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- #ifndef _ASM_X86_BARRIER_H
- #define _ASM_X86_BARRIER_H
- #include <asm/alternative.h>
- #include <asm/nops.h>
- /*
- * Force strict CPU ordering.
- * And yes, this might be required on UP too when we're talking
- * to devices.
- */
- #ifdef CONFIG_X86_32
- #define mb() asm volatile(ALTERNATIVE("lock; addl $0,0(%%esp)", "mfence", \
- X86_FEATURE_XMM2) ::: "memory", "cc")
- #define rmb() asm volatile(ALTERNATIVE("lock; addl $0,0(%%esp)", "lfence", \
- X86_FEATURE_XMM2) ::: "memory", "cc")
- #define wmb() asm volatile(ALTERNATIVE("lock; addl $0,0(%%esp)", "sfence", \
- X86_FEATURE_XMM2) ::: "memory", "cc")
- #else
- #define mb() asm volatile("mfence":::"memory")
- #define rmb() asm volatile("lfence":::"memory")
- #define wmb() asm volatile("sfence" ::: "memory")
- #endif
- #ifdef CONFIG_X86_PPRO_FENCE
- #define dma_rmb() rmb()
- #else
- #define dma_rmb() barrier()
- #endif
- #define dma_wmb() barrier()
- #define __smp_mb() mb()
- #define __smp_rmb() dma_rmb()
- #define __smp_wmb() barrier()
- #define __smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0)
- #if defined(CONFIG_X86_PPRO_FENCE)
- /*
- * For this option x86 doesn't have a strong TSO memory
- * model and we should fall back to full barriers.
- */
- #define __smp_store_release(p, v) \
- do { \
- compiletime_assert_atomic_type(*p); \
- __smp_mb(); \
- WRITE_ONCE(*p, v); \
- } while (0)
- #define __smp_load_acquire(p) \
- ({ \
- typeof(*p) ___p1 = READ_ONCE(*p); \
- compiletime_assert_atomic_type(*p); \
- __smp_mb(); \
- ___p1; \
- })
- #else /* regular x86 TSO memory ordering */
- #define __smp_store_release(p, v) \
- do { \
- compiletime_assert_atomic_type(*p); \
- barrier(); \
- WRITE_ONCE(*p, v); \
- } while (0)
- #define __smp_load_acquire(p) \
- ({ \
- typeof(*p) ___p1 = READ_ONCE(*p); \
- compiletime_assert_atomic_type(*p); \
- barrier(); \
- ___p1; \
- })
- #endif
- /* Atomic operations are already serializing on x86 */
- #define __smp_mb__before_atomic() barrier()
- #define __smp_mb__after_atomic() barrier()
- #include <asm-generic/barrier.h>
- #endif /* _ASM_X86_BARRIER_H */
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