32 lines
628 B
Plaintext
32 lines
628 B
Plaintext
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C dep+plain
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(*
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* Result: Never
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*
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* This litmus test demonstrates that in LKMM, plain accesses
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* carry dependencies much like accesses to registers:
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* The data stored to *z1 and *z2 by P0() originates from P0()'s
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* READ_ONCE(), and therefore using that data to compute the
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* conditional of P0()'s if-statement creates a control dependency
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* from that READ_ONCE() to P0()'s WRITE_ONCE().
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*)
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{}
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P0(int *x, int *y, int *z1, int *z2)
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{
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int a = READ_ONCE(*x);
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*z1 = a;
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*z2 = *z1;
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if (*z2 == 1)
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WRITE_ONCE(*y, 1);
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}
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P1(int *x, int *y)
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{
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int r = smp_load_acquire(y);
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smp_store_release(x, r);
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}
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exists (x=1 /\ y=1)
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