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Re: Boot time memory allocation

To: Ralf Baechle <>
Subject: Re: Boot time memory allocation
From: "Mark.Zhan" <>
Date: Wed, 10 May 2006 10:21:03 +0800
Cc: Alex Gonzalez <>,
In-reply-to: <>
Original-recipient: rfc822;
References: <> <>
User-agent: Thunderbird 1.5 (X11/20060313)
Ralf Baechle wrote:
On Tue, May 09, 2006 at 03:35:14PM +0100, Alex Gonzalez wrote:

I have two independent processors with access to a shared memory
region, mapped in the 256MB to 512MB region (kseg0).

One is running a propietary OS, and the second one is running Linux 2.6.12.

How would I arrange to leave that shared memory region out of the
scope of Linux's memory management system, but at the same time make
it possible for a driver to access it?

I have done similar things before with the help of alloc_bootmem, but
this time I don't want the kernel to reserve the memory, I want the
kernel to be completely unaware of it, and I need to specify its start
and end.

At kernel initialization time just don't tell the kernel about the
existence of your memory region.  For many systems that just means you
shrink the memory region passed to the add_memory_region() call to
something that suits your platform.


Maybe it is a more flexible way to specify the memory regions via command line. You know, this will produce User-defined memory regions to kernel.

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