mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 05:41:55 +00:00
5c587f9b9c
This is a revert of commit 1947bfcf81 ("tools/memory-model: Add types
to litmus tests") with conflict resolutions.
klitmus7 [1] is aware of default types of "int" and "int*".
It accepts litmus tests for herd7 without extra type info unless
non-"int" variables are referenced by an "exists", "locations",
or "filter" directive.
[1]: Tested with klitmus7 versions 7.49 or later.
Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
36 lines
825 B
Plaintext
36 lines
825 B
Plaintext
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 *buf, int *flag, spinlock_t *mylock) // Producer
|
|
{
|
|
WRITE_ONCE(*buf, 1);
|
|
spin_lock(mylock);
|
|
WRITE_ONCE(*flag, 1);
|
|
spin_unlock(mylock);
|
|
}
|
|
|
|
P1(int *buf, int *flag, spinlock_t *mylock) // Consumer
|
|
{
|
|
int r0;
|
|
int r1;
|
|
|
|
spin_lock(mylock);
|
|
r0 = READ_ONCE(*flag);
|
|
spin_unlock(mylock);
|
|
r1 = READ_ONCE(*buf);
|
|
}
|
|
|
|
exists (1:r0=1 /\ 1:r1=0) (* Bad outcome. *)
|