1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_LINKAGE_H
3#define _LINUX_LINKAGE_H
4
5#include <linux/compiler_types.h>
6#include <linux/stringify.h>
7#include <linux/export.h>
8#include <asm/linkage.h>
9
10/* Some toolchains use other characters (e.g. '`') to mark new line in macro */
11#ifndef ASM_NL
12#define ASM_NL ;
13#endif
14
15#ifdef __cplusplus
16#define CPP_ASMLINKAGE extern "C"
17#else
18#define CPP_ASMLINKAGE
19#endif
20
21#ifndef asmlinkage
22#define asmlinkage CPP_ASMLINKAGE
23#endif
24
25#ifndef cond_syscall
26#define cond_syscall(x) asm( \
27 ".weak " __stringify(x) "\n\t" \
28 ".set " __stringify(x) "," \
29 __stringify(sys_ni_syscall))
30#endif
31
32#ifndef SYSCALL_ALIAS
33#define SYSCALL_ALIAS(alias, name) asm( \
34 ".globl " __stringify(alias) "\n\t" \
35 ".set " __stringify(alias) "," \
36 __stringify(name))
37#endif
38
39#define __page_aligned_data __section(".data..page_aligned") __aligned(PAGE_SIZE)
40#define __page_aligned_bss __section(".bss..page_aligned") __aligned(PAGE_SIZE)
41
42/*
43 * For assembly routines.
44 *
45 * Note when using these that you must specify the appropriate
46 * alignment directives yourself
47 */
48#define __PAGE_ALIGNED_DATA .section ".data..page_aligned", "aw"
49#define __PAGE_ALIGNED_BSS .section ".bss..page_aligned", "aw"
50
51/*
52 * This is used by architectures to keep arguments on the stack
53 * untouched by the compiler by keeping them live until the end.
54 * The argument stack may be owned by the assembly-language
55 * caller, not the callee, and gcc doesn't always understand
56 * that.
57 *
58 * We have the return value, and a maximum of six arguments.
59 *
60 * This should always be followed by a "return ret" for the
61 * protection to work (ie no more work that the compiler might
62 * end up needing stack temporaries for).
63 */
64/* Assembly files may be compiled with -traditional .. */
65#ifndef __ASSEMBLY__
66#ifndef asmlinkage_protect
67# define asmlinkage_protect(n, ret, args...) do { } while (0)
68#endif
69#endif
70
71#ifndef __ALIGN
72#define __ALIGN .align 4,0x90
73#define __ALIGN_STR ".align 4,0x90"
74#endif
75
76#ifdef __ASSEMBLY__
77
78/* SYM_T_FUNC -- type used by assembler to mark functions */
79#ifndef SYM_T_FUNC
80#define SYM_T_FUNC STT_FUNC
81#endif
82
83/* SYM_T_OBJECT -- type used by assembler to mark data */
84#ifndef SYM_T_OBJECT
85#define SYM_T_OBJECT STT_OBJECT
86#endif
87
88/* SYM_T_NONE -- type used by assembler to mark entries of unknown type */
89#ifndef SYM_T_NONE
90#define SYM_T_NONE STT_NOTYPE
91#endif
92
93/* SYM_A_* -- align the symbol? */
94#define SYM_A_ALIGN ALIGN
95#define SYM_A_NONE /* nothing */
96
97/* SYM_L_* -- linkage of symbols */
98#define SYM_L_GLOBAL(name) .globl name
99#define SYM_L_WEAK(name) .weak name
100#define SYM_L_LOCAL(name) /* nothing */
101
102#ifndef LINKER_SCRIPT
103#define ALIGN __ALIGN
104#define ALIGN_STR __ALIGN_STR
105
106/* === DEPRECATED annotations === */
107
108#ifndef CONFIG_ARCH_USE_SYM_ANNOTATIONS
109#ifndef GLOBAL
110/* deprecated, use SYM_DATA*, SYM_ENTRY, or similar */
111#define GLOBAL(name) \
112 .globl name ASM_NL \
113 name:
114#endif
115
116#ifndef ENTRY
117/* deprecated, use SYM_FUNC_START */
118#define ENTRY(name) \
119 SYM_FUNC_START(name)
120#endif
121#endif /* CONFIG_ARCH_USE_SYM_ANNOTATIONS */
122#endif /* LINKER_SCRIPT */
123
124#ifndef CONFIG_ARCH_USE_SYM_ANNOTATIONS
125#ifndef WEAK
126/* deprecated, use SYM_FUNC_START_WEAK* */
127#define WEAK(name) \
128 SYM_FUNC_START_WEAK(name)
129#endif
130
131#ifndef END
132/* deprecated, use SYM_FUNC_END, SYM_DATA_END, or SYM_END */
133#define END(name) \
134 .size name, .-name
135#endif
136
137/* If symbol 'name' is treated as a subroutine (gets called, and returns)
138 * then please use ENDPROC to mark 'name' as STT_FUNC for the benefit of
139 * static analysis tools such as stack depth analyzer.
