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tools/memory-model: Remove duplicated code from lock.cat 

This patch simplifies the implementation of spin_is_locked in the
LKMM.  It capitalizes on the fact that a failed spin_trylock() and a
spin_is_locked() which returns True have exactly the same semantics
(those of READ_ONCE) and ordering properties (none).  Therefore the
two kinds of events can be combined and handled by the same code,
instead of treated separately as they are currently.

Tested-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Akira Yokosawa <akiyks@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luc Maranget <luc.maranget@inria.fr>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: parri.andrea@gmail.com
Link: http://lkml.kernel.org/r/1526340837-12222-12-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Alan Stern 2018-05-14 16:33:50 -07:00 committed by Ingo Molnar
parent 1bd3742043
commit 8559183cca
1 changed files with 6 additions and 22 deletions
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28
tools/memory-model/lock.cat
View File

@ -41,11 +41,15 @@ flag ~empty [FW] ; loc ; [ALL-LOCKS] as lock-final
*)
let RL = try RL with emptyset (* defined herd7 >= 7.49 *)
let RU = try RU with emptyset (* defined herd7 >= 7.49 *)
(* Treat RL as a kind of LF: a read with no ordering properties *)
let LF = LF | RL
(*
* Put lock operations in their appropriate classes, but leave UL out of W
* until after the co relation has been generated.
*)
let R = R | LKR | LF | RL | RU
let R = R | LKR | LF | RU
let W = W | LKW
let Release = Release | UL
@ -80,28 +84,8 @@ let all-possible-rfe-lf =
(* Generate all rf relations for LF events *)
with rfe-lf from cross(all-possible-rfe-lf)
let rf-lf = rfe-lf | rfi-lf
(* rf for RL events, ie islocked returning true, similar to LF above *)
(* islocked returning true inside a critical section
* must read from the opening lock
*)
let rfi-rl = ([LKW] ; po-loc ; [RL]) \ ([LKW] ; po-loc ; [UL] ; po-loc)
(* islocked returning true outside critical sections can match any
* external lock.
*)
let all-possible-rfe-rl =
let possible-rfe-lf r =
let pair-to-relation p = p ++ 0
in map pair-to-relation ((LKW * {r}) & loc & ext)
in map possible-rfe-lf (RL \ range(rfi-rl))
with rfe-rl from cross(all-possible-rfe-rl)
let rf-rl = rfe-rl | rfi-rl
(* Read from unlock, ie islocked returning false, slightly different *)
(* islocked returning false can read from the last po-previous unlock *)
@ -118,7 +102,7 @@ with rfe-ru from cross(all-possible-rfe-ru)
let rf-ru = rfe-ru | rfi-ru
(* Final rf relation *)
let rf = rf | rf-lf | rf-rl | rf-ru
let rf = rf | rf-lf | rf-ru
(* Generate all co relations, including LKW events but not UL *)
let co0 = co0 | ([IW] ; loc ; [LKW]) |