xref: /OK3568_Linux_fs/kernel/tools/memory-model/litmus-tests/R+poonceonces.litmus (revision 4882a59341e53eb6f0b4789bf948001014eff981) 
1*4882a593SmuzhiyunC R+poonceonces
2*4882a593Smuzhiyun
3*4882a593Smuzhiyun(*
4*4882a593Smuzhiyun * Result: Sometimes
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * This is the unordered (thus lacking smp_mb()) version of one of the
7*4882a593Smuzhiyun * classic counterintuitive litmus tests that illustrates the effects of
8*4882a593Smuzhiyun * store propagation delays.
9*4882a593Smuzhiyun *)
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun{}
12*4882a593Smuzhiyun
13*4882a593SmuzhiyunP0(int *x, int *y)
14*4882a593Smuzhiyun{
15*4882a593Smuzhiyun	WRITE_ONCE(*x, 1);
16*4882a593Smuzhiyun	WRITE_ONCE(*y, 1);
17*4882a593Smuzhiyun}
18*4882a593Smuzhiyun
19*4882a593SmuzhiyunP1(int *x, int *y)
20*4882a593Smuzhiyun{
21*4882a593Smuzhiyun	int r0;
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun	WRITE_ONCE(*y, 2);
24*4882a593Smuzhiyun	r0 = READ_ONCE(*x);
25*4882a593Smuzhiyun}
26*4882a593Smuzhiyun
27*4882a593Smuzhiyunexists (y=2 /\ 1:r0=0)
28