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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#ifndef __ASSEMBLY__
#include <linux/compiler_types.h>
#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__)
/* Optimization barrier *//* The "volatile" is due to gcc bugs */#define barrier() __asm__ __volatile__("": : :"memory")
#ifndef __always_inline# define __always_inline inline __attribute__((always_inline))#endif
#ifndef __always_unused#define __always_unused __attribute__((__unused__))#endif
#ifndef __noreturn#define __noreturn __attribute__((__noreturn__))#endif
#ifndef unreachable#define unreachable() __builtin_unreachable()#endif
#ifndef noinline#define noinline#endif
#ifndef __nocf_check#define __nocf_check __attribute__((nocf_check))#endif
#ifndef __naked#define __naked __attribute__((__naked__))#endif
/* Are two types/vars the same type (ignoring qualifiers)? */#ifndef __same_type# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))#endif
/* * This returns a constant expression while determining if an argument is * a constant expression, most importantly without evaluating the argument. * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de> */#define __is_constexpr(x) \ (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
/* * Similar to statically_true() but produces a constant expression * * To be used in conjunction with macros, such as BUILD_BUG_ON_ZERO(), * which require their input to be a constant expression and for which * statically_true() would otherwise fail. * * This is a trade-off: const_true() requires all its operands to be * compile time constants. Else, it would always returns false even on * the most trivial cases like: * * true || non_const_var * * On the opposite, statically_true() is able to fold more complex * tautologies and will return true on expressions such as: * * !(non_const_var * 8 % 4) * * For the general case, statically_true() is better. */#define const_true(x) __builtin_choose_expr(__is_constexpr(x), x, false)
#ifdef __ANDROID__/* * FIXME: Big hammer to get rid of tons of: * "warning: always_inline function might not be inlinable" * * At least on android-ndk-r12/platforms/android-24/arch-arm */#undef __always_inline#define __always_inline inline#endif
#define __user#define __rcu#define __read_mostly
#ifndef __attribute_const__# define __attribute_const__#endif
#ifndef __maybe_unused# define __maybe_unused __attribute__((unused))#endif
#ifndef __used# define __used __attribute__((__unused__))#endif
#ifndef __packed# define __packed __attribute__((__packed__))#endif
#ifndef __force# define __force#endif
#ifndef __iomem# define __iomem#endif
#ifndef __weak# define __weak __attribute__((weak))#endif
#ifndef likely# define likely(x) __builtin_expect(!!(x), 1)#endif
#ifndef unlikely# define unlikely(x) __builtin_expect(!!(x), 0)#endif
#include <linux/types.h>
/* * Following functions are taken from kernel sources and * break aliasing rules in their original form. * * While kernel is compiled with -fno-strict-aliasing, * perf uses -Wstrict-aliasing=3 which makes build fail * under gcc 4.4. * * Using extra __may_alias__ type to allow aliasing * in this case. */typedef __u8 __attribute__((__may_alias__)) __u8_alias_t;typedef __u16 __attribute__((__may_alias__)) __u16_alias_t;typedef __u32 __attribute__((__may_alias__)) __u32_alias_t;typedef __u64 __attribute__((__may_alias__)) __u64_alias_t;
static __always_inline void __read_once_size(const volatile void *p, void *res, int size){ switch (size) { case 1: *(__u8_alias_t *) res = *(volatile __u8_alias_t *) p; break; case 2: *(__u16_alias_t *) res = *(volatile __u16_alias_t *) p; break; case 4: *(__u32_alias_t *) res = *(volatile __u32_alias_t *) p; break; case 8: *(__u64_alias_t *) res = *(volatile __u64_alias_t *) p; break; default: barrier(); __builtin_memcpy((void *)res, (const void *)p, size); barrier(); }}
static __always_inline void __write_once_size(volatile void *p, void *res, int size){ switch (size) { case 1: *(volatile __u8_alias_t *) p = *(__u8_alias_t *) res; break; case 2: *(volatile __u16_alias_t *) p = *(__u16_alias_t *) res; break; case 4: *(volatile __u32_alias_t *) p = *(__u32_alias_t *) res; break; case 8: *(volatile __u64_alias_t *) p = *(__u64_alias_t *) 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 and print a compile-time warning. * * 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) \({ \ union { typeof(x) __val; char __c[1]; } __u = \ { .__c = { 0 } }; \ __read_once_size(&(x), __u.__c, sizeof(x)); \ __u.__val; \})
#define WRITE_ONCE(x, val) \({ \ union { typeof(x) __val; char __c[1]; } __u = \ { .__val = (val) }; \ __write_once_size(&(x), __u.__c, sizeof(x)); \ __u.__val; \})
/* Indirect macros required for expanded argument pasting, eg. __LINE__. */#define ___PASTE(a, b) a##b#define __PASTE(a, b) ___PASTE(a, b)
#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
#ifndef __BUILD_BUG_ON_ZERO_MSG#if defined(__clang__)#define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)(sizeof(struct { int:(-!!(e)); })))#else#define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))#endif#endif
#endif /* __ASSEMBLY__ */
#endif /* _TOOLS_LINUX_COMPILER_H */