1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Test weak ksyms.
4 *
5 * Copyright (c) 2021 Google
6 */
7
8#include "vmlinux.h"
9
10#include <bpf/bpf_helpers.h>
11
12int out__existing_typed = -1;
13__u64 out__existing_typeless = -1;
14
15__u64 out__non_existent_typeless = -1;
16__u64 out__non_existent_typed = -1;
17
18/* existing weak symbols */
19
20/* test existing weak symbols can be resolved. */
21extern const struct rq runqueues __ksym __weak; /* typed */
22extern const void bpf_prog_active __ksym __weak; /* typeless */
23struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym __weak;
24void bpf_testmod_test_mod_kfunc(int i) __ksym __weak;
25
26
27/* non-existent weak symbols. */
28
29/* typeless symbols, default to zero. */
30extern const void bpf_link_fops1 __ksym __weak;
31
32/* typed symbols, default to zero. */
33extern const int bpf_link_fops2 __ksym __weak;
34void invalid_kfunc(void) __ksym __weak;
35
36SEC("raw_tp/sys_enter")
37int pass_handler(const void *ctx)
38{
39	struct rq *rq;
40
41	/* tests existing symbols. */
42	rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, 0);
43	if (rq && bpf_ksym_exists(&runqueues))
44		out__existing_typed = rq->cpu;
45	out__existing_typeless = (__u64)&bpf_prog_active;
46
47	/* tests non-existent symbols. */
48	out__non_existent_typeless = (__u64)&bpf_link_fops1;
49
50	/* tests non-existent symbols. */
51	out__non_existent_typed = (__u64)&bpf_link_fops2;
52
53	if (&bpf_link_fops2) /* can't happen */
54		out__non_existent_typed = (__u64)bpf_per_cpu_ptr(&bpf_link_fops2, 0);
55
56	if (!bpf_ksym_exists(bpf_task_acquire))
57		/* dead code won't be seen by the verifier */
58		bpf_task_acquire(0);
59
60	if (!bpf_ksym_exists(bpf_testmod_test_mod_kfunc))
61		/* dead code won't be seen by the verifier */
62		bpf_testmod_test_mod_kfunc(0);
63
64	if (bpf_ksym_exists(invalid_kfunc))
65		/* dead code won't be seen by the verifier */
66		invalid_kfunc();
67
68	return 0;
69}
70
71char _license[] SEC("license") = "GPL";
72