Michael Chan wrote:
[BNX2]: Add 40-bit DMA workaround for 5708.
The internal PCIE-to-PCIX bridge of the 5708 has the same 40-bit DMA
limitation as some of the tg3 chips. Use the same workaround used in
tg3. On 64-bit systems without IOMMU, linearize the SKB if any
address is > 40-bit.
Signed-off-by: Michael Chan <[EMAIL PROTECTED]>
diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 6d05397..dba4088 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -4495,6 +4495,93 @@ bnx2_vlan_rx_kill_vid(struct net_device *dev, uint16_t
vid)
}
#endif
+/* Test for DMA addresses > 40-bit.
+ * Only 64-bit systems without IOMMU require DMA address checking.
+ */
+static inline int bnx2_40bit_overflow_test(struct bnx2 *bp, dma_addr_t mapping,
+ int len)
+{
+#if defined(CONFIG_HIGHMEM) && (BITS_PER_LONG == 64)
+ if (CHIP_NUM(bp) == CHIP_NUM_5708)
+ return (((u64) mapping + len) > DMA_40BIT_MASK);
If the mapping is at a very high address, adding len might overflow, yes?
+#if defined(CONFIG_HIGHMEM) && (BITS_PER_LONG == 64)
+ if (unlikely(would_hit_hwbug)) {
+ /* If the workaround fails due to memory/mapping
+ * failure, silently drop this packet.
+ */
+ if (bnx2_dma_hwbug_workaround(bp, &skb, &prod,
+ vlan_tag_flags, mss))
+ return NETDEV_TX_OK;
+
+ }
+#endif
You need to at least account for the drop, in packets-dropped stat.
/Completely/ silent intentional packet drops are something to be
avoided. The user should be given /some/ indication of what is going on.
Second, CONFIG_HIGHMEM is a bad test for IOMMU presence. I don't think
you /can/ test for IOMMU presence. Maybe DaveM knows a way that I do not?
+ /* 5708 cannot support DMA addresses > 40-bit.
+ * On 64-bit systems with IOMMU, use 40-bit dma_mask.
+ * On 64-bit systems without IOMMU, use 64-bit dma_mask and
+ * do DMA address check in bnx2_start_xmit().
+ */
+ if (CHIP_NUM(bp) == CHIP_NUM_5708) {
+ persist_dma_mask = dma_mask = DMA_40BIT_MASK;
+#ifdef CONFIG_HIGHMEM
+ dma_mask = DMA_64BIT_MASK;
+#endif
+ } else
+ persist_dma_mask = dma_mask = DMA_64BIT_MASK;
+
+ /* Configure DMA attributes. */
+ if (pci_set_dma_mask(pdev, dma_mask) == 0) {
+ dev->features |= NETIF_F_HIGHDMA;
+ rc = pci_set_consistent_dma_mask(pdev, persist_dma_mask);
+ if (rc) {
+ dev_err(&pdev->dev,
+ "pci_set_consistent_dma_mask failed,
aborting.\n");
+ goto err_out_unmap;
+ }
+ } else if ((rc = pci_set_dma_mask(pdev, DMA_32BIT_MASK)) != 0) {
+ dev_err(&pdev->dev, "System does not support DMA, aborting.\n");
+ goto err_out_unmap;
+ }
+
Ditto. CONFIG_HIGHMEM is not an effective test.
NAK.
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