On Mon, Jul 02, 2018 at 01:30:09AM +0800, Guo Ren wrote: > diff --git a/arch/csky/include/asm/barrier.h b/arch/csky/include/asm/barrier.h > new file mode 100644 > index 0000000..7254527 > --- /dev/null > +++ b/arch/csky/include/asm/barrier.h > @@ -0,0 +1,19 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. > +#ifndef __ASM_CSKY_BARRIER_H > +#define __ASM_CSKY_BARRIER_H > + > +#ifndef __ASSEMBLY__ > + > +#define nop() asm volatile ("nop") > + > +#ifdef CONFIG_SMP > +#define mb() asm volatile ("sync.is":::"memory") > +#else > +#define mb() asm volatile ("sync":::"memory") > +#endif This is very suspect, please elaborate. What I would've expected is: #define mb() asm volatile ("sync" ::: "memory") #ifdef CONFIG_SMP #define __smp_mb() asm volatile ("sync.is" ::: "memory") #endif Is that in fact what you meant? Do you have a reference to your architecture manual and memory model description somewhere? > + > +#include <asm-generic/barrier.h> > + > +#endif /* __ASSEMBLY__ */ > +#endif /* __ASM_CSKY_BARRIER_H */