mb.h

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#ifndef _MB_H
#define _MB_H
 
/* These definitions are not yet in distros, so I have cut and pasted just
   the needed definitions in here */
 
#ifdef __powerpc__
#define rmb() asm volatile ("sync" : : : "memory")
 
#elif defined (__s390__)
#define rmb() asm volatile("bcr 15,0" ::: "memory")
 
#elif defined (__sh__)
#if defined(__SH4A__) || defined(__SH5__)
#define rmb()          asm volatile("synco" ::: "memory")
#else
#define rmb()          asm volatile("" ::: "memory")
#endif
 
#elif defined (__hppa__)
#define rmb()           asm volatile("" ::: "memory")
 
#elif defined (__sparc__)
#define rmb()           asm volatile("":::"memory")
 
#elif defined (__alpha__)
#define rmb()           asm volatile("mb" ::: "memory")
 
#elif defined(__ia64__)
#define rmb()           asm volatile ("mf" ::: "memory")
 
#elif defined(__arm__)
/*
 * Use the __kuser_memory_barrier helper in the CPU helper page. See
 * arch/arm/kernel/entry-armv.S in the kernel source for details.
 */
#define rmb()           ((void(*)(void))0xffff0fa0)()
 
#elif defined(__aarch64__)
#define rmb()           asm volatile("dmb ld" ::: "memory")
 
#elif defined(__mips__)
#define rmb()           asm volatile(                                   \
                                ".set   mips2\n\t"                      \
                                "sync\n\t"                              \
                                ".set   mips0"                          \
                : /* no output */                       \
                : /* no input */                        \
                : "memory")
 
#elif defined(__i386__)
#define rmb() asm volatile("lock; addl $0,0(%%esp)" ::: "memory")
 
#elif defined(__NEC__)
#define rmb() asm volatile("lfence":::"memory")
 
#elif defined(__x86_64)
 
#if defined(__KNC__)
#define rmb() __sync_synchronize()
 
#else
#define rmb() asm volatile("lfence":::"memory")
#endif
 
#else
#error Need to define rmb for this architecture!
#error See the kernel source directory: tools/perf/perf.h file
#endif
 
#endif