blob: 98a3716efa37ecc9ba4fd59e8560519ef33fab0a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
C IRIW+mbonceonces+OnceOnce
(*
* Result: Never
*
* Test of independent reads from independent writes with smp_mb()
* between each pairs of reads. In other words, is smp_mb() sufficient to
* cause two different reading processes to agree on the order of a pair
* of writes, where each write is to a different variable by a different
* process? This litmus test exercises LKMM's "propagation" rule.
*)
{}
P0(int *x)
{
WRITE_ONCE(*x, 1);
}
P1(int *x, int *y)
{
int r0;
int r1;
r0 = READ_ONCE(*x);
smp_mb();
r1 = READ_ONCE(*y);
}
P2(int *y)
{
WRITE_ONCE(*y, 1);
}
P3(int *x, int *y)
{
int r0;
int r1;
r0 = READ_ONCE(*y);
smp_mb();
r1 = READ_ONCE(*x);
}
exists (1:r0=1 /\ 1:r1=0 /\ 3:r0=1 /\ 3:r1=0)
|
