MIPS: New macro smp_mb__before_llsc.

Replace some instances of smp_llsc_mb() with a new macro
smp_mb__before_llsc().  It is used before ll/sc sequences that are
documented as needing write barrier semantics.

The default implementation of smp_mb__before_llsc() is just smp_llsc_mb(),
so there are no changes in semantics.

Also simplify definition of smp_mb(), smp_rmb(), and smp_wmb() to be just
barrier() in the non-SMP case.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/851/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
David Daney
2010-01-08 17:17:43 -08:00
committed by Ralf Baechle
parent ec5380c768
commit f252ffd50c
6 changed files with 32 additions and 25 deletions

View File

@ -131,23 +131,26 @@
#endif /* !CONFIG_CPU_HAS_WB */
#if defined(CONFIG_WEAK_ORDERING) && defined(CONFIG_SMP)
#define __WEAK_ORDERING_MB " sync \n"
#define smp_mb() __asm__ __volatile__("sync" : : :"memory")
#define smp_rmb() __asm__ __volatile__("sync" : : :"memory")
#define smp_wmb() __asm__ __volatile__("sync" : : :"memory")
#else
#define __WEAK_ORDERING_MB " \n"
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#endif
#if defined(CONFIG_WEAK_REORDERING_BEYOND_LLSC) && defined(CONFIG_SMP)
#define __WEAK_LLSC_MB " sync \n"
#else
#define __WEAK_LLSC_MB " \n"
#endif
#define smp_mb() __asm__ __volatile__(__WEAK_ORDERING_MB : : :"memory")
#define smp_rmb() __asm__ __volatile__(__WEAK_ORDERING_MB : : :"memory")
#define smp_wmb() __asm__ __volatile__(__WEAK_ORDERING_MB : : :"memory")
#define set_mb(var, value) \
do { var = value; smp_mb(); } while (0)
#define smp_llsc_mb() __asm__ __volatile__(__WEAK_LLSC_MB : : :"memory")
#define smp_mb__before_llsc() smp_llsc_mb()
#endif /* __ASM_BARRIER_H */