LXR linux/include/linux/compiler

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef __LINUX_COMPILER_TYPES_H
   3#define __LINUX_COMPILER_TYPES_H
   4
   5#ifndef __ASSEMBLY__
   6
   7#ifdef __CHECKER__
   8/* address spaces */
   9# define __kernel       __attribute__((address_space(0)))
  10# define __user         __attribute__((noderef, address_space(__user)))
  11# define __iomem        __attribute__((noderef, address_space(__iomem)))
  12# define __percpu       __attribute__((noderef, address_space(__percpu)))
  13# define __rcu          __attribute__((noderef, address_space(__rcu)))
  14static inline void __chk_user_ptr(const volatile void __user *ptr) { }
  15static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
  16/* context/locking */
  17# define __must_hold(x) __attribute__((context(x,1,1)))
  18# define __acquires(x)  __attribute__((context(x,0,1)))
  19# define __releases(x)  __attribute__((context(x,1,0)))
  20# define __acquire(x)   __context__(x,1)
  21# define __release(x)   __context__(x,-1)
  22# define __cond_lock(x,c)       ((c) ? ({ __acquire(x); 1; }) : 0)
  23/* other */
  24# define __force        __attribute__((force))
  25# define __nocast       __attribute__((nocast))
  26# define __safe         __attribute__((safe))
  27# define __private      __attribute__((noderef))
  28# define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(p)->member))
  29#else /* __CHECKER__ */
  30/* address spaces */
  31# define __kernel
  32# ifdef STRUCTLEAK_PLUGIN
  33#  define __user        __attribute__((user))
  34# else
  35#  define __user
  36# endif
  37# define __iomem
  38# define __percpu
  39# define __rcu
  40# define __chk_user_ptr(x)      (void)0
  41# define __chk_io_ptr(x)        (void)0
  42/* context/locking */
  43# define __must_hold(x)
  44# define __acquires(x)
  45# define __releases(x)
  46# define __acquire(x)   (void)0
  47# define __release(x)   (void)0
  48# define __cond_lock(x,c) (c)
  49/* other */
  50# define __force
  51# define __nocast
  52# define __safe
  53# define __private
  54# define ACCESS_PRIVATE(p, member) ((p)->member)
  55# define __builtin_warning(x, y...) (1)
  56#endif /* __CHECKER__ */
  57
  58/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
  59#define ___PASTE(a,b) a##b
  60#define __PASTE(a,b) ___PASTE(a,b)
  61
  62#ifdef __KERNEL__
  63
  64/* Attributes */
  65#include <linux/compiler_attributes.h>
  66
  67/* Builtins */
  68
  69/*
  70 * __has_builtin is supported on gcc >= 10, clang >= 3 and icc >= 21.
  71 * In the meantime, to support gcc < 10, we implement __has_builtin
  72 * by hand.
  73 */
  74#ifndef __has_builtin
  75#define __has_builtin(x) (0)
  76#endif
  77
  78/* Compiler specific macros. */
  79#ifdef __clang__
  80#include <linux/compiler-clang.h>
  81#elif defined(__INTEL_COMPILER)
  82#include <linux/compiler-intel.h>
  83#elif defined(__GNUC__)
  84/* The above compilers also define __GNUC__, so order is important here. */
  85#include <linux/compiler-gcc.h>
  86#else
  87#error "Unknown compiler"
  88#endif
  89
  90/*
  91 * Some architectures need to provide custom definitions of macros provided
  92 * by linux/compiler-*.h, and can do so using asm/compiler.h. We include that
  93 * conditionally rather than using an asm-generic wrapper in order to avoid
  94 * build failures if any C compilation, which will include this file via an
  95 * -include argument in c_flags, occurs prior to the asm-generic wrappers being
  96 * generated.
