xref: /linux/scripts/gendwarfksyms/examples/symbolptr.c (revision ba6ec09911b805778a2fed6d626bfe77b011a717)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2024 Google LLC
4  *
5  * Example for symbol pointers. When compiled with Clang, gendwarfkyms
6  * uses a symbol pointer for `f`.
7  *
8  * $ clang -g -c examples/symbolptr.c -o examples/symbolptr.o
9  * $ echo -e "f\ng\np" | ./gendwarfksyms -d examples/symbolptr.o
10  */
11 
12 /* Kernel macros for userspace testing. */
13 #ifndef __used
14 #define __used __attribute__((__used__))
15 #endif
16 #ifndef __section
17 #define __section(section) __attribute__((__section__(section)))
18 #endif
19 
20 #define __GENDWARFKSYMS_EXPORT(sym)				\
21 	static typeof(sym) *__gendwarfksyms_ptr_##sym __used	\
22 		__section(".discard.gendwarfksyms") = &sym;
23 
24 extern void f(unsigned int arg);
25 void g(int *arg);
g(int * arg)26 void g(int *arg) {}
27 
28 struct s;
29 extern struct s *p;
30 
31 __GENDWARFKSYMS_EXPORT(f);
32 __GENDWARFKSYMS_EXPORT(g);
33 __GENDWARFKSYMS_EXPORT(p);
34