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authorJia-Ju Bai <baijiaju@tsinghua.edu.cn>2020-08-02 17:33:40 +0800
committerDavid S. Miller <davem@davemloft.net>2020-08-03 15:51:25 -0700
commitcbbb64f62acd97429f517bd382ada9d618c8856a (patch)
treeafcf227c8d3f9acc858c0b1fad42981d72057e05 /drivers/atm
parenta45a9e8a768c32103ffec67f9b173968a6154a11 (diff)
atm: idt77252: avoid accessing the data mapped to streaming DMA
In queue_skb(), skb->data is mapped to streaming DMA on line 850: dma_map_single(..., skb->data, ...); Then skb->data is accessed on lines 862 and 863: tbd->word_4 = (skb->data[0] << 24) | (skb->data[1] << 16) | (skb->data[2] << 8) | (skb->data[3] << 0); and on lines 893 and 894: tbd->word_4 = (skb->data[0] << 24) | (skb->data[1] << 16) | (skb->data[2] << 8) | (skb->data[3] << 0); These accesses may cause data inconsistency between CPU cache and hardware. To fix this problem, the calculation result of skb->data is stored in a local variable before DMA mapping, and then the driver accesses this local variable instead of skb->data. Signed-off-by: Jia-Ju Bai <baijiaju@tsinghua.edu.cn> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/atm')
-rw-r--r--drivers/atm/idt77252.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
index df51680e8931..65a3886f68c9 100644
--- a/drivers/atm/idt77252.c
+++ b/drivers/atm/idt77252.c
@@ -835,6 +835,7 @@ queue_skb(struct idt77252_dev *card, struct vc_map *vc,
unsigned long flags;
int error;
int aal;
+ u32 word4;
if (skb->len == 0) {
printk("%s: invalid skb->len (%d)\n", card->name, skb->len);
@@ -846,6 +847,8 @@ queue_skb(struct idt77252_dev *card, struct vc_map *vc,
tbd = &IDT77252_PRV_TBD(skb);
vcc = ATM_SKB(skb)->vcc;
+ word4 = (skb->data[0] << 24) | (skb->data[1] << 16) |
+ (skb->data[2] << 8) | (skb->data[3] << 0);
IDT77252_PRV_PADDR(skb) = dma_map_single(&card->pcidev->dev, skb->data,
skb->len, DMA_TO_DEVICE);
@@ -859,8 +862,7 @@ queue_skb(struct idt77252_dev *card, struct vc_map *vc,
tbd->word_1 = SAR_TBD_OAM | ATM_CELL_PAYLOAD | SAR_TBD_EPDU;
tbd->word_2 = IDT77252_PRV_PADDR(skb) + 4;
tbd->word_3 = 0x00000000;
- tbd->word_4 = (skb->data[0] << 24) | (skb->data[1] << 16) |
- (skb->data[2] << 8) | (skb->data[3] << 0);
+ tbd->word_4 = word4;
if (test_bit(VCF_RSV, &vc->flags))
vc = card->vcs[0];
@@ -890,8 +892,7 @@ queue_skb(struct idt77252_dev *card, struct vc_map *vc,
tbd->word_2 = IDT77252_PRV_PADDR(skb) + 4;
tbd->word_3 = 0x00000000;
- tbd->word_4 = (skb->data[0] << 24) | (skb->data[1] << 16) |
- (skb->data[2] << 8) | (skb->data[3] << 0);
+ tbd->word_4 = word4;
break;
case ATM_AAL5: