1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 // An earlier version of this file appeared 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 appeared in ASPLOS 2018.
7
8 // ONCE
9 READ_ONCE(X) __load{once}(X)
10 WRITE_ONCE(X,V) { __store{once}(X,V); }
11
12 // Release Acquire and friends
13 smp_store_release(X,V) { __store{release}(*X,V); }
14 smp_load_acquire(X) __load{acquire}(*X)
15 rcu_assign_pointer(X,V) { __store{release}(X,V); }
16 rcu_dereference(X) __load{once}(X)
17 smp_store_mb(X,V) { __store{once}(X,V); __fence{mb}; }
18
19 // Fences
20 smp_mb() { __fence{mb}; }
21 smp_rmb() { __fence{rmb}; }
22 smp_wmb() { __fence{wmb}; }
23 smp_mb__before_atomic() { __fence{before-atomic}; }
24 smp_mb__after_atomic() { __fence{after-atomic}; }
25 smp_mb__after_spinlock() { __fence{after-spinlock}; }
26 smp_mb__after_unlock_lock() { __fence{after-unlock-lock}; }
27 smp_mb__after_srcu_read_unlock() { __fence{after-srcu-read-unlock}; }
28 barrier() { __fence{barrier}; }
29
30 // Exchange
31 xchg(X,V) __xchg{mb}(X,V)
32 xchg_relaxed(X,V) __xchg{once}(X,V)
33 xchg_release(X,V) __xchg{release}(X,V)
34 xchg_acquire(X,V) __xchg{acquire}(X,V)
35 cmpxchg(X,V,W) __cmpxchg{mb}(X,V,W)
36 cmpxchg_relaxed(X,V,W) __cmpxchg{once}(X,V,W)
37 cmpxchg_acquire(X,V,W) __cmpxchg{acquire}(X,V,W)
38 cmpxchg_release(X,V,W) __cmpxchg{release}(X,V,W)
39
40 // Spinlocks
41 spin_lock(X) { __lock(X); }
42 spin_unlock(X) { __unlock(X); }
43 spin_trylock(X) __trylock(X)
44 spin_is_locked(X) __islocked(X)
45
46 // RCU
47 rcu_read_lock() { __fence{rcu-lock}; }
48 rcu_read_unlock() { __fence{rcu-unlock}; }
49 synchronize_rcu() { __fence{sync-rcu}; }
50 synchronize_rcu_expedited() { __fence{sync-rcu}; }
51
52 // SRCU
53 srcu_read_lock(X) __load{srcu-lock}(*X)
54 srcu_read_unlock(X,Y) { __store{srcu-unlock}(*X,Y); }
55 srcu_down_read(X) __load{srcu-lock}(*X)
56 srcu_up_read(X,Y) { __store{srcu-unlock}(*X,Y); }
57 synchronize_srcu(X) { __srcu{sync-srcu}(X); }
58 synchronize_srcu_expedited(X) { __srcu{sync-srcu}(X); }
59
60 // Atomic
61 atomic_read(X) READ_ONCE(*X)
62 atomic_set(X,V) { WRITE_ONCE(*X,V); }
63 atomic_read_acquire(X) smp_load_acquire(X)
64 atomic_set_release(X,V) { smp_store_release(X,V); }
65
66 atomic_add(V,X) { __atomic_op(X,+,V); }
67 atomic_sub(V,X) { __atomic_op(X,-,V); }
68 atomic_inc(X) { __atomic_op(X,+,1); }
69 atomic_dec(X) { __atomic_op(X,-,1); }
70
71 atomic_add_return(V,X) __atomic_op_return{mb}(X,+,V)
72 atomic_add_return_relaxed(V,X) __atomic_op_return{once}(X,+,V)
73 atomic_add_return_acquire(V,X) __atomic_op_return{acquire}(X,+,V)
