locking/arch: Wire up local_try_cmpxchg()

Implement target specific support for local_try_cmpxchg()
and local_cmpxchg() using typed C wrappers that call their
_local counterpart and provide additional checking of
their input arguments.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230405141710.3551-4-ubizjak@gmail.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 2 deletions

diff --git a/arch/x86/include/asm/local.h b/arch/x86/include/asm/local.h
index 349a47acaa4a..56d4ef604b91 100644
--- a/arch/x86/include/asm/local.h
+++ b/arch/x86/include/asm/local.h
@@ -120,8 +120,17 @@ static inline long local_sub_return(long i, local_t *l)
 #define local_inc_return(l)  (local_add_return(1, l))
 #define local_dec_return(l)  (local_sub_return(1, l))
 
-#define local_cmpxchg(l, o, n) \
-	(cmpxchg_local(&((l)->a.counter), (o), (n)))
+static inline long local_cmpxchg(local_t *l, long old, long new)
+{
+	return cmpxchg_local(&l->a.counter, old, new);
+}
+
+static inline bool local_try_cmpxchg(local_t *l, long *old, long new)
+{
+	typeof(l->a.counter) *__old = (typeof(l->a.counter) *) old;
+	return try_cmpxchg_local(&l->a.counter, __old, new);
+}
+
 /* Always has a lock prefix */
 #define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))