[syslinux] Plop Boot Manager quit working with 5.10

[H. Peter Anvin]

On 06/30/2013 09:45 AM, Gene Cumm wrote:
> 
> My cuent understanding is as follows: HPA is using the label "ancient
> kernel" for any kernel that has a hard-coded load address and that
> linux.c32 and all 5.xx+ (they're actually the same code) are less
> likely to be able to succeed in loading these kernels due to how the
> core/linux.c32 responds to the memory map passed to it by the BIOS(INT
> 15h E820h).
> 

Not quite.

"Ancient kernel" means Linux kernel boot protocol < 2.00.  This
hard-codes memory use at address 0x90000, which is almost universally
occupied by the PXE stack.

What we need to do is estimate how much memory will be freed up by the
PXE stack on unload -- unless we are doing keeppxe -- and if we have
used that memory and the unload fail... print a warning and run anyway?

	-hpa