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tools/memory-model: Remove rb-dep, smp_read_barrier_depends, and lockless_dereference

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Since commit 76ebbe78f7 ("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, commit 59ecbbe7b3 ("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 <stern@rowland.harvard.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: nborisov@suse.com
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1519169112-20593-12-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Alan Stern
2018-02-20 15:25:12 -08:00
committed by Ingo Molnar
parent cac79a39f2
commit bf28ae5627
5 changed files with 46 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
tools/memory-model/linux-kernel.cat
View File

@@ -25,7 +25,6 @@ include "lock.cat"
(*******************)
(* Fences *)
let rb-dep = [R] ; fencerel(Rb_dep) ; [R]
let rmb = [R \ Noreturn] ; fencerel(Rmb) ; [R \ Noreturn]
let wmb = [W] ; fencerel(Wmb) ; [W]
let mb = ([M] ; fencerel(Mb) ; [M]) |
@@ -61,11 +60,9 @@ let dep = addr | data
let rwdep = (dep | ctrl) ; [W]
let overwrite = co | fr
let to-w = rwdep | (overwrite & int)
let rrdep = addr | (dep ; rfi)
let strong-rrdep = rrdep+ & rb-dep
let to-r = strong-rrdep | rfi-rel-acq
let to-r = addr | (dep ; rfi) | rfi-rel-acq
let fence = strong-fence | wmb | po-rel | rmb | acq-po
let ppo = rrdep* ; (to-r | to-w | fence)
let ppo = to-r | to-w | fence
(* Propagation: Ordering from release operations and strong fences. *)
let A-cumul(r) = rfe? ; r