include/linux/compiler.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __LINUX_COMPILER_H
   3 #define __LINUX_COMPILER_H
   4
   5 #ifndef __ASSEMBLY__
   6
   7 #ifdef __CHECKER__
   8 # define __user         __attribute__((noderef, address_space(1)))
   9 # define __kernel       __attribute__((address_space(0)))
  10 # define __safe         __attribute__((safe))
  11 # define __force        __attribute__((force))
  12 # define __nocast       __attribute__((nocast))
  13 # define __iomem        __attribute__((noderef, address_space(2)))
  14 # define __must_hold(x) __attribute__((context(x,1,1)))
  15 # define __acquires(x)  __attribute__((context(x,0,1)))
  16 # define __releases(x)  __attribute__((context(x,1,0)))
  17 # define __acquire(x)   __context__(x,1)
  18 # define __release(x)   __context__(x,-1)
  19 # define __cond_lock(x,c)       ((c) ? ({ __acquire(x); 1; }) : 0)
  20 # define __percpu       __attribute__((noderef, address_space(3)))
  21 # define __rcu          __attribute__((noderef, address_space(4)))
  22 # define __private      __attribute__((noderef))
  23 extern void __chk_user_ptr(const volatile void __user *);
  24 extern void __chk_io_ptr(const volatile void __iomem *);
  25 # define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(p)->member))
  26 #else /* __CHECKER__ */
  27 # ifdef STRUCTLEAK_PLUGIN
  28 #  define __user __attribute__((user))
  29 # else
  30 #  define __user
  31 # endif
  32 # define __kernel
  33 # define __safe
  34 # define __force
  35 # define __nocast
  36 # define __iomem
  37 # define __chk_user_ptr(x) (void)0
  38 # define __chk_io_ptr(x) (void)0
  39 # define __builtin_warning(x, y...) (1)
  40 # define __must_hold(x)
  41 # define __acquires(x)
  42 # define __releases(x)
  43 # define __acquire(x) (void)0
  44 # define __release(x) (void)0
  45 # define __cond_lock(x,c) (c)
  46 # define __percpu
  47 # define __rcu
  48 # define __private
  49 # define ACCESS_PRIVATE(p, member) ((p)->member)
  50 #endif /* __CHECKER__ */
  51
  52 /* Indirect macros required for expanded argument pasting, eg. __LINE__. */
  53 #define ___PASTE(a,b) a##b
  54 #define __PASTE(a,b) ___PASTE(a,b)
  55
  56 #ifdef __KERNEL__
  57
  58 #ifdef __GNUC__
  59 #include <linux/compiler-gcc.h>
  60 #endif
  61
  62 #if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__)
  63 #define notrace __attribute__((hotpatch(0,0)))
  64 #else
  65 #define notrace __attribute__((no_instrument_function))
  66 #endif
  67
  68 /* Intel compiler defines __GNUC__. So we will overwrite implementations
  69  * coming from above header files here
  70  */
  71 #ifdef __INTEL_COMPILER
  72 # include <linux/compiler-intel.h>
  73 #endif
  74
  75 /* Clang compiler defines __GNUC__. So we will overwrite implementations
  76  * coming from above header files here
  77  */
  78 #ifdef __clang__
  79 #include <linux/compiler-clang.h>
  80 #endif
  81
  82 /*
  83  * Generic compiler-dependent macros required for kernel
  84  * build go below this comment. Actual compiler/compiler version
  85  * specific implementations come from the above header files
  86  */
  87
  88 struct ftrace_branch_data {
  89         const char *func;
  90         const char *file;
  91         unsigned line;
  92         union {
  93                 struct {
  94                         unsigned long correct;
  95                         unsigned long incorrect;
  96                 };
  97                 struct {
  98                         unsigned long miss;
  99                         unsigned long hit;
 100                 };
 101                 unsigned long miss_hit[2];
 102         };
 103 };
 104
 105 struct ftrace_likely_data {
 106         struct ftrace_branch_data       data;
 107         unsigned long                   constant;
 108 };
 109
 110 /*
 111  * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
 112  * to disable branch tracing on a per file basis.
