[coreboot] memtest86 reading 0k memory

Timothy Pearson tpearson at raptorengineeringinc.com
Thu Feb 5 21:06:10 CET 2015


On 02/05/2015 01:51 PM, Aaron Durbin wrote:
> Do you have the coreboot console log? Looking at memtest86 it
> constructs its own e820 when using linuxbios. Additionally, it also
> has some concept of a "window" to test as well as plim_lower and
> plim_upper variables that seem to add to the mix.
>
> What's super frightening is that find_chunks(int tst) is called in the
> code as find_chunks() while the find_chunks() function actually
> references tst as an array index. That's all from config.c. But I
> think that's only if you hit c on the keyboard. I wouldn't do that...
>
> I can't make heads or tails of that code at the moment. for selecting
> the window to test.

Please see text log attached.  It looks like the failing accesses start 
at 0xa0000, which (judging by memtest's effects on the screen) appears 
to be mapped to the VGA text buffer.  That region is *not* reserved 
under the proprietary BIOS's e820 map.

Thanks!

-- 
Timothy Pearson
Raptor Engineering
+1 (415) 727-8645
http://www.raptorengineeringinc.com
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