#ifndef _TOOLS_LINUX_COMPILER_H_#define _TOOLS_LINUX_COMPILER_H_ /* 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 #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 #ifndef __attribute_const__# define __attribute_const__#endif #ifndef __maybe_unused# define __maybe_unused		__attribute__((unused))#endif #ifndef __packed# define __packed		__attribute__((__packed__))#endif #ifndef __force# define __force#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 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) #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, WRITE_ONCE and ACCESS_ONCE (see below), 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, * WRITE_ONCE or ACCESS_ONCE() in different C statements. * * In contrast to ACCESS_ONCE 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; __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; }) #endif /* _TOOLS_LINUX_COMPILER_H */