[PATCH 1/3] tools: memory-model: Expand definition of barrier

From: Alan Stern
Date: Thu Jun 20 2019 - 12:00:54 EST


Commit 66be4e66a7f4 ("rcu: locking and unlocking need to always be at
least barriers") added compiler barriers back into rcu_read_lock() and
rcu_read_unlock(). Furthermore, srcu_read_lock() and
srcu_read_unlock() have always contained compiler barriers.

The Linux Kernel Memory Model ought to know about these barriers.
This patch adds them into the memory model.

Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

---


tools/memory-model/linux-kernel.cat | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

Index: usb-devel/tools/memory-model/linux-kernel.cat
===================================================================
--- usb-devel.orig/tools/memory-model/linux-kernel.cat
+++ usb-devel/tools/memory-model/linux-kernel.cat
@@ -47,7 +47,8 @@ let strong-fence = mb | gp
let nonrw-fence = strong-fence | po-rel | acq-po
let fence = nonrw-fence | wmb | rmb
let barrier = fencerel(Barrier | Rmb | Wmb | Mb | Sync-rcu | Sync-srcu |
- Before-atomic | After-atomic | Acquire | Release) |
+ Before-atomic | After-atomic | Acquire | Release |
+ Rcu-lock | Rcu-unlock | Srcu-lock | Srcu-unlock) |
(po ; [Release]) | ([Acquire] ; po)

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