[syslinux] [PATCH 1/1] core: Add a check at ldlinux.sys build time.

[H. Peter Anvin]

On 07/26/2013 01:36 PM, Raphael S Carvalho wrote:
> 
> Bootsector is installed into the 0-512 range, whereas 2 copies of ADV
> into (65536 - 2 * ADV_SIZE).
> Then basically ldlinux.sys must fit between the bootsector and two
> copies of ADV whose size may vary.
> 
> The range 0-64k is laid out something like this, right?!
> [0](bootsector)[512](ldlinux.sys)[65536 - 2 * ADV_SIZE](2 copies of
> ADV)[65536]
> 
> If so, the size of ldlinux.sys can be at most: 65536 - 2 * ADV_SIZE - 512.
> If ADV_SIZE change from 512 to 4k, it will be difficult to install
> ldlinux.sys at the 0-64k range of a BTRFS image.
> 

That is correct.  We may have to do something like Grub's "stage 1.5", a
totally stripped down version of ldlinux.sys containing just enough to
load the real ldlinux.sys from the filesystem.  Sigh.

	-hpa