From: Boqun Feng <boqun.feng@xxxxxxxxx> According to Luc, atomic_add_unless() is directly provided by herd7, therefore it can be used in litmus tests. So change the limitation section in README to unlimit the use of atomic_add_unless(). Cc: Luc Maranget <luc.maranget@xxxxxxxx> Acked-by: Andrea Parri <parri.andrea@xxxxxxxxx> Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- tools/memory-model/README | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/tools/memory-model/README b/tools/memory-model/README index fc07b52..b9c562e 100644 --- a/tools/memory-model/README +++ b/tools/memory-model/README @@ -207,11 +207,15 @@ The Linux-kernel memory model (LKMM) has the following limitations: case as a store release. b. The "unless" RMW operations are not currently modeled: - atomic_long_add_unless(), atomic_add_unless(), - atomic_inc_unless_negative(), and - atomic_dec_unless_positive(). These can be emulated + atomic_long_add_unless(), atomic_inc_unless_negative(), + and atomic_dec_unless_positive(). These can be emulated in litmus tests, for example, by using atomic_cmpxchg(). + One exception of this limitation is atomic_add_unless(), + which is provided directly by herd7 (so no corresponding + definition in linux-kernel.def). atomic_add_unless() is + modeled by herd7 therefore it can be used in litmus tests. + c. The call_rcu() function is not modeled. It can be emulated in litmus tests by adding another process that invokes synchronize_rcu() and the body of the callback -- 2.9.5
