Commit-ID: b464818978d45cd4d78c8f13207891142c68bea9 Gitweb: https://git.kernel.org/tip/b464818978d45cd4d78c8f13207891142c68bea9 Author: Paul E. McKenney <paul...@linux.vnet.ibm.com> AuthorDate: Mon, 16 Jul 2018 11:05:52 -0700 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 17 Jul 2018 09:29:29 +0200
tools/memory-model: Add litmus test for full multicopy atomicity This commit adds a litmus test suggested by Alan Stern that is forbidden on fully multicopy atomic systems, but allowed on other-multicopy and on non-multicopy atomic systems. For reference, s390 is fully multicopy atomic, x86 and ARMv8 are other-multicopy atomic, and ARMv7 and powerpc are non-multicopy atomic. Suggested-by: Alan Stern <st...@rowland.harvard.edu> Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> Acked-by: Alan Stern <st...@rowland.harvard.edu> Acked-by: Andrea Parri <andrea.pa...@amarulasolutions.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: aki...@gmail.com Cc: boqun.f...@gmail.com Cc: dhowe...@redhat.com Cc: j.algl...@ucl.ac.uk Cc: linux-a...@vger.kernel.org Cc: luc.maran...@inria.fr Cc: npig...@gmail.com Cc: parri.and...@gmail.com Cc: will.dea...@arm.com Link: http://lkml.kernel.org/r/20180716180605.16115-1-paul...@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- tools/memory-model/litmus-tests/README | 9 ++++++ .../litmus-tests/SB+rfionceonce-poonceonces.litmus | 32 ++++++++++++++++++++++ 2 files changed, 41 insertions(+) diff --git a/tools/memory-model/litmus-tests/README b/tools/memory-model/litmus-tests/README index 17eb9a8c222d..00140aaf58b7 100644 --- a/tools/memory-model/litmus-tests/README +++ b/tools/memory-model/litmus-tests/README @@ -111,6 +111,15 @@ SB+mbonceonces.litmus SB+poonceonces.litmus As above, but without the smp_mb() invocations. +SB+rfionceonce-poonceonces.litmus + This litmus test demonstrates that LKMM is not fully multicopy + atomic. (Neither is it other multicopy atomic.) This litmus test + also demonstrates the "locations" debugging aid, which designates + additional registers and locations to be printed out in the dump + of final states in the herd7 output. Without the "locations" + statement, only those registers and locations mentioned in the + "exists" clause will be printed. + S+poonceonces.litmus As below, but without the smp_wmb() and acquire load. diff --git a/tools/memory-model/litmus-tests/SB+rfionceonce-poonceonces.litmus b/tools/memory-model/litmus-tests/SB+rfionceonce-poonceonces.litmus new file mode 100644 index 000000000000..04a16603660b --- /dev/null +++ b/tools/memory-model/litmus-tests/SB+rfionceonce-poonceonces.litmus @@ -0,0 +1,32 @@ +C SB+rfionceonce-poonceonces + +(* + * Result: Sometimes + * + * This litmus test demonstrates that LKMM is not fully multicopy atomic. + *) + +{} + +P0(int *x, int *y) +{ + int r1; + int r2; + + WRITE_ONCE(*x, 1); + r1 = READ_ONCE(*x); + r2 = READ_ONCE(*y); +} + +P1(int *x, int *y) +{ + int r3; + int r4; + + WRITE_ONCE(*y, 1); + r3 = READ_ONCE(*y); + r4 = READ_ONCE(*x); +} + +locations [0:r1; 1:r3; x; y] (* Debug aid: Print things not in "exists". *) +exists (0:r2=0 /\ 1:r4=0)
