xref: /OK3568_Linux_fs/kernel/tools/memory-model/litmus-tests/WRC+poonceonces+Once.litmus (revision 4882a59341e53eb6f0b4789bf948001014eff981) 
1*4882a593SmuzhiyunC WRC+poonceonces+Once
2*4882a593Smuzhiyun
3*4882a593Smuzhiyun(*
4*4882a593Smuzhiyun * Result: Sometimes
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * This litmus test is an extension of the message-passing pattern,
7*4882a593Smuzhiyun * where the first write is moved to a separate process.  Note that this
8*4882a593Smuzhiyun * test has no ordering at all.
9*4882a593Smuzhiyun *)
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun{}
12*4882a593Smuzhiyun
13*4882a593SmuzhiyunP0(int *x)
14*4882a593Smuzhiyun{
15*4882a593Smuzhiyun	WRITE_ONCE(*x, 1);
16*4882a593Smuzhiyun}
17*4882a593Smuzhiyun
18*4882a593SmuzhiyunP1(int *x, int *y)
19*4882a593Smuzhiyun{
20*4882a593Smuzhiyun	int r0;
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun	r0 = READ_ONCE(*x);
23*4882a593Smuzhiyun	WRITE_ONCE(*y, 1);
24*4882a593Smuzhiyun}
25*4882a593Smuzhiyun
26*4882a593SmuzhiyunP2(int *x, int *y)
27*4882a593Smuzhiyun{
28*4882a593Smuzhiyun	int r0;
29*4882a593Smuzhiyun	int r1;
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun	r0 = READ_ONCE(*y);
32*4882a593Smuzhiyun	r1 = READ_ONCE(*x);
33*4882a593Smuzhiyun}
34*4882a593Smuzhiyun
35*4882a593Smuzhiyunexists (1:r0=1 /\ 2:r0=1 /\ 2:r1=0)
36