/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2011 Ed Schouten <ed@FreeBSD.org> *                    David Chisnall <theraven@FreeBSD.org> * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in the *    documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef _STDATOMIC_H_#define	_STDATOMIC_H_ #include <sys/cdefs.h>#include <sys/_types.h> #if (__has_extension(c_atomic) || __has_extension(cxx_atomic)) && \    defined(__clang__)#define	__CLANG_ATOMICS#elif __GNUC_PREREQ__(4, 7)#define	__GNUC_ATOMICS#elif defined(__GNUC__)#define	__SYNC_ATOMICS#else#error "stdatomic.h does not support your compiler"#endif /* * 7.17.1 Atomic lock-free macros. */ #ifdef __GCC_ATOMIC_BOOL_LOCK_FREE#define	ATOMIC_BOOL_LOCK_FREE		__GCC_ATOMIC_BOOL_LOCK_FREE#endif#ifdef __GCC_ATOMIC_CHAR_LOCK_FREE#define	ATOMIC_CHAR_LOCK_FREE		__GCC_ATOMIC_CHAR_LOCK_FREE#endif#ifdef __GCC_ATOMIC_CHAR16_T_LOCK_FREE#define	ATOMIC_CHAR16_T_LOCK_FREE	__GCC_ATOMIC_CHAR16_T_LOCK_FREE#endif#ifdef __GCC_ATOMIC_CHAR32_T_LOCK_FREE#define	ATOMIC_CHAR32_T_LOCK_FREE	__GCC_ATOMIC_CHAR32_T_LOCK_FREE#endif#ifdef __GCC_ATOMIC_WCHAR_T_LOCK_FREE#define	ATOMIC_WCHAR_T_LOCK_FREE	__GCC_ATOMIC_WCHAR_T_LOCK_FREE#endif#ifdef __GCC_ATOMIC_SHORT_LOCK_FREE#define	ATOMIC_SHORT_LOCK_FREE		__GCC_ATOMIC_SHORT_LOCK_FREE#endif#ifdef __GCC_ATOMIC_INT_LOCK_FREE#define	ATOMIC_INT_LOCK_FREE		__GCC_ATOMIC_INT_LOCK_FREE#endif#ifdef __GCC_ATOMIC_LONG_LOCK_FREE#define	ATOMIC_LONG_LOCK_FREE		__GCC_ATOMIC_LONG_LOCK_FREE#endif#ifdef __GCC_ATOMIC_LLONG_LOCK_FREE#define	ATOMIC_LLONG_LOCK_FREE		__GCC_ATOMIC_LLONG_LOCK_FREE#endif#ifdef __GCC_ATOMIC_POINTER_LOCK_FREE#define	ATOMIC_POINTER_LOCK_FREE	__GCC_ATOMIC_POINTER_LOCK_FREE#endif /* * 7.17.2 Initialization. */ #if defined(__CLANG_ATOMICS)#define	ATOMIC_VAR_INIT(value)		(value)#define	atomic_init(obj, value)		__c11_atomic_init(obj, value)#else#define	ATOMIC_VAR_INIT(value)		{ .__val = (value) }#define	atomic_init(obj, value)		((void)((obj)->__val = (value)))#endif /* * Clang and recent GCC both provide predefined macros for the memory * orderings.  If we are using a compiler that doesn't define them, use the * clang values - these will be ignored in the fallback path. */ #ifndef __ATOMIC_RELAXED#define __ATOMIC_RELAXED		0#endif#ifndef __ATOMIC_CONSUME#define __ATOMIC_CONSUME		1#endif#ifndef __ATOMIC_ACQUIRE#define __ATOMIC_ACQUIRE		2#endif#ifndef __ATOMIC_RELEASE#define __ATOMIC_RELEASE		3#endif#ifndef __ATOMIC_ACQ_REL#define __ATOMIC_ACQ_REL		4#endif#ifndef __ATOMIC_SEQ_CST#define __ATOMIC_SEQ_CST		5#endif /* * 7.17.3 Order and consistency. * * The memory_order_* constants that denote the barrier behaviour of the * atomic operations. */ typedef enum {	memory_order_relaxed = __ATOMIC_RELAXED,	memory_order_consume = __ATOMIC_CONSUME,	memory_order_acquire = __ATOMIC_ACQUIRE,	memory_order_release = __ATOMIC_RELEASE,	memory_order_acq_rel = __ATOMIC_ACQ_REL,	memory_order_seq_cst = __ATOMIC_SEQ_CST} memory_order; /* * 7.17.4 Fences. */ static __inline voidatomic_thread_fence(memory_order __order __unused){ #ifdef __CLANG_ATOMICS	__c11_atomic_thread_fence(__order);#elif defined(__GNUC_ATOMICS)	__atomic_thread_fence(__order);#else	__sync_synchronize();#endif} static __inline