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 09:49:03 -0700 [thread overview]
Message-ID: <50350D7F.30607@zytor.com> (raw)
In-Reply-To: <1345653844.2709.51.camel@bwh-desktop.uk.solarflarecom.com>
On 08/22/2012 09:44 AM, Ben Hutchings wrote:
>>
>> 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.
>
> Well, when the issue of 64-bit MMIO was discussed earlier this year, you
> said nothing about this. I thought the conclusion was that any
> definitions provided by <asm/io.h> *must* be atomic and drivers can use
> <asm-generic/io-64-nonatomic-hi-lo.h> or
> <asm-generic/io-64-nonatomic-lo-hi.h> as a fallback.
>
That is true at the exit interface from the CPU core. Beyond that
drivers have to keep in mind the possible limitations of the
communications fabric between the CPU and the device.
-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 16:49 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
2012-08-22 16:44 ` Ben Hutchings
2012-08-22 16:49 ` H. Peter Anvin [this message]
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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