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

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Message-ID: <CAE9FiQX_+WO4Zr7TGWdjCNo_cdk+aSAmRNzpPUW_NxirnMEBCw@mail.gmail.com>
Date:	Tue, 5 Mar 2013 12:14:56 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Robin Holt <holt@....com>
Cc:	"H. Peter Anvin" <hpa@...or.com>, hpa@....com,
	linux-kernel@...r.kernel.org
Subject: Re: Revert commit 5dcd14ecd4 - breaks EFI boot with SLES11 elilo.efi

On Tue, Mar 5, 2013 at 11:52 AM, Robin Holt <holt@....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);

in that case, it will keep all fields in boot_params around setup_header as
with setup code...thus 0x1ef will be 0xff.

elilo need attached fix.

Thanks

Yinghai

Download attachment "fix_boot_params.patch" of type "application/octet-stream" (1412 bytes)