tools/memory-model/litmus-tests/MP+polockmbonce+poacquiresilsil.litmus

   1 C MP+polockmbonce+poacquiresilsil
   2
   3 (*
   4  * Result: Never
   5  *
   6  * Do spinlocks combined with smp_mb__after_spinlock() provide order
   7  * to outside observers using spin_is_locked() to sense the lock-held
   8  * state, ordered by acquire?  Note that when the first spin_is_locked()
   9  * returns false and the second true, we know that the smp_load_acquire()
  10  * executed before the lock was acquired (loosely speaking).
  11  *)
  12
  13 {
  14 }
  15
  16 P0(spinlock_t *lo, int *x)
  17 {
  18         spin_lock(lo);
  19         smp_mb__after_spinlock();
  20         WRITE_ONCE(*x, 1);
  21         spin_unlock(lo);
  22 }
  23
  24 P1(spinlock_t *lo, int *x)
  25 {
  26         int r1;
  27         int r2;
  28         int r3;
  29
  30         r1 = smp_load_acquire(x);
  31         r2 = spin_is_locked(lo);
  32         r3 = spin_is_locked(lo);
  33 }
  34
  35 exists (1:r1=1 /\ 1:r2=0 /\ 1:r3=1)