 113  */
 114 #if defined(CONFIG_TRACE_BRANCH_PROFILING) \
 115     && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
 116 void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 117                           int expect, int is_constant);
 118
 119 #define likely_notrace(x)       __builtin_expect(!!(x), 1)
 120 #define unlikely_notrace(x)     __builtin_expect(!!(x), 0)
 121
 122 #define __branch_check__(x, expect, is_constant) ({                     \
 123                         int ______r;                                    \
 124                         static struct ftrace_likely_data                \
 125                                 __attribute__((__aligned__(4)))         \
 126                                 __attribute__((section("_ftrace_annotated_branch"))) \
 127                                 ______f = {                             \
 128                                 .data.func = __func__,                  \
 129                                 .data.file = __FILE__,                  \
 130                                 .data.line = __LINE__,                  \
 131                         };                                              \
 132                         ______r = __builtin_expect(!!(x), expect);      \
 133                         ftrace_likely_update(&______f, ______r,         \
 134                                              expect, is_constant);      \
 135                         ______r;                                        \
 136                 })
 137
 138 /*
 139  * Using __builtin_constant_p(x) to ignore cases where the return
 140  * value is always the same.  This idea is taken from a similar patch
 141  * written by Daniel Walker.
 142  */
 143 # ifndef likely
 144 #  define likely(x)     (__branch_check__(x, 1, __builtin_constant_p(x)))
 145 # endif
 146 # ifndef unlikely
 147 #  define unlikely(x)   (__branch_check__(x, 0, __builtin_constant_p(x)))
 148 # endif
 149
 150 #ifdef CONFIG_PROFILE_ALL_BRANCHES
 151 /*
 152  * "Define 'is'", Bill Clinton
 153  * "Define 'if'", Steven Rostedt
 154  */
 155 #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
 156 #define __trace_if(cond) \
 157         if (__builtin_constant_p(!!(cond)) ? !!(cond) :                 \
 158         ({                                                              \
 159                 int ______r;                                            \
 160                 static struct ftrace_branch_data                        \
 161                         __attribute__((__aligned__(4)))                 \
 162                         __attribute__((section("_ftrace_branch")))      \
 163                         ______f = {                                     \
 164                                 .func = __func__,                       \
 165                                 .file = __FILE__,                       \
 166                                 .line = __LINE__,                       \
 167                         };                                              \
 168                 ______r = !!(cond);                                     \
 169                 ______f.miss_hit[______r]++;                                    \
 170                 ______r;                                                \
 171         }))
 172 #endif /* CONFIG_PROFILE_ALL_BRANCHES */
 173
 174 #else
 175 # define likely(x)      __builtin_expect(!!(x), 1)
 176 # define unlikely(x)    __builtin_expect(!!(x), 0)
 177 #endif
 178
 179 /* Optimization barrier */
 180 #ifndef barrier
 181 # define barrier() __memory_barrier()
 182 #endif
 183
 184 #ifndef barrier_data
 185 # define barrier_data(ptr) barrier()
 186 #endif
 187
 188 /* Unreachable code */
 189 #ifdef CONFIG_STACK_VALIDATION
 190 #define annotate_reachable() ({                                         \
 191         asm("%c0:\n\t"                                                  \
 192             ".pushsection .discard.reachable\n\t"                       \
 193             ".long %c0b - .\n\t"                                        \
 194             ".popsection\n\t" : : "i" (__LINE__));                      \
 195 })
 196 #define annotate_unreachable() ({                                       \
 197         asm("%c0:\n\t"                                                  \
 198             ".pushsection .discard.unreachable\n\t"                     \
 199             ".long %c0b - .\n\t"                                        \
 200             ".popsection\n\t" : : "i" (__LINE__));                      \
 201 })
 202 #define ASM_UNREACHABLE                                                 \
 203         "999:\n\t"                                                      \
 204         ".pushsection .discard.unreachable\n\t"                         \
 205         ".long 999b - .\n\t"                                            \
 206         ".popsection\n\t"
 207 #else
 208 #define annotate_reachable()
 209 #define annotate_unreachable()
 210 #endif
 211
 212 #ifndef ASM_UNREACHABLE
 213 # define ASM_UNREACHABLE
 214 #endif
 215 #ifndef unreachable
 216 # define unreachable() do { annotate_reachable(); do { } while (1); } while (0)
 217 #endif
 218
 219 /*
 220  * KENTRY - kernel entry point
 221  * This can be used to annotate symbols (functions or data) that are used
 222  * without their linker symbol being referenced explicitly. For example,
 223  * interrupt vector handlers, or functions in the kernel image that are found
 224  * programatically.
