Re: x86 embedded - Problem getting past 'move compressed kernel before decompression'

From: H. Peter Anvin
Date: Mon Mar 01 2010 - 14:43:19 EST


On 03/01/2010 11:41 AM, Graeme Russ wrote:
> H. Peter Anvin wrote:
>> On 03/01/2010 03:56 AM, Graeme Russ wrote:
>>> I have done a little more digging. By adding an ascii string before
>>> relocated: label, I am able to determine that the int3 after the relocated:
>>> label exists in bzImage at offset 0x1C3FD7
>>>
>>> EAX holds (for the jump) 0x5379d0 (different bzImage of course). The
>>> contents of memory at this address is in bzImage at offset 0x1C09D7 - A
>>> difference of 0x3600 (seems too even to be random)
>>>
>>> I'm obviously doing something hideously wrong, but what?
>>>
>>
>> 0x3600 sounds like the size of the real-mode code in bzImage.
>>
>
> But what could I be doing to cause the miscalculation? From what I
> understand, everything looks to be calculated at build time
>

If I were to guess, you loaded the entire bzImage into high memory,
rather than just the PM portion thereof.

-hpa

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