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+// 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