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
16 enum Accesses = 'once (*READ_ONCE,WRITE_ONCE*) ||
17 'release (*smp_store_release*) ||
18 'acquire (*smp_load_acquire*) ||
19 'noreturn (* R of non-return RMW *)
20 instructions R[{'once,'acquire,'noreturn}]
21 instructions W[{'once,'release}]
22 instructions RMW[{'once,'acquire,'release}]
23
24 enum Barriers = 'wmb (*smp_wmb*) ||
25 'rmb (*smp_rmb*) ||
26 'mb (*smp_mb*) ||
27 'barrier (*barrier*) ||
28 'rcu-lock (*rcu_read_lock*) ||
29 'rcu-unlock (*rcu_read_unlock*) ||
30 'sync-rcu (*synchronize_rcu*) ||
31 'before-atomic (*smp_mb__before_atomic*) ||
32 'after-atomic (*smp_mb__after_atomic*) ||
33 'after-spinlock (*smp_mb__after_spinlock*) ||
34 'after-unlock-lock (*smp_mb__after_unlock_lock*) ||
35 'after-srcu-read-unlock (*smp_mb__after_srcu_read_unlock*)
36 instructions F[Barriers]
37
38 (* SRCU *)
39 enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu
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 and Rcu-unlock *)
45 let rcu-rscs = let rec
46 unmatched-locks = Rcu-lock \ domain(matched)
47 and unmatched-unlocks = Rcu-unlock \ range(matched)
48 and unmatched = unmatched-locks | unmatched-unlocks
49 and unmatched-po = [unmatched] ; po ; [unmatched]
50 and unmatched-locks-to-unlocks =
51 [unmatched-locks] ; po ; [unmatched-unlocks]
52 and matched = matched | (unmatched-locks-to-unlocks \
53 (unmatched-po ; unmatched-po))
54 in matched
55
56 (* Validate nesting *)
57 flag ~empty Rcu-lock \ domain(rcu-rscs) as unmatched-rcu-lock
58 flag ~empty Rcu-unlock \ range(rcu-rscs) as unmatched-rcu-unlock
59
60 (* Compute matching pairs of nested Srcu-lock and Srcu-unlock *)
61 let carry-srcu-data = (data ; [~ Srcu-unlock] ; rf)*
62 let srcu-rscs = ([Srcu-lock] ; carry-srcu-data ; data ; [Srcu-unlock]) & loc
63
64 (* Validate nesting *)
65 flag ~empty Srcu-lock \ domain(srcu-rscs) as unmatched-srcu-lock
66 flag ~empty Srcu-unlock \ range(srcu-rscs) as unmatched-srcu-unlock
67 flag ~empty (srcu-rscs^-1 ; srcu-rscs) \ id as multiple-srcu-matches
68
69 (* Check for use of synchronize_srcu() inside an RCU critical section *)
70 flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep
71
72 (* Validate SRCU dynamic match *)
73 flag ~empty different-values(srcu-rscs) as srcu-bad-value-match
74
75 (* Compute marked and plain memory accesses *)
76 let Marked = (~M) | IW | Once | Release | Acquire | domain(rmw) | range(rmw) |
77 LKR | LKW | UL | LF | RL | RU | Srcu-lock | Srcu-unlock
78 let Plain = M \ Marked
79
80 (* Redefine dependencies to include those carried through plain accesses *)
81 let carry-dep = (data ; [~ Srcu-unlock] ; rfi)*
82 let addr = carry-dep ; addr
83 let ctrl = carry-dep ; ctrl
84 let data = carry-dep ; data
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.