140 */
141#ifndef ENDPROC
142/* deprecated, use SYM_FUNC_END */
143#define ENDPROC(name) \
144 SYM_FUNC_END(name)
145#endif
146#endif /* CONFIG_ARCH_USE_SYM_ANNOTATIONS */
147
148/* === generic annotations === */
149
150/* SYM_ENTRY -- use only if you have to for non-paired symbols */
151#ifndef SYM_ENTRY
152#define SYM_ENTRY(name, linkage, align...) \
153 linkage(name) ASM_NL \
154 align ASM_NL \
155 name:
156#endif
157
158/* SYM_START -- use only if you have to */
159#ifndef SYM_START
160#define SYM_START(name, linkage, align...) \
161 SYM_ENTRY(name, linkage, align)
162#endif
163
164/* SYM_END -- use only if you have to */
165#ifndef SYM_END
166#define SYM_END(name, sym_type) \
167 .type name sym_type ASM_NL \
168 .set .L__sym_size_##name, .-name ASM_NL \
169 .size name, .L__sym_size_##name
170#endif
171
172/* SYM_ALIAS -- use only if you have to */
173#ifndef SYM_ALIAS
174#define SYM_ALIAS(alias, name, linkage) \
175 linkage(alias) ASM_NL \
176 .set alias, name ASM_NL
177#endif
178
179/* === code annotations === */
180
181/*
182 * FUNC -- C-like functions (proper stack frame etc.)
183 * CODE -- non-C code (e.g. irq handlers with different, special stack etc.)
184 *
185 * Objtool validates stack for FUNC, but not for CODE.
186 * Objtool generates debug info for both FUNC & CODE, but needs special
187 * annotations for each CODE's start (to describe the actual stack frame).
188 *
189 * Objtool requires that all code must be contained in an ELF symbol. Symbol
190 * names that have a .L prefix do not emit symbol table entries. .L
191 * prefixed symbols can be used within a code region, but should be avoided for
192 * denoting a range of code via ``SYM_*_START/END`` annotations.
193 *
194 * ALIAS -- does not generate debug info -- the aliased function will
195 */
196
197/* SYM_INNER_LABEL_ALIGN -- only for labels in the middle of code */
198#ifndef SYM_INNER_LABEL_ALIGN
199#define SYM_INNER_LABEL_ALIGN(name, linkage) \
200 .type name SYM_T_NONE ASM_NL \
201 SYM_ENTRY(name, linkage, SYM_A_ALIGN)
202#endif
203
204/* SYM_INNER_LABEL -- only for labels in the middle of code */
205#ifndef SYM_INNER_LABEL
206#define SYM_INNER_LABEL(name, linkage) \
207 .type name SYM_T_NONE ASM_NL \
208 SYM_ENTRY(name, linkage, SYM_A_NONE)
209#endif
210
211/* SYM_FUNC_START -- use for global functions */
212#ifndef SYM_FUNC_START
213#define SYM_FUNC_START(name) \
214 SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
215#endif
216
217/* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */
218#ifndef SYM_FUNC_START_NOALIGN
219#define SYM_FUNC_START_NOALIGN(name) \
220 SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
221#endif
222
223/* SYM_FUNC_START_LOCAL -- use for local functions */
224#ifndef SYM_FUNC_START_LOCAL
225#define SYM_FUNC_START_LOCAL(name) \
226 SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)
227#endif
228
229/* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */
230#ifndef SYM_FUNC_START_LOCAL_NOALIGN
231#define SYM_FUNC_START_LOCAL_NOALIGN(name) \
232 SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
233#endif
234
235/* SYM_FUNC_START_WEAK -- use for weak functions */
236#ifndef SYM_FUNC_START_WEAK
237#define SYM_FUNC_START_WEAK(name) \
238 SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN)
239#endif
240
241/* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */
242#ifndef SYM_FUNC_START_WEAK_NOALIGN
243#define SYM_FUNC_START_WEAK_NOALIGN(name) \
244 SYM_START(name, SYM_L_WEAK, SYM_A_NONE)
245#endif
246
247/*
248 * SYM_FUNC_END -- the end of SYM_FUNC_START_LOCAL, SYM_FUNC_START,
249 * SYM_FUNC_START_WEAK, ...
