18c2ecf20Sopenharmony_ciC MP+fencewmbonceonce+fencermbonceonce 28c2ecf20Sopenharmony_ci 38c2ecf20Sopenharmony_ci(* 48c2ecf20Sopenharmony_ci * Result: Never 58c2ecf20Sopenharmony_ci * 68c2ecf20Sopenharmony_ci * This litmus test demonstrates that smp_wmb() and smp_rmb() provide 78c2ecf20Sopenharmony_ci * sufficient ordering for the message-passing pattern. However, it 88c2ecf20Sopenharmony_ci * is usually better to use smp_store_release() and smp_load_acquire(). 98c2ecf20Sopenharmony_ci *) 108c2ecf20Sopenharmony_ci 118c2ecf20Sopenharmony_ci{} 128c2ecf20Sopenharmony_ci 138c2ecf20Sopenharmony_ciP0(int *x, int *y) 148c2ecf20Sopenharmony_ci{ 158c2ecf20Sopenharmony_ci WRITE_ONCE(*x, 1); 168c2ecf20Sopenharmony_ci smp_wmb(); 178c2ecf20Sopenharmony_ci WRITE_ONCE(*y, 1); 188c2ecf20Sopenharmony_ci} 198c2ecf20Sopenharmony_ci 208c2ecf20Sopenharmony_ciP1(int *x, int *y) 218c2ecf20Sopenharmony_ci{ 228c2ecf20Sopenharmony_ci int r0; 238c2ecf20Sopenharmony_ci int r1; 248c2ecf20Sopenharmony_ci 258c2ecf20Sopenharmony_ci r0 = READ_ONCE(*y); 268c2ecf20Sopenharmony_ci smp_rmb(); 278c2ecf20Sopenharmony_ci r1 = READ_ONCE(*x); 288c2ecf20Sopenharmony_ci} 298c2ecf20Sopenharmony_ci 308c2ecf20Sopenharmony_ciexists (1:r0=1 /\ 1:r1=0) 31