Re: [PATCH v6 18/27] x86, boot: add fields to support load bzImageand ramdisk above 4G

[H. Peter Anvin]

On 12/13/2012 03:28 PM, Yinghai Lu wrote:
> On Thu, Dec 13, 2012 at 2:54 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> > 0x1f0 is unsuitable for use as sentinel -- or in fact for any purpose --
> > because it is quite plausible that someone may (fairly sanely) start the
> > copy range at 0x1f0 instead of 0x1f1... we really should have documented
> > it that way but it is too late now.
> >
> > However, we can use 0x1ef.
>
> right. updated to use 0x1ef.

> +1EF/001	ALL	sentinel	0: states _ext_* fields are valid

Not the correct documentation.  What this does is detect broken 
32/64-bit bootloaders, and the remediation code should zero not just the 
ext_* fields but all the fields that were identified as uninitialized -- 
we're kind of assuming that kexec is representative here, since it 
doesn't help us by giving an ID.

	-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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