1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _STATIC_CALL_TYPES_H
3 #define _STATIC_CALL_TYPES_H
4 
5 #include <linux/types.h>
6 #include <linux/stringify.h>
7 #include <linux/compiler.h>
8 
9 #define STATIC_CALL_KEY_PREFIX		__SCK__
10 #define STATIC_CALL_KEY_PREFIX_STR	__stringify(STATIC_CALL_KEY_PREFIX)
11 #define STATIC_CALL_KEY_PREFIX_LEN	(sizeof(STATIC_CALL_KEY_PREFIX_STR) - 1)
12 #define STATIC_CALL_KEY(name)		__PASTE(STATIC_CALL_KEY_PREFIX, name)
13 #define STATIC_CALL_KEY_STR(name)	__stringify(STATIC_CALL_KEY(name))
14 
15 #define STATIC_CALL_TRAMP_PREFIX	__SCT__
16 #define STATIC_CALL_TRAMP_PREFIX_STR	__stringify(STATIC_CALL_TRAMP_PREFIX)
17 #define STATIC_CALL_TRAMP_PREFIX_LEN	(sizeof(STATIC_CALL_TRAMP_PREFIX_STR) - 1)
18 #define STATIC_CALL_TRAMP(name)		__PASTE(STATIC_CALL_TRAMP_PREFIX, name)
19 #define STATIC_CALL_TRAMP_STR(name)	__stringify(STATIC_CALL_TRAMP(name))
20 
21 /*
22  * Flags in the low bits of static_call_site::key.
23  */
24 #define STATIC_CALL_SITE_TAIL 1UL	/* tail call */
25 #define STATIC_CALL_SITE_INIT 2UL	/* init section */
26 #define STATIC_CALL_SITE_FLAGS 3UL
27 
28 /*
29  * The static call site table needs to be created by external tooling (objtool
30  * or a compiler plugin).
31  */
32 struct static_call_site {
33 	s32 addr;
34 	s32 key;
35 };
36 
37 #define DECLARE_STATIC_CALL(name, func)					\
38 	extern struct static_call_key STATIC_CALL_KEY(name);		\
39 	extern typeof(func) STATIC_CALL_TRAMP(name);
40 
41 #ifdef CONFIG_HAVE_STATIC_CALL
42 
43 #define __raw_static_call(name)	(&STATIC_CALL_TRAMP(name))
44 
45 #ifdef CONFIG_HAVE_STATIC_CALL_INLINE
46 
47 /*
48  * __ADDRESSABLE() is used to ensure the key symbol doesn't get stripped from
49  * the symbol table so that objtool can reference it when it generates the
50  * .static_call_sites section.
51  */
52 #define __STATIC_CALL_ADDRESSABLE(name) \
53 	__ADDRESSABLE(STATIC_CALL_KEY(name))
54 
55 #define __static_call(name)						\
56 ({									\
57 	__STATIC_CALL_ADDRESSABLE(name);				\
58 	__raw_static_call(name);					\
59 })
60 
61 struct static_call_key {
62 	void *func;
63 	union {
64 		/* bit 0: 0 = mods, 1 = sites */
65 		unsigned long type;
66 		struct static_call_mod *mods;
67 		struct static_call_site *sites;
68 	};
69 };
70 
71 #else /* !CONFIG_HAVE_STATIC_CALL_INLINE */
72 
73 #define __STATIC_CALL_ADDRESSABLE(name)
74 #define __static_call(name)	__raw_static_call(name)
75 
76 struct static_call_key {
77 	void *func;
78 };
79 
80 #endif /* CONFIG_HAVE_STATIC_CALL_INLINE */
81 
82 #ifdef MODULE
83 #define __STATIC_CALL_MOD_ADDRESSABLE(name)
84 #define static_call_mod(name)	__raw_static_call(name)
85 #else
86 #define __STATIC_CALL_MOD_ADDRESSABLE(name) __STATIC_CALL_ADDRESSABLE(name)
87 #define static_call_mod(name)	__static_call(name)
88 #endif
89 
90 #define static_call(name)	__static_call(name)
91 
92 #else
93 
94 struct static_call_key {
95 	void *func;
96 };
97 
98 #define static_call(name)						\
99 	((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
100 
101 #endif /* CONFIG_HAVE_STATIC_CALL */
102 
103 #endif /* _STATIC_CALL_TYPES_H */
104