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851b6cb17c
When we have virtio enabled, we must have real barriers since we may be running on an SMP machine (quite likely are, in fact), so the other process can be on another CPU. Since in any other case we don't really use DMA barriers, remove their override completely so real barriers will get used. In the future we might need them for other cases as well. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
28 lines
747 B
C
28 lines
747 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_UM_BARRIER_H_
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#define _ASM_UM_BARRIER_H_
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#include <asm/alternative.h>
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/*
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* Force strict CPU ordering.
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* And yes, this is required on UP too when we're talking
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* to devices.
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*/
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#ifdef CONFIG_X86_32
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#define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
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#define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
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#define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM)
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#else /* CONFIG_X86_32 */
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#define mb() asm volatile("mfence" : : : "memory")
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#define rmb() asm volatile("lfence" : : : "memory")
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#define wmb() asm volatile("sfence" : : : "memory")
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#endif /* CONFIG_X86_32 */
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#include <asm-generic/barrier.h>
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#endif
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