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#ifndef _ASM_UM_BARRIER_H_
#define _ASM_UM_BARRIER_H_
#include <asm/asm.h>
#include <asm/segment.h>
#include <asm/cpufeature.h>
#include <asm/cmpxchg.h>
#include <asm/nops.h>
#include <linux/kernel.h>
#include <linux/irqflags.h>
/*
* Force strict CPU ordering.
* And yes, this is required on UP too when we're talking
* to devices.
*/
#ifdef CONFIG_X86_32
#define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
#define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
#define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM)
#else /* CONFIG_X86_32 */
#define mb() asm volatile("mfence" : : : "memory")
#define rmb() asm volatile("lfence" : : : "memory")
#define wmb() asm volatile("sfence" : : : "memory")
#endif /* CONFIG_X86_32 */
#ifdef CONFIG_X86_PPRO_FENCE
#define dma_rmb() rmb()
#else /* CONFIG_X86_PPRO_FENCE */
#define dma_rmb() barrier()
#endif /* CONFIG_X86_PPRO_FENCE */
#define dma_wmb() barrier()
#ifdef CONFIG_SMP
#define smp_mb() mb()
#define smp_rmb() dma_rmb()
#define smp_wmb() barrier()
#define set_mb(var, value) do { (void)xchg(&var, value); } while (0)
#else /* CONFIG_SMP */
#define smp_mb() barrier()
#define smp_rmb() barrier()
#define smp_wmb() barrier()
#define set_mb(var, value) do { var = value; barrier(); } while (0)
#endif /* CONFIG_SMP */
#define read_barrier_depends() do { } while (0)
#define smp_read_barrier_depends() do { } while (0)
/*
* Stop RDTSC speculation. This is needed when you need to use RDTSC
* (or get_cycles or vread that possibly accesses the TSC) in a defined
* code region.
*
* (Could use an alternative three way for this if there was one.)
*/
static inline void rdtsc_barrier(void)
{
alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
}
#endif
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