voidatomic_signal_fence(memory_order __order __unused){ #ifdef __CLANG_ATOMICS	__c11_atomic_signal_fence(__order);#elif defined(__GNUC_ATOMICS)	__atomic_signal_fence(__order);#else	__asm volatile ("" ::: "memory");#endif} #if defined(__cplusplus) && !defined(_Bool)#define	_Bool	bool#define	__bool_locally_defined#endif /* * 7.17.5 Lock-free property. */ #if defined(_KERNEL)/* Atomics in kernelspace are always lock-free. */#define	atomic_is_lock_free(obj) \	((void)(obj), (_Bool)1)#elif defined(__CLANG_ATOMICS) || defined(__GNUC_ATOMICS)#define	atomic_is_lock_free(obj) \	__atomic_is_lock_free(sizeof(*(obj)), obj)#else#define	atomic_is_lock_free(obj) \	((void)(obj), sizeof((obj)->__val) <= sizeof(void *))#endif /* * 7.17.6 Atomic integer types. */ typedef _Atomic(_Bool)			atomic_bool;typedef _Atomic(char)			atomic_char;typedef _Atomic(signed char)		atomic_schar;typedef _Atomic(unsigned char)		atomic_uchar;typedef _Atomic(short)			atomic_short;typedef _Atomic(unsigned short)		atomic_ushort;typedef _Atomic(int)			atomic_int;typedef _Atomic(unsigned int)		atomic_uint;typedef _Atomic(long)			atomic_long;typedef _Atomic(unsigned long)		atomic_ulong;typedef _Atomic(long long)		atomic_llong;typedef _Atomic(unsigned long long)	atomic_ullong;#if 0typedef _Atomic(__char16_t)		atomic_char16_t;typedef _Atomic(__char32_t)		atomic_char32_t;#endiftypedef _Atomic(wchar_t)		atomic_wchar_t;typedef _Atomic(int_least8_t)		atomic_int_least8_t;typedef _Atomic(uint_least8_t)		atomic_uint_least8_t;typedef _Atomic(int_least16_t)		atomic_int_least16_t;typedef _Atomic(uint_least16_t)		atomic_uint_least16_t;typedef _Atomic(int_least32_t)		atomic_int_least32_t;typedef _Atomic(uint_least32_t)		atomic_uint_least32_t;typedef _Atomic(int_least64_t)		atomic_int_least64_t;typedef _Atomic(uint_least64_t)		atomic_uint_least64_t;typedef _Atomic(int_fast8_t)		atomic_int_fast8_t;typedef _Atomic(uint_fast8_t)		atomic_uint_fast8_t;typedef _Atomic(int_fast16_t)		atomic_int_fast16_t;typedef _Atomic(uint_fast16_t)		atomic_uint_fast16_t;typedef _Atomic(int_fast32_t)		atomic_int_fast32_t;typedef _Atomic(uint_fast32_t)		atomic_uint_fast32_t;typedef _Atomic(int_fast64_t)		atomic_int_fast64_t;typedef _Atomic(uint_fast64_t)		atomic_uint_fast64_t;typedef _Atomic(intptr_t)		atomic_intptr_t;typedef _Atomic(uintptr_t)		atomic_uintptr_t;typedef _Atomic(size_t)			atomic_size_t;typedef _Atomic(ptrdiff_t)		atomic_ptrdiff_t;typedef _Atomic(intmax_t)		atomic_intmax_t;typedef _Atomic(uintmax_t)		atomic_uintmax_t; /* * 7.17.7 Operations on atomic types. */ /* * Compiler-specific operations. */ #if defined(__CLANG_ATOMICS)#define	atomic_compare_exchange_strong_explicit(object, expected,	\    desired, success, failure)						\	__c11_atomic_compare_exchange_strong(object, expected, desired,	\	    success, failure)#define	atomic_compare_exchange_weak_explicit(object, expected,		\    desired, success, failure)						\	__c11_atomic_compare_exchange_weak(object, expected, desired,	\	    success, failure)#define	atomic_exchange_explicit(object, desired, order)		\	__c11_atomic_exchange(object, desired, order)#define	atomic_fetch_add_explicit(object, operand, order)		\	__c11_atomic_fetch_add(object, operand, order)#define	atomic_fetch_and_explicit(object, operand, order)		