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 '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*) 36instructions F[Barriers] 37 38(* SRCU *) 39enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu 40instructions SRCU[SRCU] 41(* All srcu events *) 42let Srcu = Srcu-lock | Srcu-unlock | Sync-srcu 43 44(* Compute matching pairs of nested Rcu-lock and Rcu-unlock *) 45let 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 *) 57flag ~empty Rcu-lock \ domain(rcu-rscs) as unmatched-rcu-lock 58flag ~empty Rcu-unlock \ range(rcu-rscs) as unmatched-rcu-unlock 59 60(* Compute matching pairs of nested Srcu-lock and Srcu-unlock *) 61let carry-srcu-data = (data ; [~ Srcu-unlock] ; rf)* 62let srcu-rscs = ([Srcu-lock] ; carry-srcu-data ; data ; [Srcu-unlock]) & loc 63 64(* Validate nesting *) 65flag ~empty Srcu-lock \ domain(srcu-rscs) as unmatched-srcu-lock 66flag ~empty Srcu-unlock \ range(srcu-rscs) as unmatched-srcu-unlock 67flag ~empty (srcu-rscs^-1 ; srcu-rscs) \ id as multiple-srcu-matches 68 69(* Check for use of synchronize_srcu() inside an RCU critical section *) 70flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep 71 72(* Validate SRCU dynamic match *) 73flag ~empty different-values(srcu-rscs) as srcu-bad-value-match 74 75(* Compute marked and plain memory accesses *) 76let Marked = (~M) | IW | Once | Release | Acquire | domain(rmw) | range(rmw) | 77 LKR | LKW | UL | LF | RL | RU | Srcu-lock | Srcu-unlock 78let Plain = M \ Marked 79 80(* Redefine dependencies to include those carried through plain accesses *) 81let carry-dep = (data ; [~ Srcu-unlock] ; rfi)* 82let addr = carry-dep ; addr 83let ctrl = carry-dep ; ctrl 84let data = carry-dep ; data 85