 225  *
 226  * Not required for symbols exported with EXPORT_SYMBOL, or initcalls. Those
 227  * are handled in their own way (with KEEP() in linker scripts).
 228  *
 229  * KENTRY can be avoided if the symbols in question are marked as KEEP() in the
 230  * linker script. For example an architecture could KEEP() its entire
 231  * boot/exception vector code rather than annotate each function and data.
 232  */
 233 #ifndef KENTRY
 234 # define KENTRY(sym)                                            \
 235         extern typeof(sym) sym;                                 \
 236         static const unsigned long __kentry_##sym               \
 237         __used                                                  \
 238         __attribute__((section("___kentry" "+" #sym ), used))   \
 239         = (unsigned long)&sym;
 240 #endif
 241
 242 #ifndef RELOC_HIDE
 243 # define RELOC_HIDE(ptr, off)                                   \
 244   ({ unsigned long __ptr;                                       \
 245      __ptr = (unsigned long) (ptr);                             \
 246     (typeof(ptr)) (__ptr + (off)); })
 247 #endif
 248
 249 #ifndef OPTIMIZER_HIDE_VAR
 250 #define OPTIMIZER_HIDE_VAR(var) barrier()
 251 #endif
 252
 253 /* Not-quite-unique ID. */
 254 #ifndef __UNIQUE_ID
 255 # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
 256 #endif
 257
 258 #include <uapi/linux/types.h>
 259
 260 #define __READ_ONCE_SIZE                                                \
 261 ({                                                                      \
 262         switch (size) {                                                 \
 263         case 1: *(__u8 *)res = *(volatile __u8 *)p; break;              \
 264         case 2: *(__u16 *)res = *(volatile __u16 *)p; break;            \
 265         case 4: *(__u32 *)res = *(volatile __u32 *)p; break;            \
 266         case 8: *(__u64 *)res = *(volatile __u64 *)p; break;            \
 267         default:                                                        \
 268                 barrier();                                              \
 269                 __builtin_memcpy((void *)res, (const void *)p, size);   \
 270                 barrier();                                              \
 271         }                                                               \
 272 })
 273
 274 static __always_inline
 275 void __read_once_size(const volatile void *p, void *res, int size)
 276 {
 277         __READ_ONCE_SIZE;
 278 }
 279
 280 #ifdef CONFIG_KASAN
 281 /*
 282  * This function is not 'inline' because __no_sanitize_address confilcts
 283  * with inlining. Attempt to inline it may cause a build failure.
