* [PATCH net v2 1/2] sfc: use 64-bit writes for PIO. [not found] <cover.1401268725.git.sshah@solarflare.com> @ 2014-05-28 9:27 ` Shradha Shah 2014-05-28 9:32 ` Shradha Shah 2014-05-28 14:48 ` Sergei Shtylyov 2014-05-28 9:28 ` [PATCH net v2 2/2] sfc: Restrict PIO to 64-bit architectures Shradha Shah 1 sibling, 2 replies; 6+ messages in thread From: Shradha Shah @ 2014-05-28 9:27 UTC (permalink / raw) To: netdev; +Cc: linux-net-drivers 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, ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH net v2 1/2] sfc: use 64-bit writes for PIO. 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 1 sibling, 0 replies; 6+ messages in thread From: Shradha Shah @ 2014-05-28 9:32 UTC (permalink / raw) To: netdev; +Cc: linux-net-drivers Please ignore this patch. I have sent out the correct patch with a cover letter. My Apologies for duplication Regards, Shradha On 28/05/14 10:27, Shradha Shah wrote: > 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, > -- Many Thanks, Regards, Shradha Shah ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net v2 1/2] sfc: use 64-bit writes for PIO. 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 1 sibling, 0 replies; 6+ messages in thread From: Sergei Shtylyov @ 2014-05-28 14:48 UTC (permalink / raw) To: Shradha Shah, netdev; +Cc: linux-net-drivers On 05/28/2014 01:27 PM, Shradha Shah wrote: > 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 Same comment as in the patch #2 > orig-hg-hash: 853f313def1e5e9c733f980f2b4e6330a7d063ef What's this? > 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); Be consistent with spaces after a typecast, please. > + 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. > */ [...] WBR, Sergei ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH net v2 2/2] sfc: Restrict PIO to 64-bit architectures [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 9:28 ` Shradha Shah 2014-05-28 14:45 ` Sergei Shtylyov 1 sibling, 1 reply; 6+ messages in thread From: Shradha Shah @ 2014-05-28 9:28 UTC (permalink / raw) To: netdev; +Cc: linux-net-drivers From: Jon Cooper <jcooper@solarflare.com> Enable PIO for x86_64 architecture only. Not tested on platforms other than x86_64. Fixes:ee45fd92c739db5b7950163d91dfe5f016af6d24 orig-hg-hash: 53dc43553d9bbe1c5a64c49e580ca571ddc470ae Signed-off-by: Shradha Shah <sshah@solarflare.com> --- drivers/net/ethernet/sfc/io.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/net/ethernet/sfc/io.h b/drivers/net/ethernet/sfc/io.h index 4d3f119..adadcf0 100644 --- a/drivers/net/ethernet/sfc/io.h +++ b/drivers/net/ethernet/sfc/io.h @@ -66,10 +66,18 @@ #define EFX_USE_QWORD_IO 1 #endif +/* PIO only works on 64-bit architectures */ +#if BITS_PER_LONG == 64 +/* not strictly necessary to restrict to x86 arch, but done for safety + * since unusual write combining behaviour can break PIO. + */ +#ifdef CONFIG_X86_64 /* PIO is a win only if write-combining is possible */ #ifdef ARCH_HAS_IOREMAP_WC #define EFX_USE_PIO 1 #endif +#endif +#endif #ifdef EFX_USE_QWORD_IO static inline void _efx_writeq(struct efx_nic *efx, __le64 value, ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH net v2 2/2] sfc: Restrict PIO to 64-bit architectures 2014-05-28 9:28 ` [PATCH net v2 2/2] sfc: Restrict PIO to 64-bit architectures Shradha Shah @ 2014-05-28 14:45 ` Sergei Shtylyov 0 siblings, 0 replies; 6+ messages in thread From: Sergei Shtylyov @ 2014-05-28 14:45 UTC (permalink / raw) To: Shradha Shah, netdev; +Cc: linux-net-drivers Hello. On 05/28/2014 01:28 PM, Shradha Shah wrote: > From: Jon Cooper <jcooper@solarflare.com> > Enable PIO for x86_64 architecture only. > Not tested on platforms other than x86_64. > Fixes:ee45fd92c739db5b7950163d91dfe5f016af6d24 12 digits is enough. And please specify that commit's summary enclosed in parens and quotes. > orig-hg-hash: 53dc43553d9bbe1c5a64c49e580ca571ddc470ae > Signed-off-by: Shradha Shah <sshah@solarflare.com> > --- > drivers/net/ethernet/sfc/io.h | 8 ++++++++ > 1 file changed, 8 insertions(+) WBR, Sergei ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH net v2 0/2] sfc: Restrict PIO for 64bit arch in order to avoid data corruption @ 2014-05-28 9:23 Shradha Shah 2014-05-28 9:28 ` [PATCH net v2 1/2] sfc: use 64-bit writes for PIO Shradha Shah 0 siblings, 1 reply; 6+ messages in thread From: Shradha Shah @ 2014-05-28 9:23 UTC (permalink / raw) To: netdev; +Cc: linux-net-drivers This patch series Fixes: ee45fd92c739db5b7950163d91dfe5f016af6d24 The linux net driver uses memcpy_toio() in order to copy into the PIO buffers. Even on a 64bit machine this causes 32bit accesses to a write- combined memory region. There are hardware limitations that mean that only 64bit naturally aligned accesses are safe in all cases. Due to being write-combined memory region two 32bit accesses may be coalesced to form a 64bit non 64bit aligned access. Solution was to open-code the memory copy routines using pointers and to only enable PIO for x86_64 machines. This bug fix applies to v3.13 and v3.14 stable branches. Jon Cooper (2): sfc: use 64-bit writes for PIO. sfc: Restrict PIO to 64-bit architectures drivers/net/ethernet/sfc/io.h | 8 ++++++++ drivers/net/ethernet/sfc/tx.c | 24 +++++++++++++++++++----- 2 files changed, 27 insertions(+), 5 deletions(-) ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH net v2 1/2] sfc: use 64-bit writes for PIO. 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 0 siblings, 0 replies; 6+ messages in thread From: Shradha Shah @ 2014-05-28 9:28 UTC (permalink / raw) Cc: netdev, linux-net-drivers 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, ^ permalink raw reply related [flat|nested] 6+ messages in thread
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[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
2014-05-28 9:28 ` [PATCH net v2 2/2] sfc: Restrict PIO to 64-bit architectures Shradha Shah
2014-05-28 14:45 ` Sergei Shtylyov
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 ` [PATCH net v2 1/2] sfc: use 64-bit writes for PIO Shradha Shah
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