1// SPDX-License-Identifier: GPL-2.0+
2//
3// An earlier version of this file appears in the companion webpage for
4// "Frightening small children and disconcerting grown-ups: Concurrency
5// in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern,
6// which is to appear in ASPLOS 2018.
7
8// ONCE
9READ_ONCE(X) __load{once}(X)
10WRITE_ONCE(X,V) { __store{once}(X,V); }
11
12// Release Acquire and friends
13smp_store_release(X,V) { __store{release}(*X,V); }
14smp_load_acquire(X) __load{acquire}(*X)
15rcu_assign_pointer(X,V) { __store{release}(X,V); }
16rcu_dereference(X) __load{once}(X)
17smp_store_mb(X,V) { __store{once}(X,V); __fence{mb}; }
18
19// Fences
20smp_mb() { __fence{mb} ; }
21smp_rmb() { __fence{rmb} ; }
22smp_wmb() { __fence{wmb} ; }
23smp_mb__before_atomic() { __fence{before-atomic} ; }
24smp_mb__after_atomic() { __fence{after-atomic} ; }
25smp_mb__after_spinlock() { __fence{after-spinlock} ; }
26
27// Exchange
28xchg(X,V)  __xchg{mb}(X,V)
29xchg_relaxed(X,V) __xchg{once}(X,V)
30xchg_release(X,V) __xchg{release}(X,V)
31xchg_acquire(X,V) __xchg{acquire}(X,V)
32cmpxchg(X,V,W) __cmpxchg{mb}(X,V,W)
33cmpxchg_relaxed(X,V,W) __cmpxchg{once}(X,V,W)
34cmpxchg_acquire(X,V,W) __cmpxchg{acquire}(X,V,W)
35cmpxchg_release(X,V,W) __cmpxchg{release}(X,V,W)
36
37// Spinlocks
38spin_lock(X) { __lock(X) ; }
39spin_unlock(X) { __unlock(X) ; }
40spin_trylock(X) __trylock(X)
41
42// RCU
43rcu_read_lock() { __fence{rcu-lock}; }
44rcu_read_unlock() { __fence{rcu-unlock};}
45synchronize_rcu() { __fence{sync-rcu}; }
46synchronize_rcu_expedited() { __fence{sync-rcu}; }
47
48// Atomic
49atomic_read(X) READ_ONCE(*X)
50atomic_set(X,V) { WRITE_ONCE(*X,V) ; }
51atomic_read_acquire(X) smp_load_acquire(X)
52atomic_set_release(X,V) { smp_store_release(X,V); }
53
54atomic_add(V,X) { __atomic_op(X,+,V) ; }
55atomic_sub(V,X) { __atomic_op(X,-,V) ; }
56atomic_inc(X)   { __atomic_op(X,+,1) ; }
57atomic_dec(X)   { __atomic_op(X,-,1) ; }
58
59atomic_add_return(V,X) __atomic_op_return{mb}(X,+,V)
60atomic_add_return_relaxed(V,X) __atomic_op_return{once}(X,+,V)
61atomic_add_return_acquire(V,X) __atomic_op_return{acquire}(X,+,V)
62atomic_add_return_release(V,X) __atomic_op_return{release}(X,+,V)
63atomic_fetch_add(V,X) __atomic_fetch_op{mb}(X,+,V)
64atomic_fetch_add_relaxed(V,X) __atomic_fetch_op{once}(X,+,V)
65atomic_fetch_add_acquire(V,X) __atomic_fetch_op{acquire}(X,+,V)
66atomic_fetch_add_release(V,X) __atomic_fetch_op{release}(X,+,V)
67
68atomic_inc_return(X) __atomic_op_return{mb}(X,+,1)
69atomic_inc_return_relaxed(X) __atomic_op_return{once}(X,+,1)
70atomic_inc_return_acquire(X) __atomic_op_return{acquire}(X,+,1)
71atomic_inc_return_release(X) __atomic_op_return{release}(X,+,1)
72atomic_fetch_inc(X) __atomic_fetch_op{mb}(X,+,1)
73atomic_fetch_inc_relaxed(X) __atomic_fetch_op{once}(X,+,1)
74atomic_fetch_inc_acquire(X) __atomic_fetch_op{acquire}(X,+,1)
75atomic_fetch_inc_release(X) __atomic_fetch_op{release}(X,+,1)
76
77atomic_sub_return(V,X) __atomic_op_return{mb}(X,-,V)
78atomic_sub_return_relaxed(V,X) __atomic_op_return{once}(X,-,V)
79atomic_sub_return_acquire(V,X) __atomic_op_return{acquire}(X,-,V)
80atomic_sub_return_release(V,X) __atomic_op_return{release}(X,-,V)
81atomic_fetch_sub(V,X) __atomic_fetch_op{mb}(X,-,V)
82atomic_fetch_sub_relaxed(V,X) __atomic_fetch_op{once}(X,-,V)
83atomic_fetch_sub_acquire(V,X) __atomic_fetch_op{acquire}(X,-,V)
84atomic_fetch_sub_release(V,X) __atomic_fetch_op{release}(X,-,V)
85
86atomic_dec_return(X) __atomic_op_return{mb}(X,-,1)
87atomic_dec_return_relaxed(X) __atomic_op_return{once}(X,-,1)
88atomic_dec_return_acquire(X) __atomic_op_return{acquire}(X,-,1)
89atomic_dec_return_release(X) __atomic_op_return{release}(X,-,1)
90atomic_fetch_dec(X) __atomic_fetch_op{mb}(X,-,1)
91atomic_fetch_dec_relaxed(X) __atomic_fetch_op{once}(X,-,1)
92atomic_fetch_dec_acquire(X) __atomic_fetch_op{acquire}(X,-,1)
93atomic_fetch_dec_release(X) __atomic_fetch_op{release}(X,-,1)
94
95atomic_xchg(X,V) __xchg{mb}(X,V)
96atomic_xchg_relaxed(X,V) __xchg{once}(X,V)
97atomic_xchg_release(X,V) __xchg{release}(X,V)
98atomic_xchg_acquire(X,V) __xchg{acquire}(X,V)
99atomic_cmpxchg(X,V,W) __cmpxchg{mb}(X,V,W)
100atomic_cmpxchg_relaxed(X,V,W) __cmpxchg{once}(X,V,W)
101atomic_cmpxchg_acquire(X,V,W) __cmpxchg{acquire}(X,V,W)
102atomic_cmpxchg_release(X,V,W) __cmpxchg{release}(X,V,W)
103
104atomic_sub_and_test(V,X) __atomic_op_return{mb}(X,-,V) == 0
105atomic_dec_and_test(X)  __atomic_op_return{mb}(X,-,1) == 0
106atomic_inc_and_test(X)  __atomic_op_return{mb}(X,+,1) == 0
107atomic_add_negative(V,X) __atomic_op_return{mb}(X,+,V) < 0
108