From: Alan Stern <st...@rowland.harvard.edu> lock.cat contains old comments and code referring to the possibility of LKR events that are not part of an RMW pair. This is a holdover from when I though we might end up using LKR events to implement spin_is_locked(). Reword the comments to remove this assumption and replace domain(lk-rmw) in the code with LKR.
Signed-off-by: Alan Stern <st...@rowland.harvard.edu> CC: Akira Yokosawa <aki...@gmail.com> CC: Andrea Parri <andrea.pa...@amarulasolutions.com> CC: Boqun Feng <boqun.f...@gmail.com> CC: David Howells <dhowe...@redhat.com> CC: Jade Alglave <j.algl...@ucl.ac.uk> CC: Luc Maranget <luc.maran...@inria.fr> CC: Nicholas Piggin <npig...@gmail.com> CC: "Paul E. McKenney" <paul...@linux.vnet.ibm.com> CC: Peter Zijlstra <pet...@infradead.org> CC: Will Deacon <will.dea...@arm.com> Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> Tested-by: Andrea Parri <andrea.pa...@amarulasolutions.com> [ paulmck: Pulled "as lock-nest" into previous line as discussed. ] --- tools/memory-model/lock.cat | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/tools/memory-model/lock.cat b/tools/memory-model/lock.cat index 7217cd4941a4..cd002a33ca8a 100644 --- a/tools/memory-model/lock.cat +++ b/tools/memory-model/lock.cat @@ -47,18 +47,15 @@ flag ~empty [M \ IW] ; loc ; [ALL-LOCKS] as mixed-lock-accesses let lk-rmw = ([LKR] ; po-loc ; [LKW]) \ (po ; po) let rmw = rmw | lk-rmw +(* The litmus test is invalid if an LKR/LKW event is not part of an RMW pair *) +flag ~empty LKW \ range(lk-rmw) as unpaired-LKW +flag ~empty LKR \ domain(lk-rmw) as unpaired-LKR + (* - * A paired LKR must always see an unlocked value; spin_lock() calls nested + * An LKR must always see an unlocked value; spin_lock() calls nested * inside a critical section (for the same lock) always deadlock. *) -empty ([LKW] ; po-loc ; [domain(lk-rmw)]) \ (po-loc ; [UL] ; po-loc) - as lock-nest - -(* The litmus test is invalid if an LKW event is not part of an RMW pair *) -flag ~empty LKW \ range(lk-rmw) as unpaired-LKW - -(* This will be allowed if we implement spin_is_locked() *) -flag ~empty LKR \ domain(lk-rmw) as unpaired-LKR +empty ([LKW] ; po-loc ; [LKR]) \ (po-loc ; [UL] ; po-loc) as lock-nest (* The final value of a spinlock should not be tested *) flag ~empty [FW] ; loc ; [ALL-LOCKS] as lock-final -- 2.5.2
