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| C MP+polocks
|
| (*
| * Result: Never
| *
| * This litmus test demonstrates how lock acquisitions and releases can
| * stand in for smp_load_acquire() and smp_store_release(), respectively.
| * In other words, when holding a given lock (or indeed after releasing a
| * given lock), a CPU is not only guaranteed to see the accesses that other
| * CPUs made while previously holding that lock, it is also guaranteed
| * to see all prior accesses by those other CPUs.
| *)
|
| {}
|
| P0(int *x, int *y, spinlock_t *mylock)
| {
| WRITE_ONCE(*x, 1);
| spin_lock(mylock);
| WRITE_ONCE(*y, 1);
| spin_unlock(mylock);
| }
|
| P1(int *x, int *y, spinlock_t *mylock)
| {
| int r0;
| int r1;
|
| spin_lock(mylock);
| r0 = READ_ONCE(*y);
| spin_unlock(mylock);
| r1 = READ_ONCE(*x);
| }
|
| exists (1:r0=1 /\ 1:r1=0)
|
|
