From: Shradha Shah <sshah@solarflare•com>
To: unlisted-recipients:; (no To-header on input)
Cc: <netdev@vger•kernel.org>, <linux-net-drivers@solarflare•com>
Subject: [PATCH net v2 1/2] sfc: use 64-bit writes for PIO.
Date: Wed, 28 May 2014 10:28:04 +0100 [thread overview]
Message-ID: <5385AC24.6030007@solarflare.com> (raw)
In-Reply-To: <5385AAF5.7090001@solarflare.com>
From: Jon Cooper <jcooper@solarflare•com>
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 <sshah@solarflare•com>
---
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,
next prev parent reply other threads:[~2014-05-28 9:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-28 9:23 [PATCH net v2 0/2] sfc: Restrict PIO for 64bit arch in order to avoid data corruption Shradha Shah
2014-05-28 9:28 ` Shradha Shah [this message]
2014-05-28 9:30 ` [PATCH net v2 2/2] sfc: Restrict PIO to 64-bit architectures Shradha Shah
2014-05-31 0:38 ` [PATCH net v2 0/2] sfc: Restrict PIO for 64bit arch in order to avoid data corruption David Miller
[not found] <cover.1401268725.git.sshah@solarflare.com>
2014-05-28 9:27 ` [PATCH net v2 1/2] sfc: use 64-bit writes for PIO Shradha Shah
2014-05-28 9:32 ` Shradha Shah
2014-05-28 14:48 ` Sergei Shtylyov
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