include/linux/linkage.h

   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         .size name, .-name
 169 #endif
 170
 171 /* === code annotations === */
 172
 173 /*
 174  * FUNC -- C-like functions (proper stack frame etc.)
 175  * CODE -- non-C code (e.g. irq handlers with different, special stack etc.)
 176  *
 177  * Objtool validates stack for FUNC, but not for CODE.
 178  * Objtool generates debug info for both FUNC & CODE, but needs special
 179  * annotations for each CODE's start (to describe the actual stack frame).
 180  *
 181  * Objtool requires that all code must be contained in an ELF symbol. Symbol
 182  * names that have a  .L prefix do not emit symbol table entries. .L
 183  * prefixed symbols can be used within a code region, but should be avoided for
 184  * denoting a range of code via ``SYM_*_START/END`` annotations.
 185  *
 186  * ALIAS -- does not generate debug info -- the aliased function will
 187  */
 188
 189 /* SYM_INNER_LABEL_ALIGN -- only for labels in the middle of code */
 190 #ifndef SYM_INNER_LABEL_ALIGN
 191 #define SYM_INNER_LABEL_ALIGN(name, linkage)    \
 192         .type name SYM_T_NONE ASM_NL                    \
 193         SYM_ENTRY(name, linkage, SYM_A_ALIGN)
 194 #endif
 195
 196 /* SYM_INNER_LABEL -- only for labels in the middle of code */
 197 #ifndef SYM_INNER_LABEL
 198 #define SYM_INNER_LABEL(name, linkage)          \
 199         .type name SYM_T_NONE ASM_NL                    \
 200         SYM_ENTRY(name, linkage, SYM_A_NONE)
 201 #endif
 202
 203 /*
 204  * SYM_FUNC_START_LOCAL_ALIAS -- use where there are two local names for one
 205  * function
 206  */
 207 #ifndef SYM_FUNC_START_LOCAL_ALIAS
 208 #define SYM_FUNC_START_LOCAL_ALIAS(name)                \
 209         SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)
 210 #endif
 211
 212 /*
 213  * SYM_FUNC_START_ALIAS -- use where there are two global names for one
 214  * function
 215  */
 216 #ifndef SYM_FUNC_START_ALIAS
 217 #define SYM_FUNC_START_ALIAS(name)                      \
 218         SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
 219 #endif
 220
 221 /* SYM_FUNC_START -- use for global functions */
 222 #ifndef SYM_FUNC_START
 223 /*
 224  * The same as SYM_FUNC_START_ALIAS, but we will need to distinguish these two
 225  * later.
 226  */
 227 #define SYM_FUNC_START(name)                            \
 228         SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
 229 #endif
 230
 231 /* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */
 232 #ifndef SYM_FUNC_START_NOALIGN
 233 #define SYM_FUNC_START_NOALIGN(name)                    \
 234         SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
 235 #endif
 236
 237 /* SYM_FUNC_START_LOCAL -- use for local functions */
 238 #ifndef SYM_FUNC_START_LOCAL
 239 /* the same as SYM_FUNC_START_LOCAL_ALIAS, see comment near SYM_FUNC_START */
 240 #define SYM_FUNC_START_LOCAL(name)                      \
 241         SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)
 242 #endif
 243
 244 /* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */
 245 #ifndef SYM_FUNC_START_LOCAL_NOALIGN
 246 #define SYM_FUNC_START_LOCAL_NOALIGN(name)              \
 247         SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
 248 #endif
 249
 250 /* SYM_FUNC_START_WEAK -- use for weak functions */
 251 #ifndef SYM_FUNC_START_WEAK
 252 #define SYM_FUNC_START_WEAK(name)                       \
 253         SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN)
 254 #endif
 255
 256 /* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */
 257 #ifndef SYM_FUNC_START_WEAK_NOALIGN
 258 #define SYM_FUNC_START_WEAK_NOALIGN(name)               \
 259         SYM_START(name, SYM_L_WEAK, SYM_A_NONE)
 260 #endif
 261
 262 /* SYM_FUNC_END_ALIAS -- the end of LOCAL_ALIASed or ALIASed function */
 263 #ifndef SYM_FUNC_END_ALIAS
 264 #define SYM_FUNC_END_ALIAS(name)                        \
 265         SYM_END(name, SYM_T_FUNC)
 266 #endif
 267
 268 /*
 269  * SYM_FUNC_END -- the end of SYM_FUNC_START_LOCAL, SYM_FUNC_START,
 270  * SYM_FUNC_START_WEAK, ...
