/src/u-boot/include/linux/compiler.h

Source
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_COMPILER_H
#define __LINUX_COMPILER_H

#include <linux/compiler_types.h>

#ifndef __ASSEMBLY__

#ifdef __KERNEL__

/*
 * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
 * to disable branch tracing on a per file basis.
 */
#if defined(CONFIG_TRACE_BRANCH_PROFILING) \
    && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
void ftrace_likely_update(struct ftrace_likely_data *f, int val,
        int expect, int is_constant);

#define likely_notrace(x) __builtin_expect(!!(x), 1)
#define unlikely_notrace(x) __builtin_expect(!!(x), 0)

#define __branch_check__(x, expect, is_constant) ({     \
      long ______r;         \
      static struct ftrace_likely_data    \
        __aligned(4)        \
        __section("_ftrace_annotated_branch") \
        ______f = {       \
        .data.func = __func__,      \
        .data.file = __FILE__,      \
        .data.line = __LINE__,      \
      };            \
      ______r = __builtin_expect(!!(x), expect);  \
      ftrace_likely_update(&______f, ______r,   \
               expect, is_constant);  \
      ______r;          \
    })

/*
 * Using __builtin_constant_p(x) to ignore cases where the return
 * value is always the same.  This idea is taken from a similar patch
 * written by Daniel Walker.
 */
# ifndef likely
#  define likely(x) (__branch_check__(x, 1, __builtin_constant_p(x)))
# endif
# ifndef unlikely
#  define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
# endif

#ifdef CONFIG_PROFILE_ALL_BRANCHES
/*
 * "Define 'is'", Bill Clinton
 * "Define 'if'", Steven Rostedt
 */
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )

#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))

#define __trace_if_value(cond) ({     \
  static struct ftrace_branch_data    \
    __aligned(4)        \
    __section("_ftrace_branch")   \
    __if_trace = {        \
      .func = __func__,   \
      .file = __FILE__,   \
      .line = __LINE__,   \
    };          \
  (cond) ?          \
    (__if_trace.miss_hit[1]++,1) :    \
    (__if_trace.miss_hit[0]++,0);   \
})

#endif /* CONFIG_PROFILE_ALL_BRANCHES */

#else
# define likely(x)  __builtin_expect(!!(x), 1)
# define unlikely(x)  __builtin_expect(!!(x), 0)
#endif

/* Optimization barrier */
#ifndef barrier
# define barrier() __memory_barrier()
#endif

#ifndef barrier_data
# define barrier_data(ptr) barrier()
#endif

/* workaround for GCC PR82365 if needed */
#ifndef barrier_before_unreachable
# define barrier_before_unreachable() do { } while (0)
#endif

/* Unreachable code */
#ifdef CONFIG_STACK_VALIDATION
/*
 * These macros help objtool understand GCC code flow for unreachable code.
 * The __COUNTER__ based labels are a hack to make each instance of the macros
 * unique, to convince GCC not to merge duplicate inline asm statements.
 */
#define annotate_reachable() ({           \
  asm volatile("%c0:\n\t"           \
         ".pushsection .discard.reachable\n\t"    \
         ".long %c0b - .\n\t"       \
         ".popsection\n\t" : : "i" (__COUNTER__));    \
})
#define annotate_unreachable() ({         \
  asm volatile("%c0:\n\t"           \
         ".pushsection .discard.unreachable\n\t"    \
         ".long %c0b - .\n\t"       \
         ".popsection\n\t" : : "i" (__COUNTER__));    \
})
#define ASM_UNREACHABLE             \
  "999:\n\t"              \
  ".pushsection .discard.unreachable\n\t"       \
  ".long 999b - .\n\t"            \
  ".popsection\n\t"

/* Annotate a C jump table to allow objtool to follow the code flow */
#define __annotate_jump_table __section(".rodata..c_jump_table")

#else
#define annotate_reachable()
#define annotate_unreachable()
#define __annotate_jump_table
#endif

#ifndef ASM_UNREACHABLE
# define ASM_UNREACHABLE
#endif
#ifndef unreachable
# define unreachable() do {   \
  annotate_unreachable();   \
  __builtin_unreachable();  \
} while (0)
#endif

