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36 lines
719 B
Plaintext
36 lines
719 B
Plaintext
C LB+unlocklockonceonce+poacquireonce
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(*
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* Result: Never
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*
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* If two locked critical sections execute on the same CPU, all accesses
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* in the first must execute before any accesses in the second, even if the
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* critical sections are protected by different locks. Note: Even when a
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* write executes before a read, their memory effects can be reordered from
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* the viewpoint of another CPU (the kind of reordering allowed by TSO).
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*)
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{}
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P0(spinlock_t *s, spinlock_t *t, int *x, int *y)
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{
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int r1;
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spin_lock(s);
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r1 = READ_ONCE(*x);
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spin_unlock(s);
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spin_lock(t);
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WRITE_ONCE(*y, 1);
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spin_unlock(t);
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}
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P1(int *x, int *y)
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{
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int r2;
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r2 = smp_load_acquire(y);
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WRITE_ONCE(*x, 1);
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}
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exists (0:r1=1 /\ 1:r2=1)
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