There were no memory barriers on cmpxchg64() _at_all_. Fix this.
Cc: Paul Burton <paul.bur...@mips.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
arch/mips/include/asm/cmpxchg.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/arch/mips/include/asm/cmpxchg.h
+++ b/arch/mips/include/asm/cmpxchg.h
@@ -290,9 +290,11 @@ static inline unsigned long __cmpxchg64(
* will cause a build error unless cpu_has_64bits is a \
* compile-time constant 1. \
*/ \
- if (cpu_has_64bits && kernel_uses_llsc) \
+ if (cpu_has_64bits && kernel_uses_llsc) { \
+ smp_mb__before_llsc(); \
__res = __cmpxchg64((ptr), __old, __new); \
- else \
+ smp_llsc_mb(); \
+ } else \
__res = __cmpxchg64_unsupported(); \
\
__res; \
