sfc: Ensure MCDI buffers, but not lengths, are dword aligned
We currently require that MCDI request and response lengths are
multiples of 4 bytes, because we will copy dwords in and out of shared
memory and we want to be sure we won't read or write out of bounds.
But all we really need to know is that there is sufficient padding for
that. Also, we should ensure that buffers are dword-aligned, as on
some architectures misaligned access will result in data corruption or
a crash.
Change the buffer type to array-of-efx_dword_t and remove the
requirement that the lengths are multiples of 4.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index ec2cf4d..5612021 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -571,9 +571,8 @@
struct efx_ptp_data *ptp_data = efx->ptp_data;
struct skb_shared_hwtstamps timestamps;
int rc = -EIO;
- /* MCDI driver requires word aligned lengths */
- size_t len = ALIGN(MC_CMD_PTP_IN_TRANSMIT_LEN(skb->len), 4);
MCDI_DECLARE_BUF(txtime, MC_CMD_PTP_OUT_TRANSMIT_LEN);
+ size_t len;
MCDI_SET_DWORD(ptp_data->txbuf, PTP_IN_OP, MC_CMD_PTP_OP_TRANSMIT);
MCDI_SET_DWORD(ptp_data->txbuf, PTP_IN_TRANSMIT_LENGTH, skb->len);
@@ -591,9 +590,10 @@
skb_copy_from_linear_data(skb,
MCDI_PTR(ptp_data->txbuf,
PTP_IN_TRANSMIT_PACKET),
- len);
- rc = efx_mcdi_rpc(efx, MC_CMD_PTP, ptp_data->txbuf, len, txtime,
- sizeof(txtime), &len);
+ skb->len);
+ rc = efx_mcdi_rpc(efx, MC_CMD_PTP,
+ ptp_data->txbuf, MC_CMD_PTP_IN_TRANSMIT_LEN(skb->len),
+ txtime, sizeof(txtime), &len);
if (rc != 0)
goto fail;