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 
8 extern int LINUX_KERNEL_VERSION __kconfig;
9 /* when an extern is defined as both strong and weak, resulting symbol will be strong */
10 extern bool CONFIG_BPF_SYSCALL __kconfig;
11 extern const void __start_BTF __ksym;
12 
13 int input_bss2;
14 int input_data2 = 2;
15 const volatile int input_rodata2 = 22;
16 
17 int input_bss_weak __weak;
18 /* these two weak variables should lose */
19 int input_data_weak __weak = 20;
20 const volatile int input_rodata_weak __weak = 200;
21 
22 extern int input_bss1;
23 extern int input_data1;
24 extern const int input_rodata1;
25 
26 int output_bss2;
27 int output_data2;
28 int output_rodata2;
29 
30 int output_sink2;
31 
get_data_res(void)32 static __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 
38 SEC("raw_tp/sys_enter")
BPF_PROG(handler2)39 int 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 
55 char LICENSE[] SEC("license") = "GPL";
56