[src/trunk]: src/sys/external/bsd/drm2/include/linux linux: Just use __sync_*...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/52c6216e62aa
branches:  trunk
changeset: 1028620:52c6216e62aa
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 11:31:11 2021 +0000

description:
linux: Just use __sync_* for xchg and cmpxchg.

Easier than figuring out the dance with __builtin_choose_expr to make
these work with all types they need to work with.

diffstat:

 sys/external/bsd/drm2/include/linux/atomic.h |  18 ++++--------------
 1 files changed, 4 insertions(+), 14 deletions(-)

diffs (32 lines):

diff -r 4dd8885ffae8 -r 52c6216e62aa sys/external/bsd/drm2/include/linux/atomic.h
--- a/sys/external/bsd/drm2/include/linux/atomic.h      Sun Dec 19 11:31:04 2021 +0000
+++ b/sys/external/bsd/drm2/include/linux/atomic.h      Sun Dec 19 11:31:11 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: atomic.h,v 1.38 2021/12/19 11:26:42 riastradh Exp $    */
+/*     $NetBSD: atomic.h,v 1.39 2021/12/19 11:31:11 riastradh Exp $    */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -38,19 +38,9 @@
 
 #include <asm/barrier.h>
 
-#define        xchg(P, V)                                                            \
-       (sizeof(*(P)) == 4 ? atomic_swap_32((volatile uint32_t *)(P),         \
-               (uint32_t)(V))                                                \
-           : sizeof(*(P)) == 8 ? atomic_swap_64((volatile uint64_t *)(P),    \
-               (uint64_t)(V))                                                \
-           : (__builtin_abort(), 0))
-
-#define        cmpxchg(P, O, N)                                                      \
-       (sizeof(*(P)) == 4 ? atomic_cas_32((volatile uint32_t *)(P),          \
-               (uint32_t)(O), (uint32_t)(N))                                 \
-           : sizeof(*(P)) == 8 ? atomic_cas_64((volatile uint64_t *)(P),     \
-               (uint64_t)(O), (uint64_t)(N))                                 \
-           : (__builtin_abort(), 0))
+/* XXX Hope the GCC __sync builtins work everywhere we care about!  */
+#define        xchg(P, V)              __sync_lock_test_and_set(P, V)
+#define        cmpxchg(P, O, N)        __sync_val_compare_and_swap(P, O, N)
 
 /*
  * atomic (u)int operations