 284  *      https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
 285  * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
 286  */
 287 static __no_sanitize_address __maybe_unused
 288 void __read_once_size_nocheck(const volatile void *p, void *res, int size)
 289 {
 290         __READ_ONCE_SIZE;
 291 }
 292 #else
 293 static __always_inline
 294 void __read_once_size_nocheck(const volatile void *p, void *res, int size)
 295 {
 296         __READ_ONCE_SIZE;
 297 }
 298 #endif
 299
 300 static __always_inline void __write_once_size(volatile void *p, void *res, int size)
 301 {
 302         switch (size) {
 303         case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
 304         case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
 305         case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
 306         case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
 307         default:
 308                 barrier();
 309                 __builtin_memcpy((void *)p, (const void *)res, size);
 310                 barrier();
 311         }
 312 }
 313
 314 /*
 315  * Prevent the compiler from merging or refetching reads or writes. The
 316  * compiler is also forbidden from reordering successive instances of
 317  * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
 318  * compiler is aware of some particular ordering.  One way to make the
 319  * compiler aware of ordering is to put the two invocations of READ_ONCE,
 320  * WRITE_ONCE or ACCESS_ONCE() in different C statements.
 321  *
 322  * In contrast to ACCESS_ONCE these two macros will also work on aggregate
 323  * data types like structs or unions. If the size of the accessed data
 324  * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
 325  * READ_ONCE() and WRITE_ONCE() will fall back to memcpy(). There's at
 326  * least two memcpy()s: one for the __builtin_memcpy() and then one for
 327  * the macro doing the copy of variable - '__u' allocated on the stack.
 328  *
 329  * Their two major use cases are: (1) Mediating communication between
 330  * process-level code and irq/NMI handlers, all running on the same CPU,
 331  * and (2) Ensuring that the compiler does not  fold, spindle, or otherwise
 332  * mutilate accesses that either do not require ordering or that interact
 333  * with an explicit memory barrier or atomic instruction that provides the
 334  * required ordering.
 335  */
 336
 337 #define __READ_ONCE(x, check)                                           \
 338 ({                                                                      \
 339         union { typeof(x) __val; char __c[1]; } __u;                    \
 340         if (check)                                                      \
 341                 __read_once_size(&(x), __u.__c, sizeof(x));             \
 342         else                                                            \
 343                 __read_once_size_nocheck(&(x), __u.__c, sizeof(x));     \
 344         __u.__val;                                                      \
 345 })
 346 #define READ_ONCE(x) __READ_ONCE(x, 1)
 347
 348 /*
 349  * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need
 350  * to hide memory access from KASAN.
 351  */
 352 #define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0)
 353
 354 #define WRITE_ONCE(x, val) \
 355 ({                                                      \
 356         union { typeof(x) __val; char __c[1]; } __u =   \
 357                 { .__val = (__force typeof(x)) (val) }; \
 358         __write_once_size(&(x), __u.__c, sizeof(x));    \
 359         __u.__val;                                      \
 360 })
 361
 362 #endif /* __KERNEL__ */
 363
 364 #endif /* __ASSEMBLY__ */
 365
 366 #ifdef __KERNEL__
 367 /*
 368  * Allow us to mark functions as 'deprecated' and have gcc emit a nice
 369  * warning for each use, in hopes of speeding the functions removal.
 370  * Usage is:
 371  *              int __deprecated foo(void)
 372  */
 373 #ifndef __deprecated
 374 # define __deprecated           /* unimplemented */
 375 #endif
 376
 377 #ifdef MODULE
 378 #define __deprecated_for_modules __deprecated
 379 #else
 380 #define __deprecated_for_modules
 381 #endif
 382
 383 #ifndef __must_check
 384 #define __must_check
 385 #endif
 386
 387 #ifndef CONFIG_ENABLE_MUST_CHECK
 388 #undef __must_check
 389 #define __must_check
 390 #endif
 391 #ifndef CONFIG_ENABLE_WARN_DEPRECATED
 392 #undef __deprecated
 393 #undef __deprecated_for_modules
 394 #define __deprecated
 395 #define __deprecated_for_modules
 396 #endif
 397
 398 #ifndef __malloc
 399 #define __malloc
 400 #endif
 401
 402 /*
 403  * Allow us to avoid 'defined but not used' warnings on functions and data,
 404  * as well as force them to be emitted to the assembly file.
 405  *
 406  * As of gcc 3.4, static functions that are not marked with attribute((used))
 407  * may be elided from the assembly file.  As of gcc 3.4, static data not so
 408  * marked will not be elided, but this may change in a future gcc version.