/*
 * KENTRY - kernel entry point
 * This can be used to annotate symbols (functions or data) that are used
 * without their linker symbol being referenced explicitly. For example,
 * interrupt vector handlers, or functions in the kernel image that are found
 * programatically.
 *
 * Not required for symbols exported with EXPORT_SYMBOL, or initcalls. Those
 * are handled in their own way (with KEEP() in linker scripts).
 *
 * KENTRY can be avoided if the symbols in question are marked as KEEP() in the
 * linker script. For example an architecture could KEEP() its entire
 * boot/exception vector code rather than annotate each function and data.
 */
#ifndef KENTRY
# define KENTRY(sym)            \
  extern typeof(sym) sym;         \
  static const unsigned long __kentry_##sym   \
  __used              \
  __section("___kentry" "+" #sym )      \
  = (unsigned long)&sym;
#endif

#ifndef RELOC_HIDE
# define RELOC_HIDE(ptr, off)         \
  ({ unsigned long __ptr;         \
     __ptr = (unsigned long) (ptr);       \
    (typeof(ptr)) (__ptr + (off)); })
#endif

#ifndef OPTIMIZER_HIDE_VAR
/* Make the optimizer believe the variable can be manipulated arbitrarily. */
#define OPTIMIZER_HIDE_VAR(var)           \
  __asm__ ("" : "=r" (var) : "0" (var))
#endif

/* Not-quite-unique ID. */
#ifndef __UNIQUE_ID
# define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
#endif

#include <linux/types.h>

#define __READ_ONCE_SIZE            \
({                  \
  switch (size) {             \
  case 1: *(__u8 *)res = *(volatile __u8 *)p; break;   \
  case 2: *(__u16 *)res = *(volatile __u16 *)p; break;   \
  case 4: *(__u32 *)res = *(volatile __u32 *)p; break;   \
  case 8: *(__u64 *)res = *(volatile __u64 *)p; break;   \
  default:              \
    barrier();           \
    __builtin_memcpy((void *)res, (const void *)p, size); \
    barrier();           \
  }               \
})

static __always_inline
void __read_once_size(const volatile void *p, void *res, int size)
{
  __READ_ONCE_SIZE;
}

#ifdef CONFIG_KASAN
/*
 * We can't declare function 'inline' because __no_sanitize_address confilcts
 * with inlining. Attempt to inline it may cause a build failure.
 *  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
 * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
 */
# define __no_kasan_or_inline __no_sanitize_address notrace __maybe_unused
#else
# define __no_kasan_or_inline __always_inline
#endif

static __no_kasan_or_inline
void __read_once_size_nocheck(const volatile void *p, void *res, int size)
{
  __READ_ONCE_SIZE;
}

static __always_inline void __write_once_size(volatile void *p, void *res, int size)
{
  switch (size) {
  case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
  case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
  case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
  case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
  default:
    barrier();
    __builtin_memcpy((void *)p, (const void *)res, size);
    barrier();
  }
}

/*
 * Prevent the compiler from merging or refetching reads or writes. The
 * compiler is also forbidden from reordering successive instances of
 * READ_ONCE and WRITE_ONCE, but only when the compiler is aware of some
 * particular ordering. One way to make the compiler aware of ordering is to
 * put the two invocations of READ_ONCE or WRITE_ONCE in different C
 * statements.
 *
 * These two macros will also work on aggregate data types like structs or
 * unions. If the size of the accessed data type exceeds the word size of
 * the machine (e.g., 32 bits or 64 bits) READ_ONCE() and WRITE_ONCE() will
 * fall back to memcpy(). There's at least two memcpy()s: one for the
 * __builtin_memcpy() and then one for the macro doing the copy of variable
 * - '__u' allocated on the stack.
 *
 * Their two major use cases are: (1) Mediating communication between
 * process-level code and irq/NMI handlers, all running on the same CPU,
 * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
 * mutilate accesses that either do not require ordering or that interact
 * with an explicit memory barrier or atomic instruction that provides the
 * required ordering.
 */

#define __READ_ONCE(x, check)           \
({                  \
  union { typeof(x) __val; char __c[1]; } __u;      \
  if (check)             \
    __read_once_size(&(x), __u.__c, sizeof(x));   \
  else                \
    __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \
  __u.__val;              \
})
#define READ_ONCE(x) __READ_ONCE(x, 1)

