Re: [PATCH] x86 Boot enhancements, boot protocol 2.04 7/9

[H. Peter Anvin]

Eric W. Biederman wrote:
>
>>There can't be a "default load address".  0x90000 is actively dangerous and
>>trying to encourage it for anything than legacy kernels is WRONG. If you can't
>>handle this, then you need to go back to the drawing board.
> 
> 
> I agree.  But I do think being able to hard code the load address is a
> very good thing.
> 
> After digesting the requirements I plan on having setup.S call int 12h
> (so the information is available), and then having misc.c relocate the
> real mode code, and the command line, out of the way, of it's
> decompression buffer.  This removes the need for bootloaders to
> make a tradeoff between memory use efficiency and reliability.
> 
> This should give me about 630KB on machines designed to run DOS, where
> this matters.   Better than the current best of 572KB, with the real
> mode code @ 0x90000. 
> 
> And when your total size is 1-4MB.  +-640KB is a significant change.
> 

Agreed.  Note that so far putting the real mode code *above* 0x90000 is 
completely untested.  It *should* work with boot protocol 2.02 support; 
it almost certainly *does not* work with earlier boot protocols (due to 
the "move it back to 0x90000" braindamage.)

	-hpa