 409  *
 410  * NOTE: Because distributions shipped with a backported unit-at-a-time
 411  * compiler in gcc 3.3, we must define __used to be __attribute__((used))
 412  * for gcc >=3.3 instead of 3.4.
 413  *
 414  * In prior versions of gcc, such functions and data would be emitted, but
 415  * would be warned about except with attribute((unused)).
 416  *
 417  * Mark functions that are referenced only in inline assembly as __used so
 418  * the code is emitted even though it appears to be unreferenced.
 419  */
 420 #ifndef __used
 421 # define __used                 /* unimplemented */
 422 #endif
 423
 424 #ifndef __maybe_unused
 425 # define __maybe_unused         /* unimplemented */
 426 #endif
 427
 428 #ifndef __always_unused
 429 # define __always_unused        /* unimplemented */
 430 #endif
 431
 432 #ifndef noinline
 433 #define noinline
 434 #endif
 435
 436 /*
 437  * Rather then using noinline to prevent stack consumption, use
 438  * noinline_for_stack instead.  For documentation reasons.
 439  */
 440 #define noinline_for_stack noinline
 441
 442 #ifndef __always_inline
 443 #define __always_inline inline
 444 #endif
 445
 446 #endif /* __KERNEL__ */
 447
 448 /*
 449  * From the GCC manual:
 450  *
 451  * Many functions do not examine any values except their arguments,
 452  * and have no effects except the return value.  Basically this is
 453  * just slightly more strict class than the `pure' attribute above,
 454  * since function is not allowed to read global memory.
 455  *
 456  * Note that a function that has pointer arguments and examines the
 457  * data pointed to must _not_ be declared `const'.  Likewise, a
 458  * function that calls a non-`const' function usually must not be
 459  * `const'.  It does not make sense for a `const' function to return
 460  * `void'.
 461  */
 462 #ifndef __attribute_const__
 463 # define __attribute_const__    /* unimplemented */
 464 #endif
 465
 466 #ifndef __designated_init
 467 # define __designated_init
 468 #endif
 469
 470 #ifndef __latent_entropy
 471 # define __latent_entropy
 472 #endif
 473
 474 #ifndef __randomize_layout
 475 # define __randomize_layout __designated_init
 476 #endif
 477
 478 #ifndef __no_randomize_layout
 479 # define __no_randomize_layout
 480 #endif
 481
 482 #ifndef randomized_struct_fields_start
 483 # define randomized_struct_fields_start
 484 # define randomized_struct_fields_end
 485 #endif
 486
 487 /*
 488  * Tell gcc if a function is cold. The compiler will assume any path
 489  * directly leading to the call is unlikely.
 490  */
 491
 492 #ifndef __cold
 493 #define __cold
 494 #endif
 495
 496 /* Simple shorthand for a section definition */
 497 #ifndef __section
 498 # define __section(S) __attribute__ ((__section__(#S)))
 499 #endif
 500
 501 #ifndef __visible
 502 #define __visible
 503 #endif
 504
 505 #ifndef __nostackprotector
 506 # define __nostackprotector
 507 #endif
 508
 509 /*
 510  * Assume alignment of return value.
 511  */
 512 #ifndef __assume_aligned
 513 #define __assume_aligned(a, ...)