250 */
251#ifndef SYM_FUNC_END
252#define SYM_FUNC_END(name) \
253 SYM_END(name, SYM_T_FUNC)
254#endif
255
256/*
257 * SYM_FUNC_ALIAS -- define a global alias for an existing function
258 */
259#ifndef SYM_FUNC_ALIAS
260#define SYM_FUNC_ALIAS(alias, name) \
261 SYM_ALIAS(alias, name, SYM_L_GLOBAL)
262#endif
263
264/*
265 * SYM_FUNC_ALIAS_LOCAL -- define a local alias for an existing function
266 */
267#ifndef SYM_FUNC_ALIAS_LOCAL
268#define SYM_FUNC_ALIAS_LOCAL(alias, name) \
269 SYM_ALIAS(alias, name, SYM_L_LOCAL)
270#endif
271
272/*
273 * SYM_FUNC_ALIAS_WEAK -- define a weak global alias for an existing function
274 */
275#ifndef SYM_FUNC_ALIAS_WEAK
276#define SYM_FUNC_ALIAS_WEAK(alias, name) \
277 SYM_ALIAS(alias, name, SYM_L_WEAK)
278#endif
279
280/* SYM_CODE_START -- use for non-C (special) functions */
281#ifndef SYM_CODE_START
282#define SYM_CODE_START(name) \
283 SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
284#endif
285
286/* SYM_CODE_START_NOALIGN -- use for non-C (special) functions, w/o alignment */
287#ifndef SYM_CODE_START_NOALIGN
288#define SYM_CODE_START_NOALIGN(name) \
289 SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
290#endif
291
292/* SYM_CODE_START_LOCAL -- use for local non-C (special) functions */
293#ifndef SYM_CODE_START_LOCAL
294#define SYM_CODE_START_LOCAL(name) \
295 SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)
296#endif
297
298/*
299 * SYM_CODE_START_LOCAL_NOALIGN -- use for local non-C (special) functions,
300 * w/o alignment
301 */
302#ifndef SYM_CODE_START_LOCAL_NOALIGN
303#define SYM_CODE_START_LOCAL_NOALIGN(name) \
304 SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
305#endif
306
307/* SYM_CODE_END -- the end of SYM_CODE_START_LOCAL, SYM_CODE_START, ... */
308#ifndef SYM_CODE_END
309#define SYM_CODE_END(name) \
310 SYM_END(name, SYM_T_NONE)
311#endif
312
313/* === data annotations === */
314
315/* SYM_DATA_START -- global data symbol */
316#ifndef SYM_DATA_START
317#define SYM_DATA_START(name) \
318 SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
319#endif
320
321/* SYM_DATA_START -- local data symbol */
322#ifndef SYM_DATA_START_LOCAL
323#define SYM_DATA_START_LOCAL(name) \
324 SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
325#endif
326
327/* SYM_DATA_END -- the end of SYM_DATA_START symbol */
328#ifndef SYM_DATA_END
329#define SYM_DATA_END(name) \
330 SYM_END(name, SYM_T_OBJECT)
331#endif
332
333/* SYM_DATA_END_LABEL -- the labeled end of SYM_DATA_START symbol */
334#ifndef SYM_DATA_END_LABEL
335#define SYM_DATA_END_LABEL(name, linkage, label) \
336 linkage(label) ASM_NL \
337 .type label SYM_T_OBJECT ASM_NL \
338 label: \
339 SYM_END(name, SYM_T_OBJECT)
340#endif
341
342/* SYM_DATA -- start+end wrapper around simple global data */
343#ifndef SYM_DATA
344#define SYM_DATA(name, data...) \
345 SYM_DATA_START(name) ASM_NL \
346 data ASM_NL \
347 SYM_DATA_END(name)
348#endif
349
350/* SYM_DATA_LOCAL -- start+end wrapper around simple local data */
351#ifndef SYM_DATA_LOCAL
352#define SYM_DATA_LOCAL(name, data...) \
353 SYM_DATA_START_LOCAL(name) ASM_NL \
354 data ASM_NL \
355 SYM_DATA_END(name)
356#endif
357
358#endif /* __ASSEMBLY__ */
359
360#endif /* _LINUX_LINKAGE_H */
361

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