xref: /linux/tools/testing/selftests/bpf/progs/epilogue_tailcall.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
3 
4 #include <vmlinux.h>
5 #include <bpf/bpf_tracing.h>
6 #include "bpf_misc.h"
7 #include "../bpf_testmod/bpf_testmod.h"
8 #include "../bpf_testmod/bpf_testmod_kfunc.h"
9 
10 char _license[] SEC("license") = "GPL";
11 
12 static __noinline __used int subprog(struct st_ops_args *args)
13 {
14 	args->a += 1;
15 	return args->a;
16 }
17 
18 SEC("struct_ops/test_epilogue_subprog")
19 int BPF_PROG(test_epilogue_subprog, struct st_ops_args *args)
20 {
21 	subprog(args);
22 	return args->a;
23 }
24 
25 struct {
26 	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
27 	__uint(max_entries, 1);
28 	__uint(key_size, sizeof(__u32));
29 	__uint(value_size, sizeof(__u32));
30 	__array(values, void (void));
31 } epilogue_map SEC(".maps") = {
32 	.values = {
33 		[0] = (void *)&test_epilogue_subprog,
34 	}
35 };
36 
37 SEC("struct_ops/test_epilogue_tailcall")
38 int test_epilogue_tailcall(unsigned long long *ctx)
39 {
40 	bpf_tail_call(ctx, &epilogue_map, 0);
41 	return 0;
42 }
43 
44 SEC(".struct_ops.link")
45 struct bpf_testmod_st_ops epilogue_tailcall = {
46 	.test_epilogue = (void *)test_epilogue_tailcall,
47 };
48 
49 SEC(".struct_ops.link")
50 struct bpf_testmod_st_ops epilogue_subprog = {
51 	.test_epilogue = (void *)test_epilogue_subprog,
52 };
53 
54 SEC("syscall")
55 int syscall_epilogue_tailcall(struct st_ops_args *args)
56 {
57 	return bpf_kfunc_st_ops_test_epilogue(args);
58 }
59