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*)
33instructions F[Barriers]
34
35(* Compute matching pairs of nested Rcu-lock and Rcu-unlock *)
36let matched = let rec
37	    unmatched-locks = Rcu-lock \ domain(matched)
38	and unmatched-unlocks = Rcu-unlock \ range(matched)
39	and unmatched = unmatched-locks | unmatched-unlocks
40	and unmatched-po = [unmatched] ; po ; [unmatched]
41	and unmatched-locks-to-unlocks =
42		[unmatched-locks] ; po ; [unmatched-unlocks]
43	and matched = matched | (unmatched-locks-to-unlocks \
44		(unmatched-po ; unmatched-po))
45	in matched
46
47(* Validate nesting *)
48flag ~empty Rcu-lock \ domain(matched) as unbalanced-rcu-locking
49flag ~empty Rcu-unlock \ range(matched) as unbalanced-rcu-locking
50
51(* Outermost level of nesting only *)
52let crit = matched \ (po^-1 ; matched ; po^-1)
53