, 0);
  32        bpf_tail_call_static(skb, &jmp_table, 0);
  33
  34        bpf_tail_call_static(skb, &jmp_table, 1);
  35        bpf_tail_call_static(skb, &jmp_table, 1);
  36        bpf_tail_call_static(skb, &jmp_table, 1);
  37        bpf_tail_call_static(skb, &jmp_table, 1);
  38
  39        bpf_tail_call_static(skb, &jmp_table, 2);
  40        bpf_tail_call_static(skb, &jmp_table, 2);
  41        bpf_tail_call_static(skb, &jmp_table, 2);
  42        bpf_tail_call_static(skb, &jmp_table, 2);
  43
  44        return 3;
  45}
  46
  47char __license[] SEC("license") = "GPL";
  48int _version SEC("version") = 1;
  49