\	__c11_atomic_fetch_and(object, operand, order)#define	atomic_fetch_or_explicit(object, operand, order)		\	__c11_atomic_fetch_or(object, operand, order)#define	atomic_fetch_sub_explicit(object, operand, order)		\	__c11_atomic_fetch_sub(object, operand, order)#define	atomic_fetch_xor_explicit(object, operand, order)		\	__c11_atomic_fetch_xor(object, operand, order)#define	atomic_load_explicit(object, order)				\	__c11_atomic_load(object, order)#define	atomic_store_explicit(object, desired, order)			\	__c11_atomic_store(object, desired, order)#elif defined(__GNUC_ATOMICS)#define	atomic_compare_exchange_strong_explicit(object, expected,	\    desired, success, failure)						\	__atomic_compare_exchange_n(object, expected,			\	    desired, 0, success, failure)#define	atomic_compare_exchange_weak_explicit(object, expected,		\    desired, success, failure)						\	__atomic_compare_exchange_n(object, expected,			\	    desired, 1, success, failure)#define	atomic_exchange_explicit(object, desired, order)		\	__atomic_exchange_n(object, desired, order)#define	atomic_fetch_add_explicit(object, operand, order)		\	__atomic_fetch_add(object, operand, order)#define	atomic_fetch_and_explicit(object, operand, order)		\	__atomic_fetch_and(object, operand, order)#define	atomic_fetch_or_explicit(object, operand, order)		\	__atomic_fetch_or(object, operand, order)#define	atomic_fetch_sub_explicit(object, operand, order)		\	__atomic_fetch_sub(object, operand, order)#define	atomic_fetch_xor_explicit(object, operand, order)		\	__atomic_fetch_xor(object, operand, order)#define	atomic_load_explicit(object, order)				\	__atomic_load_n(object, order)#define	atomic_store_explicit(object, desired, order)			\	__atomic_store_n(object, desired, order)#else#define	__atomic_apply_stride(object, operand) \	(((__typeof__((object)->__val))0) + (operand))#define	atomic_compare_exchange_strong_explicit(object, expected,	\    desired, success, failure)	__extension__ ({			\	__typeof__(expected) __ep = (expected);				\	__typeof__(*__ep) __e = *__ep;					\	(void)(success); (void)(failure);				\	(_Bool)((*__ep = __sync_val_compare_and_swap(&(object)->__val,	\	    __e, desired)) == __e);					\})#define	atomic_compare_exchange_weak_explicit(object, expected,		\    desired, success, failure)						\	atomic_compare_exchange_strong_explicit(object, expected,	\		desired, success, failure)#if __has_builtin(__sync_swap)/* Clang provides a full-barrier atomic exchange - use it if available. */#define	atomic_exchange_explicit(object, desired, order)		\	((void)(order), __sync_swap(&(object)->__val, desired))#else/* * __sync_lock_test_and_set() is only an acquire barrier in theory (although in * practice it is usually a full barrier) so we need an explicit barrier before * it. */#define	atomic_exchange_explicit(object, desired, order)		\__extension__ ({							\	__typeof__(object) __o = (object);				\	__typeof__(desired) __d = (desired);				\	(void)(order);							\	__sync_synchronize();						\	__sync_lock_test_and_set(&(__o)->__val, __d);			\})#endif#define	atomic_fetch_add_explicit(object, operand, order)		\	((void)(order), __sync_fetch_and_add(&(object)->__val,		\	    __atomic_apply_stride(object, operand)))#define	