[mirror_ubuntu-hirsute-kernel.git] / tools / memory-model / litmus-tests / MP+fencewmbonceonce+fencermbonceonce.litmus

C MP+fencewmbonceonce+fencermbonceonce

(*
 * Result: Never
 *
 * This litmus test demonstrates that smp_wmb() and smp_rmb() provide
 * sufficient ordering for the message-passing pattern.  However, it
 * is usually better to use smp_store_release() and smp_load_acquire().
 *)

{}

P0(int *x, int *y)
{
	WRITE_ONCE(*x, 1);
	smp_wmb();
	WRITE_ONCE(*y, 1);
}

P1(int *x, int *y)
{
	int r0;
	int r1;

	r0 = READ_ONCE(*y);
	smp_rmb();
	r1 = READ_ONCE(*x);
}

exists (1:r0=1 /\ 1:r1=0)
Commit	Line	Data
71b7ff5e	1	C MP+fencewmbonceonce+fencermbonceonce
1c27b644	2
8f32543b PM	3	(*
	4	* Result: Never
	5	*
	6	* This litmus test demonstrates that smp_wmb() and smp_rmb() provide
	7	* sufficient ordering for the message-passing pattern. However, it
	8	* is usually better to use smp_store_release() and smp_load_acquire().
	9	*)
	10
1c27b644 PM	11	{}
	12
	13	P0(int x, int y)
	14	{
	15	WRITE_ONCE(*x, 1);
	16	smp_wmb();
	17	WRITE_ONCE(*y, 1);
	18	}
	19
	20	P1(int x, int y)
	21	{
	22	int r0;
	23	int r1;
	24
	25	r0 = READ_ONCE(*y);
	26	smp_rmb();
	27	r1 = READ_ONCE(*x);
	28	}
	29
	30	exists (1:r0=1 /\ 1:r1=0)