From: Matt Fleming <matt@console-pimps.org>
To: "hpanvin@gmail.com" <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>,
linux-kernel@vger.kernel.org, x86@kernel.org,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <ming@elte.hu>,
Zhang Rui <rui.zhang@intel.com>,
Huang Ying <huang.ying.caritas@gmail.com>
Subject: Re: [PATCH] x86, efi: Calling __pa() with an ioremap'd address is invalid
Date: Tue, 11 Oct 2011 16:58:09 +0100 [thread overview]
Message-ID: <1318348689.4060.118.camel@mfleming-mobl1.ger.corp.intel.com> (raw)
In-Reply-To: <df88dc7c-e404-4190-a15c-4c3ef44ed45f@email.android.com>
On Tue, 2011-10-11 at 08:45 -0700, hpanvin@gmail.com wrote:
> I think ioremap_cache() should work for either.
Sorry yeah, it will work but I don't think it's desirable (that's what I
meant, though I realise it's not what I wrote).
The reason being: aren't you doing an extra step of indirection because
you have to jump through the vmalloc space?
With 32-bit this is obviously necessary because of the lack of space for
the direct kernel map, but on 64-bit we can just extend the kernel map
and do quick conversions between physical and virtual space with __va()
and __pa().
Maybe the extra indirection isn't that bad and no one will care? If so,
then sure, a unified version sounds like a plan. I was just hesitant of
changing the existing 64-bit implementation for fear of receiving
replies like "you've now made the 64-bit path slower".
--
Matt Fleming, Intel Open Source Technology Center
next prev parent reply other threads:[~2011-10-11 15:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-11 12:54 Matt Fleming
2011-10-11 13:03 ` Matthew Garrett
2011-10-11 13:10 ` Matt Fleming
2011-10-11 15:45 ` hpanvin@gmail.com
2011-10-11 15:58 ` Matt Fleming [this message]
2011-10-11 16:23 ` Matthew Garrett
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