1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3
4#include "vmlinux.h"
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7
8extern int LINUX_KERNEL_VERSION __kconfig;
9/* when an extern is defined as both strong and weak, resulting symbol will be strong */
10extern bool CONFIG_BPF_SYSCALL __kconfig;
11extern const void __start_BTF __ksym;
12
13int input_bss2;
14int input_data2 = 2;
15const volatile int input_rodata2 = 22;
16
17int input_bss_weak __weak;
18/* these two weak variables should lose */
19int input_data_weak __weak = 20;
20const volatile int input_rodata_weak __weak = 200;
21
22extern int input_bss1;
23extern int input_data1;
24extern const int input_rodata1;
25
26int output_bss2;
27int output_data2;
28int output_rodata2;
29
30int output_sink2;
31
32static __noinline int get_data_res(void)
33{
34 /* just make sure all the relocations work against .text as well */
35 return input_data1 + input_data2 + input_data_weak;
36}
37
38SEC("raw_tp/sys_enter")
39int BPF_PROG(handler2)
40{
41 output_bss2 = input_bss1 + input_bss2 + input_bss_weak;
42 output_data2 = get_data_res();
43 output_rodata2 = input_rodata1 + input_rodata2 + input_rodata_weak;
44
45 /* make sure we actually use above special externs, otherwise compiler
46 * will optimize them out
47 */
48 output_sink2 = LINUX_KERNEL_VERSION
49 + CONFIG_BPF_SYSCALL
50 + (long)&__start_BTF;
51
52 return 0;
53}
54
55char LICENSE[] SEC("license") = "GPL";
56

source code of linux/tools/testing/selftests/bpf/progs/linked_vars2.c