[syslinux] SysLinux Development Questions

[r0m30]

Hello,

I'm thinking of using sysliux as the basis for a TCG OPAL Pre-Boot
Authorization program (COM32 module). I can add AHCI and SATA support
in a COM32 module to implement IDENTIFY, iF-SEND and IF-RECV, but my
understanding of syslinux falls short in several areas.

I have a few questions that I would like to ask:

com32 modules in UEFI 64bit mode:
The AHCI and SATA memory layouts have a lot of memory address
structures that are broken into two 32bit fields (an upper and lower
address field) this isn't an issue for the bios COM32 modules as they
run in 32bit mode and malloc returns 32bit memory allocations.
However when the 64bit uefi build pass runs there are multiple
warnings about forcing pointers into 32bit fields and I would also
assume that malloc is free to return storage above the 32bit
addressable range. Is lmalloc the solution to keeping allocated memory
in 32bit addressable storage?  A grep gives me HEAP_LOWMEM parameter
for lmalloc but that is just an enum without explanation and I can't
see how/where this changes the memory allocation in malloc.c

Syslinux shared libraries:
As part of the PBA process the disk image presented to syslinux will
change completely.  Once the drive is unlocked, the "shadow mbr" is
replaced with the real disk drive image which will almost certainly
not match the layout/structure of the booted disk image.  Are the
shared libraries loaded into and kept in memory once they are
referenced?  If not is there a way to force my com32 module to be
statically linked?

chainloading:
I should be able to use syslinux "chainload the boot drive" for bios
implementations, but looking at the archives it appears that there is
currently no chainloading for UEFI support.  Can anyone point me at
doc or possible starting points for adding UEFI chainloading to
syslinux? Rebooting will work but is a terrible user experience.
----------
Mike