 514 #endif
 515
 516
 517 /* Are two types/vars the same type (ignoring qualifiers)? */
 518 #ifndef __same_type
 519 # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 520 #endif
 521
 522 /* Is this type a native word size -- useful for atomic operations */
 523 #ifndef __native_word
 524 # define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
 525 #endif
 526
 527 /* Compile time object size, -1 for unknown */
 528 #ifndef __compiletime_object_size
 529 # define __compiletime_object_size(obj) -1
 530 #endif
 531 #ifndef __compiletime_warning
 532 # define __compiletime_warning(message)
 533 #endif
 534 #ifndef __compiletime_error
 535 # define __compiletime_error(message)
 536 /*
 537  * Sparse complains of variable sized arrays due to the temporary variable in
 538  * __compiletime_assert. Unfortunately we can't just expand it out to make
 539  * sparse see a constant array size without breaking compiletime_assert on old
 540  * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
 541  */
 542 # ifndef __CHECKER__
 543 #  define __compiletime_error_fallback(condition) \
 544         do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
 545 # endif
 546 #endif
 547 #ifndef __compiletime_error_fallback
 548 # define __compiletime_error_fallback(condition) do { } while (0)
 549 #endif
 550
 551 #ifdef __OPTIMIZE__
 552 # define __compiletime_assert(condition, msg, prefix, suffix)           \
 553         do {                                                            \
 554                 bool __cond = !(condition);                             \
 555                 extern void prefix ## suffix(void) __compiletime_error(msg); \
 556                 if (__cond)                                             \
 557                         prefix ## suffix();                             \
 558                 __compiletime_error_fallback(__cond);                   \
 559         } while (0)
 560 #else
 561 # define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)
 562 #endif
 563
 564 #define _compiletime_assert(condition, msg, prefix, suffix) \
 565         __compiletime_assert(condition, msg, prefix, suffix)
 566
 567 /**
 568  * compiletime_assert - break build and emit msg if condition is false
 569  * @condition: a compile-time constant condition to check
 570  * @msg:       a message to emit if condition is false
 571  *
 572  * In tradition of POSIX assert, this macro will break the build if the
 573  * supplied condition is *false*, emitting the supplied error message if the
 574  * compiler has support to do so.
 575  */
 576 #define compiletime_assert(condition, msg) \
 577         _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
 578
 579 #define compiletime_assert_atomic_type(t)                               \
 580         compiletime_assert(__native_word(t),                            \
 581                 "Need native word sized stores/loads for atomicity.")
 582
 583 /*
 584  * Prevent the compiler from merging or refetching accesses.  The compiler
 585  * is also forbidden from reordering successive instances of ACCESS_ONCE(),
 586  * but only when the compiler is aware of some particular ordering.  One way
 587  * to make the compiler aware of ordering is to put the two invocations of
 588  * ACCESS_ONCE() in different C statements.
 589  *
 590  * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
 591  * on a union member will work as long as the size of the member matches the
 592  * size of the union and the size is smaller than word size.
 593  *
 594  * The major use cases of ACCESS_ONCE used to be (1) Mediating communication
 595  * between process-level code and irq/NMI handlers, all running on the same CPU,
 596  * and (2) Ensuring that the compiler does not  fold, spindle, or otherwise
 597  * mutilate accesses that either do not require ordering or that interact
 598  * with an explicit memory barrier or atomic instruction that provides the
 599  * required ordering.
 600  *
 601  * If possible use READ_ONCE()/WRITE_ONCE() instead.
 602  */
 603 #define __ACCESS_ONCE(x) ({ \
 604          __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
 605         (volatile typeof(x) *)&(x); })
 606 #define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
 607
 608 /**
 609  * lockless_dereference() - safely load a pointer for later dereference
 610  * @p: The pointer to load
 611  *
 612  * Similar to rcu_dereference(), but for situations where the pointed-to
 613  * object's lifetime is managed by something other than RCU.  That
 614  * "something other" might be reference counting or simple immortality.
 615  *
 616  * The seemingly unused variable ___typecheck_p validates that @p is
 617  * indeed a pointer type by using a pointer to typeof(*p) as the type.
 618  * Taking a pointer to typeof(*p) again is needed in case p is void *.
 619  */
 620 #define lockless_dereference(p) \
 621 ({ \
 622         typeof(p) _________p1 = READ_ONCE(p); \
 623         typeof(*(p)) *___typecheck_p __maybe_unused; \
 624         smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
 625         (_________p1); \
 626 })
 627
 628 #endif /* __LINUX_COMPILER_H */