Re: Physical Memory...

Kurt Garloff (
Wed, 25 Feb 1998 21:54:13 +0100 (CET)

On 24 Feb 1998, Michael O'Reilly wrote:

> I'm writing a scrub module for ECC ram, that simply need to walk
> physical ram page by page reading and writing every word in the page.
> Question is: From a module, what does the memory address space look
> like? Where is physical ram located? Is it mapped at address 0 up? or
> from 0xC0000000 up? or where?

In kernel space, you can access the physical memory beginning at linear
address 0xc0000000 on the ix86, or to be more exact phys_to_virt(0) ==
0xc0000000. Use the phys_to_virt () function, as you want to write a
portable module and on the ix86, too, this could be changed (to
0x80000000 in later kernel revs in order to support up to 2GB of RAM).

Kurt Garloff, Dortmund
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