LXR linux/arch/x86/um/asm/barrier.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ASM_UM_BARRIER_H_
   3#define _ASM_UM_BARRIER_H_
   4
   5#include <asm/asm.h>
   6#include <asm/segment.h>
   7#include <asm/cpufeatures.h>
   8#include <asm/cmpxchg.h>
   9#include <asm/nops.h>
  10
  11#include <linux/kernel.h>
  12#include <linux/irqflags.h>
  13
  14/*
  15 * Force strict CPU ordering.
  16 * And yes, this is required on UP too when we're talking
  17 * to devices.
  18 */
  19#ifdef CONFIG_X86_32
  20
  21#define mb()    alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
  22#define rmb()   alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
  23#define wmb()   alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM)
  24
  25#else /* CONFIG_X86_32 */
  26
  27#define mb()    asm volatile("mfence" : : : "memory")
  28#define rmb()   asm volatile("lfence" : : : "memory")
  29#define wmb()   asm volatile("sfence" : : : "memory")
  30
  31#endif /* CONFIG_X86_32 */
  32
  33#define dma_rmb()       barrier()
  34#define dma_wmb()       barrier()
  35
  36#include <asm-generic/barrier.h>
  37
  38#endif
  39