[gPXE-devel] [PATCH v3][lkrn] add ramdisk support

[Michael Brown]

On Thursday 03 Jun 2010 13:40:51 Wu Fengguang wrote:
> I guess the main difference between the two approaches are, one takes
> care not to make any assumption about the ramdisk location/size (still
> leaves out HIGHMEM_LOADPOINT though), while the other takes the good
> KISS attitude.
> 
> As far as I know, GRUB and PXELinux both loads ramdisk to the highest
> allowed address. For them Shao's code works just OK. (There is still
> theoretical possibility for umalloc to overwrite ramdisk region, but I
> don't regard it as practical issue.) I would vote for the simplicity
> of Shao's patch if I'm sure that all relevant boot loaders are as safe
> as GRUB. So expecting some experts' viewpoint in this area.

I would expect it to be safe to assume that all bootloaders will load the 
initrd high, but will defer to hpa on this.

> I'm not expert, just sharing a wild idea: what if we introduce a
> .data16.copy section that is part of .data16, except that it's copied
> (instead of uncompressed) to new location? This should allow various
> prefixes to convey values to the latter stages conveniently. This also
> decouples libprefix from any domain specific variables.

Even if you did that, the .data16.copy section wouldn't be writeable prior to 
the call to install().  After the call to install(), you have the real .data16 
section available anyway.

Michael