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| author | Jia-Ju Bai <baijiaju@tsinghua.edu.cn> | 2020-08-02 17:16:11 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-08-03 15:50:48 -0700 |
| commit | a45a9e8a768c32103ffec67f9b173968a6154a11 (patch) | |
| tree | 2a7ce1800b8c274c0426c5717b99756825054518 | |
| parent | 6d78e473e018e15065d3004ee73ac77acf82baa2 (diff) | |
| download | linux-a45a9e8a768c32103ffec67f9b173968a6154a11.tar.gz linux-a45a9e8a768c32103ffec67f9b173968a6154a11.tar.bz2 linux-a45a9e8a768c32103ffec67f9b173968a6154a11.zip | |
atm: eni: avoid accessing the data mapped to streaming DMA
In do_tx(), skb->data is mapped to streaming DMA on line 1111:
paddr = dma_map_single(...,skb->data,DMA_TO_DEVICE);
Then skb->data is accessed on line 1153:
(skb->data[3] & 0xf)
This access may cause data inconsistency between CPU cache and hardware.
To fix this problem, skb->data[3] is assigned to a local variable before
DMA mapping, and then the driver accesses this local variable instead of
skb->data[3].
Signed-off-by: Jia-Ju Bai <baijiaju@tsinghua.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/atm/eni.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/atm/eni.c b/drivers/atm/eni.c index b3d8e00e7671..39be444534d0 100644 --- a/drivers/atm/eni.c +++ b/drivers/atm/eni.c @@ -1034,6 +1034,7 @@ static enum enq_res do_tx(struct sk_buff *skb) u32 dma_rd,dma_wr; u32 size; /* in words */ int aal5,dma_size,i,j; + unsigned char skb_data3; DPRINTK(">do_tx\n"); NULLCHECK(skb); @@ -1108,6 +1109,7 @@ DPRINTK("iovcnt = %d\n",skb_shinfo(skb)->nr_frags); vcc->dev->number); return enq_jam; } + skb_data3 = skb->data[3]; paddr = dma_map_single(&eni_dev->pci_dev->dev,skb->data,skb->len, DMA_TO_DEVICE); ENI_PRV_PADDR(skb) = paddr; @@ -1150,7 +1152,7 @@ DPRINTK("doing direct send\n"); /* @@@ well, this doesn't work anyway */ (size/(ATM_CELL_PAYLOAD/4)),tx->send+tx->tx_pos*4); /*printk("dsc = 0x%08lx\n",(unsigned long) readl(tx->send+tx->tx_pos*4));*/ writel((vcc->vci << MID_SEG_VCI_SHIFT) | - (aal5 ? 0 : (skb->data[3] & 0xf)) | + (aal5 ? 0 : (skb_data3 & 0xf)) | (ATM_SKB(skb)->atm_options & ATM_ATMOPT_CLP ? MID_SEG_CLP : 0), tx->send+((tx->tx_pos+1) & (tx->words-1))*4); DPRINTK("size: %d, len:%d\n",size,skb->len); |