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/*
* Copyright (c) 2018 Richard Braun.
* Copyright (c) 2017 Agustina Arzille.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*
* Type-generic memory-model aware atomic operations.
*
* For portability reasons, this interface restricts atomic operation
* sizes to 32-bit and 64-bit.
*
* Some configurations may not support 64-bit operations. Check if the
* ATOMIC_HAVE_64B_OPS macro is defined to find out.
*
* TODO Replace mentions of "memory barriers" throughout the code with
* C11 memory model terminology.
*/
#ifndef KERN_ATOMIC_H
#define KERN_ATOMIC_H
#include <stdbool.h>
#include <machine/atomic.h>
/*
* Supported memory orders.
*/
#define ATOMIC_RELAXED __ATOMIC_RELAXED
#define ATOMIC_CONSUME __ATOMIC_CONSUME
#define ATOMIC_ACQUIRE __ATOMIC_ACQUIRE
#define ATOMIC_RELEASE __ATOMIC_RELEASE
#define ATOMIC_ACQ_REL __ATOMIC_ACQ_REL
#define ATOMIC_SEQ_CST __ATOMIC_SEQ_CST
#include <kern/atomic_i.h>
#define atomic_load(ptr, memorder) \
((typeof(*(ptr)))atomic_select(ptr, load)(ptr, memorder))
#define atomic_store(ptr, val, memorder) \
atomic_select(ptr, store)(ptr, val, memorder)
/*
* For compare-and-swap, deviate a little from the standard, and only
* return the value before the comparison, leaving it up to the user to
* determine whether the swap was actually performed or not.
*
* Also, note that the memory order in case of failure is relaxed. This is
* because atomic CAS is typically used in a loop. However, if a different
* code path is taken on failure (rather than retrying), then the user
* should be aware that a memory fence might be necessary.
*/
#define atomic_cas(ptr, oval, nval, memorder) \
((typeof(*(ptr)))atomic_select(ptr, cas)(ptr, oval, nval, memorder))
#define atomic_swap(ptr, val, memorder) \
((typeof(*(ptr)))atomic_select(ptr, swap)(ptr, val, memorder))
#define atomic_fetch_add(ptr, val, memorder) \
((typeof(*(ptr)))atomic_select(ptr, fetch_add)(ptr, val, memorder))
#define atomic_fetch_sub(ptr, val, memorder) \
((typeof(*(ptr)))atomic_select(ptr, fetch_sub)(ptr, val, memorder))
#define atomic_fetch_and(ptr, val, memorder) \
((typeof(*(ptr)))atomic_select(ptr, fetch_and)(ptr, val, memorder))
#define atomic_fetch_or(ptr, val, memorder) \
((typeof(*(ptr)))atomic_select(ptr, fetch_or)(ptr, val, memorder))
#define atomic_fetch_xor(ptr, val, memorder) \
((typeof(*(ptr)))atomic_select(ptr, fetch_xor)(ptr, val, memorder))
#define atomic_add(ptr, val, memorder) \
atomic_select(ptr, add)(ptr, val, memorder)
#define atomic_sub(ptr, val, memorder) \
atomic_select(ptr, sub)(ptr, val, memorder)
#define atomic_and(ptr, val, memorder) \
atomic_select(ptr, and)(ptr, val, memorder)
#define atomic_or(ptr, val, memorder) \
atomic_select(ptr, or)(ptr, val, memorder)
#define atomic_xor(ptr, val, memorder) \
atomic_select(ptr, xor)(ptr, val, memorder)
#define atomic_fence(memorder) __atomic_thread_fence(memorder)
#endif /* KERN_ATOMIC_H */
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