Re: Revert commit 5dcd14ecd4 - breaks EFI boot with SLES11 elilo.efi

[Robin Holt <holt@sgi.com>]

On Tue, Mar 05, 2013 at 12:14:56PM -0800, Yinghai Lu wrote:
> On Tue, Mar 5, 2013 at 11:52 AM, Robin Holt <holt@sgi.com> wrote:
> > That fixed it for me.
> >
> > Can you help me understand why sentinel is non-zero?  It looks to me
> > like 3.14 allocates 16kB plus strlen of the command line, zeros it,
> > and then proceeds to fill in fields, some differing from what is in the
> > boot_params structure.  That said, it looks like the sentinel field
> > should remain 0.  I am still trying to understand, but if this patch
> > makes it in, I am happy.
> 
> sentinel is out of setup_header.
> it is 0x1ef. setup_header is from 0x1f1.
> 
> it will be 0xff from arch/x86/boot/header.S for bzImage.
> 
>         .section ".header", "a"
>         .globl  sentinel
> sentinel:       .byte 0xff, 0xff        /* Used to detect broken loaders */
> 
> elilo first copy first page, and get 0x1f1 for setup code sector number.
> then it copies all setup code ( include setup header).
> 
> after that sysdeps_create_boot_params will copy first two pages to bp...
> CopyMem(bp, param_start, 0x2000);

Had not gotten that far in my understanding of elilo.  Now I understand.

Robin