74 atomic_add_return_release(V,X) __atomic_op_return{release}(X,+,V)
75 atomic_fetch_add(V,X) __atomic_fetch_op{mb}(X,+,V)
76 atomic_fetch_add_relaxed(V,X) __atomic_fetch_op{once}(X,+,V)
77 atomic_fetch_add_acquire(V,X) __atomic_fetch_op{acquire}(X,+,V)
78 atomic_fetch_add_release(V,X) __atomic_fetch_op{release}(X,+,V)
79
80 atomic_inc_return(X) __atomic_op_return{mb}(X,+,1)
81 atomic_inc_return_relaxed(X) __atomic_op_return{once}(X,+,1)
82 atomic_inc_return_acquire(X) __atomic_op_return{acquire}(X,+,1)
83 atomic_inc_return_release(X) __atomic_op_return{release}(X,+,1)
84 atomic_fetch_inc(X) __atomic_fetch_op{mb}(X,+,1)
85 atomic_fetch_inc_relaxed(X) __atomic_fetch_op{once}(X,+,1)
86 atomic_fetch_inc_acquire(X) __atomic_fetch_op{acquire}(X,+,1)
87 atomic_fetch_inc_release(X) __atomic_fetch_op{release}(X,+,1)
88
89 atomic_sub_return(V,X) __atomic_op_return{mb}(X,-,V)
90 atomic_sub_return_relaxed(V,X) __atomic_op_return{once}(X,-,V)
91 atomic_sub_return_acquire(V,X) __atomic_op_return{acquire}(X,-,V)
92 atomic_sub_return_release(V,X) __atomic_op_return{release}(X,-,V)
93 atomic_fetch_sub(V,X) __atomic_fetch_op{mb}(X,-,V)
94 atomic_fetch_sub_relaxed(V,X) __atomic_fetch_op{once}(X,-,V)
95 atomic_fetch_sub_acquire(V,X) __atomic_fetch_op{acquire}(X,-,V)
96 atomic_fetch_sub_release(V,X) __atomic_fetch_op{release}(X,-,V)
97
98 atomic_dec_return(X) __atomic_op_return{mb}(X,-,1)
99 atomic_dec_return_relaxed(X) __atomic_op_return{once}(X,-,1)
100 atomic_dec_return_acquire(X) __atomic_op_return{acquire}(X,-,1)
101 atomic_dec_return_release(X) __atomic_op_return{release}(X,-,1)
102 atomic_fetch_dec(X) __atomic_fetch_op{mb}(X,-,1)
103 atomic_fetch_dec_relaxed(X) __atomic_fetch_op{once}(X,-,1)
104 atomic_fetch_dec_acquire(X) __atomic_fetch_op{acquire}(X,-,1)
105 atomic_fetch_dec_release(X) __atomic_fetch_op{release}(X,-,1)
106
107 atomic_xchg(X,V) __xchg{mb}(X,V)
108 atomic_xchg_relaxed(X,V) __xchg{once}(X,V)
109 atomic_xchg_release(X,V) __xchg{release}(X,V)
110 atomic_xchg_acquire(X,V) __xchg{acquire}(X,V)
111 atomic_cmpxchg(X,V,W) __cmpxchg{mb}(X,V,W)
112 atomic_cmpxchg_relaxed(X,V,W) __cmpxchg{once}(X,V,W)
113 atomic_cmpxchg_acquire(X,V,W) __cmpxchg{acquire}(X,V,W)
114 atomic_cmpxchg_release(X,V,W) __cmpxchg{release}(X,V,W)
115
116 atomic_sub_and_test(V,X) __atomic_op_return{mb}(X,-,V) == 0
117 atomic_dec_and_test(X) __atomic_op_return{mb}(X,-,1) == 0
118 atomic_inc_and_test(X) __atomic_op_return{mb}(X,+,1) == 0
119 atomic_add_negative(V,X) __atomic_op_return{mb}(X,+,V) < 0
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