  97 */
  98#ifdef CONFIG_HAVE_ARCH_COMPILER_H
  99#include <asm/compiler.h>
 100#endif
 101
 102struct ftrace_branch_data {
 103        const char *func;
 104        const char *file;
 105        unsigned line;
 106        union {
 107                struct {
 108                        unsigned long correct;
 109                        unsigned long incorrect;
 110                };
 111                struct {
 112                        unsigned long miss;
 113                        unsigned long hit;
 114                };
 115                unsigned long miss_hit[2];
 116        };
 117};
 118
 119struct ftrace_likely_data {
 120        struct ftrace_branch_data       data;
 121        unsigned long                   constant;
 122};
 123
 124#if defined(CC_USING_HOTPATCH)
 125#define notrace                 __attribute__((hotpatch(0, 0)))
 126#elif defined(CC_USING_PATCHABLE_FUNCTION_ENTRY)
 127#define notrace                 __attribute__((patchable_function_entry(0, 0)))
 128#else
 129#define notrace                 __attribute__((__no_instrument_function__))
 130#endif
 131
 132/*
 133 * it doesn't make sense on ARM (currently the only user of __naked)
 134 * to trace naked functions because then mcount is called without
 135 * stack and frame pointer being set up and there is no chance to
 136 * restore the lr register to the value before mcount was called.
 137 */
 138#define __naked                 __attribute__((__naked__)) notrace
 139
 140#define __compiler_offsetof(a, b)       __builtin_offsetof(a, b)
 141
 142/*
 143 * Prefer gnu_inline, so that extern inline functions do not emit an
 144 * externally visible function. This makes extern inline behave as per gnu89
 145 * semantics rather than c99. This prevents multiple symbol definition errors
 146 * of extern inline functions at link time.
 147 * A lot of inline functions can cause havoc with function tracing.
 148 */
 149#define inline inline __gnu_inline __inline_maybe_unused notrace
 150
 151/*
 152 * gcc provides both __inline__ and __inline as alternate spellings of
 153 * the inline keyword, though the latter is undocumented. New kernel
 154 * code should only use the inline spelling, but some existing code
 155 * uses __inline__. Since we #define inline above, to ensure
 156 * __inline__ has the same semantics, we need this #define.
 157 *
 158 * However, the spelling __inline is strictly reserved for referring
 159 * to the bare keyword.
 160 */
 161#define __inline__ inline
 162
 163/*
 164 * GCC does not warn about unused static inline functions for -Wunused-function.
 165 * Suppress the warning in clang as well by using __maybe_unused, but enable it
 166 * for W=1 build. This will allow clang to find unused functions. Remove the
 167 * __inline_maybe_unused entirely after fixing most of -Wunused-function warnings.
 168 */
 169#ifdef KBUILD_EXTRA_WARN1
 170#define __inline_maybe_unused
 171#else
 172#define __inline_maybe_unused __maybe_unused
 173#endif
 174
 175/*
 176 * Rather then using noinline to prevent stack consumption, use
 177 * noinline_for_stack instead.  For documentation reasons.
 178 */
 179#define noinline_for_stack noinline
 180
 181/*
 182 * Sanitizer helper attributes: Because using __always_inline and
 183 * __no_sanitize_* conflict, provide helper attributes that will either expand
 184 * to __no_sanitize_* in compilation units where instrumentation is enabled
 185 * (__SANITIZE_*__), or __always_inline in compilation units without
 186 * instrumentation (__SANITIZE_*__ undefined).
 187 */
 188#ifdef __SANITIZE_ADDRESS__
 189/*
 190 * We can't declare function 'inline' because __no_sanitize_address conflicts
 191 * with inlining. Attempt to inline it may cause a build failure.
 192 *     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
 193 * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
 194 */
 195# define __no_kasan_or_inline __no_sanitize_address notrace __maybe_unused
 196# define __no_sanitize_or_inline __no_kasan_or_inline
 197#else
 198# define __no_kasan_or_inline __always_inline
 199#endif
 200
 201#define __no_kcsan __no_sanitize_thread
 202#ifdef __SANITIZE_THREAD__
 203# define __no_sanitize_or_inline __no_kcsan notrace __maybe_unused
 204#endif
 205
 206#ifndef __no_sanitize_or_inline
 207#define __no_sanitize_or_inline __always_inline
 208#endif
 209
 210/* Section for code which can't be instrumented at all */
 211#define noinstr                                                         \
 212        noinline notrace __attribute((__section__(".noinstr.text")))    \
 213        __no_kcsan __no_sanitize_address __no_profile __no_sanitize_coverage
 214
 215#endif /* __KERNEL__ */
 216
 217#endif /* __ASSEMBLY__ */
 218
 219/*
 220 * The below symbols may be defined for one or more, but not ALL, of the above
 221 * compilers. We don't consider that to be an error, so set them to nothing.
 222 * For example, some of them are for compiler specific plugins.
