From: "H. Peter Anvin" <hpa@zytor.com>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
jbarnes@virtuousgeek.org
Subject: Re: [PATCH 2/4] x86: ioremap: fix physical address check
Date: Mon, 14 Jun 2010 08:11:04 -0700 [thread overview]
Message-ID: <4C164688.2030107@zytor.com> (raw)
In-Reply-To: <alpine.LFD.2.00.1006140735040.11549@eddie.linux-mips.org>
On 06/13/2010 11:38 PM, Maciej W. Rozycki wrote:
> On Mon, 14 Jun 2010, Kenji Kaneshige wrote:
>
>> - Architectural limit of physical address in x86 32-bit mode is 40-bit
>> (depnds on processor version).
>
> According to documentation I happen to have handy this limit is actually
> 52 bits (and space is currently available in the data structures used for
> a possible future extension up to 63 bits).
>
Yes. There are, however, very likely bugs in several classes due to
incorrect bitmasks as well as 32-bit PFNs.
We have made the decision based on data structure limitations (and just
usability) to not support more than 2^36 bytes of RAM on 32 bits, but
those data structures should not affect I/O. I;d like to track down and
fix the bugs instead of papering over the problem...
-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:[~2010-06-14 15:11 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-11 9:17 [RFC][PATCH 0/4] x86: ioremap() problem in X86_32 PAE Kenji Kaneshige
2010-06-11 9:18 ` [PATCH 1/4] x86: ioremap: fix wrong address masking Kenji Kaneshige
2010-06-11 9:20 ` [PATCH 2/4] x86: ioremap: fix physical address check Kenji Kaneshige
2010-06-11 17:43 ` H. Peter Anvin
2010-06-14 0:18 ` KAMEZAWA Hiroyuki
2010-06-14 8:59 ` KAMEZAWA Hiroyuki
2010-06-14 9:13 ` Kenji Kaneshige
2010-06-14 11:06 ` Kenji Kaneshige
2010-06-14 18:36 ` H. Peter Anvin
2010-06-15 2:21 ` Kenji Kaneshige
2010-06-14 20:16 ` Rolf Eike Beer
2010-06-15 2:33 ` Kenji Kaneshige
2010-06-14 1:54 ` Kenji Kaneshige
2010-06-14 6:38 ` Maciej W. Rozycki
2010-06-14 8:23 ` Kenji Kaneshige
2010-06-14 9:02 ` Kenji Kaneshige
2010-06-14 15:40 ` H. Peter Anvin
2010-06-14 15:11 ` H. Peter Anvin [this message]
2010-06-14 8:27 ` Kenji Kaneshige
2010-06-14 15:12 ` H. Peter Anvin
2010-06-11 9:20 ` [PATCH 3/4] x86: ioremap: remove physical address warning message Kenji Kaneshige
2010-06-11 17:44 ` H. Peter Anvin
2010-06-14 2:06 ` Kenji Kaneshige
2010-06-11 9:21 ` [PATCH 4/4] x86: ioremap: fix normal ram range check Kenji Kaneshige
2010-06-11 17:41 ` [RFC][PATCH 0/4] x86: ioremap() problem in X86_32 PAE H. Peter Anvin
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