From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shradha Shah Subject: [PATCH net v2 1/2] sfc: use 64-bit writes for PIO. Date: Wed, 28 May 2014 10:28:04 +0100 Message-ID: <5385AC24.6030007@solarflare.com> References: <5385AAF5.7090001@solarflare.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: , To: unlisted-recipients:; (no To-header on input) Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:17135 "EHLO webmail.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752283AbaE1J2H (ORCPT ); Wed, 28 May 2014 05:28:07 -0400 In-Reply-To: <5385AAF5.7090001@solarflare.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Jon Cooper Patch to open-code the memory copy routines. 32bit writes over the PCI bus causes data corruption. Fixes:ee45fd92c739db5b7950163d91dfe5f016af6d24 orig-hg-hash: 853f313def1e5e9c733f980f2b4e6330a7d063ef Signed-off-by: Shradha Shah --- drivers/net/ethernet/sfc/tx.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c index fa94753..bd6a4b8 100644 --- a/drivers/net/ethernet/sfc/tx.c +++ b/drivers/net/ethernet/sfc/tx.c @@ -189,6 +189,20 @@ struct efx_short_copy_buffer { u8 buf[L1_CACHE_BYTES]; }; +/* Copy in explicit 64-bit writes. */ +static void efx_memcpy_64(void *dest, void *src, size_t len) +{ + uint64_t *src64 = src, *dest64 = dest; + size_t i, l64 = len / 8; + + WARN_ON_ONCE(len % 8 != 0); + WARN_ON_ONCE(((u8 *)dest - (u8 *) 0) % 8 != 0); + BUILD_BUG_ON(sizeof(uint64_t) != 8); + + for(i = 0; i < l64; ++i) + dest64[i] = src64[i]; +} + /* Copy to PIO, respecting that writes to PIO buffers must be dword aligned. * Advances piobuf pointer. Leaves additional data in the copy buffer. */ @@ -198,7 +212,7 @@ static void efx_memcpy_toio_aligned(struct efx_nic *efx, u8 __iomem **piobuf, { int block_len = len & ~(sizeof(copy_buf->buf) - 1); - memcpy_toio(*piobuf, data, block_len); + efx_memcpy_64(*piobuf, data, block_len); *piobuf += block_len; len -= block_len; @@ -230,7 +244,7 @@ static void efx_memcpy_toio_aligned_cb(struct efx_nic *efx, u8 __iomem **piobuf, if (copy_buf->used < sizeof(copy_buf->buf)) return; - memcpy_toio(*piobuf, copy_buf->buf, sizeof(copy_buf->buf)); + efx_memcpy_64(*piobuf, copy_buf->buf, sizeof(copy_buf->buf)); *piobuf += sizeof(copy_buf->buf); data += copy_to_buf; len -= copy_to_buf; @@ -245,7 +259,7 @@ static void efx_flush_copy_buffer(struct efx_nic *efx, u8 __iomem *piobuf, { /* if there's anything in it, write the whole buffer, including junk */ if (copy_buf->used) - memcpy_toio(piobuf, copy_buf->buf, sizeof(copy_buf->buf)); + efx_memcpy_64(piobuf, copy_buf->buf, sizeof(copy_buf->buf)); } /* Traverse skb structure and copy fragments in to PIO buffer. @@ -304,8 +318,8 @@ efx_enqueue_skb_pio(struct efx_tx_queue *tx_queue, struct sk_buff *skb) */ BUILD_BUG_ON(L1_CACHE_BYTES > SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); - memcpy_toio(tx_queue->piobuf, skb->data, - ALIGN(skb->len, L1_CACHE_BYTES)); + efx_memcpy_64(tx_queue->piobuf, skb->data, + ALIGN(skb->len, L1_CACHE_BYTES)); } EFX_POPULATE_QWORD_5(buffer->option,