tools include: Provide gcc based cmpxchg fallback for !x86

We've been using an atomic_t implementation subset based on the gcc
builtin functions for a while, now, with refcount.h we need cmpxchg(),
use gcc's __sync_val_compare_and_swap() for that.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-b9zovyxgpa0c4vi3nm0kjo97@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/include/asm-generic/atomic-gcc.h b/tools/include/asm-generic/atomic-gcc.h
index 2ba78c9..5e9738f 100644 (file)
--- a/tools/include/asm-generic/atomic-gcc.h
+++ b/tools/include/asm-generic/atomic-gcc.h
@@ -60,4 +60,12 @@ static inline int atomic_dec_and_test(atomic_t *v)
        return __sync_sub_and_fetch(&v->counter, 1) == 0;
 }
 
+#define cmpxchg(ptr, oldval, newval) \
+       __sync_val_compare_and_swap(ptr, oldval, newval)
+
+static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval)
+{
+       return cmpxchg(&(v)->counter, oldval, newval);
+}
+
 #endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */