RE: Calculating kernel logical address ..

Imran Badr
2002-09-09T17:07:03Z

So, what you gurus suggest me to do? How can I get physical address of a
user buffer (which was originally mmap'ed() from a kmalloc() allocation) and
which would also be protable across multiple platforms?

Thanks.
Imran.

-----Original Message-----
From: David S. Miller [mailto:davem@redhat.com]
Sent: Sunday, September 08, 2002 10:28 PM
To: phillips@arcor.de
Cc: imran.badr@cavium.com; linux-kernel@vger.kernel.org
Subject: Re: Calculating kernel logical address ..

From: Daniel Phillips <phillips@arcor.de>
Date: Mon, 9 Sep 2002 07:17:30 +0200

On Monday 09 September 2002 07:00, David S. Miller wrote:
> Actually, KSEG0 the most Linux friendly design in the world
> particularly in 64-bit mode.

That's easy to say until you try and work with it (I assume you have,
and forgot). Just try to do a 3G/1G split on it, for example.

Maybe you missed the "64-bit mode" part of what I said. :-)

In 64-bit mode there is no need to do any kind of split.
You just use the KSEG mapping with full cache coherency for
all of physical memory as the PAGE_OFFSET area.

I forget if it was KSEG0 or some other number, but I know it
works.