Re: [PATCH] x86_64, i386: Add command line length to boot protocol

From: Pavel Machek
Date: Mon Mar 12 2007 - 19:12:56 EST


Hi!

> > > > +cmdline_size: .long COMMAND_LINE_SIZE-1 #length of the command line,
> > >
> > > Why a long? It's unlikely that someone is going to have a command line
> > > bigger than 0xffff.
> >
> > Well, I could imagine overflowing that. Describing your numa setup,
> > excluding few bad bits of ram using memmap=exact, set up your boot
> > over iscsi on cmdline.... these are likely to eat insane ammount of
> > cmdline space.
>
> 65535 characters? Are you for real?
> Stop and think about just how big that is. If you have to create
> a boot command line that long, you have serious, serious issues.

Well, it is about the same size as my .config...

I agree we are unlikely to hit it any time soon... I could imagine
some (ab)uses, like fixed_acpi_bios=<lots of hex digits>, but those
are ugly. I could also imagine some uses where entire embedded machine
is described at kernel commandline.

Yes, all those are ugly/unlikely. OTOH saving 2 bytes does not seem
like that great goal.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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