tools/memory-model: Add atomic_andnot() with its variants

Pull-855[1] added the support of atomic_andnot() to the herd tool. Use this to add the implementation in the LKMM. All of the ordering variants are also added.

Here is a small litmus-test that uses this operation:

C andnot

{
atomic_t u = ATOMIC_INIT(7);
}

P0(atomic_t *u)
{

        r0 = atomic_fetch_andnot(3, u);
        r1 = READ_ONCE(*u);
}

exists (0:r0=7 /\ 0:r1=4)

Test andnot Allowed
States 1
0:r0=7; 0:r1=4;
Ok
Witnesses
Positive: 1 Negative: 0
Condition exists (0:r0=7 /\ 0:r1=4)
Observation andnot Always 1 0
Time andnot 0.00
Hash=78f011a0b5a0c65fa1cf106fcd62c845

[1] https://github.com/herd/herdtools7/pull/855

---

This commit is based on the commit[1] that is adding &, |, and ^.

Both of these patches should go together when the next version of herd7 is released. I will update the "REQUIREMENTS" section when the new version is released.

Later on, I will add some example litmus tests to showcase the usage of these new operations.

[1] https://lore.kernel.org/all/[email protected]/

---
 tools/memory-model/linux-kernel.def | 6 ++++++
 1 file changed, 6 insertions(+)

index d1f11930ec51..a12b96c547b7 100644
@@ -70,6 +70,7 @@ atomic_or(V,X)  { __atomic_op(X,|,V); }
 atomic_xor(V,X) { __atomic_op(X,^,V); }
 atomic_inc(X)   { __atomic_op(X,+,1); }
 atomic_dec(X)   { __atomic_op(X,-,1); }
+atomic_andnot(V,X) { __atomic_op(X,&~,V); }
 
 atomic_add_return(V,X) __atomic_op_return{mb}(X,+,V)
 atomic_add_return_relaxed(V,X) __atomic_op_return{once}(X,+,V)

@@ -138,3 +139,8 @@ atomic_add_negative(V,X) __atomic_op_return{mb}(X,+,V) < 0
 atomic_add_negative_relaxed(V,X) __atomic_op_return{once}(X,+,V) < 0
 atomic_add_negative_acquire(V,X) __atomic_op_return{acquire}(X,+,V) < 0
 atomic_add_negative_release(V,X) __atomic_op_return{release}(X,+,V) < 0
+
+atomic_fetch_andnot(V,X) __atomic_fetch_op{mb}(X,&~,V)
+atomic_fetch_andnot_acquire(V,X) __atomic_fetch_op{acquire}(X,&~,V)
+atomic_fetch_andnot_release(V,X) __atomic_fetch_op{release}(X,&~,V)
+atomic_fetch_andnot_relaxed(V,X) __atomic_fetch_op{once}(X,&~,V)

2.40.1

Fair enough for the changelog. If/when submitting proper tests, please check their format using klitmus7 (besides herd7); say,

  $ mkdir mymodule
  $ klitmus7 -o mymodule <.litmus file>
  $ cd mymodule ; make
  $ sudo sh run.sh

Documentation/litmus-tests/ provides some examples litmus tests.

Andrea

Queued and pushed, thank you both!

Again, I will hold off pushing this until herd7 releases a version supporting this.

Thanx, Paul