162306a36Sopenharmony_ciC WRC+pooncerelease+fencermbonceonce+Once 262306a36Sopenharmony_ci 362306a36Sopenharmony_ci(* 462306a36Sopenharmony_ci * Result: Never 562306a36Sopenharmony_ci * 662306a36Sopenharmony_ci * This litmus test is an extension of the message-passing pattern, where 762306a36Sopenharmony_ci * the first write is moved to a separate process. Because it features 862306a36Sopenharmony_ci * a release and a read memory barrier, it should be forbidden. More 962306a36Sopenharmony_ci * specifically, this litmus test is forbidden because smp_store_release() 1062306a36Sopenharmony_ci * is A-cumulative in LKMM. 1162306a36Sopenharmony_ci *) 1262306a36Sopenharmony_ci 1362306a36Sopenharmony_ci{} 1462306a36Sopenharmony_ci 1562306a36Sopenharmony_ciP0(int *x) 1662306a36Sopenharmony_ci{ 1762306a36Sopenharmony_ci WRITE_ONCE(*x, 1); 1862306a36Sopenharmony_ci} 1962306a36Sopenharmony_ci 2062306a36Sopenharmony_ciP1(int *x, int *y) 2162306a36Sopenharmony_ci{ 2262306a36Sopenharmony_ci int r0; 2362306a36Sopenharmony_ci 2462306a36Sopenharmony_ci r0 = READ_ONCE(*x); 2562306a36Sopenharmony_ci smp_store_release(y, 1); 2662306a36Sopenharmony_ci} 2762306a36Sopenharmony_ci 2862306a36Sopenharmony_ciP2(int *x, int *y) 2962306a36Sopenharmony_ci{ 3062306a36Sopenharmony_ci int r0; 3162306a36Sopenharmony_ci int r1; 3262306a36Sopenharmony_ci 3362306a36Sopenharmony_ci r0 = READ_ONCE(*y); 3462306a36Sopenharmony_ci smp_rmb(); 3562306a36Sopenharmony_ci r1 = READ_ONCE(*x); 3662306a36Sopenharmony_ci} 3762306a36Sopenharmony_ci 3862306a36Sopenharmony_ciexists (1:r0=1 /\ 2:r0=1 /\ 2:r1=0) 39