 223 */
 224#ifndef __latent_entropy
 225# define __latent_entropy
 226#endif
 227
 228#ifndef __randomize_layout
 229# define __randomize_layout __designated_init
 230#endif
 231
 232#ifndef __no_randomize_layout
 233# define __no_randomize_layout
 234#endif
 235
 236#ifndef randomized_struct_fields_start
 237# define randomized_struct_fields_start
 238# define randomized_struct_fields_end
 239#endif
 240
 241#ifndef __noscs
 242# define __noscs
 243#endif
 244
 245#ifndef __nocfi
 246# define __nocfi
 247#endif
 248
 249#ifndef __cficanonical
 250# define __cficanonical
 251#endif
 252
 253#ifndef asm_volatile_goto
 254#define asm_volatile_goto(x...) asm goto(x)
 255#endif
 256
 257#ifdef CONFIG_CC_HAS_ASM_INLINE
 258#define asm_inline asm __inline
 259#else
 260#define asm_inline asm
 261#endif
 262
 263/* Are two types/vars the same type (ignoring qualifiers)? */
 264#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 265
 266/*
 267 * __unqual_scalar_typeof(x) - Declare an unqualified scalar type, leaving
 268 *                             non-scalar types unchanged.
 269 */
 270/*
 271 * Prefer C11 _Generic for better compile-times and simpler code. Note: 'char'
 272 * is not type-compatible with 'signed char', and we define a separate case.
 273 */
 274#define __scalar_type_to_expr_cases(type)                               \
 275                unsigned type:  (unsigned type)0,                       \
 276                signed type:    (signed type)0
 277
 278#define __unqual_scalar_typeof(x) typeof(                               \
 279                _Generic((x),                                           \
 280                         char:  (char)0,                                \
 281                         __scalar_type_to_expr_cases(char),             \
 282                         __scalar_type_to_expr_cases(short),            \
 283                         __scalar_type_to_expr_cases(int),              \
 284                         __scalar_type_to_expr_cases(long),             \
 285                         __scalar_type_to_expr_cases(long long),        \
 286                         default: (x)))
 287
 288/* Is this type a native word size -- useful for atomic operations */
 289#define __native_word(t) \
 290        (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \
 291         sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
 292
 293/* Compile time object size, -1 for unknown */
 294#ifndef __compiletime_object_size
 295# define __compiletime_object_size(obj) -1
 296#endif
 297
 298#ifdef __OPTIMIZE__
 299# define __compiletime_assert(condition, msg, prefix, suffix)           \
 300        do {                                                            \
 301                extern void prefix ## suffix(void) __compiletime_error(msg); \
 302                if (!(condition))                                       \
 303                        prefix ## suffix();                             \
 304        } while (0)
 305#else
 306# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)
 307#endif
 308
 309#define _compiletime_assert(condition, msg, prefix, suffix) \
 310        __compiletime_assert(condition, msg, prefix, suffix)
 311
 312/**
 313 * compiletime_assert - break build and emit msg if condition is false
 314 * @condition: a compile-time constant condition to check
 315 * @msg:       a message to emit if condition is false
 316 *
 317 * In tradition of POSIX assert, this macro will break the build if the
 318 * supplied condition is *false*, emitting the supplied error message if the
 319 * compiler has support to do so.
 320 */
 321#define compiletime_assert(condition, msg) \
 322        _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
 323
 324#define compiletime_assert_atomic_type(t)                               \
 325        compiletime_assert(__native_word(t),                            \
 326                "Need native word sized stores/loads for atomicity.")
 327
 328/* Helpers for emitting diagnostics in pragmas. */
 329#ifndef __diag
 330#define __diag(string)
 331#endif
 332
 333#ifndef __diag_GCC
 334#define __diag_GCC(version, severity, string)
 335#endif
 336
 337#define __diag_push()   __diag(push)
 338#define __diag_pop()    __diag(pop)
 339
 340#define __diag_ignore(compiler, version, option, comment) \
 341        __diag_ ## compiler(version, ignore, option)
 342#define __diag_warn(compiler, version, option, comment) \
 343        __diag_ ## compiler(version, warn, option)
 344#define __diag_error(compiler, version, option, comment) \
 345        __diag_ ## compiler(version, error, option)
 346
 347#endif /* __LINUX_COMPILER_TYPES_H */
 348