| // SPDX-License-Identifier: GPL-2.0+ |
| (* |
| * Copyright (C) 2015 Jade Alglave <j.alglave@ucl.ac.uk>, |
| * Copyright (C) 2016 Luc Maranget <luc.maranget@inria.fr> for Inria |
| * Copyright (C) 2017 Alan Stern <stern@rowland.harvard.edu>, |
| * Andrea Parri <parri.andrea@gmail.com> |
| * |
| * An earlier version of this file appeared in the companion webpage for |
| * "Frightening small children and disconcerting grown-ups: Concurrency |
| * in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern, |
| * which appeared in ASPLOS 2018. |
| *) |
| |
| "Linux-kernel memory consistency model" |
| |
| enum Accesses = 'ONCE (*READ_ONCE,WRITE_ONCE*) || |
| 'RELEASE (*smp_store_release*) || |
| 'ACQUIRE (*smp_load_acquire*) || |
| 'NORETURN (* R of non-return RMW *) || |
| 'MB (*xchg(),cmpxchg(),...*) |
| instructions R[Accesses] |
| instructions W[Accesses] |
| instructions RMW[Accesses] |
| |
| enum Barriers = 'wmb (*smp_wmb*) || |
| 'rmb (*smp_rmb*) || |
| 'MB (*smp_mb*) || |
| 'barrier (*barrier*) || |
| 'rcu-lock (*rcu_read_lock*) || |
| 'rcu-unlock (*rcu_read_unlock*) || |
| 'sync-rcu (*synchronize_rcu*) || |
| 'before-atomic (*smp_mb__before_atomic*) || |
| 'after-atomic (*smp_mb__after_atomic*) || |
| 'after-spinlock (*smp_mb__after_spinlock*) || |
| 'after-unlock-lock (*smp_mb__after_unlock_lock*) || |
| 'after-srcu-read-unlock (*smp_mb__after_srcu_read_unlock*) |
| instructions F[Barriers] |
| |
| |
| (* |
| * Filter out syntactic annotations that do not provide the corresponding |
| * semantic ordering, such as Acquire on a store or Mb on a failed RMW. |
| *) |
| let FailedRMW = RMW \ (domain(rmw) | range(rmw)) |
| let Acquire = ACQUIRE \ W \ FailedRMW |
| let Release = RELEASE \ R \ FailedRMW |
| let Mb = MB \ FailedRMW |
| let Noreturn = NORETURN \ W |
| |
| (* SRCU *) |
| enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu |
| instructions SRCU[SRCU] |
| (* All srcu events *) |
| let Srcu = Srcu-lock | Srcu-unlock | Sync-srcu |
| |
| (* Compute matching pairs of nested Rcu-lock and Rcu-unlock *) |
| let rcu-rscs = let rec |
| unmatched-locks = Rcu-lock \ domain(matched) |
| and unmatched-unlocks = Rcu-unlock \ range(matched) |
| and unmatched = unmatched-locks | unmatched-unlocks |
| and unmatched-po = [unmatched] ; po ; [unmatched] |
| and unmatched-locks-to-unlocks = |
| [unmatched-locks] ; po ; [unmatched-unlocks] |
| and matched = matched | (unmatched-locks-to-unlocks \ |
| (unmatched-po ; unmatched-po)) |
| in matched |
| |
| (* Validate nesting *) |
| flag ~empty Rcu-lock \ domain(rcu-rscs) as unmatched-rcu-lock |
| flag ~empty Rcu-unlock \ range(rcu-rscs) as unmatched-rcu-unlock |
| |
| (* Compute matching pairs of nested Srcu-lock and Srcu-unlock *) |
| let carry-srcu-data = (data ; [~ Srcu-unlock] ; rf)* |
| let srcu-rscs = ([Srcu-lock] ; carry-srcu-data ; data ; [Srcu-unlock]) & loc |
| |
| (* Validate nesting *) |
| flag ~empty Srcu-lock \ domain(srcu-rscs) as unmatched-srcu-lock |
| flag ~empty Srcu-unlock \ range(srcu-rscs) as unmatched-srcu-unlock |
| flag ~empty (srcu-rscs^-1 ; srcu-rscs) \ id as multiple-srcu-matches |
| |
| (* Check for use of synchronize_srcu() inside an RCU critical section *) |
| flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep |
| |
| (* Validate SRCU dynamic match *) |
| flag ~empty different-values(srcu-rscs) as srcu-bad-value-match |
| |
| (* Compute marked and plain memory accesses *) |
| let Marked = (~M) | IW | ONCE | RELEASE | ACQUIRE | MB | RMW | |
| LKR | LKW | UL | LF | RL | RU | Srcu-lock | Srcu-unlock |
| let Plain = M \ Marked |
| |
| (* Redefine dependencies to include those carried through plain accesses *) |
| let carry-dep = (data ; [~ Srcu-unlock] ; rfi)* |
| let addr = carry-dep ; addr |
| let ctrl = carry-dep ; ctrl |
| let data = carry-dep ; data |
| |
| flag ~empty (if "lkmmv2" then 0 else _) |
| as this-model-requires-variant-higher-than-lkmmv1 |
