From dfc8d8de855d566eb83a27e58a69741de42a90da Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 13 Jun 2019 15:43:18 +0200 Subject: [PATCH] mips/atomic: Fix cmpxchg64 barriers There were no memory barriers on the 32bit implementation of cmpxchg64(). Fix this. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Paul Burton --- arch/mips/include/asm/cmpxchg.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h index f345a873742d..59cf5cbb3883 100644 --- a/arch/mips/include/asm/cmpxchg.h +++ b/arch/mips/include/asm/cmpxchg.h @@ -290,10 +290,13 @@ static inline unsigned long __cmpxchg64(volatile void *ptr, * 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; \ })