atomic_fetch_and_explicit(object, operand, order)		\	((void)(order), __sync_fetch_and_and(&(object)->__val, operand))#define	atomic_fetch_or_explicit(object, operand, order)		\	((void)(order), __sync_fetch_and_or(&(object)->__val, operand))#define	atomic_fetch_sub_explicit(object, operand, order)		\	((void)(order), __sync_fetch_and_sub(&(object)->__val,		\	    __atomic_apply_stride(object, operand)))#define	atomic_fetch_xor_explicit(object, operand, order)		\	((void)(order), __sync_fetch_and_xor(&(object)->__val, operand))#define	atomic_load_explicit(object, order)				\	((void)(order), __sync_fetch_and_add(&(object)->__val, 0))#define	atomic_store_explicit(object, desired, order)			\	((void)atomic_exchange_explicit(object, desired, order))#endif /* * Convenience functions. * * Don't provide these in kernel space. In kernel space, we should be * disciplined enough to always provide explicit barriers. */ #ifndef _KERNEL#define	atomic_compare_exchange_strong(object, expected, desired)	\	atomic_compare_exchange_strong_explicit(object, expected,	\	    desired, memory_order_seq_cst, memory_order_seq_cst)#define	atomic_compare_exchange_weak(object, expected, desired)		\	atomic_compare_exchange_weak_explicit(object, expected,		\	    desired, memory_order_seq_cst, memory_order_seq_cst)#define	atomic_exchange(object, desired)				\	atomic_exchange_explicit(object, desired, memory_order_seq_cst)#define	atomic_fetch_add(object, operand)				\	atomic_fetch_add_explicit(object, operand, memory_order_seq_cst)#define	atomic_fetch_and(object, operand)				\	atomic_fetch_and_explicit(object, operand, memory_order_seq_cst)#define	atomic_fetch_or(object, operand)				\	atomic_fetch_or_explicit(object, operand, memory_order_seq_cst)#define	atomic_fetch_sub(object, operand)				\	atomic_fetch_sub_explicit(object, operand, memory_order_seq_cst)#define	atomic_fetch_xor(object, operand)				\	atomic_fetch_xor_explicit(object, operand, memory_order_seq_cst)#define	atomic_load(object)						\	atomic_load_explicit(object, memory_order_seq_cst)#define	atomic_store(object, desired)					\	atomic_store_explicit(object, desired, memory_order_seq_cst)#endif /* !_KERNEL */ /* * 7.17.8 Atomic flag type and operations. * * XXX: Assume atomic_bool can be used as an atomic_flag. Is there some * kind of compiler built-in type we could use? */ typedef struct {	atomic_bool	__flag;} atomic_flag;#define	ATOMIC_FLAG_INIT		{ ATOMIC_VAR_INIT(0) } static __inline _Boolatomic_flag_test_and_set_explicit(volatile atomic_flag *__object,    memory_order __order){	return (atomic_exchange_explicit(&__object->__flag, 1, __order));} static __inline voidatomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order){ 	atomic_store_explicit(&__object->__flag, 0, __order);} #ifndef _KERNELstatic __inline _Boolatomic_flag_test_and_set(volatile atomic_flag *__object){ 	return (atomic_flag_test_and_set_explicit(__object,	    memory_order_seq_cst));} static __inline voidatomic_flag_clear(volatile atomic_flag *__object){ 	atomic_flag_clear_explicit(__object, memory_order_seq_cst);}#endif /* !_KERNEL */ #ifdef __bool_locally_defined#undef _Bool#undef __bool_locally_defined#endif #endif /* !_STDATOMIC_H_ */