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Alan Stern
bf28ae5627
Since commit76ebbe78f7("locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()") was merged for the 4.15 kernel, it has not been necessary to use smp_read_barrier_depends(). Similarly, commit59ecbbe7b3("locking/barriers: Kill lockless_dereference()") removed lockless_dereference() from the kernel. Since these primitives are no longer part of the kernel, they do not belong in the Linux Kernel Memory Consistency Model. This patch removes them, along with the internal rb-dep relation, and updates the revelant documentation. Signed-off-by: Alan Stern <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
53 lines
1.9 KiB
Plaintext
53 lines
1.9 KiB
Plaintext
// SPDX-License-Identifier: GPL-2.0+
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(*
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* Copyright (C) 2015 Jade Alglave <[email protected]>,
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* Copyright (C) 2016 Luc Maranget <[email protected]> for Inria
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* Copyright (C) 2017 Alan Stern <[email protected]>,
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* Andrea Parri <[email protected]>
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*
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* An earlier version of this file appears in the companion webpage for
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* "Frightening small children and disconcerting grown-ups: Concurrency
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* in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern,
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* which is to appear in ASPLOS 2018.
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*)
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"Linux-kernel memory consistency model"
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enum Accesses = 'once (*READ_ONCE,WRITE_ONCE,ACCESS_ONCE*) ||
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'release (*smp_store_release*) ||
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'acquire (*smp_load_acquire*) ||
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'noreturn (* R of non-return RMW *)
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instructions R[{'once,'acquire,'noreturn}]
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instructions W[{'once,'release}]
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instructions RMW[{'once,'acquire,'release}]
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enum Barriers = 'wmb (*smp_wmb*) ||
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'rmb (*smp_rmb*) ||
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'mb (*smp_mb*) ||
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'rcu-lock (*rcu_read_lock*) ||
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'rcu-unlock (*rcu_read_unlock*) ||
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'sync-rcu (*synchronize_rcu*) ||
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'before-atomic (*smp_mb__before_atomic*) ||
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'after-atomic (*smp_mb__after_atomic*) ||
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'after-spinlock (*smp_mb__after_spinlock*)
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instructions F[Barriers]
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(* Compute matching pairs of nested Rcu-lock and Rcu-unlock *)
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let matched = let rec
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unmatched-locks = Rcu-lock \ domain(matched)
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and unmatched-unlocks = Rcu-unlock \ range(matched)
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and unmatched = unmatched-locks | unmatched-unlocks
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and unmatched-po = [unmatched] ; po ; [unmatched]
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and unmatched-locks-to-unlocks =
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[unmatched-locks] ; po ; [unmatched-unlocks]
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and matched = matched | (unmatched-locks-to-unlocks \
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(unmatched-po ; unmatched-po))
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in matched
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(* Validate nesting *)
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flag ~empty Rcu-lock \ domain(matched) as unbalanced-rcu-locking
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flag ~empty Rcu-unlock \ range(matched) as unbalanced-rcu-locking
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(* Outermost level of nesting only *)
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let crit = matched \ (po^-1 ; matched ; po^-1)
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