From: "H. Peter Anvin" <hpa@zytor.com>
To: Ben Hutchings <bhutchings@solarflare.com>
Cc: David Laight <David.Laight@ACULAB.COM>,
Benjamin LaHaise <bcrl@kvack.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
David Miller <davem@davemloft.net>,
tglx@linutronix.de, mingo@redhat.com, netdev@vger.kernel.org,
linux-net-drivers@solarflare.com, x86@kernel.org
Subject: Re: [PATCH 2/3] x86_64: Define 128-bit memory-mapped I/O operations
Date: Wed, 22 Aug 2012 08:54:00 -0700 [thread overview]
Message-ID: <50350098.6030100@zytor.com> (raw)
In-Reply-To: <1345650689.2709.32.camel@bwh-desktop.uk.solarflarecom.com>
On 08/22/2012 08:51 AM, Ben Hutchings wrote:
>>
>> FWIW can you even guarantee to do an atomic 64bit PCIe transfer
>> on many systems (without resorting to a dma unit).
>
> On any architecture that implements readq and writeq these had better be
> atomic.
>
Sorry, you fail. There are definitely systems in the field where
readq() and writeq() are implemented, because the CPU supports them,
where the fabric does not guarantee they are intact.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2012-08-22 15:54 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 1:17 [PATCH 0/3] x86_64, sfc: 128-bit memory-mapped I/O Ben Hutchings
2012-08-22 1:20 ` [PATCH 1/3] x86_64: Define 128-bit types for kernel code only Ben Hutchings
2012-08-22 1:23 ` [PATCH 2/3] x86_64: Define 128-bit memory-mapped I/O operations Ben Hutchings
2012-08-22 1:37 ` H. Peter Anvin
2012-08-22 2:04 ` Ben Hutchings
2012-08-22 2:34 ` David Miller
2012-08-22 3:24 ` H. Peter Anvin
2012-08-22 3:29 ` David Miller
2012-08-22 3:49 ` H. Peter Anvin
2012-08-22 3:52 ` Linus Torvalds
2012-08-22 3:59 ` H. Peter Anvin
2012-08-22 4:14 ` David Miller
2012-08-22 21:14 ` David Miller
2012-08-22 21:28 ` Linus Torvalds
2012-08-22 21:38 ` David Miller
2012-08-22 4:35 ` Linus Torvalds
2012-08-22 5:00 ` David Miller
2012-08-22 14:06 ` Linus Torvalds
2012-08-22 4:42 ` Linus Torvalds
2012-08-22 13:26 ` Ben Hutchings
2012-08-22 14:20 ` Linus Torvalds
2012-08-22 14:24 ` Ben Hutchings
2012-08-22 14:30 ` Benjamin LaHaise
2012-08-22 14:58 ` Ben Hutchings
2012-08-22 15:13 ` H. Peter Anvin
2012-08-22 15:27 ` David Laight
2012-08-22 15:49 ` H. Peter Anvin
2012-08-22 15:51 ` Ben Hutchings
2012-08-22 15:54 ` H. Peter Anvin [this message]
2012-08-22 16:44 ` Ben Hutchings
2012-08-22 16:49 ` H. Peter Anvin
2012-08-22 16:55 ` Linus Torvalds
2012-08-22 17:09 ` Ben Hutchings
2012-08-22 17:12 ` H. Peter Anvin
2012-08-22 17:27 ` Ben Hutchings
2012-08-22 17:54 ` Linus Torvalds
2012-08-22 18:11 ` Ben Hutchings
2012-08-22 18:18 ` H. Peter Anvin
2012-08-22 18:28 ` Linus Torvalds
2012-08-22 19:01 ` Ben Hutchings
2012-08-22 17:26 ` Linus Torvalds
2012-08-22 16:51 ` Linus Torvalds
2012-08-22 16:59 ` H. Peter Anvin
2012-08-22 15:51 ` H. Peter Anvin
2012-08-22 14:50 ` Linus Torvalds
2012-08-22 14:56 ` Linus Torvalds
2012-08-22 15:05 ` David Laight
2012-08-22 15:16 ` Linus Torvalds
2012-08-22 15:41 ` Ben Hutchings
2012-08-22 14:42 ` David Laight
2012-08-22 1:26 ` [PATCH 3/3] sfc: Use __raw_writeo() to perform TX descriptor push where possible Ben Hutchings
2012-08-22 1:38 ` [PATCH 0/3] x86_64, sfc: 128-bit memory-mapped I/O H. Peter Anvin
2012-08-22 1:43 ` Ben Hutchings
2012-08-22 1:59 ` H. Peter Anvin
2012-08-22 2:10 ` Ben Hutchings
2012-08-22 2:31 ` H. Peter Anvin
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