xref: /linux/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf_hierarchy1.c (revision 07fdad3a93756b872da7b53647715c48d0f4a2d0)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/bpf.h>
3 #include <bpf/bpf_helpers.h>
4 #include "bpf_legacy.h"
5 #include "bpf_test_utils.h"
6 
7 struct {
8 	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
9 	__uint(max_entries, 1);
10 	__uint(key_size, sizeof(__u32));
11 	__uint(value_size, sizeof(__u32));
12 } jmp_table SEC(".maps");
13 
14 int count = 0;
15 
16 static __noinline
17 int subprog_tail(struct __sk_buff *skb)
18 {
19 	bpf_tail_call_static(skb, &jmp_table, 0);
20 	return 0;
21 }
22 
23 SEC("tc")
24 int entry(struct __sk_buff *skb)
25 {
26 	int ret = 1;
27 
28 	clobber_regs_stack();
29 
30 	count++;
31 	subprog_tail(skb);
32 	subprog_tail(skb);
33 
34 	return ret;
35 }
36 
37 char __license[] SEC("license") = "GPL";
38