162306a36Sopenharmony_ciC IRIW+fencembonceonces+OnceOnce
262306a36Sopenharmony_ci
362306a36Sopenharmony_ci(*
462306a36Sopenharmony_ci * Result: Never
562306a36Sopenharmony_ci *
662306a36Sopenharmony_ci * Test of independent reads from independent writes with smp_mb()
762306a36Sopenharmony_ci * between each pairs of reads.  In other words, is smp_mb() sufficient to
862306a36Sopenharmony_ci * cause two different reading processes to agree on the order of a pair
962306a36Sopenharmony_ci * of writes, where each write is to a different variable by a different
1062306a36Sopenharmony_ci * process?  This litmus test exercises LKMM's "propagation" rule.
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	int r1;
2462306a36Sopenharmony_ci
2562306a36Sopenharmony_ci	r0 = READ_ONCE(*x);
2662306a36Sopenharmony_ci	smp_mb();
2762306a36Sopenharmony_ci	r1 = READ_ONCE(*y);
2862306a36Sopenharmony_ci}
2962306a36Sopenharmony_ci
3062306a36Sopenharmony_ciP2(int *y)
3162306a36Sopenharmony_ci{
3262306a36Sopenharmony_ci	WRITE_ONCE(*y, 1);
3362306a36Sopenharmony_ci}
3462306a36Sopenharmony_ci
3562306a36Sopenharmony_ciP3(int *x, int *y)
3662306a36Sopenharmony_ci{
3762306a36Sopenharmony_ci	int r0;
3862306a36Sopenharmony_ci	int r1;
3962306a36Sopenharmony_ci
4062306a36Sopenharmony_ci	r0 = READ_ONCE(*y);
4162306a36Sopenharmony_ci	smp_mb();
4262306a36Sopenharmony_ci	r1 = READ_ONCE(*x);
4362306a36Sopenharmony_ci}
4462306a36Sopenharmony_ci
4562306a36Sopenharmony_ciexists (1:r0=1 /\ 1:r1=0 /\ 3:r0=1 /\ 3:r1=0)
46