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#ifndef __ASSEMBLY__
29
30/*
31 * The static call site table needs to be created by external tooling (objtool
32 * or a compiler plugin).
33 */
34struct static_call_site {
35 s32 addr;
36 s32 key;
37};
38
39#define DECLARE_STATIC_CALL(name, func) \
40 extern struct static_call_key STATIC_CALL_KEY(name); \
41 extern typeof(func) STATIC_CALL_TRAMP(name);
42
43#ifdef CONFIG_HAVE_STATIC_CALL
44
45#define __raw_static_call(name) (&STATIC_CALL_TRAMP(name))
46
47#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
48
49/*
50 * __ADDRESSABLE() is used to ensure the key symbol doesn't get stripped from
51 * the symbol table so that objtool can reference it when it generates the
52 * .static_call_sites section.
53 */
54#define __STATIC_CALL_ADDRESSABLE(name) \
55 __ADDRESSABLE(STATIC_CALL_KEY(name))
56
57#define __static_call(name) \
58({ \
59 __STATIC_CALL_ADDRESSABLE(name); \
60 __raw_static_call(name); \
61})
62
63struct static_call_key {
64 void *func;
65 union {
66 /* bit 0: 0 = mods, 1 = sites */
67 unsigned long type;
68 struct static_call_mod *mods;
69 struct static_call_site *sites;
70 };
71};
72
73#else /* !CONFIG_HAVE_STATIC_CALL_INLINE */
74
75#define __STATIC_CALL_ADDRESSABLE(name)
76#define __static_call(name) __raw_static_call(name)
77
78struct static_call_key {
79 void *func;
80};
81
82#endif /* CONFIG_HAVE_STATIC_CALL_INLINE */
83
84#ifdef MODULE
85#define __STATIC_CALL_MOD_ADDRESSABLE(name)
86#define static_call_mod(name) __raw_static_call(name)
87#else
88#define __STATIC_CALL_MOD_ADDRESSABLE(name) __STATIC_CALL_ADDRESSABLE(name)
89#define static_call_mod(name) __static_call(name)
90#endif
91
92#define static_call(name) __static_call(name)
93
94#else
95
96struct static_call_key {
97 void *func;
98};
99
100#define static_call(name) \
101 ((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
102
103#endif /* CONFIG_HAVE_STATIC_CALL */
104
105#endif /* __ASSEMBLY__ */
106
107#endif /* _STATIC_CALL_TYPES_H */
108

source code of linux/include/linux/static_call_types.h