tools/testing/selftests/bpf/progs/tailcall_bpf2bpf_hierarchy_fentry.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright Leon Hwang */
   3
   4 #include "vmlinux.h"
   5 #include <bpf/bpf_helpers.h>
   6 #include <bpf/bpf_tracing.h>
   7
   8 struct {
   9         __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
  10         __uint(max_entries, 1);
  11         __uint(key_size, sizeof(__u32));
  12         __uint(value_size, sizeof(__u32));
  13 } jmp_table SEC(".maps");
  14
  15 int count = 0;
  16
  17 static __noinline
  18 int subprog_tail(void *ctx)
  19 {
  20         bpf_tail_call_static(ctx, &jmp_table, 0);
  21         return 0;
  22 }
  23
  24 SEC("fentry/dummy")
  25 int BPF_PROG(fentry, struct sk_buff *skb)
  26 {
  27         count++;
  28         subprog_tail(ctx);
  29         subprog_tail(ctx);
  30
  31         return 0;
  32 }
  33
  34
  35 char _license[] SEC("license") = "GPL";