[gPXE] Local menu system for gpxe

[Miller, Shao]

Good day Ben, Andrew,

I did indeed have a good nap, so thanks for passing that info along to
Ben, Andrew. :)

I've revisited the initrd and cmdline patch.  A modern revision is
available here[1] and is based on the gPXE 1.0.0+ as of the time of this
e-mail.  You may learn a bit more about how to make use of the enhanced
functionality here[2] (or below).

- Shao Miller

[1]
http://git.etherboot.org/?p=people/sha0/gpxe.git;a=shortlog;h=refs/heads
/lkrn_initrd-sha0
[2]
http://git.etherboot.org/?p=people/sha0/gpxe.git;a=commitdiff;h=6bada87a
533725f6de02c83240519a316bbb88ec

[lkrn] Add support for initrds, commandlines  lkrn_initrd-sha0

Shao Miller [Thu, 15 Apr 2010 06:12:17 +0000 (02:12 -0400)]

The *.lkrn gPXE build targets will process and use an initrd and/or
a commandline passed to it by a previous boot-loader.

To pass a command-line from Syslinux, you might do:

 LABEL gpxe_cmdline
   KERNEL gpxe.lkrn
   APPEND foo bar cmd=echo baz

where gPXE will take everything _after_ "cmd=" and use it as a
startup script.  gPXE will ignore "foo bar cmd=".

To pass an initrd from Syslinux, you might do:

 LABEL gpxe_script1
   KERNEL gpxe.lkrn
   INITRD my_script1.gpxe

Both the passed "cmd=" command as well as the passed initrd will
be images available with 'imgstat'.  A startup image will be tried
in the following order:
 1. Compiled-in embedded images
 2. Passed "cmd=" command (as gPXE script)
 3. Passed initrd (whatever image that might be)
 4. If these fail, we fall through to 'autoboot' behaviour