1// SPDX-License-Identifier: GPL-2.0+
2(*
3 * Copyright (C) 2015 Jade Alglave <j.alglave@ucl.ac.uk>,
4 * Copyright (C) 2016 Luc Maranget <luc.maranget@inria.fr> for Inria
5 * Copyright (C) 2017 Alan Stern <stern@rowland.harvard.edu>,
6 *                    Andrea Parri <parri.andrea@gmail.com>
7 *
8 * An earlier version of this file appeared in the companion webpage for
9 * "Frightening small children and disconcerting grown-ups: Concurrency
10 * in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern,
11 * which appeared in ASPLOS 2018.
12 *)
13
14"Linux-kernel memory consistency model"
15
16enum Accesses = 'once (*READ_ONCE,WRITE_ONCE*) ||
17		'release (*smp_store_release*) ||
18		'acquire (*smp_load_acquire*) ||
19		'noreturn (* R of non-return RMW *)
20instructions R[{'once,'acquire,'noreturn}]
21instructions W[{'once,'release}]
22instructions RMW[{'once,'acquire,'release}]
23
24enum Barriers = 'wmb (*smp_wmb*) ||
25		'rmb (*smp_rmb*) ||
26		'mb (*smp_mb*) ||
27		'rcu-lock (*rcu_read_lock*)  ||
28		'rcu-unlock (*rcu_read_unlock*) ||
29		'sync-rcu (*synchronize_rcu*) ||
30		'before-atomic (*smp_mb__before_atomic*) ||
31		'after-atomic (*smp_mb__after_atomic*) ||
32		'after-spinlock (*smp_mb__after_spinlock*) ||
33		'after-unlock-lock (*smp_mb__after_unlock_lock*)
34instructions F[Barriers]
35
36(* SRCU *)
37enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu
38instructions SRCU[SRCU]
39(* All srcu events *)
40let Srcu = Srcu-lock | Srcu-unlock | Sync-srcu
41
42(* Compute matching pairs of nested Rcu-lock and Rcu-unlock *)
43let rcu-rscs = let rec
44	    unmatched-locks = Rcu-lock \ domain(matched)
45	and unmatched-unlocks = Rcu-unlock \ range(matched)
46	and unmatched = unmatched-locks | unmatched-unlocks
47	and unmatched-po = [unmatched] ; po ; [unmatched]
48	and unmatched-locks-to-unlocks =
49		[unmatched-locks] ; po ; [unmatched-unlocks]
50	and matched = matched | (unmatched-locks-to-unlocks \
51		(unmatched-po ; unmatched-po))
52	in matched
53
54(* Validate nesting *)
55flag ~empty Rcu-lock \ domain(rcu-rscs) as unbalanced-rcu-locking
56flag ~empty Rcu-unlock \ range(rcu-rscs) as unbalanced-rcu-locking
57
58(* Compute matching pairs of nested Srcu-lock and Srcu-unlock *)
59let srcu-rscs = let rec
60	    unmatched-locks = Srcu-lock \ domain(matched)
61	and unmatched-unlocks = Srcu-unlock \ range(matched)
62	and unmatched = unmatched-locks | unmatched-unlocks
63	and unmatched-po = ([unmatched] ; po ; [unmatched]) & loc
64	and unmatched-locks-to-unlocks =
65		([unmatched-locks] ; po ; [unmatched-unlocks]) & loc
66	and matched = matched | (unmatched-locks-to-unlocks \
67		(unmatched-po ; unmatched-po))
68	in matched
69
70(* Validate nesting *)
71flag ~empty Srcu-lock \ domain(srcu-rscs) as unbalanced-srcu-locking
72flag ~empty Srcu-unlock \ range(srcu-rscs) as unbalanced-srcu-locking
73
74(* Check for use of synchronize_srcu() inside an RCU critical section *)
75flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep
76
77(* Validate SRCU dynamic match *)
78flag ~empty different-values(srcu-rscs) as srcu-bad-nesting
79