Kexec command line length

Bernhard Walle bwalle at
Tue Jan 29 13:17:01 EST 2008

* Vivek Goyal <vgoyal at> [2008-01-29 16:41]:
> I think 2048 command line support came much later. I think it came between
> version 2.05 and 2.06 (But somebody needs to dive into archive to verify).
> Because command line size could go beyond 256, we introduced cmdline_size
> parameter in version 2.06 to let a boot loader know.

Large command line support was added with


which means that it was merged 2.6.21.

> What Bernanrd seems to be talking about a small window where boot protocol
> was 2.05 but supported command line size was still 2048.

2.05 was added with


which means that it was merged 2.6.20. But it got implemented for i386
only that time, so x86_64 still had the 2.04 version.

The command line length in the boot protocol was added with


which menas that it was merged 2.6.22.

> if (protocol version > 2.06)
> 	error user depending on cmdline_size;
> else if (protocol version > 2.05 && protocol version < 2.06)
> 	warn on cmdline being more than 256. We don't know for sure.
> else
> 	error out if cmdline is greater than 256

The problem is 2.6.21: It had on x86_64 2.04 boot protocol but
2048 command line size. I just verified this via the tarball. :(

Maybe it could be implemented with versions ...


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