Re: [Etherboot-developers] [COMMIT] 5.1.2+ boot from disk.

[Michael B. <mb...@fe...>]

On 30 Aug 2002, Eric W. Biederman wrote:
> > OK, it works.  I can now boot a full Linux kernel from EB 5.1.x, using the
> > same image as for EB 5.0.x.  Have checked in two changes to osloader.c,
> > both of which I'm not 100% sure about:
> I have just put in some updated fixes, that solve the problems more
> cleanly (assuming they work.)

Sorry - it broke.  I now get
  "segment [00000054, 92800054) overlaps etherboot [00020000, 0002FA30)"

Found the problem - sh was being initialised to the start of the NBI
header rather than the start of the segment table.  Fixed, checked in, now
works.

> > 2. When load_block() is called with eof=1, os_download() gets called
> >    twice: once with the normal data block and once more as
> >    os_download(NULL,0,eof).  This is how tagged_download() expects to be
> >    used.
> >    Q: Will this break the other *_download() routines?
> It won't break them because they honor the eof flag, and so the
> code will never be called.  So mostly the second call is bloat.
> I have instead changed the while loop in tagged download:
>                 data += i;
> -	} while (len > 0)
> +	} while ((len > 0) || eof);
> 	return 0;

OK - I can see only one potential problem with that: if an image is
corrupted by being incomplete (missing bytes from the end) then Etherboot
will (I think) lock up in an endless loop with len=0, eof=1 and
tctx.seglen != 0.

Michael Brown
http://www.fensystems.co.uk