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