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authorAlan Stern <stern@rowland.harvard.edu>2018-05-14 16:33:50 -0700
committerIngo Molnar <mingo@kernel.org>2018-05-15 08:11:17 +0200
commit8559183ccaec97454b2515ac426f113967256cf9 (patch)
tree6aee2f09189b0b9441ecfb3c399078158424fb71 /tools/memory-model
parent1bd3742043fa44dd0ec25770abdcdfe1f6e8681e (diff)
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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>
Diffstat (limited to 'tools/memory-model')
-rw-r--r--tools/memory-model/lock.cat28
1 files changed, 6 insertions, 22 deletions
diff --git a/tools/memory-model/lock.cat b/tools/memory-model/lock.cat
index 3b1439edc818..1f6d67e79065 100644
--- a/tools/memory-model/lock.cat
+++ b/tools/memory-model/lock.cat
@@ -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]) |