 271  */
 272 #ifndef SYM_FUNC_END
 273 /* the same as SYM_FUNC_END_ALIAS, see comment near SYM_FUNC_START */
 274 #define SYM_FUNC_END(name)                              \
 275         SYM_END(name, SYM_T_FUNC)
 276 #endif
 277
 278 /* SYM_CODE_START -- use for non-C (special) functions */
 279 #ifndef SYM_CODE_START
 280 #define SYM_CODE_START(name)                            \
 281         SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
 282 #endif
 283
 284 /* SYM_CODE_START_NOALIGN -- use for non-C (special) functions, w/o alignment */
 285 #ifndef SYM_CODE_START_NOALIGN
 286 #define SYM_CODE_START_NOALIGN(name)                    \
 287         SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
 288 #endif
 289
 290 /* SYM_CODE_START_LOCAL -- use for local non-C (special) functions */
 291 #ifndef SYM_CODE_START_LOCAL
 292 #define SYM_CODE_START_LOCAL(name)                      \
 293         SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN)
 294 #endif
 295
 296 /*
 297  * SYM_CODE_START_LOCAL_NOALIGN -- use for local non-C (special) functions,
 298  * w/o alignment
 299  */
 300 #ifndef SYM_CODE_START_LOCAL_NOALIGN
 301 #define SYM_CODE_START_LOCAL_NOALIGN(name)              \
 302         SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
 303 #endif
 304
 305 /* SYM_CODE_END -- the end of SYM_CODE_START_LOCAL, SYM_CODE_START, ... */
 306 #ifndef SYM_CODE_END
 307 #define SYM_CODE_END(name)                              \
 308         SYM_END(name, SYM_T_NONE)
 309 #endif
 310
 311 /* === data annotations === */
 312
 313 /* SYM_DATA_START -- global data symbol */
 314 #ifndef SYM_DATA_START
 315 #define SYM_DATA_START(name)                            \
 316         SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE)
 317 #endif
 318
 319 /* SYM_DATA_START -- local data symbol */
 320 #ifndef SYM_DATA_START_LOCAL
 321 #define SYM_DATA_START_LOCAL(name)                      \
 322         SYM_START(name, SYM_L_LOCAL, SYM_A_NONE)
 323 #endif
 324
 325 /* SYM_DATA_END -- the end of SYM_DATA_START symbol */
 326 #ifndef SYM_DATA_END
 327 #define SYM_DATA_END(name)                              \
 328         SYM_END(name, SYM_T_OBJECT)
 329 #endif
 330
 331 /* SYM_DATA_END_LABEL -- the labeled end of SYM_DATA_START symbol */
 332 #ifndef SYM_DATA_END_LABEL
 333 #define SYM_DATA_END_LABEL(name, linkage, label)        \
 334         linkage(label) ASM_NL                           \
 335         .type label SYM_T_OBJECT ASM_NL                 \
 336         label:                                          \
 337         SYM_END(name, SYM_T_OBJECT)
 338 #endif
 339
 340 /* SYM_DATA -- start+end wrapper around simple global data */
 341 #ifndef SYM_DATA
 342 #define SYM_DATA(name, data...)                         \
 343         SYM_DATA_START(name) ASM_NL                             \
 344         data ASM_NL                                             \
 345         SYM_DATA_END(name)
 346 #endif
 347
 348 /* SYM_DATA_LOCAL -- start+end wrapper around simple local data */
 349 #ifndef SYM_DATA_LOCAL
 350 #define SYM_DATA_LOCAL(name, data...)                   \
 351         SYM_DATA_START_LOCAL(name) ASM_NL                       \
 352         data ASM_NL                                             \
 353         SYM_DATA_END(name)
 354 #endif
 355
 356 #endif /* __ASSEMBLY__ */
 357
 358 #endif /* _LINUX_LINKAGE_H */