Re: HIGH MEMORY access

Manfred Spraul (manfreds@colorfullife.com)
Tue, 11 Apr 2000 00:39:42 +0200

From: "Lyle Coder" <x_coder@hotmail.com>
>
> Also you are right that it will crash if someone specifies mem=512M when
the
> BIOS actually put the tables in say 2GB range. How do we solve this?
>
We can't use kmap().

We need a boot-only ioremap function that maps arbitrary memory blocks.
It should be very simple:

* no kmalloc, use __initdata structures.
* we don't need unmap.
* limited to a few mappings (2MB), AFAICS only the mp table parser and some
ACPI tables will need it.

I'll use virtual addresses < PAGE_ADDRESS, then zap_low_mappings() will
clear the page tables for me :-)

--
    Manfred






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