From: Shradha Shah <sshah@solarflare.com>
To: <netdev@vger.kernel.org>
Cc: <linux-net-drivers@solarflare.com>
Subject: [PATCH net v2 0/2] sfc: Restrict PIO for 64bit arch in order to avoid data corruption
Date: Wed, 28 May 2014 10:23:01 +0100 [thread overview]
Message-ID: <5385AAF5.7090001@solarflare.com> (raw)
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(-)
next reply other threads:[~2014-05-28 9:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-28 9:23 Shradha Shah [this message]
2014-05-28 9:28 ` [PATCH net v2 1/2] sfc: use 64-bit writes for PIO Shradha Shah
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
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