LXR linux/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 */
 359