RE: Reading BIOS information from a kernel driver

From: Aleksey Gorelov
Date: Thu Nov 10 2005 - 18:31:26 EST


>-----Original Message-----
>From: linux-kernel-owner@xxxxxxxxxxxxxxx
>[mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of
>Steven Schveighoffer
>Sent: Wednesday, November 09, 2005 12:36 PM
>To: linux-kernel@xxxxxxxxxxxxxxx
>Subject: Reading BIOS information from a kernel driver
>
>I am trying to read a string that the BIOS has placed into memory.
>
>The BIOS placed the string into memory at real-mode address F000:FA00
>(i.e. physical address FFA00h).
>
>1. Is there a linear address which always contains this address
>location? i.e. if there is a spot where I can do:
>
>char * mystring = (char *)0xMagicAddress;
>
>2. If not, how do I map a linear address to this physical address so I
>can read it?
>
>I'm pretty sure that the string can be read, but I would prefer to know
>exactly where the string is located before looking. For example, the
>following command finds the string:
>
>dd if=/proc/kcore bs=1024 count=3000 | grep mystring
>
>-Steve

I think you are looking for phys_to_virt(0xffa00)

Aleks.
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