1 // SPDX-License-Identifier: GPL-2.0+ 1 // SPDX-License-Identifier: GPL-2.0+
2 (* 2 (*
3 * Copyright (C) 2015 Jade Alglave <j.alglave@u 3 * Copyright (C) 2015 Jade Alglave <j.alglave@ucl.ac.uk>,
4 * Copyright (C) 2016 Luc Maranget <luc.marange 4 * Copyright (C) 2016 Luc Maranget <luc.maranget@inria.fr> for Inria
5 * Copyright (C) 2017 Alan Stern <stern@rowland 5 * Copyright (C) 2017 Alan Stern <stern@rowland.harvard.edu>,
6 * Andrea Parri <parri.andre 6 * Andrea Parri <parri.andrea@gmail.com>
7 * 7 *
8 * An earlier version of this file appeared in 8 * An earlier version of this file appeared in the companion webpage for
9 * "Frightening small children and disconcerti 9 * "Frightening small children and disconcerting grown-ups: Concurrency
10 * in the Linux kernel" by Alglave, Maranget, 10 * in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern,
11 * which appeared in ASPLOS 2018. 11 * which appeared in ASPLOS 2018.
12 *) 12 *)
13 13
14 "Linux-kernel memory consistency model" 14 "Linux-kernel memory consistency model"
15 15
16 enum Accesses = 'once (*READ_ONCE,WRITE_ONCE*) !! 16 enum Accesses = 'once (*READ_ONCE,WRITE_ONCE,ACCESS_ONCE*) ||
17 'release (*smp_store_release*) 17 'release (*smp_store_release*) ||
18 'acquire (*smp_load_acquire*) 18 'acquire (*smp_load_acquire*) ||
19 'noreturn (* R of non-return R 19 'noreturn (* R of non-return RMW *)
20 instructions R[{'once,'acquire,'noreturn}] 20 instructions R[{'once,'acquire,'noreturn}]
21 instructions W[{'once,'release}] 21 instructions W[{'once,'release}]
22 instructions RMW[{'once,'acquire,'release}] 22 instructions RMW[{'once,'acquire,'release}]
23 23
24 enum Barriers = 'wmb (*smp_wmb*) || 24 enum Barriers = 'wmb (*smp_wmb*) ||
25 'rmb (*smp_rmb*) || 25 'rmb (*smp_rmb*) ||
26 'mb (*smp_mb*) || 26 'mb (*smp_mb*) ||
27 'barrier (*barrier*) || <<
28 'rcu-lock (*rcu_read_lock*) | 27 'rcu-lock (*rcu_read_lock*) ||
29 'rcu-unlock (*rcu_read_unlock* 28 'rcu-unlock (*rcu_read_unlock*) ||
30 'sync-rcu (*synchronize_rcu*) 29 'sync-rcu (*synchronize_rcu*) ||
31 'before-atomic (*smp_mb__befor 30 'before-atomic (*smp_mb__before_atomic*) ||
32 'after-atomic (*smp_mb__after_ 31 'after-atomic (*smp_mb__after_atomic*) ||
33 'after-spinlock (*smp_mb__afte !! 32 'after-spinlock (*smp_mb__after_spinlock*)
34 'after-unlock-lock (*smp_mb__a <<
35 'after-srcu-read-unlock (*smp_ <<
36 instructions F[Barriers] 33 instructions F[Barriers]
37 34
38 (* SRCU *) <<
39 enum SRCU = 'srcu-lock || 'srcu-unlock || 'syn <<
40 instructions SRCU[SRCU] <<
41 (* All srcu events *) <<
42 let Srcu = Srcu-lock | Srcu-unlock | Sync-srcu <<
43 <<
44 (* Compute matching pairs of nested Rcu-lock a 35 (* Compute matching pairs of nested Rcu-lock and Rcu-unlock *)
45 let rcu-rscs = let rec !! 36 let matched = let rec
46 unmatched-locks = Rcu-lock \ domai 37 unmatched-locks = Rcu-lock \ domain(matched)
47 and unmatched-unlocks = Rcu-unlock \ r 38 and unmatched-unlocks = Rcu-unlock \ range(matched)
48 and unmatched = unmatched-locks | unma 39 and unmatched = unmatched-locks | unmatched-unlocks
49 and unmatched-po = [unmatched] ; po ; 40 and unmatched-po = [unmatched] ; po ; [unmatched]
50 and unmatched-locks-to-unlocks = 41 and unmatched-locks-to-unlocks =
51 [unmatched-locks] ; po ; [unma 42 [unmatched-locks] ; po ; [unmatched-unlocks]
52 and matched = matched | (unmatched-loc 43 and matched = matched | (unmatched-locks-to-unlocks \
53 (unmatched-po ; unmatched-po)) 44 (unmatched-po ; unmatched-po))
54 in matched 45 in matched
55 46
56 (* Validate nesting *) 47 (* Validate nesting *)
57 flag ~empty Rcu-lock \ domain(rcu-rscs) as unm !! 48 flag ~empty Rcu-lock \ domain(matched) as unbalanced-rcu-locking
58 flag ~empty Rcu-unlock \ range(rcu-rscs) as un !! 49 flag ~empty Rcu-unlock \ range(matched) as unbalanced-rcu-locking
59 <<
60 (* Compute matching pairs of nested Srcu-lock <<
61 let carry-srcu-data = (data ; [~ Srcu-unlock] <<
62 let srcu-rscs = ([Srcu-lock] ; carry-srcu-data <<
63 <<
64 (* Validate nesting *) <<
65 flag ~empty Srcu-lock \ domain(srcu-rscs) as u <<
66 flag ~empty Srcu-unlock \ range(srcu-rscs) as <<
67 flag ~empty (srcu-rscs^-1 ; srcu-rscs) \ id as <<
68 <<
69 (* Check for use of synchronize_srcu() inside <<
70 flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) <<
71 <<
72 (* Validate SRCU dynamic match *) <<
73 flag ~empty different-values(srcu-rscs) as src <<
74 <<
75 (* Compute marked and plain memory accesses *) <<
76 let Marked = (~M) | IW | Once | Release | Acqu <<
77 LKR | LKW | UL | LF | RL | RU <<
78 let Plain = M \ Marked <<
79 50
80 (* Redefine dependencies to include those carr !! 51 (* Outermost level of nesting only *)
81 let carry-dep = (data ; [~ Srcu-unlock] ; rfi) !! 52 let crit = matched \ (po^-1 ; matched ; po^-1)
82 let addr = carry-dep ; addr <<
83 let ctrl = carry-dep ; ctrl <<
84 let data = carry-dep ; data <<
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