/*
 * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need
 * to hide memory access from KASAN.
 */
#define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0)

static __no_kasan_or_inline
unsigned long read_word_at_a_time(const void *addr)
{
  return *(unsigned long *)addr;
}

#define WRITE_ONCE(x, val) \
({              \
  union { typeof(x) __val; char __c[1]; } __u = \
    { .__val = (__force typeof(x)) (val) }; \
  __write_once_size(&(x), __u.__c, sizeof(x));  \
  __u.__val;          \
})

#endif /* __KERNEL__ */

/*
 * Force the compiler to emit 'sym' as a symbol, so that we can reference
 * it from inline assembler. Necessary in case 'sym' could be inlined
 * otherwise, or eliminated entirely due to lack of references that are
 * visible to the compiler.
 */
#define __ADDRESSABLE(sym) \
  static void * __section(".discard.addressable") __used \
    __UNIQUE_ID(__PASTE(__addressable_,sym)) = (void *)&sym;

/**
 * offset_to_ptr - convert a relative memory offset to an absolute pointer
 * @off:  the address of the 32-bit offset value
 */
static inline void *offset_to_ptr(const int *off)
{
  return (void *)((unsigned long)off + *off);
}

#endif /* __ASSEMBLY__ */

/* Compile time object size, -1 for unknown */
#ifndef __compiletime_object_size
# define __compiletime_object_size(obj) -1
#endif
#ifndef __compiletime_warning
# define __compiletime_warning(message)
#endif
#ifndef __compiletime_error
# define __compiletime_error(message)
#endif

#ifdef __OPTIMIZE__
# define __compiletime_assert(condition, msg, prefix, suffix)   \
  do {               \
    extern void prefix ## suffix(void) __compiletime_error(msg); \
    if (!(condition))          \
      prefix ## suffix();       \
  } while (0)
#else
# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)
#endif

#define _compiletime_assert(condition, msg, prefix, suffix) \
  __compiletime_assert(condition, msg, prefix, suffix)

/**
 * compiletime_assert - break build and emit msg if condition is false
 * @condition: a compile-time constant condition to check
 * @msg:       a message to emit if condition is false
 *
 * In tradition of POSIX assert, this macro will break the build if the
 * supplied condition is *false*, emitting the supplied error message if the
 * compiler has support to do so.
 */
#define compiletime_assert(condition, msg) \
  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)

#define compiletime_assert_atomic_type(t)       \
  compiletime_assert(__native_word(t),        \
    "Need native word sized stores/loads for atomicity.")

/* &a[0] degrades to a pointer: a different type from an array */
#define __must_be_array(a)  BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))

#endif /* __LINUX_COMPILER_H */

Coverage Report

Created: 2026-03-11 06:21

Line	Count	Source
1		/* SPDX-License-Identifier: GPL-2.0 */
2		#ifndef __LINUX_COMPILER_H
3		#define __LINUX_COMPILER_H
4
5		#include <linux/compiler_types.h>
6
7		#ifndef __ASSEMBLY__
8
9		#ifdef __KERNEL__
10
11		/*
12		* Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
13		* to disable branch tracing on a per file basis.
14		*/
15		#if defined(CONFIG_TRACE_BRANCH_PROFILING) \
16		&& !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
17		void ftrace_likely_update(struct ftrace_likely_data *f, int val,
18		int expect, int is_constant);
19
20		#define likely_notrace(x) __builtin_expect(!!(x), 1)
21		#define unlikely_notrace(x) __builtin_expect(!!(x), 0)
22
23		#define __branch_check__(x, expect, is_constant) ({ \
24		long ______r; \
25		static struct ftrace_likely_data \
26		__aligned(4) \
27		__section("_ftrace_annotated_branch") \
28		______f = { \
29		.data.func = __func__, \
30		.data.file = __FILE__, \
31		.data.line = __LINE__, \
32		}; \
33		______r = __builtin_expect(!!(x), expect); \
34		ftrace_likely_update(&______f, ______r, \
35		expect, is_constant); \
36		______r; \
37		})
38
39		/*