/*- * 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. * * $FreeBSD$ */ #ifndef _STDATOMIC_H_ #define _STDATOMIC_H_ #include <sys/cdefs.h> #include <sys/types.h> #include <stdbool.h> #if __has_extension(c_atomic) || __has_extension(cxx_atomic) #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 void atomic_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 void atomic_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 } /* * 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) #define atomic_is_lock_free(obj) \ __atomic_is_lock_free(sizeof(*(obj)), obj) #elif defined(__GNUC_ATOMICS) #define atomic_is_lock_free(obj) \ __atomic_is_lock_free(sizeof((obj)->__val), &(obj)->__val) #else #define atomic_is_lock_free(obj) \ ((void)(obj), sizeof((obj)->__val) <= sizeof(void *)) #endif /* * 7.17.6 Atomic integer types. */ #if !__has_extension(c_atomic) && !__has_extension(cxx_atomic) /* * No native support for _Atomic(). Place object in structure to prevent * most forms of direct non-atomic access. */ #define _Atomic(T) struct { T volatile __val; } #endif 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; typedef _Atomic(char16_t) atomic_char16_t; typedef _Atomic(char32_t) atomic_char32_t; typedef _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)->__val, expected, \ desired, 0, success, failure) #define atomic_compare_exchange_weak_explicit(object, expected, \ desired, success, failure) \ __atomic_compare_exchange_n(&(object)->__val, expected, \ desired, 1, success, failure) #define atomic_exchange_explicit(object, desired, order) \ __atomic_exchange_n(&(object)->__val, desired, order) #define atomic_fetch_add_explicit(object, operand, order) \ __atomic_fetch_add(&(object)->__val, operand, order) #define atomic_fetch_and_explicit(object, operand, order) \ __atomic_fetch_and(&(object)->__val, operand, order) #define atomic_fetch_or_explicit(object, operand, order) \ __atomic_fetch_or(&(object)->__val, operand, order) #define atomic_fetch_sub_explicit(object, operand, order) \ __atomic_fetch_sub(&(object)->__val, operand, order) #define atomic_fetch_xor_explicit(object, operand, order) \ __atomic_fetch_xor(&(object)->__val, operand, order) #define atomic_load_explicit(object, order) \ __atomic_load_n(&(object)->__val, order) #define atomic_store_explicit(object, desired, order) \ __atomic_store_n(&(object)->__val, 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 bool atomic_flag_test_and_set_explicit(volatile atomic_flag *__object, memory_order __order) { return (atomic_exchange_explicit(&__object->__flag, 1, __order)); } static __inline void atomic_flag_clear_explicit(volatile atomic_flag *__object, memory_order __order) { atomic_store_explicit(&__object->__flag, 0, __order); } #ifndef _KERNEL static __inline bool atomic_flag_test_and_set(volatile atomic_flag *__object) { return (atomic_flag_test_and_set_explicit(__object, memory_order_seq_cst)); } static __inline void atomic_flag_clear(volatile atomic_flag *__object) { atomic_flag_clear_explicit(__object, memory_order_seq_cst); } #endif /* !_KERNEL */ #endif /* !_STDATOMIC_H_ */