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

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Message-ID: <4B8C1CBA.5050007@gmail.com>
Date:	Tue, 02 Mar 2010 06:59:54 +1100
From:	Graeme Russ <graeme.russ@...il.com>
To:	"H. Peter Anvin" <hpa@...or.com>
CC:	linux-kernel@...r.kernel.org
Subject: Re: x86 embedded - Problem getting past 'move compressed kernel 
 before decompression'

H. Peter Anvin wrote:
> 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.
> 
I which case I would not think I would be jumping to 0x100000 as the
entry-point for the 32-bit protocol (at a guess I would be jumping to 0x103600)

Graeme
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