From 847a1c75765aaf038285a6e20239b6f5ed002824 Mon Sep 17 00:00:00 2001
From: WangRunji <wangrunji0408@163.com>
Date: Tue, 29 Jan 2019 16:08:00 +0800
Subject: [PATCH] use core::sync::atomic::fence

---
 kernel/src/arch/aarch64/cpu.rs       | 4 ----
 kernel/src/arch/riscv32/cpu.rs       | 4 ----
 kernel/src/arch/x86_64/cpu.rs        | 4 ----
 kernel/src/drivers/net/virtio_net.rs | 5 +++--
 4 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/kernel/src/arch/aarch64/cpu.rs b/kernel/src/arch/aarch64/cpu.rs
index 701150d..bf495bc 100644
--- a/kernel/src/arch/aarch64/cpu.rs
+++ b/kernel/src/arch/aarch64/cpu.rs
@@ -6,7 +6,3 @@ pub fn id() -> usize {
     // TODO: cpu id
     0
 }
-
-pub fn fence() {
-    unsafe { asm!("dmb ish" ::: "memory"); }
-}
diff --git a/kernel/src/arch/riscv32/cpu.rs b/kernel/src/arch/riscv32/cpu.rs
index b42f447..0a33080 100644
--- a/kernel/src/arch/riscv32/cpu.rs
+++ b/kernel/src/arch/riscv32/cpu.rs
@@ -35,7 +35,3 @@ pub unsafe fn start_others(hart_mask: usize) {
 pub fn halt() {
     unsafe { riscv::asm::wfi() }
 }
-
-pub fn fence() {
-    unsafe { asm!("fence" ::: "memory"); }
-}
diff --git a/kernel/src/arch/x86_64/cpu.rs b/kernel/src/arch/x86_64/cpu.rs
index 6a1ff41..3229554 100644
--- a/kernel/src/arch/x86_64/cpu.rs
+++ b/kernel/src/arch/x86_64/cpu.rs
@@ -30,7 +30,3 @@ pub fn halt() {
     use x86_64::instructions::hlt;
     hlt();
 }
-
-pub fn fence() {
-    unsafe { asm!("mfence" ::: "memory"); }
-}
diff --git a/kernel/src/drivers/net/virtio_net.rs b/kernel/src/drivers/net/virtio_net.rs
index 69b2b3c..595b6ab 100644
--- a/kernel/src/drivers/net/virtio_net.rs
+++ b/kernel/src/drivers/net/virtio_net.rs
@@ -4,6 +4,7 @@ use alloc::prelude::*;
 use alloc::sync::Arc;
 use core::mem::size_of;
 use core::slice;
+use core::sync::atomic::{fence, Ordering};
 
 use bitflags::*;
 use device_tree::Node;
@@ -215,7 +216,7 @@ impl phy::TxToken for VirtIONetTxToken {
         desc.len.write((len + size_of::<VirtIONetHeader>()) as u32);
 
         // memory barrier
-        crate::arch::cpu::fence();
+        fence(Ordering::SeqCst);
         
         // add desc to available ring
         ring.idx.write(ring.idx.read() + 1);
@@ -376,7 +377,7 @@ pub fn virtio_net_init(node: &Node) {
             desc.flags.write(0);
         }
         // memory barrier
-        crate::arch::cpu::fence();
+        fence(Ordering::SeqCst);
 
 
         if queue == VIRTIO_QUEUE_RECEIVE {